Regioselective SN2 reactions for rapid syntheses of azido-inositols by one-pot sequence-specific nucleophilysis.

PubMed

Ravi, Arthi; Hassan, Syed Zahid; Vanikrishna, Ajithkumar N; Sureshan, Kana M

2017-04-04

Triflates of myo-inositol undergo facile solvolysis in DMSO and DMF yielding S N 2 products substituted with O-nucleophiles; DMF showed slower kinetics. Axial O-triflate undergoes faster substitution than equatorial O-triflate. By exploiting this difference in kinetics, solvent-tuning and sequence-controlled nucleophilysis, rapid synthesis of three azido-inositols of myo-configuration from myo-inositol itself has been achieved.

Acid–base bifunctional shell cross-linked micelle nanoreactor for one-pot tandem reaction

DOE PAGES

Lee, Li -Chen; Lu, Jie; Weck, Marcus; ...

2015-12-29

In shell cross-linked micelles (SCMs) containing acid sites in the shell and base sites in the core are prepared from amphiphilic poly(2-oxazoline) triblock copolymers. These materials are utilized as two-chamber nanoreactors for a prototypical acid-base bifunctional tandem deacetalization-nitroaldol reaction. Furthermore, the acid and base sites are localized in different regions of the micelle, allowing the two steps in the reaction sequence to largely proceed in separate compartments, akin to the compartmentalization that occurs in biological systems.

Natural product-inspired cascade synthesis yields modulators of centrosome integrity.

PubMed

Dückert, Heiko; Pries, Verena; Khedkar, Vivek; Menninger, Sascha; Bruss, Hanna; Bird, Alexander W; Maliga, Zoltan; Brockmeyer, Andreas; Janning, Petra; Hyman, Anthony; Grimme, Stefan; Schürmann, Markus; Preut, Hans; Hübel, Katja; Ziegler, Slava; Kumar, Kamal; Waldmann, Herbert

2011-12-25

In biology-oriented synthesis, the scaffolds of biologically relevant compound classes inspire the synthesis of focused compound collections enriched in bioactivity. This criterion is, in particular, met by the scaffolds of natural products selected in evolution. The synthesis of natural product-inspired compound collections calls for efficient reaction sequences that preferably combine multiple individual transformations in one operation. Here we report the development of a one-pot, twelve-step cascade reaction sequence that includes nine different reactions and two opposing kinds of organocatalysis. The cascade sequence proceeds within 10-30 min and transforms readily available substrates into complex indoloquinolizines that resemble the core tetracyclic scaffold of numerous polycyclic indole alkaloids. Biological investigation of a corresponding focused compound collection revealed modulators of centrosome integrity, termed centrocountins, which caused fragmented and supernumerary centrosomes, chromosome congression defects, multipolar mitotic spindles, acentrosomal spindle poles and multipolar cell division by targeting the centrosome-associated proteins nucleophosmin and Crm1.

Application of Ionic Liquids in Pot-in-Pot Reactions.

PubMed

Çınar, Simge; Schulz, Michael D; Oyola-Reynoso, Stephanie; Bwambok, David K; Gathiaka, Symon M; Thuo, Martin

2016-02-26

Pot-in-pot reactions are designed such that two reaction media (solvents, catalysts and reagents) are isolated from each other by a polymeric membrane similar to matryoshka dolls (Russian nesting dolls). The first reaction is allowed to progress to completion before triggering the second reaction in which all necessary solvents, reactants, or catalysts are placed except for the starting reagent for the target reaction. With the appropriate trigger, in most cases unidirectional flux, the product of the first reaction is introduced to the second medium allowing a second transformation in the same glass reaction pot--albeit separated by a polymeric membrane. The basis of these reaction systems is the controlled selective flux of one reagent over the other components of the first reaction while maintaining steady-state catalyst concentration in the first "pot". The use of ionic liquids as tools to control chemical potential across the polymeric membranes making the first pot is discussed based on standard diffusion models--Fickian and Payne's models. Besides chemical potential, use of ionic liquids as delivery agent for a small amount of a solvent that slightly swells the polymeric membrane, hence increasing flux, is highlighted. This review highlights the critical role ionic liquids play in site-isolation of multiple catalyzed reactions in a standard pot-in-pot reaction.

Synthesis of 2'-deoxy-2'-[.sup.18F]fluoro-5-methyl-1-B-D-arabinofuranosyluracil (.sup.18F-FMAU)

DOEpatents

Li, Zibo; Cai, Hancheng; Conti, Peter S

2014-12-16

The present invention relates to methods of synthesizing .sup.18F-FMAU. In particular, .sup.18F-FMAU is synthesized using one-pot reaction conditions in the presence of Friedel-Crafts catalysts. The one-pot reaction conditions are incorporated into a fully automated cGMP-compliant radiosynthesis module, which results in a reduction in synthesis time and simplifies reaction conditions. The one-pot reaction conditions are also suitable for the production of 5-substituted thymidine or cytidine analogs. The products from the one-pot reaction (e.g. the labeled thymidine or cytidine analogs) can be used as probes for imaging tumor proliferative activity. More specifically, these [.sup.18F]-labeled thymidine or cytidine analogs can be used as a PET tracer for certain medical conditions, including, but not limited to, cancer disease, autoimmunity inflammation, and bone marrow transplant.

One-pot DNA construction for synthetic biology: the Modular Overlap-Directed Assembly with Linkers (MODAL) strategy

PubMed Central

Casini, Arturo; MacDonald, James T.; Jonghe, Joachim De; Christodoulou, Georgia; Freemont, Paul S.; Baldwin, Geoff S.; Ellis, Tom

2014-01-01

Overlap-directed DNA assembly methods allow multiple DNA parts to be assembled together in one reaction. These methods, which rely on sequence homology between the ends of DNA parts, have become widely adopted in synthetic biology, despite being incompatible with a key principle of engineering: modularity. To answer this, we present MODAL: a Modular Overlap-Directed Assembly with Linkers strategy that brings modularity to overlap-directed methods, allowing assembly of an initial set of DNA parts into a variety of arrangements in one-pot reactions. MODAL is accompanied by a custom software tool that designs overlap linkers to guide assembly, allowing parts to be assembled in any specified order and orientation. The in silico design of synthetic orthogonal overlapping junctions allows for much greater efficiency in DNA assembly for a variety of different methods compared with using non-designed sequence. In tests with three different assembly technologies, the MODAL strategy gives assembly of both yeast and bacterial plasmids, composed of up to five DNA parts in the kilobase range with efficiencies of between 75 and 100%. It also seamlessly allows mutagenesis to be performed on any specified DNA parts during the process, allowing the one-step creation of construct libraries valuable for synthetic biology applications. PMID:24153110

Solvent-dependent reactions for the synthesis of β-keto-benzo-δ-sultone scaffolds via DBU-catalyzed O-sulfonylation/intramolecular Baylis-Hillman/1,3-H shift or dehydration tandem sequences.

PubMed

Ghandi, Mehdi; Bozcheloei, Abolfazl Hasani; Nazari, Seyed Hadi; Sadeghzadeh, Masoud

2011-12-16

We have developed a solvent-dependent method for the synthesis of novel benzo-δ-sultone scaffolds. A variety of benzylbenzo[e][1,2]oxathiin-4(3H)-one-2,2-dioxides were obtained in high yields in DMF using a one-pot, DBU-catalyzed condensation of 2-hydroxybenzaldehydes with a number of (E)-2-phenylethenesulfonyl chlorides. On the other hand, the initially prepared 2-formylphenyl-(E)-2-phenylethenesulfonate derivatives underwent DBU-catalyzed reactions to a series of 3-[methoxy(phenyl)methyl]benzo[e][1,2]oxathiine-2,2-dioxides in moderate to good yields in MeOH. These reactions presumably proceed via DBU-catalyzed O-sulfonylation/intramolecular Baylis-Hillman/1,3-H shift or dehydration tandem sequences, respectively.

Coding the Assembly of Polyoxotungstates with a Programmable Reaction System

PubMed Central

2017-01-01

Chemical transformations are normally conducted in batch or flow mode, thereby allowing the chemistry to be temporally or spatially controlled, but these approaches are not normally combined dynamically. However, the investigation of the underlying chemistry masked by the self-assembly processes that often occur in one-pot reactions and exploitation of the potential of complex chemical systems requires control in both time and space. Additionally, maintaining the intermediate constituents of a self-assembled system “off equilibrium” and utilizing them dynamically at specific time intervals provide access to building blocks that cannot coexist under one-pot conditions and ultimately to the formation of new clusters. Herein, we implement the concept of a programmable networked reaction system, allowing us to connect discrete “one-pot” reactions that produce the building block{W11O38} ≡ {W11} under different conditions and control, in real time, the assembly of a series of polyoxometalate clusters {W12O42} ≡ {W12}, {W22O74} ≡ {W22} 1a, {W34O116} ≡ {W34} 2a, and {W36O120} ≡ {W36} 3a, using pH and ultraviolet–visible monitoring. The programmable networked reaction system reveals that is possible to assemble a range of different clusters using {W11}-based building blocks, demonstrating the relationship between the clusters within the family of iso-polyoxotungstates, with the final structural motif being entirely dependent on the building block libraries generated in each separate reaction space within the network. In total, this approach led to the isolation of five distinct inorganic clusters using a “fixed” set of reagents and using a fully automated sequence code, rather than five entirely different reaction protocols. As such, this approach allows us to discover, record, and implement complex one-pot reaction syntheses in a more general way, increasing the yield and reproducibility and potentially giving access to nonspecialists. PMID:28414229

Enantioselective Synthesis of α-Methylene-β-hydroxy Carboxylic Acid Derivatives via a Diastereoselective Aldol-β-Elimination Sequence: Application to the C(15)–C(21) Fragment of Tedanolide C

PubMed Central

Barth, Roland; Roush, William R.

2010-01-01

An enantioselective synthesis of α-methylene-β-hydroxy carboxylic acid derivatives via a highly diastereoselective, one-pot syn-aldol and β-elimination sequence utilizing the chiral β-(phenylselenyl)propionyl imide 15 is described. This new method, which constitutes an alternative to the Baylis-Hillman reaction, has been applied to the synthesis of the C(15)-C(21) fragment of tedanolide C. PMID:20405855

One-Pot Two-Step Multicomponent Process of Indole and Other Nitrogenous Heterocycles or Amines toward α-Oxo-acetamidines.

PubMed

Martinez-Ariza, Guillermo; McConnell, Nicholas; Hulme, Christopher

2016-04-15

A cesium carbonate promoted three-component reaction of N-H containing heterocycles, primary or secondary amines, arylglyoxaldehydes, and anilines is reported. The key step involves a tandem sequence of N-1 addition of a heterocycle or an amine to preformed α-iminoketones, followed by an air- or oxygen-mediated oxidation to form α-oxo-acetamidines. The scope of the reaction is enticingly broad, and this novel methodology is applied toward the synthesis of various polycyclic heterocycles.

Copper(II) sulfamate: an efficient catalyst for the one-pot synthesis of 3,4-dihydropyrimidine-2(1H)-ones and thiones.

PubMed

Liu, Chen-Jiang; Wang, Ji-De

2009-02-13

A simple, efficient procedure for the one-pot Biginelli condensation reaction of aldehydes, beta-ketoesters and urea or thiourea employing copper(II) sulfamate as a novel catalyst is described. Compared to the classical Biginelli reaction conditions, the present method has the advantages of good yields, short reaction times and experimental simplicity.

Room-temperature Pd-catalyzed C-H chlorination by weak coordination: one-pot synthesis of 2-chlorophenols with excellent regioselectivity.

PubMed

Sun, Xiuyun; Sun, Yonghui; Zhang, Chao; Rao, Yu

2014-02-07

A room-temperature Pd(II)-catalyzed regioselective chlorination reaction has been developed for a facile one-pot synthesis of a broad range of 2-chlorophenols. The reaction demonstrates an excellent regioselectivity and reactivity for C-H chlorination. This reaction represents one of the rare examples of mild C-H functionalization at ambient temperature.

A trifunctional mesoporous silica-based, highly active catalyst for one-pot, three-step cascade reactions.

PubMed

Biradar, Ankush V; Patil, Vijayshinha S; Chandra, Prakash; Doke, Dhananjay S; Asefa, Tewodros

2015-05-18

We report the synthesis of a trifunctional catalyst containing amine, sulphonic acid and Pd nanoparticle catalytic groups anchored on the pore walls of SBA-15. The catalyst efficiently catalyzes one-pot three-step cascade reactions comprising deacetylation, Henry reaction and hydrogenation, giving up to ∼100% conversion and 92% selectivity to the final product.

Computer Assisted Design, Prediction, and Execution of Economical Organic Syntheses

NASA Astrophysics Data System (ADS)

Gothard, Nosheen Akber

The synthesis of useful organic molecules via simple and cost-effective routes is a core challenge in organic chemistry. In industry or academia, organic chemists use their chemical intuition, technical expertise and published procedures to determine an optimal pathway. This approach, not only takes time and effort, but also is cost prohibitive. Many potential optimal routes scratched on paper fail to get experimentally tested. In addition, with new methods being discovered daily are often overlooked by established techniques. This thesis reports a computational technique that assist the discovery of economical synthetic routes to useful organic targets. Organic chemistry exists as a network where chemicals are connected by reactions, analogous to citied connected by roads in a geographic map. This network topology of organic reactions in the network of organic chemistry (NOC) allows the application of graph-theory to devise algorithms for synthetic optimization of organic targets. A computational approach comprised of customizable algorithms, pre-screening filters, and existing chemoinformatic techniques is capable of answering complex questions and perform mechanistic tasks desired by chemists such as optimization of organic syntheses. One-pot reactions are central to modern synthesis since they save resources and time by avoiding isolation, purification, characterization, and production of chemical waste after each synthetic step. Sometimes, such reactions are identified by chance or, more often, by careful inspection of individual steps that are to be wired together. Algorithms are used to discover one-pot reactions and validated experimentally. Which demonstrate that the computationally predicted sequences can indeed by carried out experimentally in good overall yields. The experimental examples are chosen to from small networks of reactions around useful chemicals such as quinoline scaffolds, quinoline-based inhibitors of phosphoinositide 3-kinase delta (PI3Kdelta) enzyme, and thiophene derivatives. In this way, we replace individual synthetic connections with two-, three-, or even four-step one-pot sequences. Lastly, the computational method is utilized to devise hypothetical synthetic route to popular pharmaceutical drugs like NaproxenRTM and TaxolRTM. The algorithmically generated optimal pathways are evaluated with chemistry logic. By applying labor/cost factor It was revealed that not all shorter synthesis routes are economical, sometimes "Longest way round is the shortest way home" lengthier routes are found to be more economical and environmentally friendly.

Formal Synthesis of (±)-Aplykurodinone-1 through a Hetero-Pauson-Khand Cycloaddition Approach.

PubMed

Tao, Cheng; Zhang, Jing; Chen, Xiaoming; Wang, Huifei; Li, Yun; Cheng, Bin; Zhai, Hongbin

2017-03-03

The tricyclic intermediate 2 has been synthesized in eight steps from known compound 6 in 20% overall yield. As such, this constitutes a highly efficient formal synthesis of (±)-aplykurodinone-1. This synthesis features a unique, one-pot, intramolecular hetero-Pauson-Khand reaction (h-PKR)/desilylation sequence to expeditiously construct the tricyclic framework, providing valuable insights for expanding the scope and boundaries of h-PKR.

TANDEM BIS-ALDOL REACTION OF KETONES: A FACILE ONE-POT SYNTHESIS OF 1,3-DIOXANES IN AQUEOUS MEDIUM

EPA Science Inventory

A novel tandem bis-aldol reaction of ketone with paraformaldehyde catalyzed by polystyrenesulfonic acid in aqueous medium delivers 1,3-dioxanes in high yield. This one pot, operationally simple microwave-assisted synthetic protocol proceeds efficiently in water in the absence of ...

Synthesis of unnatural amino acids via microwave-assisted regio-selective one-pot multi-component reactions of sulfamidates

EPA Science Inventory

Synthesis of triazole-based unnatural amino acids, triazole bisaminoacids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW irradiation conditions. The developed method is app...

Selective One-Pot Production of High-Grade Diesel-Range Alkanes from Furfural and 2-Methylfuran over Pd/NbOPO4.

PubMed

Xia, Qineng; Xia, Yinjiang; Xi, Jinxu; Liu, Xiaohui; Zhang, Yongguang; Guo, Yong; Wang, Yanqin

2017-02-22

A one-pot method for the selective production of high-grade diesel-range alkanes from biomass-derived furfural and 2-methylfuran (2-MF) was developed by combining the hydroxyalkylation/alkylation (HAA) condensation of furfural with 2-MF and the subsequent hydrodeoxygenation (HDO) over a multifunctional Pd/NbOPO 4 catalyst. The effects of various reaction conditions as well as a variety of solid-acid catalysts and metal-loaded NbOPO 4 catalysts were systematically investigated to optimize the reaction conditions for both reactions. Under the optimal reaction conditions up to 89.1 % total yield of diesel-range alkanes was obtained from furfural and 2-MF by this one-pot method. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Domino Way to Heterocycles

PubMed Central

Padwa, Albert; Bur, Scott K.

2007-01-01

Sequential transformations enable the facile synthesis of complex target molecules from simple building blocks in a single preparative step. Their value is amplified if they also create multiple stereogenic centers. In the ongoing search for new domino processes, emphasis is usually placed on sequential reactions which occur cleanly and without forming by-products. As a prerequisite for an ideally proceeding one-pot sequential transformation, the reactivity pattern of all participating components has to be such that each building block gets involved in a reaction only when it is supposed to do so. The development of sequences that combine transformations of fundamentally different mechanisms broadens the scope of such procedures in synthetic chemistry. This mini review contains a representative sampling from the last 15 years on the kinds of reactions that have been sequenced into cascades to produce heterocyclic molecules. PMID:17940591

Pd-catalyzed one-pot synthesis of polysubstituted acrylamidines from isocyanides, diazo compounds, and imines.

PubMed

Yan, Xu; Liao, Jinxi; Lu, Yongzhi; Liu, Jinsong; Zeng, Youlin; Cai, Qian

2013-05-17

A novel and efficient Pd-catalyzed one-pot reaction of ethyl diazoacetate, isocyanides, and imines for the synthesis of acrylamidines was developed. The multicomponent reaction may have occurred through an unpredicted ring-opening process of the ketenimine-imine [2 + 2] intermediate to form the acrylamidine products.

Praseodymium methanesulfonate catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones.

PubMed

Wang, Min; Song, Zhiguo; Gong, Hong; Jiang, Heng

2008-01-01

A series of 3,4-dihydropyrimidin-2-(1H)-ones compounds was synthesized efficiently by a one-pot cyclocondensation of an aldehyde, 1,3-dicarbonyl compound, and urea in absolute ethanol under refluxing temperature using praseodymium methanesulfonate as catalyst. After the reaction, the catalyst can be easily recovered and reused several times without distinct decrease in reaction yields.

One-Pot Conversion of Carbohydrates into Furan Derivatives via Furfural and 5-Hydroxylmethylfurfural as Intermediates.

PubMed

Liu, Bing; Zhang, Zehui

2016-08-23

Recently, there has been growing interest in the transformation of renewable biomass into value-added fuels and chemicals. The catalytic conversion of naturally abundant carbohydrates can generate two-important furan chemicals: 5-hydroxymethylfurfural (HMF) from C6 carbohydrates and furfural from C5 carbohydrates. Both HMF and furfural have received great interest as precursors in the synthesis of commodity chemicals and liquid fuels. In recent years, a trend has emerged to integrate sequential catalytic processes involving multistep reactions for the direct one-pot transformation of carbohydrates into the aimed fuels and chemicals. One-pot reactions have remarkably unique and environmentally friendly benefits, including the fact that isolation and purification of intermediate compounds can be avoided. Herein, the present article aims to review recent advances in the one-pot conversion of carbohydrates into furan derivatives via furfural and HMF as intermediates. Special attention will be paid to the catalytic systems, mechanistic insight, reaction pathways, and catalyst stability. It is expected that this review will guide researchers to develop effective catalytic systems for the one-pot transformation of carbohydrates into furan derivatives. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rh-Catalyzed Annulations of N-Methoxybenzamides and Ketenimines: Sterically and Electronically Controlled Synthesis of Isoquinolinones and Isoindolinones.

PubMed

Zhou, Xiaorong; Zhang, Zhiyin; Zhao, Hongyang; Lu, Ping; Wang, Yanguang

2017-04-07

Rhodium-catalyzed C-H activation/annulation reactions of ketenimines with N-methoxybenzamides are reported. The outcome of reactions is dependent on the structure of ketenimines. The β-alkyl-substituted ketenimines furnish 3-iminoisoquinolin-1(2H)-ones in a formal [4 + 2] annulation manner, while the β-ester substituted ketenimines afford 3-aminoisoindolin-1-ones in a formal [4 + 1] annulation manner. The synthesized [4 + 2] products undergo an intramolecular Cu-catalyzed C-N coupling to be converted to benzo[4,5]imidazo[1,2-b]isoquinolin-11-ones, which can be directly prepared from ketenimines and N-methoxybenzamides by a one-pot Rh-catalyzed annulation/Cu-catalyzed C-N coupling sequence.

One-pot, two-step synthesis of imidazo[1,2-a]benzimidazoles via a multicomponent [4 + 1] cycloaddition reaction.

PubMed

Hsiao, Ya-Shan; Narhe, Bharat D; Chang, Ying-Sheng; Sun, Chung-Ming

2013-10-14

A one-pot, two-step synthesis of imidazo[1,2-a]benzimidazoles has been achieved by a three-component reaction of 2-aminobenzimidazoles with an aromatic aldehyde and an isocyanide. The reaction involving condensation of 2-aminobenzimidazole with an aldehyde is run under microwave activation to generate an imine intermediate under basic conditions which then undergoes [4 + 1] cycloaddition with an isocyanide.

An efficient route for annulation of pyrimidines to steroids and non-steroids via a base catalyzed one-pot three component reaction.

PubMed

Saikia, Pallabi; Gogoi, Shyamalee; Gogoi, Sanjib; Boruah, Romesh C

2014-10-01

A facile strategy for the synthesis of steroidal A- and D-ring fused pyrimidines has been accomplished in high yields via a one-pot reaction of steroidal ketones, aromatic aldehydes and amidine derivatives in presence of potassium tert-butoxide in refluxing ethanol. The generality of the reaction was also extended to non-steroidal ketones. Copyright © 2014 Elsevier Inc. All rights reserved.

The synthesis of highly functionalised pyridines using Ghosez-type reactions of dihydropyrazoles.

PubMed

Catti, Federica; Kiuru, Paula S; Slawin, Alexandra M Z; Westwood, Nicholas J

2008-09-29

The aza-Diels-Alder reaction of αβ-unsaturated hydrazones is a general methodology that has been applied both to the synthesis of natural products and in the development of multicomponent reactions. Trends have emerged as to the effect of substituents on the efficiency of this reaction with substituents at the C2 and C4-positions of the aza-diene in general suppressing the reaction. Here we report that 4,5-dihydropyrazoles can function as substrates in this process despite the presence of substituents at both of these positions. A one pot, four chemical step sequence carried out under standard thermal or microwave conditions results in the formation of the corresponding pyridine-containing compounds. The scope of the reaction is explored and additional insights into the proposed mechanism of this reaction are provided.

Base-promoted one-pot tandem reaction of 3-(1-alkynyl)chromones under microwave irradiation to functionalized amino-substituted xanthones.

PubMed

Liu, Yang; Huang, Liping; Xie, Fuchun; Hu, Youhong

2010-09-17

A base-promoted one-pot tandem reaction has been developed from 3-(1-alkynyl)chromones with various acetonitriles to afford functionalized amino-substituted xanthones 3 under microwave irradiation. This tandem process involves multiple reactions, such as Michael addition/cyclization/1,2-addition, without a transition metal catalyst. This method provides an efficient approach to build up natural product-like diversified amino-substituted xanthone scaffolds rapidly.

Inter vs. intraglycosidic acetal linkages control sulfation pattern in semi-synthetic chondroitin sulfate.

PubMed

Laezza, Antonio; De Castro, Cristina; Parrilli, Michelangelo; Bedini, Emiliano

2014-11-04

Microbial-sourced unsulfated chondroitin could be converted into chondroitin sulfate (CS) polysaccharide by a multi-step strategy relying upon benzylidenation and acetylation reactions as key-steps for its regioselective protection. By conducting the two reactions one- or two-pots, CSs with different sulfation patterns could be obtained at the end of the semi-synthesis. In particular, a CS polysaccharide possessing sulfate groups randomly distributed between positions 4 and 6 of N-acetyl-galactosamine (GalNAc) units could be obtained through the two-pots route, whereas the one-pot pathway allowed an additional sulfation at position 3 of some glucuronic acid (GlcA) units. This difference was ascribed to the stabilization of a labile interglycosidic benzylidene acetal involving positions O-3 and O-6 of some GlcA and GalNAc, respectively, when the benzylidene-acetylation reactions were conducted in a one-pot fashion. Isolation and characterization of a polysaccharide intermediate showing interglycosidic acetal moieties was accomplished. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multiplexed in vivo His-tagging of enzyme pathways for in vitro single-pot multienzyme catalysis.

PubMed

Wang, Harris H; Huang, Po-Yi; Xu, George; Haas, Wilhelm; Marblestone, Adam; Li, Jun; Gygi, Steven P; Forster, Anthony C; Jewett, Michael C; Church, George M

2012-02-17

Protein pathways are dynamic and highly coordinated spatially and temporally, capable of performing a diverse range of complex chemistries and enzymatic reactions with precision and at high efficiency. Biotechnology aims to harvest these natural systems to construct more advanced in vitro reactions, capable of new chemistries and operating at high yield. Here, we present an efficient Multiplex Automated Genome Engineering (MAGE) strategy to simultaneously modify and co-purify large protein complexes and pathways from the model organism Escherichia coli to reconstitute functional synthetic proteomes in vitro. By application of over 110 MAGE cycles, we successfully inserted hexa-histidine sequences into 38 essential genes in vivo that encode for the entire translation machinery. Streamlined co-purification and reconstitution of the translation protein complex enabled protein synthesis in vitro. Our approach can be applied to a growing area of applications in in vitro one-pot multienzyme catalysis (MEC) to manipulate or enhance in vitro pathways such as natural product or carbohydrate biosynthesis.

Multicomponent Reaction of Z-Chlorooximes, Isocyanides, and Hydroxylamines as Hypernucleophilic Traps. A One-Pot Route to Aminodioximes and Their Transformation into 5-Amino-1,2,4-oxadiazoles by Mitsunobu-Beckmann Rearrangement.

PubMed

Mercalli, Valentina; Massarotti, Alberto; Varese, Monica; Giustiniano, Mariateresa; Meneghetti, Fiorella; Novellino, Ettore; Tron, Gian Cesare

2015-10-02

Synthetically useful aminodioximes are prepared via a novel three-component reaction among Z-chlorooximes, isocyanides, and hydroxylamines by exploiting the preferential attack of isocyanides to nitrile N-oxides via a [3 + 1] cycloaddition reaction. The results of quantum mechanical studies of the reaction mechanism are also discussed. Furthermore, the one-pot conversion of aminodioximes to 1,2,3-oxadiazole-5-amines via Mitsunobu-Beckmann rearrangement is reported for the first time.

AJIPHASE®: A Highly Efficient Synthetic Method for One-Pot Peptide Elongation in the Solution Phase by an Fmoc Strategy.

PubMed

Takahashi, Daisuke; Inomata, Tatsuji; Fukui, Tatsuya

2017-06-26

We previously reported an efficient peptide synthesis method, AJIPHASE®, that comprises repeated reactions and isolations by precipitation. This method utilizes an anchor molecule with long-chain alkyl groups as a protecting group for the C-terminus. To further improve this method, we developed a one-pot synthesis of a peptide sequence wherein the synthetic intermediates were isolated by solvent extraction instead of precipitation. A branched-chain anchor molecule was used in the new process, significantly enhancing the solubility of long peptides and the operational efficiency compared with the previous method, which employed precipitation for isolation and a straight-chain aliphatic group. Another prerequisite for this solvent-extraction-based strategy was the use of thiomalic acid and DBU for Fmoc deprotection, which facilitates the removal of byproducts, such as the fulvene adduct. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of cyclopentadiene-fused chromanones via one-pot multicomponent reactions.

PubMed

Ghandi, Mehdi; Ghomi, Ali-Tabatabaei; Kubicki, Maciej

2013-03-15

We have developed one-pot method for the synthesis of functionalized novel cyclopentadiene-fused chromanone scaffolds. A variety of 4-oxo-2,4-dihydrocyclopenta[c]chromene-1,2-dicarboxylates were obtained in moderate to good yields via condensation of 2-hydroxybenzaldehydes and ethyl acetoacetate with 1:1 acetylenecarboxylate-isocyanides in toluene. These reactions presumably proceed via reaction of the in situ generated 3-acetyl-2H-chromen-2-ones with acetylenecarboxylate-isocyanide zwitterionic intermediates through Michael addition/intramolecular cyclization and double [1,5] acyl shift rearrangement cascade.

A Robust, "One-Pot" Method for Acquiring Kinetic Data for Hammett Plots Used to Demonstrate Transmission of Substituent Effects in Reactions of Aromatic Ethyl Esters

ERIC Educational Resources Information Center

Yau, Hon Man; Haines, Ronald S.; Harper, Jason B.

2015-01-01

A "one-pot" method for acquiring kinetic data for the reactions of a series of substituted aromatic esters with potassium hydroxide using [supserscript 13]C NMR spectroscopy is described, which provides an efficient way to obtain sufficient data to demonstrate the Hammett equation in undergraduate laboratories. The method is…

One-pot synthesis of spiropyrroloquinoline-isoindolinone and their aza-analogs via the Ugi-4CR/metal-free intramolecular bis-annulation process.

PubMed

Ghandi, Mehdi; Zarezadeh, Nahid; Abbasi, Alireza

2015-08-14

This presentation discloses a one-pot synthesis of a series of spiropyrroloquinoline isoindolinone and spiropyrroloquinoline aza-isoindolinone scaffolds. The reaction proceeds by the combination of a Ugi four-component reaction (4CR) and two intramolecular cyclizations under metal-free conditions. The proof of the structures relies on analytical investigation and X-ray crystallography.

One-Pot Synthesis of Fused Pyrroles via a Key Gold Catalysis-Triggered Cascade

PubMed Central

Zheng, Zhitong; Tu, Huangfei

2014-01-01

A two-step, one-pot synthesis of fused pyrroles is realized by firstly condensing N-alkynylhydroxammonium salt with readily enolizable ketone under mild basic condition and then subjecting the reaction mixture to a gold catalyst, which triggers a cascade reaction featured by a facile initial 3.3-sigmatropic rearrangement of the gold catalysis product, i.e., an N,O-dialkenylhydroxamine. The reaction provides a facile access to polycyclic pyrroles in moderate to good yields. PMID:24482098

Spiroacetal formation through telescoped cycloaddition and carbon-hydrogen bond functionalization: total synthesis of bistramide A.

PubMed

Han, Xun; Floreancig, Paul E

2014-10-06

Spiroacetals can be formed through a one-pot sequence of a hetero-Diels-Alder reaction, an oxidative carbon-hydrogen bond cleavage, and an acid treatment. This convergent approach expedites access to a complex molecular subunit which is present in numerous biologically active structures. The utility of the protocol is demonstrated through its application to a brief synthesis of the actin-binding cytotoxin bistramide A. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Caryophyllene driven diversity in an one-pot rearrangement of oxidation and transanular reactions

NASA Astrophysics Data System (ADS)

Tang, Hao-Yu; Quan, Lu-Lu; Yu, Jie; Zhang, Qiang; Gao, Jin-Ming

2018-03-01

Diversity oriented synthesis starting from natural products is a newly coming strategy to build diverse skeletons to meet the demands of high throughput screening in drug development. Caryophyllene was being considered as an ideal starting point to build divers natural-like sesquiterpenes due to its rich sources and build-in reactivity. In this paper, six new natural-like products (2-7) were synthesized form the natural cryophyllene oxide via cascade oxidation and transannular reactions in a one-pot procedure. Their structures were elucidated by exhaustive spectra method including 2D NMR and X-ray diffraction. Of the products, compounds 6 and 7 possess very similar skeleton to natural products. Our findings demonstrated that one-pot cascade reactions on macrocyclic natural products is a concise strategy to create diverse natural-like skeletons.

Sliding over the Blocks in Enzyme-Free RNA Copying – One-Pot Primer Extension in Ice

PubMed Central

Löffler, Philipp M. G.; Groen, Joost; Dörr, Mark; Monnard, Pierre-Alain

2013-01-01

Template-directed polymerization of RNA in the absence of enzymes is the basis for an information transfer in the ‘RNA-world’ hypothesis and in novel nucleic acid based technology. Previous investigations established that only cytidine rich strands are efficient templates in bulk aqueous solutions while a few specific sequences completely block the extension of hybridized primers. We show that a eutectic water/ice system can support Pb2+/Mg2+-ion catalyzed extension of a primer across such sequences, i.e. AA, AU and AG, in a one-pot synthesis. Using mixtures of imidazole activated nucleotide 5′-monophosphates, the two first “blocking” residues could be passed during template-directed polymerization, i.e., formation of triply extended products containing a high fraction of faithful copies was demonstrated. Across the AG sequence, a mismatch sequence was formed in similar amounts to the correct product due to U·G wobble pairing. Thus, the template-directed extension occurs both across pyrimidine and purine rich sequences and insertions of pyrimidines did not inhibit the subsequent insertions. Products were mainly formed with 2′-5′-phosphodiester linkages, however, the abundance of 3′–5′-linkages was higher than previously reported for pyrimidine insertions. When enzyme-free, template-directed RNA polymerization is performed in a eutectic water ice environment, various intrinsic reaction limitations observed in bulk solution can then be overcome. PMID:24058695

Organocatalytic Enantioselective Michael/Cyclization Domino Reaction between 3-Amideoxindoles and α,β-Unsaturated Aldehydes: One-Pot Preparation of Chiral Spirocyclic Oxindole-γ-lactams.

PubMed

Yang, Peng; Wang, Xiao; Chen, Feng; Zhang, Zheng-Bing; Chen, Chao; Peng, Lin; Wang, Li-Xin

2017-04-07

The first organocatalytic enantioselective Michael/cyclization domino reaction between 3-amideoxindoles and α,β-unsaturated aldehydes is described. After sequential oxidation with pyridinium chlorochromate, a direct and one-pot preparation of highly sterically hindered spirocyclic oxindole-γ-lactams was achieved in 51-81% yields with 75-97% ee and ≤80/20 dr.

Shaken not stirred: a facile synthesis of 1,4-bis(furo[2,3-d]-pyrimidine-2,4(1H,3H)-dione-5-yl)benzenes by one-pot reaction of isocyanides, N,N'-dimethylbarbituric acid, and terephthaldialdehyde.

PubMed

Teimouri, Mohammad Bagher; Bazhrang, Reihaneh

2006-07-15

A simple and efficient synthesis of 1,4-bis(furo[2,3-d]pyrimidine-2,4(1H,3H)-dione-5-yl)benzene derivatives was achieved via a one-pot three-component reaction of isocyanides, N,N'-dimethylbarbituric acid, and terephthaldialdehyde in DMF at room temperature for 30 min. These improved reaction conditions allow the preparation of highly substituted furopyrimidinones in high yields and purity under mild reaction conditions.

Copper-catalyzed, C-C coupling-based one-pot tandem reactions for the synthesis of benzofurans using o-iodophenols, acyl chlorides, and phosphorus ylides.

PubMed

Liu, Yunyun; Wang, Hang; Wan, Jie-Ping

2014-11-07

One-pot reactions involving acyl chlorides, phosphorus ylides, and o-iodophenols with copper catalysis have been established for the rapid synthesis of functionalized benzofurans. With all of these easily available and stable reactants, the construction of the target products has been accomplished via tandem transformations involving a key C-C coupling, leading to the formation of one C(sp(2))-C bond, one C(sp(2))-O bond, and one C ═ C bond.

A concise synthesis of benzimidazoles via the microwave-assisted one-pot batch reaction of amino acids up to a 10-g scale.

PubMed

Peng, Pai; Xiong, Jin-Feng; Mo, Guang-Zhen; Zheng, Jia-Li; Chen, Ren-Hong; Chen, Xiao-Yun; Wang, Zhao-Yang

2014-10-01

An efficient method for the synthesis of aminomethyl benzimidazoles is developed by using a one-pot batch reaction between amino acids and o-phenylenediamines. This reaction proceeds smoothly in an unmodified household microwave oven, even though scale-up is to 10 g. A desirable method for the quick synthesis of benzimidazoles, which are used as a kind of important intermediates in drug synthesis, is provided by the scale-up utilization of amino acid resource.

Synthesis of a new class of Betti bases by the Mannich-type reaction: efficient, facile, solvent-free and one-pot protocol.

PubMed

Shahrisa, Aziz; Teimuri-Mofrad, Reza; Gholamhosseini-Nazari, Mahdi

2015-02-01

A variety of organocatalysts has been screened for the synthesis of arylaminonaphthols. It has been shown that (N,N-dimethylethanolamine) is a highly efficient organocatalyst for the direct synthesis of a novel class of arylaminonaphthols via three-component condensation of 2-naphthol, aldehydes, and arylamines under solvent-free conditions. Mild, one-pot, and green reaction conditions, relatively short reaction times and good yields make this protocol highly significant. 25 new compounds have been synthesized by this method.

Organocatalyzed, Visible-Light Photoredox-Mediated, One-Pot Minisci Reaction Using Carboxylic Acids via N-(Acyloxy)phthalimides.

PubMed

Sherwood, Trevor C; Li, Ning; Yazdani, Aliza N; Dhar, T G Murali

2018-03-02

An improved, one-pot Minisci reaction has been developed using visible light, an organic photocatalyst, and carboxylic acids as radical precursors via the intermediacy of in situ-generated N-(acyloxy)phthalimides. The conditions employed are mild, demonstrate a high degree of functional group tolerance, and do not require a large excess of the carboxylic acid reactant. As a result, this reaction can be applied to drug-like scaffolds and molecules with sensitive functional groups, enabling late-stage functionalization, which is of high interest to medicinal chemistry.

One-pot synthesis of β-acetamido ketones using boric acid at room temperature.

PubMed

Karimi-Jaberi, Zahed; Mohammadi, Korosh

2012-01-01

β-acetamido ketones were synthesized in excellent yields through one-pot condensation reaction of aldehydes, acetophenones, acetyl chloride, and acetonitrile in the presence of boric acid as a solid heterogeneous catalyst at room temperature. It is the first successful report of boric acid that has been used as solid acid catalyst for the preparation of β-acetamido ketones. The remarkable advantages offered by this method are green catalyst, mild reaction conditions, simple procedure, short reaction times, and good-to-excellent yields of products.

One-Pot Synthesis of β-Acetamido Ketones Using Boric Acid at Room Temperature

PubMed Central

Karimi-Jaberi, Zahed; Mohammadi, Korosh

2012-01-01

β-acetamido ketones were synthesized in excellent yields through one-pot condensation reaction of aldehydes, acetophenones, acetyl chloride, and acetonitrile in the presence of boric acid as a solid heterogeneous catalyst at room temperature. It is the first successful report of boric acid that has been used as solid acid catalyst for the preparation of β-acetamido ketones. The remarkable advantages offered by this method are green catalyst, mild reaction conditions, simple procedure, short reaction times, and good-to-excellent yields of products. PMID:22666168

One-pot synthesis of novel 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives via an Ugi-azide 4CR process.

PubMed

Ghandi, Mehdi; Salahi, Saleh; Taheri, Abuzar; Abbasi, Alireza

2018-05-01

A facile one-pot method has been developed for the synthesis of novel pyrrolo[2,1-a]pyrazine scaffolds. A variety of 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives were obtained in moderate to high yields in methanol using a one-pot four-component condensation of 1-(2-bromoethyl)-1H-pyrrole-2-carbaldehyde, amine, isocyanide and sodium azide at room temperature. These reactions presumably proceed via a domino imine formation, intramolecular annulation and Ugi-azide reaction. Unambiguous assignment of the molecular structures was carried out by single-crystal X-ray diffraction.

Oligopeptides and copeptides of homochiral sequence, via beta-sheets, from mixtures of racemic alpha-amino acids, in a one-pot reaction in water; relevance to biochirogenesis.

PubMed

Illos, Roni A; Bisogno, Fabricio R; Clodic, Gilles; Bolbach, Gerard; Weissbuch, Isabelle; Lahav, Meir

2008-07-09

As part of our studies on the biochirogenesis of peptides of homochiral sequence during early evolution, the formation of oligopeptides composed of 14-24 residues of the same handedness in the polymerization of dl-leucine (Leu), dl-phenylalanine (Phe), and dl-valine (Val) in aqueous solutions, by activation with N, N'-carbonyldiimidazole and then initiation with a primary amine, in a one-pot reaction, was demonstrated by MALDI-TOF MS using deuterium enantio-labeled alpha-amino acids. The formation of long isotactic peptides is rationalized by the following steps occurring in tandem: (i) creation of a library of short diasteroisomeric oligopeptides containing isotactic peptides in excess in comparison to a binomial kinetics, as a result of an asymmetric induction exerted by the N-terminal residue of a given handedness; (ii) precipitation of the less soluble racemic isotactic penta- and hexapeptides in the form of beta-sheets that are delineated by homochiral rims; (iii) regio-enantiospecific chain elongation occurring heterogeneously at the beta-sheets/solution interface. Polymerization of l-Leu with l-isoleucine (Ile) or l-Phe with l- (1) N-Me-histidine yielded mixtures of copeptides containing both residues. In contrast, in the polymerization of the corresponding mixtures of l- + d-alpha-amino acids, the long oligopeptides were composed mainly from oligo- l-Leu and oligo- d-Ile in the first system and oligo- d-Phe in the second. Furthermore, in the polymerization of mixtures of hydrophobic racemic alpha-amino acids dl-Leu, dl-Val, and dl-Phe and with added racemic dl-alanine and dl-tyrosine, copeptides of homochiral sequences are most dominantly represented. Possible routes for a spontaneous "mirror-symmetry breaking" process of the racemic mixtures of homochiral peptides are presented.

Dienamine and Friedel-Crafts one-pot synthesis, and antitumor evaluation of diheteroarylalkanals.

PubMed

Frías, María; Padrón, José M; Alemán, José

2015-05-26

An asymmetric synthesis of diheteroarylalkanals through one-pot dienamine and Friedel-Crafts reaction is presented. The reaction tolerates a large variety of substituents at different positions of the starting aldehyde and also in the indole nucleophile, and a range of diheterocyclic alkanals can be achieved. Furthermore, we have studied the antiproliferative activity of these new compounds in representative cancer tumor cell lines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cu-catalyzed aerobic oxidative cyclizations of 3-N-hydroxyamino-1,2-propadienes with alcohols, thiols, and amines to form α-O-, S-, and N-substituted 4-methylquinoline derivatives.

PubMed

Sharma, Pankaj; Liu, Rai-Shung

2015-03-16

A one-pot, two-step synthesis of α-O-, S-, and N-substituted 4-methylquinoline derivatives through Cu-catalyzed aerobic oxidations of N-hydroxyaminoallenes with alcohols, thiols, and amines is described. This reaction sequence involves an initial oxidation of N-hydroxyaminoallenes with NuH (Nu = OH, OR, NHR, and SR) to form 3-substituted 2-en-1-ones, followed by Brønsted acid catalyzed intramolecular cyclizations of the resulting products. Our mechanistic analysis suggests that the reactions proceed through a radical-type mechanism rather than a typical nitrone-intermediate route. The utility of this new Cu-catalyzed reaction is shown by its applicability to the synthesis of several 2-amino-4-methylquinoline derivatives, which are known to be key precursors to several bioactive molecules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal-free trifluoromethylation of aromatic and heteroaromatic aldehydes and ketones.

PubMed

Qiao, Yupu; Si, Tuda; Yang, Ming-Hsiu; Altman, Ryan A

2014-08-01

The ability to convert simple and common substrates into fluoroalkyl derivatives under mild conditions remains an important goal for medicinal and agricultural chemists. One representative example of a desirable transformation involves the conversion of aromatic and heteroaromatic ketones and aldehydes into aryl and heteroaryl β,β,β-trifluoroethylarenes and -heteroarenes. The traditional approach for this net transformation involves stoichiometric metals and/or multistep reaction sequences that consume excessive time, material, and labor resources while providing low yields of products. To complement these traditional strategies, we report a one-pot metal-free decarboxylative procedure for accessing β,β,β-trifluoroethylarenes and -heteroarenes from readily available ketones and aldehydes. This method features several benefits, including ease of operation, readily available reagents, mild reaction conditions, high functional-group compatibility, and scalability.

Metal-Free Trifluoromethylation of Aromatic and Heteroaromatic Aldehydes and Ketones

PubMed Central

2015-01-01

The ability to convert simple and common substrates into fluoroalkyl derivatives under mild conditions remains an important goal for medicinal and agricultural chemists. One representative example of a desirable transformation involves the conversion of aromatic and heteroaromatic ketones and aldehydes into aryl and heteroaryl β,β,β-trifluoroethylarenes and -heteroarenes. The traditional approach for this net transformation involves stoichiometric metals and/or multistep reaction sequences that consume excessive time, material, and labor resources while providing low yields of products. To complement these traditional strategies, we report a one-pot metal-free decarboxylative procedure for accessing β,β,β-trifluoroethylarenes and -heteroarenes from readily available ketones and aldehydes. This method features several benefits, including ease of operation, readily available reagents, mild reaction conditions, high functional-group compatibility, and scalability. PMID:25001876

Highly efficient one-pot three-component synthesis of naphthopyran derivatives in water catalyzed by hydroxyapatite

EPA Science Inventory

An expeditious and efficient protocol for the synthesis of naphthopyrans has been developed that proceeds via one-pot three-component sequential reaction in water catalyzed by hydroxyapatite or sodium-modified-hydroxyapatite. The title compounds have been obtained in high yield a...

Precise Tuning of Facile One-Pot Gelatin Methacryloyl (GelMA) Synthesis

NASA Astrophysics Data System (ADS)

Shirahama, Hitomi; Lee, Bae Hoon; Tan, Lay Poh; Cho, Nam-Joon

2016-08-01

Gelatin-methacryloyl (GelMA) is one of the most commonly used photopolymerizable biomaterials in bio-applications. However, GelMA synthesis remains suboptimal, as its reaction parameters have not been fully investigated. The goal of this study is to establish an optimal route for effective and controllable GelMA synthesis by systematically examining reaction parameters including carbonate-bicarbonate (CB) buffer molarity, initial pH adjustment, MAA concentration, gelatin concentration, reaction temperature, and reaction time. We employed several analytical techniques in order to determine the degree of substitution (DS) and conducted detailed structural analysis of the synthesized polymer. The results enabled us to optimize GelMA synthesis, showing the optimal conditions to balance the deprotonation of amino groups with minimizing MAA hydrolysis, which led to nearly complete substitution. The optimized conditions (low feed ratio of MAA to gelatin (0.1 mL/g), 0.25 M CB buffer at pH 9, and a gelatin concentration of 10-20%) enable a simplified reaction scheme that produces GelMA with high substitution with just one-step addition of MAA in one pot. Looking forward, these optimal conditions not only enable facile one-pot GelMA synthesis but can also guide researchers to explore the efficient, high methacrylation of other biomacromolecules.

Precise Tuning of Facile One-Pot Gelatin Methacryloyl (GelMA) Synthesis

PubMed Central

Shirahama, Hitomi; Lee, Bae Hoon; Tan, Lay Poh; Cho, Nam-Joon

2016-01-01

Gelatin-methacryloyl (GelMA) is one of the most commonly used photopolymerizable biomaterials in bio-applications. However, GelMA synthesis remains suboptimal, as its reaction parameters have not been fully investigated. The goal of this study is to establish an optimal route for effective and controllable GelMA synthesis by systematically examining reaction parameters including carbonate-bicarbonate (CB) buffer molarity, initial pH adjustment, MAA concentration, gelatin concentration, reaction temperature, and reaction time. We employed several analytical techniques in order to determine the degree of substitution (DS) and conducted detailed structural analysis of the synthesized polymer. The results enabled us to optimize GelMA synthesis, showing the optimal conditions to balance the deprotonation of amino groups with minimizing MAA hydrolysis, which led to nearly complete substitution. The optimized conditions (low feed ratio of MAA to gelatin (0.1 mL/g), 0.25 M CB buffer at pH 9, and a gelatin concentration of 10–20%) enable a simplified reaction scheme that produces GelMA with high substitution with just one-step addition of MAA in one pot. Looking forward, these optimal conditions not only enable facile one-pot GelMA synthesis but can also guide researchers to explore the efficient, high methacrylation of other biomacromolecules. PMID:27503340

Imides: forgotten players in the Ugi reaction. One-pot multicomponent synthesis of quinazolinones.

PubMed

Mossetti, Riccardo; Pirali, Tracey; Saggiorato, Dèsirèe; Tron, Gian Cesare

2011-06-28

Up to now, the synthesis of quinazolinones has required lengthy synthetic procedures. Here, we describe an innovative one-pot multicomponent reaction leading to highly substituted quinazolinones. We believe that this novel transformation may open the door for the generation of new and pharmacologically active quinazolinones, but, most important of all, the resurrection of the imide-Ugi scaffold paves the way for the synthesis of novel molecular architectures. This journal is © The Royal Society of Chemistry 2011

A One-Pot Tandem Strategy in Catalytic Asymmetric Vinylogous Aldol Reaction of Homoallylic Alcohols.

PubMed

Hou, Xufeng; Jing, Zhenzhong; Bai, Xiangbin; Jiang, Zhiyong

2016-06-27

Reported is a rationally-designed one-pot sequential strategy that allows homoallylic alcohols to be employed in a catalytic, asymmetric, direct vinylogous aldol reaction with a series of activated acyclic ketones, including trifluoromethyl ketones, γ-ketoesters, and α-keto phosphonates, in high yields (up to 95%) with excellent regio- and enantio-selectivity (up to 99% ee). This modular combination, including Jones oxidation and asymmetric organocatalysis, has satisfactory compatibility and reliability even at a 20 mmol scale, albeit without intermediary purification.

A Rapid, One-Pot Synthesis of β-Siloxy-α-Haloaldehydes

PubMed Central

Saadi, Jakub; Akakura, Matsujiro

2011-01-01

The Mukaiyama cross aldol reaction of α-fluoro-, α-chloro-, and α-bromoacetaldehyde-derived (Z)-tris(trimethylsilyl)- silyl enol ethers furnishing anti-β-siloxy-α-haloaldehydes is described. A highly diastereoselective, one-pot, sequential double aldol process, affording novel β,δ-bissiloxy-α,γ-bishaloaldehydes is developed. Reactions are catalyzed by C6F5CHTf2 and C6F5CTf2AlMe2 (0.5–1.5 mol%) and provide access to halogenated polyketide fragments. PMID:21815682

Water-tolerant and reusable Lewis acid catalyst for the one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent-free conditions.

PubMed

Wang, Min; Song, Zhiguo; Jiang, Heng; Gong, Hong

2010-01-01

3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of an aldehyde, a 1,3-dicarbonyl compound, and urea using copper methanesulfonate (2 mol%) as a recyclable catalyst under solvent-free conditions in short reaction time (1-2 h).

An efficient microwave-assisted synthesis method for the production of water soluble amine-terminated Si nanoparticles.

PubMed

Atkins, Tonya M; Louie, Angelique Y; Kauzlarich, Susan M

2012-07-27

Silicon nanoparticles can be considered a green material, especially when prepared via a microwave-assisted method without the use of highly reactive reducing agents or hydrofluoric acid. A simple solution synthesis of hydrogen-terminated Si- and Mn-doped Si nanoparticles via microwave-assisted synthesis is demonstrated. The reaction of the Zintl salt, Na(4)Si(4), or Mn-doped Na(4)Si(4), Na(4)Si(4(Mn)), with ammonium bromide, NH(4)Br, produces small dispersible nanoparticles along with larger particles that precipitate. Allylamine and 1-amino-10-undecene were reacted with the hydrogen-terminated Si nanoparticles to provide water solubility and stability. A one-pot, single-reaction process and a one-pot, two-step reaction process were investigated. Details of the microwave-assisted process are provided, with the optimal synthesis being the one-pot, two-step reaction procedure and a total time of about 15 min. The nanoparticles were characterized by transmission electron microscopy (TEM), x-ray diffraction, and fluorescence spectroscopies. The microwave-assisted method reliably produces a narrow size distribution of Si nanoparticles in solution.

One-Pot, Three-Component Arylalkynyl Sulfone Synthesis

PubMed Central

2015-01-01

A one-pot three-component protocol for the preparation of arylsulfonyl alkynes through the reaction of ethynyl-benziodoxolone (EBX) reagents, DABSO (DABCO·SO2), and either organomagnesium reagents or aryl iodides with a palladium catalyst is reported. A broad range of aryl and heteroarylalkynyl sulfones were obtained in 46–85% overall yield. PMID:25633719

Stereo- and regio-selective one-pot synthesis of triazole-based unnatural amino acids and β- amino triazoles

EPA Science Inventory

Synthesis of triazole based unnatural amino acids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope a...

Catalyst-free synthesis of skipped dienes from phosphorus ylides, allylic carbonates, and aldehydes via a one-pot SN2' allylation-Wittig strategy.

PubMed

Xu, Silong; Zhu, Shaoying; Shang, Jian; Zhang, Junjie; Tang, Yuhai; Dou, Jianwei

2014-04-18

A catalyst-free allylic alkylation of stabilized phosphorus ylides with allylic carbonates via a regioselective SN2' process is presented. Subsequent one-pot Wittig reaction with both aliphatic and aromatic aldehydes as well as ketenes provides structurally diverse skipped dienes (1,4-dienes) in generally high yields and moderate to excellent stereoselectivity with flexible substituent patterns. This one-pot SN2' allylation-Wittig strategy constitutes a convenient and efficient synthetic method for highly functionalized skipped dienes from readily available starting materials.

One-pot reaction for the preparation of biofunctionalized self-assembled monolayers on gold surfaces

NASA Astrophysics Data System (ADS)

Raigoza, Annette F.; Fies, Whitney; Lim, Amber; Onyirioha, Kristeen; Webb, Lauren J.

2017-02-01

The Huisgen cycloaddition reaction (;click; chemistry) has been used extensively to functionalize surfaces with macromolecules in a straightforward manner. We have previously developed a procedure using the copper(I)-catalyzed click reaction to tether synthetic α-helical peptides carrying two alkyne groups to a well-ordered azide-terminated alkanethiol self-assembled monolayer (SAM) on a Au(111) surface. While convenient, click-based strategies potentially pose significant problems from reagents, solvents, and reaction temperatures that may irreversibly damage some molecules or substrates. Tuning click chemistry conditions would allow individual optimization of reaction conditions for a wide variety of biomolecules and substrate materials. Here, we explore the utility of simultaneous SAM formation and peptide-attachment chemistry in a one-pot reaction. We demonstrate that a formerly multistep reaction can be successfully carried out concurrently by mixing azide-terminated alkanethiols, CuCl, and a propargylglycine-containing peptide over a bare gold surface in ethanol and reacting at 70 °C. X-ray photoelectron spectroscopy (XPS), surface infrared spectroscopy, surface circular dichroic (CD) spectroscopy, and scanning tunneling microscopy (STM) were used to determine that this one-pot reaction strategy resulted in a high density of surface-bound α-helices without aggregation. This work demonstrates the simplicity and versatility of a SAM-plus-click chemistry strategy for functionalizing Au surfaces with structured biomolecules.

Multistep divergent synthesis of benzimidazole linked benzoxazole/benzothiazole via copper catalyzed domino annulation.

PubMed

Liao, Jen-Yu; Selvaraju, Manikandan; Chen, Chih-Hau; Sun, Chung-Ming

2013-04-21

An efficient, facile synthesis of structurally diverse benzimidazole integrated benzoxazole and benzothiazoles has been developed. In a multi-step synthetic sequence, 4-fluoro-3-nitrobenzoic acid was converted into benzimidazole bis-heterocycles, via the intermediacy of benzimidazole linked ortho-chloro amines. The amphiphilic reactivity of this intermediate was designed to achieve the title compounds by the reaction of various acid chlorides and isothiocyanates in a single step through the in situ formation of ortho-chloro anilides and thioureas under microwave irradiation. A versatile one pot domino annulation reaction was developed to involve the reaction of benzimidazole linked ortho-chloro amines with acid chlorides and isothiocyanates. The initial acylation and urea formation followed by copper catalyzed intramolecular C-O and C-S cross coupling reactions furnished the angularly oriented bis-heterocycles which bear a close resemblance to the streptomyces antibiotic UK-1.

Solid state synthesis of poly(dichlorophosphazene)

DOEpatents

Allen, Christopher W.; Hneihen, Azzam S.; Peterson, Eric S.

2001-01-01

A method for making poly(dichlorophosphazene) using solid state reactants is disclosed and described. The present invention improves upon previous methods by removing the need for chlorinated hydrocarbon solvents, eliminating complicated equipment and simplifying the overall process by providing a "single pot" two step reaction sequence. This may be accomplished by the condensation reaction of raw materials in the melt phase of the reactants and in the absence of an environmentally damaging solvent.

Novel multicomponent reaction for the combinatorial synthesis of 2-imidazolines.

PubMed

Bon, Robin S; Hong, Chongen; Bouma, Marinus J; Schmitz, Rob F; de Kanter, Frans J J; Lutz, Martin; Spek, Anthony L; Orru, Romano V A

2003-10-02

[reaction: see text] The three-component condensation between an amine, an aldehyde, and an alpha-acidic isocyanide efficiently provides substituted 2-imidazolines in a one-pot reaction under mild conditions.

Rapid Optimization of Engineered Metabolic Pathways with Serine Integrase Recombinational Assembly (SIRA).

PubMed

Merrick, C A; Wardrope, C; Paget, J E; Colloms, S D; Rosser, S J

2016-01-01

Metabolic pathway engineering in microbial hosts for heterologous biosynthesis of commodity compounds and fine chemicals offers a cheaper, greener, and more reliable method of production than does chemical synthesis. However, engineering metabolic pathways within a microbe is a complicated process: levels of gene expression, protein stability, enzyme activity, and metabolic flux must be balanced for high productivity without compromising host cell viability. A major rate-limiting step in engineering microbes for optimum biosynthesis of a target compound is DNA assembly, as current methods can be cumbersome and costly. Serine integrase recombinational assembly (SIRA) is a rapid DNA assembly method that utilizes serine integrases, and is particularly applicable to rapid optimization of engineered metabolic pathways. Using six pairs of orthogonal attP and attB sites with different central dinucleotide sequences that follow SIRA design principles, we have demonstrated that ΦC31 integrase can be used to (1) insert a single piece of DNA into a substrate plasmid; (2) assemble three, four, and five DNA parts encoding the enzymes for functional metabolic pathways in a one-pot reaction; (3) generate combinatorial libraries of metabolic pathway constructs with varied ribosome binding site strengths or gene orders in a one-pot reaction; and (4) replace and add DNA parts within a construct through targeted postassembly modification. We explain the mechanism of SIRA and the principles behind designing a SIRA reaction. We also provide protocols for making SIRA reaction components and practical methods for applying SIRA to rapid optimization of metabolic pathways. © 2016 Elsevier Inc. All rights reserved.

Synthesis of Thieno[3,2-b]indoles via Halogen Dance and Ligand-Controlled One-Pot Sequential Coupling Reaction.

PubMed

Hayashi, Yuki; Okano, Kentaro; Mori, Atsunori

2018-02-16

A two-pot synthesis of thieno[3,2-b]indole from 2,5-dibromothiophene is described. A halogen dance of 2,5-dibromothiophene was performed with LDA, and subsequent Negishi coupling was performed with 2-iodoaniline derivatives to provide the corresponding coupling products. The resulting two bromo groups have different reactivities, which were utilized for the one-pot Suzuki-Miyaura coupling/intramolecular Buchwald-Hartwig amination to produce thieno[3,2-b]indole via an assisted tandem catalysis that involved in situ ligand exchange.

MICROWAVE-ACCELERATED MULTICOMPONENT REACTIONS UNDER SOLVENT-FREE CONDITIONS

EPA Science Inventory

The application of microwave-accelerated solventless synthetic protocols in multicomponent (MCC) reactions will be exemplified by several condensation and cyclization reactions including the rapid one-pot assembly of valuable heterocyclic compounds from in situ generated intermed...

Synthesis of a Fluorescent Acridone Using a Grignard Addition, Oxidation, and Nucleophilic Aromatic Substitution Reaction Sequence

ERIC Educational Resources Information Center

Goodrich, Samuel; Patel, Miloni; Woydziak, Zachary R.

2015-01-01

A three-pot synthesis oriented for an undergraduate organic chemistry laboratory was developed to construct a fluorescent acridone molecule. This laboratory experiment utilizes Grignard addition to an aldehyde, alcohol oxidation, and iterative nucleophilic aromatic substitution steps to produce the final product. Each of the intermediates and the…

MICROWAVE-FACILITATED MULTICOMPONENT REACTIONS UNDER SOLVENT-FREE CONDITIONS

EPA Science Inventory

The application of microwave-expedited solvent-free synthetic protocols in multi-component (MCC) reactions will be exemplified by several condensation and cyclization reactions including the rapid one-pot assembly of heterocyclic compounds from in situ generated intermediates. R...

Synthesis of functionalized imidazolidine-2-thiones via NHC/base-promoted aza-benzoin/aza-acetalization domino reactions.

PubMed

Di Carmine, Graziano; Ragno, Daniele; De Risi, Carmela; Bortolini, Olga; Giovannini, Pier Paolo; Fantin, Giancarlo; Massi, Alessandro

2017-10-25

A strategy for the synthesis of biologically relevant 5-hydroxy-imidazolidine-2-thione derivatives is presented. A novel class of α-sulfonylamines have been suitably prepared (46-81% yield) as precursors of formal benzylidenethiourea acceptors; these are generated in situ and intercepted by N-heterocyclic carbene (NHC)-activated aldehydes affording open-chain aza-benzoin-type adducts, which in turn undergo an intramolecular aza-acetalization reaction in a one-pot fashion. A thiazolium salt/triethylamine couple proved to be the more effective system to trigger the domino sequence giving the target heterocycles in good yields (45-97%) and diastereoselectivities (up to 99 : 1 dr). The multigram scale synthesis and elaboration of a selected 5-hydroxy-imidazolidine-2-thione compound is also described.

One-pot in situ redox synthesis of hexacyanoferrate/conductive polymer hybrids as lithium-ion battery cathodes.

PubMed

Wong, Min Hao; Zhang, Zixuan; Yang, Xianfeng; Chen, Xiaojun; Ying, Jackie Y

2015-09-14

An efficient and adaptable method is demonstrated for the synthesis of lithium hexacyanoferrate/conductive polymer hybrids for Li-ion battery cathodes. The hybrids were synthesized via a one-pot method, involving a redox-coupled reaction between pyrrole monomers and the Li3Fe(CN)6 precursor. The hybrids showed much better cyclability relative to reported Prussian Blue (PB) analogs.

A rapid and efficient one-pot method for the reduction of N-protected α-amino acids to chiral α-amino aldehydes using CDI/DIBAL-H.

PubMed

Ivkovic, Jakov; Lembacher-Fadum, Christian; Breinbauer, Rolf

2015-11-14

N-Protected amino acids can be easily converted into chiral α-amino aldehydes in a one-pot reaction by activation with CDI followed by reduction with DIBAL-H. This method delivers Boc-, Cbz- and Fmoc-protected amino aldehydes from proteinogenic amino acids in very good isolated yields and complete stereointegrity.

Substituted 1H-1,2,3-Triazol-4-yl-1H-pyrrolo[2,3-b]pyridines by De Novo One-Pot Ring Forming Coupling-Cyclization-Desilylation-CuAAC-Sequence.

PubMed

Müller, Thomas J J; Lessing, Timo; van Mark, Hauke

2018-05-04

Substituted 1H-1,2,3-triazol-4-yl-pyrrolo[2,3-b]pyridines are efficiently prepared by a one-pot coupling-cyclization-desilylation-CuAAC-sequence in the sense of a consecutive three-component fashion. The key feature of this novel de novo formation of azole and triazole anellation is the sequentially Pd/Cu-catalyzed process employing tri(iso-propyl)silylbutadiyne (TIPS-butadiyne) as a four-carbon building block. In addition, the sequence can be expanded in a four-component fashion also employing the in situ formation of the require azides. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-Pot Synthesis of D-Phenylalanine-Functionalized Multi-Walled Carbon Nanotubes: a Metal-Free Chiral Material for the Asymmetric Electroreduction of Aromatic Ketones.

PubMed

Yue, Ying-Na; Zeng, Sheng; Wang, Hui; Wang, Shuo; Wang, Huan; Lu, Jia-Xing

2018-06-19

A simple protocol to synthesize D-phenylalanine (D-PHE)-functionalized multi-walled carbon nanotubes (MWCNTs) via one-pot method was established by grafting D-PHE onto MWCNTs to obtain D-PHE-MWCNTs under mild reaction conditions. The resulting D-PHE-MWCNTs were detailedly characterized via spectroscopy and surface analysis. The electroreduction of 2,2,2-trifluoroacetophenone at D-PHE-MWCNTs cathode afforded (S)-α-(trifluoromethyl) benzyl alcohol whose yield was 65% and the enantiomeric excess was 40%. No extra catalysts were required in this electrochemical reaction solution compared with other reactions requiring homogeneous catalysis. The metal-free chiral material also showed acceptable asymmetric electroreduction performance, considerable stability and favorable reusability.

Fast dye salts provide fast access to azidoarene synthons in multi-step one-pot tandem click transformations

PubMed Central

Fletcher, James T.; Reilly, Jacquelline E.

2012-01-01

This study examined whether commercially available diazonium salts could be used as efficient aromatic azide precursors in one-pot multi-step click transformations. Seven different diazonium salts, including Fast Red RC, Fast Blue B, Fast Corinth V and Variamine Blue B were surveyed under aqueous click reaction conditions of CuSO4/Na ascorbate catalyst with 1:1 t-BuOH:H2O solvent. Two-step tandem reactions with terminal alkyne and diyne co-reactants led to 1,2,3-triazole products in 66%-88% yields, while three-step tandem reactions with trimethylsilyl-protected alkyne and diyne co-reactants led to 1,2,3-triazole products in 61%-78% yields. PMID:22368306

Tetraethylene glycol promoted two-step, one-pot rapid synthesis of indole-3-[1- 11C]acetic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sojeong; Qu, Wenchao; Alexoff, David L.

2014-12-12

An operationally friendly, two-step, one-pot process has been developed for the rapid synthesis of carbon-11 labeled indole-3-acetic acid ([ 11]IAA or [ 11]auxin). By replacing an aprotic polar solvent with tetraethylene glycol, nucleophilic [ 11]cyanation and alkaline hydrolysis reactions were performed consecutively in a single pot without a time-consuming intermediate purification step. The entire production time for this updated procedure is 55 min, which dramatically simplifies the entire synthesis and reduces the starting radioactivity required for a whole plant imaging study.

Comparative Analysis of Sequential Proximal Optimizing Technique Versus Kissing Balloon Inflation Technique in Provisional Bifurcation Stenting: Fractal Coronary Bifurcation Bench Test.

PubMed

Finet, Gérard; Derimay, François; Motreff, Pascal; Guerin, Patrice; Pilet, Paul; Ohayon, Jacques; Darremont, Olivier; Rioufol, Gilles

2015-08-24

This study used a fractal bifurcation bench model to compare 6 optimization sequences for coronary bifurcation provisional stenting, including 1 novel sequence without kissing balloon inflation (KBI), comprising initial proximal optimizing technique (POT) + side-branch inflation (SBI) + final POT, called "re-POT." In provisional bifurcation stenting, KBI fails to improve the rate of major adverse cardiac events. Proximal geometric deformation increases the rate of in-stent restenosis and target lesion revascularization. A bifurcation bench model was used to compare KBI alone, KBI after POT, KBI with asymmetric inflation pressure after POT, and 2 sequences without KBI: initial POT plus SBI, and initial POT plus SBI with final POT (called "re-POT"). For each protocol, 5 stents were tested using 2 different drug-eluting stent designs: that is, a total of 60 tests. Compared with the classic KBI-only sequence and those associating POT with modified KBI, the re-POT sequence gave significantly (p < 0.05) better geometric results: it reduced SB ostium stent-strut obstruction from 23.2 ± 6.0% to 5.6 ± 8.3%, provided perfect proximal stent apposition with almost perfect circularity (ellipticity index reduced from 1.23 ± 0.02 to 1.04 ± 0.01), reduced proximal area overstretch from 24.2 ± 7.6% to 8.0 ± 0.4%, and reduced global strut malapposition from 40 ± 6.2% to 2.6 ± 1.4%. In comparison with 5 other techniques, the re-POT sequence significantly optimized the final result of provisional coronary bifurcation stenting, maintaining circular geometry while significantly reducing SB ostium strut obstruction and global strut malapposition. These experimental findings confirm that provisional stenting may be optimized more effectively without KBI using re-POT. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Copper-catalyzed one-pot synthesis of 1,2,4-triazoles from nitriles and hydroxylamine.

PubMed

Xu, Hao; Ma, Shuang; Xu, Yuanqing; Bian, Longxiang; Ding, Tao; Fang, Xiaomin; Zhang, Wenkai; Ren, Yanrong

2015-02-06

A simple and efficient copper-catalyzed one-pot synthesis of substituted 1,2,4-triazoles through reactions of two nitriles with hydroxylamine has been developed. The protocol uses simple and readily available nitriles and hydroxylamine hydrochloride as the starting materials and inexpensive Cu(OAc)2 as the catalyst, and the corresponding 1,2,4-triazole derivatives are obtained in moderate to good yields. The reactions include sequential intermolecular addition of hydroxylamine to one nitrile to provide amidoxime, copper-catalyzed treatment of the amidoxime with another nitrile, and intramolecular dehydration/cyclization. This finding provides a new and useful strategy for synthesis of 1,2,4-triazole derivatives.

Exploring the Chemistry of Bicyclic Isoxazolidines for the Multicomponent Synthesis of Glycomimetic Building Blocks.

PubMed

Hoogenboom, Jorin; Lutz, Martin; Zuilhof, Han; Wennekes, Tom

2016-10-07

Starting from a chiral furanone, the nitrone-olefin [3 + 2] cycloaddition can be used to obtain bicyclic isoxazolidines for which we report a set of reactions to selectively modify each functional position. These synthetically versatile bicyclic isoxazolidines allowed us to obtain complex glycomimetic building blocks, like iminosugars, via multicomponent chemistry. For example, a library of 20 pipecolic acid derivatives, a recurring motif in various prescription drugs, could be obtained via a one-pot Staudinger/aza-Wittig/Ugi three-component reaction of a bicyclic isoxazolidine-derived azido-hemiacetal. Notably, specific pipecolic acids in this library were obtained via hydrolysis of an unique tricyclic imidate side product of the Ugi reaction. The azido-hemiacetal was also converted into an aza-C-glycoside iminosugar via an unprecendented one-pot Staudinger/aza-Wittig/Mannich reaction.

Eco-efficient one-pot synthesis of quinazoline-2,4(1H,3H)-diones at room temperature in water.

PubMed

Tian, Xin-Chuan; Huang, Xing; Wang, Dan; Gao, Feng

2014-01-01

An efficient one-pot synthesis of quinazoline-2,4(1H,3H)-diones was developed. First, the reactions of anthranilic acid derivatives with potassium cyanate afforded the corresponding urea derivatives. Then, cyclization of the urea derivatives with NaOH afforded the monosodium salts of benzoylene urea. Finally, HCl treatment afforded the desired products in near-quantitative yields. This is an eco-efficient method because all the reactions were carried out in water, and the desired products were obtained simply by filtration. The aqueous filtrate was the only waste generated from the reaction. We scaled up the reaction to 1 kg starting material, thus establishing an alternative approach for the green synthesis of quinazoline-2,4(1H,3H)-diones in the chemical and pharmaceutical industries.

Citrus Peel Additives for One-Pot Triazole Formation by Decarboxylation, Nucleophilic Substitution, and Azide-Alkyne Cycloaddition Reactions

ERIC Educational Resources Information Center

Mendes, Desiree E.; Schoffstall, Allen M.

2011-01-01

This undergraduate organic laboratory experiment consists of three different reactions occurring in the same flask: a cycloaddition reaction, preceded by decarboxylation and nucleophilic substitution reactions. The decarboxylation and cycloaddition reactions occur using identical Cu(I) catalyst and conditions. Orange, lemon, and other citrus fruit…

Dual role of allylsamarium bromide as a Grignard reagent and a single electron transfer reagent in the one-pot synthesis of terminal olefins.

PubMed

Li, Ying; Hu, Yuan-Yuan; Zhang, Song-Lin

2013-11-21

The utility of allylsamarium bromide, both as a nucleophilic reagent and a single-electron transfer reagent, in the reaction of carbonyl compounds with allylsamarium bromide in the presence of diethyl phosphate is reported in this communication. From a synthetic point of view, a simple one-pot method for the preparation of terminal olefins is developed.

One-pot Sequential Reactions Featuring a Copper-catalyzed Amination Leading to Pyrido[2',1':2,3]imidazo[4,5-c]quinolines and Dihydropyrido[2',1':2,3]imidazo[4,5-c]quinolines.

PubMed

Fan, Xue-Sen; Zhang, Ju; Li, Bin; Zhang, Xin-Ying

2015-06-01

Tetracyclic skeletons combining an imidazo[1,2-a]pyridine moiety with a quinoline framework such as pyrido[2',1':2,3]imidazo[4,5-b]quinoline are stimulating increasing interests since they are close isosteres of a series of powerful antiproliferative compounds. In this paper, we report a novel methodology for the synthesis of pyrido[2',1':2,3]imidazo[4,5-c]quinolines through one-pot sequential reactions of commercially available or readily obtainable 2-aminopyridines, 2-bromophenacyl bromides, aqueous ammonia, and aldehydes. Moreover, dihydropyrido[2',1':2,3]imidazo[4,5-c]quinolines could also be obtained in a similar manner by using various ketones as the substrates in place of aldehydes. Notably, the whole procedure combines condensation/amination/cyclization reactions in one pot to give complex compounds in a simple and practical manner. Compared with literature methods, the synthetic strategy reported herein has the advantages of readily available starting materials, structural diversity of products, good functional group tolerance, and obviation of step-by-step operations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-Pot Synthesis of Multifunctional Polymers by Light-Controlled Radical Polymerization and Enzymatic Catalysis with Candida antarctica Lipase B.

PubMed

Hrsic, Emin; Keul, Helmut; Möller, Martin

2015-12-01

The preparation of multifunctional polymers and block copolymers by a straightforward one-pot reaction process that combines enzymatic transacylation with light-controlled polymerization is described. Functional methacrylate monomers are synthesized by enzymatic transacylation and used in situ for light-controlled polymerization, leading to multifunctional methacrylate-based polymers with well-defined microstructure. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A one-pot synthesis of 1,6,9,13-tetraoxadispiro(4.2.4.2)tetradecane by hydrodeoxygenation of xylose using a palladium catalyst

USDA-ARS?s Scientific Manuscript database

In an effort to expand the number of biobased chemicals available from sugars, xylose has been converted to 1,6,9,13-tetraoxadispiro(4.2.4.2)tetradecane in a one-pot reaction using palladium supported on silica-alumina as the catalyst. The title compound is produced in 35-40% yield under 7 MPa H2 pr...

Novel dextran derivatives with unconventional structure formed in an efficient one-pot reaction.

PubMed

Hotzel, Konrad; Heinze, Thomas

2016-11-03

An efficient one-pot synthesis of new dextran derivatives is described. The functional groups of β-alanine, i.e., the carboxyl- and amine group, are converted independently in one-step by iminium chloride to form products with a single substituent. The dextran N-[(dimethylamino)methylene]-β-alanine ester is formed selectively. The structure of the resulting polymers is unambiguously determined by means of NMR- and FTIR-spectroscopy and elemental analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recent developments on ultrasound-assisted one-pot multicomponent synthesis of biologically relevant heterocycles.

PubMed

Banerjee, Bubun

2017-03-01

Heterocycles are the backbone of organic compounds. Specially, N- &O-containing heterocycles represent privileged structural subunits well distributed in naturally occurring compounds with immense biological activities. Multicomponent reactions (MCRs) are becoming valuable tool for synthesizing structurally diverse molecular entities. On the other hand, the last decade has seen a tremendous outburst in modifying chemical processes to make them sustainable for the betterment of our environment. The application of ultrasound in organic synthesis is fulfilling some of the goals of 'green and sustainable chemistry' as it has some advantages over the traditional thermal methods in terms of reaction rates, yields, purity of the products, product selectivity, etc. Therefore the synthesis of biologically relevant heterocycles using one-pot multi-component technique coupled with the application of ultrasound is one of the thrusting areas in the 21st Century among the organic chemists. The present review deals with the "up to date" developments on ultrasound assisted one-pot multi-component synthesis of biologically relevant heterocycles reported so far. Copyright © 2016 Elsevier B.V. All rights reserved.

Polyunsaturated C-Glycosidic 4-Hydroxy-2-pyrone Derivatives: Total Synthesis Shows that Putative Orevactaene Is Likely Identical with Epipyrone A.

PubMed

Preindl, Johannes; Schulthoff, Saskia; Wirtz, Conny; Lingnau, Julia; Fürstner, Alois

2017-06-19

Orevactaene and epipyrone A were previously thought to comprise the same polyunsaturated tail but notably different C-glycosylated 4-hydroxy-2-pyrone head groups. Total synthesis now shows that the signature bicyclic framework assigned to orevactaene is a chimera; the compound is almost certainly identical with epipyrone A, whose previously unknown stereochemistry has also been established during this study. Key to success was the ready formation of the bicyclic core of putative orevactaene by a sequence of two alkyne cycloisomerization reactions using tungsten and gold catalysis. Equally important was the flexibility in the assembly process gained by the use of heterobimetallic polyunsaturated modules whose termini could be selectively and consecutively addressed in a practical one-pot cross-coupling sequence. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Process for preparing polymer reinforced silica aerogels

NASA Technical Reports Server (NTRS)

Meador, Mary Ann B. (Inventor); Capadona, Lynn A. (Inventor)

2011-01-01

Process for preparing polymer-reinforced silica aerogels which comprises a one-pot reaction of at least one alkoxy silane in the presence of effective amounts of a polymer precursor to obtain a silica reaction product, the reaction product is gelled and subsequently subjected to conditions that promotes polymerization of the precursor and then supercritically dried to obtain the polymer-reinforced monolithic silica aerogels.

Consecutive three-component synthesis of (hetero)arylated propargyl amides by chemoenzymatic aminolysis-Sonogashira coupling sequence.

PubMed

Hassan, Sidra; Ullrich, Anja; Müller, Thomas J J

2015-02-07

A novel chemoenzymatic three-component synthesis of (hetero)arylated propargyl amides in good yields based upon Novozyme® 435 (Candida antarctica lipase B (CAL-B)) catalyzed aminolysis of methyl carboxylates followed by Sonogashira coupling with (hetero)aryliodides in a consecutive one-pot fashion has been presented. This efficient methodology can be readily concatenated with a CuAAC (Cu catalyzed alkyne azide cycloaddition) as a third consecutive step to furnish 1,4-disubstituted 1,2,3-triazole ligated arylated propargyl amides. This one-pot process can be regarded as a transition metal catalyzed sequence that takes advantage of the copper source still present from the cross-coupling step.

Combining silver catalysis and organocatalysis: a sequential Michael addition/hydroalkoxylation one-pot approach to annulated coumarins.

PubMed

Hack, Daniel; Chauhan, Pankaj; Deckers, Kristina; Hermann, Gary N; Mertens, Lucas; Raabe, Gerhard; Enders, Dieter

2014-10-03

A highly stereoselective one-pot procedure for the synthesis of five-membered annulated hydroxycoumarins has been developed. By merging primary amine catalysis with silver catalysis, a series of functionalized coumarin derivatives were obtained in good yields (up to 91%) and good to excellent enantioselectivities (up to 99% ee) via a Michael addition/hydroalkoxylation reaction. Depending on the substituents on the enynone, the synthesis of annulated six-membered rings is also feasible.

One-Pot Synthesis of a bis-Pocket Corrole through a 14-fold Bromination Reaction

DOE PAGES

Norheim, Hans-Kristian; Schneider, Christian; Gagnon, Kevin J.; ...

2017-02-14

For a one-pot protocol, effecting 14-fold bromination with elemental bromine, has afforded copper β-octabromo-meso-tris(2,6-dibromo-3,5-dimethoxyphenyl)corrole, a new bis-pocket metallocorrole. The Cu complex underwent smooth demetalation under reductive conditions, affording the free corrole ligand, which in turn could be readily complexed to Mn III and Au III. Finally, a single-crystal X-ray structure was obtained for the MnIII complex.

One-pot synthesis of hypervalent iodine reagents for electrophilic trifluoromethylation.

PubMed

Matoušek, Václav; Pietrasiak, Ewa; Schwenk, Rino; Togni, Antonio

2013-07-05

Simplified syntheses suited for large scale preparations of the two hypervalent iodine reagents 1 and 2 for electrophilic trifluoromethylation are reported. In both cases, the stoichiometric oxidants sodium metaperiodate and tert-butyl hypochlorite have been replaced by trichloroisocyanuric acid. Reagent 1 is accessible in a one-pot procedure from 2-iodobenzoic acid in 72% yield. Reagent 2 was prepared via fluoroiodane 11 in a considerably shorter reaction time and with no need of an accurate temperature control.

One-pot, two-step desymmetrization of symmetrical benzils catalyzed by the methylsulfinyl (dimsyl) anion.

PubMed

Ragno, Daniele; Bortolini, Olga; Giovannini, Pier Paolo; Massi, Alessandro; Pacifico, Salvatore; Zaghi, Anna

2014-08-14

An operationally simple one-pot, two-step procedure for the desymmetrization of benzils is herein described. This consists in the chemoselective cross-benzoin reaction of symmetrical benzils with aromatic aldehydes catalyzed by the methyl sulfinyl (dimsyl) anion, followed by microwave-assisted oxidation of the resulting benzoylated benzoins with nitrate, avoiding the costly isolation procedure. Both electron-withdrawing and electron-donating substituents may be accommodated on the aromatic rings of the final unsymmetrical benzil.

One-pot fabrication of high-quality InP/ZnS (core/shell) quantum dots and their application to cellular imaging.

PubMed

Hussain, Sahid; Won, Nayoun; Nam, Jutaek; Bang, Jiwon; Chung, Hyokyun; Kim, Sungjee

2009-07-13

True colors: High-quality InP and InP/ZnS quantum dots (QDs) are obtained by means of a simple one-pot method in the presence of polyethylene glycol (PEG). Rapid and size-controlled reactions lead to highly crystalline and nearly monodisperse QDs at relatively low temperatures. The particles emit from cyan blue to far-red, and are successfully used in cellular imaging (see figure).

A One-Pot Synthesis of m-Terphenyls: A Guided Exploration of Reaction Chemistry, Chromatography, and Spectroscopy. A Miniproject for the Advanced Organic Chemistry Laboratory

NASA Astrophysics Data System (ADS)

Anam, Kishorekumar T.; Curtis, Michael P.; Irfan, Muhammad J.; Johnson, Michael P.; Royer, Andrew P.; Shahmohammadi, Kianor; Vinod, Thottumkara K.

2002-05-01

This four-week project-based laboratory exercise, developed for advanced organic chemistry students, involves a one-pot synthesis of m-terphenyls. Chemistry of aryl diazonium salts and Grignard reagents and reactivity of aryne intermediates toward nucleophilic reagents form the reaction chemistry basis for the project. The project exposes students to a number of important laboratory techniques (thin-layer chromatography, gas chromatography-mass spectrometry, and column chromatography) for monitoring reaction progress and product isolation. A variety of spectroscopic techniques, including IR, 1H NMR, 13C NMR, and attached proton test are used for product characterization. Students are also introduced to a useful empirical relationship to help predict (with considerable accuracy) the 13C chemical shift values of carbon atoms of substituted benzenes.

Synthesis of β-Peptide Standards for Use in Model Prebiotic Reactions

NASA Astrophysics Data System (ADS)

Forsythe, Jay G.; English, Sloane L.; Simoneaux, Rachel E.; Weber, Arthur L.

2018-05-01

A one-pot method was developed for the preparation of a series of β-alanine standards of moderate size (2 to ≥12 residues) for studies concerning the prebiotic origins of peptides. The one-pot synthesis involved two sequential reactions: (1) dry-down self-condensation of β-alanine methyl ester, yielding β-alanine peptide methyl ester oligomers, and (2) subsequent hydrolysis of β-alanine peptide methyl ester oligomers, producing a series of β-alanine peptide standards. These standards were then spiked into a model prebiotic product mixture to confirm by HPLC the formation of β-alanine peptides under plausible reaction conditions. The simplicity of this approach suggests it can be used to prepare a variety of β-peptide standards for investigating differences between α- and β-peptides in the context of prebiotic chemistry.

Stereodivergent synthesis with a programmable molecular machine

NASA Astrophysics Data System (ADS)

Kassem, Salma; Lee, Alan T. L.; Leigh, David A.; Marcos, Vanesa; Palmer, Leoni I.; Pisano, Simone

2017-09-01

It has been convincingly argued that molecular machines that manipulate individual atoms, or highly reactive clusters of atoms, with Ångström precision are unlikely to be realized. However, biological molecular machines routinely position rather less reactive substrates in order to direct chemical reaction sequences, from sequence-specific synthesis by the ribosome to polyketide synthases, where tethered molecules are passed from active site to active site in multi-enzyme complexes. Artificial molecular machines have been developed for tasks that include sequence-specific oligomer synthesis and the switching of product chirality, a photo-responsive host molecule has been described that is able to mechanically twist a bound molecular guest, and molecular fragments have been selectively transported in either direction between sites on a molecular platform through a ratchet mechanism. Here we detail an artificial molecular machine that moves a substrate between different activating sites to achieve different product outcomes from chemical synthesis. This molecular robot can be programmed to stereoselectively produce, in a sequential one-pot operation, an excess of any one of four possible diastereoisomers from the addition of a thiol and an alkene to an α,β-unsaturated aldehyde in a tandem reaction process. The stereodivergent synthesis includes diastereoisomers that cannot be selectively synthesized through conventional iminium-enamine organocatalysis. We anticipate that future generations of programmable molecular machines may have significant roles in chemical synthesis and molecular manufacturing.

Orthogonal protection of saccharide polyols through solvent-free one-pot sequences based on regioselective silylations

PubMed Central

Traboni, Serena; Bedini, Emiliano

2016-01-01

tert-Butyldimethylsilyl (TBDMS) and tert-butyldiphenylsilyl (TBDPS) are alcohol protecting groups widely employed in organic synthesis in view of their compatibility with a wide range of conditions. Their regioselective installation on polyols generally requires lengthy reactions and the use of high boiling solvents. In the first part of this paper we demonstrate that regioselective silylation of sugar polyols can be conducted in short times with the requisite silyl chloride and a very limited excess of pyridine (2–3 equivalents). Under these conditions, that can be regarded as solvent-free conditions in view of the insolubility of the polyol substrates, the reactions are faster than in most examples reported in the literature, and can even be further accelerated with a catalytic amount of tetrabutylammonium bromide (TBAB). The strategy proved also useful for either the selective TBDMS protection of secondary alcohols or the fast per-O-trimethylsilylation of saccharide polyols. In the second part of the paper the scope of the silylation approach was significantly extended with the development of unprecedented “one-pot” and “solvent-free” sequences allowing the regioselective silylation/alkylation (or the reverse sequence) of saccharide polyols in short times. The developed methodologies represent a very useful and experimentally simple tool for the straightforward access to saccharide building-blocks useful in organic synthesis. PMID:28144345

Synthesis of novel heterocycles through reaction of indolin-2-one derivatives with active methylene and amino reagents.

PubMed

Abdel-Latif, F F; Ahmed, E K; Mekheimer, R; Mashaly, M M

1997-10-01

Several new spiro compounds were synthesized via one-pot ternary condensation of isatin, malononitrile and each of thiobarbituric acid, barbituric acid, 3-methyl-pyrazolin-5-one, 1-phenyl-3-methyl-pyrazolin-5-one, acetylacetone, benzoylacetone, ethyl acetoacetate, phenacyl cyanide or ethyl-cyanoacetate dimer. Structures and reaction mechanism were reported and supported via a second synthetic route.

One-pot tandem Ugi-4CR/S(N)Ar approach to highly functionalized quino[2,3-b][1,5]benzoxazepines.

PubMed

Ghandi, Mehdi; Zarezadeh, Nahid; Abbasi, Alireza

2016-05-01

We have developed a convenient and facile method for the synthesis of functionalized diverse quino[2,3-b][1,5]benzoxazepines. These new compounds were synthesized through a one-pot sequential Ugi-4CR/base-free intramolecular aromatic nucleophilic substitution (S(N)Ar) reaction in moderate to good yields from readily available starting materials. Structural confirmation of the products is confirmed by analytical data and X-ray crystallography.

Efficient one-pot synthesis of indol-3-yl-glycines via uncatalyzed Friedel-Crafts reaction in water.

PubMed

Ghandi, Mehdi; Taheri, Abuzar

2009-03-05

The three component reaction of primary aliphatic amines, glyoxalic acid and indole or N-methylindole in water at ambient temperature affords indol-3-yl or N-methylindol-3-yl-glycine in almost quantitative yields.

Synthesis of isoxazolo[5,4-b]pyridines by microwave-assisted multi-component reactions in water.

PubMed

Tu, Shu-Jiang; Zhang, Xiao-Hong; Han, Zheng-Guo; Cao, Xu-Dong; Wu, Shan-Shan; Yan, Shu; Hao, Wen-Juan; Zhang, Ge; Ma, Ning

2009-01-01

A series of new polycyclic-fused isoxazolo[5,4-b]pyridines were obtained by a one-pot tandem reaction under microwave irradiation in water. Without any use of additional reagent or catalyst, the synthetic protocol represents a green one and makes this methodology suitable for library synthesis in drug discovery efforts.

A new synthetic approach to functionalize pyrimido[4,5-b]quinoline-2,4(1H,3H)-diones via a three-component one-pot reaction.

PubMed

Aknin, Karen; Desbène-Finck, Stéphanie; Helissey, Philippe; Giorgi-Renault, Sylviane

2010-02-01

Functionalized pyrimido[4,5-b]quinoline-2,4 (1H,3H)-diones were synthesized by a three-component one-pot reaction involving barbituric acid, aldehydes, and anilines. The use of commercially available anilines allowed the facile syntheses of pyrimido[4,5-b]quinolinediones substituted in all the positions on the benzene ring with electron donor or electron withdrawing groups. This straightforward method circumvents the preparation of unstable substituted 2-aminobenzaldehydes that limits the scope of previously described syntheses. Furthermore, access to the 5-substituted derivatives is now also possible starting from aliphatic or aromatic aldehydes. Our strategy and methodology offer significant and practical improvements over other methodologies.

Synthesis of 2-Amino-3-hydroxy-3H-indoles via Palladium-Catalyzed One-Pot Reaction of Isonitriles, Oxygen, and N-Tosylhydrazones Derived from 2-Acylanilines.

PubMed

Chu, Haoke; Dai, Qiang; Jiang, Yan; Cheng, Jiang

2017-08-04

A cyanide-free one-pot procedure was developed to access 2-amino-3-hydroxy-3H-indoles, which involved: (1) in situ formation of ketenimines by the reaction of N'-(1-(2-aminophenyl)ethylidene)-p-tosylhydrazones with isonitriles; (2) the intramolecular nucleophilic attack of ketenimines by the amino in phenyl furnishing the ring closure leading to 2-aminoindoles; (3) the oxidation of 2-aminoindoles by O 2 leading to 2-amino-3-hydroxy-3H-indoles. This strategy represents not only a key compliment to the sporadic synthetic methods toward 2-amino-3-hydroxy-3H-indoles but also progress in N-tosylhydrazone, isonitrile, and ketenimine chemistry.

One-Pot Amide Bond Formation from Aldehydes and Amines via a Photoorganocatalytic Activation of Aldehydes.

PubMed

Papadopoulos, Giorgos N; Kokotos, Christoforos G

2016-08-19

A mild, one-pot, and environmentally friendly synthesis of amides from aldehydes and amines is described. Initially, a photoorganocatalytic reaction of aldehydes with di-isopropyl azodicarboxylate leads to an intermediate carbonyl imide, which can react with a variety of amines to afford the desired amides. The initial visible light-mediated activation of a variety of monosubstituted or disubstituted aldehydes is usually fast, occurring in a few hours. Following the photocatalytic reaction, addition of the primary amine at room temperature or the secondary amine at elevated temperatures leads to the corresponding amide from moderate to excellent yields without epimerization. This methodology was applied in the synthesis of Moclobemide, a drug against depression and social anxiety.

ZnO nanoparticles as an efficient, heterogeneous, reusable, and ecofriendly catalyst for four-component one-pot green synthesis of pyranopyrazole derivatives in water.

PubMed

Sachdeva, Harshita; Saroj, Rekha

2013-01-01

An extremely efficient catalytic protocol for the synthesis of a series of pyranopyrazole derivatives developed in a one-pot four-component approach in the presence of ZnO nanoparticles as heterogeneous catalyst using water as a green solvent is reported. Greenness of the process is well instituted as water is exploited both as reaction media and medium for synthesis of catalyst. The ZnO nanoparticles exhibited excellent catalytic activity, and the proposed methodology is capable of providing the desired products in good yield (85-90%) and short reaction time. After reaction course, ZnO nanoparticles can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. All the synthesized compounds have been characterized on the basis of elemental analysis, IR, ¹H NMR, and ¹³C NMR spectral studies.

Stereodivergent Mannich reaction of bis(trimethylsilyl)ketene acetals with N-tert-butanesulfinyl imines by Lewis acid or Lewis base activation, a one-pot protocol to obtain chiral β-amino acids.

PubMed

Cantú-Reyes, Margarita; Alvarado-Beltrán, Isabel; Ballinas-Indilí, Ricardo; Álvarez-Toledano, Cecilio; Hernández-Rodríguez, Marcos

2017-09-20

We report a one-pot synthesis of chiral β 2,2,3 -amino acids by the Mannich addition of bistrimethylsilyl ketene acetals to N-tert-butanesulfinyl imines followed by the removal of the chiral auxiliary. The synthesis and isolation of pure β-amino acid hydrochlorides were conducted under mild conditions, without strong bases and this method is operationally simple. The stereoselective reaction was promoted by two different activation methods that lead to different stereoisomers: (1) Lewis Acid (LA) catalysis with boron trifluoride diethyl etherate and (2) Lewis Base (LB) catalysis with tetrabutylammonium difluorotriphenylsilicate. The reaction presented good diastereoselectivity with LB activation and moderate to good dr with LA catalysis. The exceptions in both protocols were imines with electron donating groups in the aromatic ring.

Microwave-Assisted Organic Synthesis Using Benign Reaction Medium and Reagents

EPA Science Inventory

Account of chemical reactions expedited by microwave (MW) exposure of neat reactants for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermediates via enamines or using hypervalent iodine reagents will be described that can be adapted for ...

A stereoselective synthesis of (+)-physoperuvine using a tandem aza-Claisen rearrangement and ring closing metathesis reaction.

PubMed

Zaed, Ahmed M; Swift, Michael D; Sutherland, Andrew

2009-07-07

A stereoselective synthesis of (+)-physoperuvine, a tropane alkaloid from Physalis peruviana Linne has been developed using a one-pot tandem aza-Claisen rearrangement and ring closing metathesis reaction to form the key amino-substituted cycloheptene ring.

C–C Cross-Coupling Reactions of O6-Alkyl-2-Haloinosine Derivatives and a One-Pot Cross-Coupling/O6-Deprotection Procedure

PubMed Central

Gurram, Venkateshwarlu; Pottabathini, Narender; Garlapati, Ramesh; Chaudhary, Avinash B.; Patro, Balaram; Lakshman, Mahesh K.

2012-01-01

Reaction conditions for the C–C cross-coupling of O6-alkyl-2-bromo- and 2-chloroinosine derivatives with aryl-, hetaryl-, and alkylboronic acids were studied. Optimization experiments with silyl-protected 2-bromo-O6-methylinosine led to the identification of [PdCl2(dcpf)]/K3PO4 in 1,4-dioxane as the best condition for these reactions (dcpf = 1,1’-bis(dicyclohexylphosphino)ferrocene). Attempted O6-demethylation, as well as the replacement of the C-6 methoxy group by amines, was unsuccessful, which led to the consideration of Pd-cleavable groups such that C–C cross-coupling and O6-deprotection could be accomplished in a single step. Thus, inosine 2-chloro-O6-allylinosine was chosen as the substrate and, after re-evaluation of the cross-coupling conditions with 2-chloro-O6-methylinosine as a model substrate, one-step C–C cross-coupling/deprotection reactions were performed with the O6-allyl analogue. These reactions are the first such examples of a one-pot procedure for the modification and deprotection of purine nucleosides under C–C cross-coupling conditions. PMID:22570232

Total synthesis of mycobacterial arabinogalactan containing 92 monosaccharide units

NASA Astrophysics Data System (ADS)

Wu, Yong; Xiong, De-Cai; Chen, Si-Cong; Wang, Yong-Shi; Ye, Xin-Shan

2017-03-01

Carbohydrates are diverse bio-macromolecules with highly complex structures that are involved in numerous biological processes. Well-defined carbohydrates obtained by chemical synthesis are essential to the understanding of their functions. However, synthesis of carbohydrates is greatly hampered by its insufficient efficiency. So far, assembly of long carbohydrate chains remains one of the most challenging tasks for synthetic chemists. Here we describe a highly efficient assembly of a 92-mer polysaccharide by the preactivation-based one-pot glycosylation protocol. Several linear and branched oligosaccharide/polysaccharide fragments ranging from 5-mer to 31-mer in length have been rapidly constructed in one-pot manner, which enables the first total synthesis of a biologically important mycobacterial arabinogalactan through a highly convergent [31+31+30] coupling reaction. Our results show that the preactivation-based one-pot glycosylation protocol may provide access to the construction of long and complicated carbohydrate chains.

A versatile platform for precise synthesis of asymmetric molecular brush in one shot.

PubMed

Xu, Binbin; Feng, Chun; Huang, Xiaoyu

2017-08-24

Asymmetric molecular brushes emerge as a unique class of nanostructured polymers, while their versatile synthesis keeps a challenge for chemists. Here we show the synthesis of well-defined asymmetric molecular double-brushes comprising two different side chains linked to the same repeat unit along the backbone by one-pot concurrent atom transfer radical polymerization (ATRP) and Cu-catalyzed azide/alkyne cycloaddition (CuAAC) reaction. The double-brushes are based on a poly(Br-acrylate-alkyne) homopolymer possessing an alkynyl for CuAAC reaction and a 2-bromopropionate initiating group for ATRP in each repeat unit. The versatility of this one-shot approach is demonstrated by CuAAC reaction of alkynyl/poly(ethylene oxide)-N 3 and ATRP of various monomers. We also show the quantitative conversion of pentafluorophenyl ester groups to amide groups in side chains, allowing for the further fabrication of diverse building blocks. This work provides a versatile platform for facile synthesis of Janus-type double-brushes with structural and functional control, in a minimum number of reactions.Producing well-defined polymer compositions and structures facilitates their use in many different applications. Here the authors show the synthesis of well-defined asymmetric double-brushes by a one-pot concurrent atom transfer radical polymerization and Cu-catalyzed Click reaction.

One-pot synthesis of pyrrole-2-carboxylates and -carboxamides via an electrocyclization/oxidation sequence.

PubMed

Imbri, Dennis; Netz, Natalie; Kucukdisli, Murat; Kammer, Lisa Marie; Jung, Philipp; Kretzschmann, Annika; Opatz, Till

2014-12-05

An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.

One-Pot Conversion of Epoxidized Soybean Oil (ESO) into Soy-Based Polyurethanes by MoCl₂O₂ Catalysis.

PubMed

Pantone, Vincenzo; Annese, Cosimo; Fusco, Caterina; Fini, Paola; Nacci, Angelo; Russo, Antonella; D'Accolti, Lucia

2017-02-21

An innovative and eco-friendly one-pot synthesis of bio-based polyurethanes is proposed via the epoxy-ring opening of epoxidized soybean oil (ESO) with methanol, followed by the reaction of methoxy bio-polyols intermediates with 2,6-tolyl-diisocyanate (TDI). Both synthetic steps, methanolysis and polyurethane linkage formation, are promoted by a unique catalyst, molybdenum(VI) dichloride dioxide (MoCl₂O₂), which makes this procedure an efficient, cost-effective, and environmentally safer method amenable to industrial scale-up.

One-pot Diels–Alder cycloaddition/gold(I)-catalyzed 6-endo-dig cyclization for the synthesis of the complex bicyclo[3.3.1]alkenone framework

PubMed Central

Sow, Boubacar; Bellavance, Gabriel; Barabé, Francis

2011-01-01

Summary The rapid synthesis of bicyclo[m.n.1]alkanone cores possessing quaternary carbon centers adjacent to a bridged ketone represents a significant synthetic challenge. This type of architectural feature is embedded in various complex biologically active compounds such as hyperforin and garsubellin A. Herein, we report a highly diastereoselective one-pot Diels–Alder reaction/Au(I)-catalyzed carbocyclization to generate bicyclo[3.3.1]alkanones in yields ranging from 48–93%. PMID:21915201

A Highly Stereocontrolled, One-Pot Approach toward Pyrrolobenzoxazinones and Pyrroloquinazolinones through a Lewis Acid-Catalyzed [3 + 2]-Cycloannulation Process.

PubMed

Boomhoff, Michael; Ukis, Rostyslav; Schneider, Christoph

2015-08-21

We report herein a stereocontrolled [3 + 2]-cycloheteroannulation of bis-silyl dienediolate 1 with 2-aminobenzoic acid- and 2-aminobenzamide-derived imines to furnish highly substituted pyrrolo[1,2-a]benzoxazinones 3 and pyrrolo[1,2-a]quinazolinones 4, respectively, in good overall yields. This one-pot process rapidly generates molecular complexity and comprises a Lewis acid-catalyzed, vinylogous Mannich reaction of 1 followed by an intramolecular N,O-acetal- and N,N-aminal formation, respectively, which proceeds with good to excellent stereocontrol.

Access to unusual polycyclic spiro-enones from 2,2'-bis(allyloxy)-1,1'-binaphthyls using Grubbs' catalysts: an unprecedented one-pot RCM/Claisen sequence.

PubMed

Piedra, Estefanía; Francos, Javier; Nebra, Noel; Suárez, Francisco J; Díez, Josefina; Cadierno, Victorio

2011-07-21

Treatment of 2,2'-bis(allyloxy)-1,1'-binaphthyls with the first-generation Grubbs' carbene under MW-irradiation results in the formation of new polycyclic spiro-enones through an unprecedented RCM/Claisen sequence.

Radioactive Phosphorylation of Alcohols to Monitor Biocatalytic Diels-Alder Reactions

PubMed Central

Nierth, Alexander; Jäschke, Andres

2011-01-01

Nature has efficiently adopted phosphorylation for numerous biological key processes, spanning from cell signaling to energy storage and transmission. For the bioorganic chemist the number of possible ways to attach a single phosphate for radioactive labeling is surprisingly small. Here we describe a very simple and fast one-pot synthesis to phosphorylate an alcohol with phosphoric acid using trichloroacetonitrile as activating agent. Using this procedure, we efficiently attached the radioactive phosphorus isotope 32P to an anthracene diene, which is a substrate for the Diels-Alderase ribozyme—an RNA sequence that catalyzes the eponymous reaction. We used the 32P-substrate for the measurement of RNA-catalyzed reaction kinetics of several dye-labeled ribozyme variants for which precise optical activity determination (UV/vis, fluorescence) failed due to interference of the attached dyes. The reaction kinetics were analyzed by thin-layer chromatographic separation of the 32P-labeled reaction components and densitometric analysis of the substrate and product radioactivities, thereby allowing iterative optimization of the dye positions for future single-molecule studies. The phosphorylation strategy with trichloroacetonitrile may be applicable for labeling numerous other compounds that contain alcoholic hydroxyl groups. PMID:21731729

A highly active and magnetically retrievable nanoferrite-DOPA-copper catalyst for the coupling of thiophenols with aryl halides

EPA Science Inventory

Diaryl sulfides were synthesized using magnetically recoverable heterogeneous Cu catalyst via one-pot multi component reaction using MW irradiation; the use of isopropanol as a benign reaction medium, easy recovery of the catalyst using an external magnet, efficient recycling...

A facile one-pot solvothermal method for synthesis of magnetically recoverable Pd-Fe3O4 hybrid nanocatalysts for the Mizoroki-Heck reaction

NASA Astrophysics Data System (ADS)

Zhen, Fangchen; Ran, Maofei; Chu, Wei; Jiang, Chengfa; Sun, Wenjing

2018-03-01

Pd-Fe3O4 hybrid nanostructures were prepared using a simple one-pot hydrothermal method. The prepared materials were characterized by Fourier transform-infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, inductively coupled plasma, N2 adsorption-desorption, and vibrating sample magnetometry. This self-assembled nanosystem acted as an efficient magnetically recyclable noble metal-based multi-functional nanocatalyst. It showed excellent catalytic activity and stability for the Heck reaction of iodobenzene and styrene under mild conditions. The methods used to prepare the Pd-Fe3O4 catalysts were simple and low-cost, which will be useful for the large-scale development and application of a magnetically recoverable Pd catalyst.

Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes

PubMed Central

Engelen, Bernward; Panthöfer, Martin; Deiseroth, Hans-Jörg; Schlirf, Jens

2016-01-01

Summary A one-pot transformation, which involves the reaction of ketones with aldehydes in the presence of metal halides to furnish tetrahydro-2H-pyran-2,4-diols in a highly diastereoselective manner, is investigated thoroughly by experiments and computations. The reaction was also successfully implemented on a flow micro reactor system. PMID:27340472

A rapid, one-pot, microwave-influenced synthesis of spiro-2,5-diketopiperazines via a cascade Ugi/6-exo-trig aza-Michael reaction.

PubMed

Santra, Soumava; Andreana, Peter R

2011-04-01

A rapid, cascade reaction process has been developed to access biologically validated spiro-2,5-diketopiperazines. The facile and environmentally benign method capitalizes on commercially available starting reagents for a sequential Ugi/6-exo-trig aza-Michael reaction, water as a solvent, and microwave irradiation without any extraneous additives.

A Research-Based Undergraduate Organic Laboratory Project: Investigation of a One-Pot, Multicomponent, Environmentally Friendly Prins-Friedel-Crafts-Type Reaction

ERIC Educational Resources Information Center

Dintzner, Matthew R.; Maresh, Justin J.; Kinzie, Charles R.; Arena, Anthony F.; Speltz, Thomas

2012-01-01

Students in the undergraduate organic laboratory synthesize tetrahydro-2-(4-nitrophenyl)-4-phenyl-2"H"-pyran via the Montmorillonite K10 clay-catalyzed reaction of p-nitrobenzaldehye with methanol, 3-buten-1-ol, and benzene. The synthesis comprises an environmentally friendly tandem Prins-Friedel-Crafts-type multicomponent reaction (MCR) and sets…

Highly efficient one-pot/one-step synthesis of multiblock copolymers from three-component polymerization of carbon dioxide, epoxide and lactone.

PubMed

Li, Yang; Hong, Jiali; Wei, Renjian; Zhang, Yingying; Tong, Zaizai; Zhang, Xinghong; Du, Binyang; Xu, Junting; Fan, Zhiqiang

2015-02-01

It is a long-standing challenge to combine mixed monomers into multiblock copolymer (MBC) in a one-pot/one-step polymerization manner. We report the first example of MBC with biodegradable polycarbonate and polyester blocks that were synthesized from highly efficient one-pot/one-step polymerization of cyclohexene oxide (CHO), CO 2 and ε-caprolactone (ε-CL) in the presence of zinc-cobalt double metal cyanide complex and stannous octoate. In this protocol, two cross-chain exchange reactions (CCER) occurred at dual catalysts respectively and connected two independent chain propagation procedures ( i.e. , polycarbonate formation and polyester formation) simultaneously in a block-by-block manner, affording MBC without tapering structure. The multiblock structure of MBC was determined by the rate ratio of CCER to the two chain propagations and could be simply tuned by various kinetic factors. This protocol is also of significance due to partial utilization of renewable CO 2 and improved mechanical properties of the resultant MBC.

An Expedient Regio- and Diastereoselective Synthesis of Hybrid Frameworks with Embedded Spiro[9,10]dihydroanthracene [9,3']-pyrrolidine and Spiro[oxindole-3,2'-pyrrolidine] Motifs via an Ionic Liquid-Mediated Multicomponent Reaction.

PubMed

Arumugam, Natarajan; Almansour, Abdulrahman I; Kumar, Raju Suresh; Menéndez, J Carlos; Sultan, Mujeeb A; Karama, Usama; Ghabbour, Hazem A; Fun, Hoong-Kun

2015-09-03

A series of hitherto unreported anthracene-embedded dispirooxindoles has been synthesized via a one-pot three-component 1,3-dipolar cycloaddition reaction of an azomethine ylide, generated in situ from the reaction of isatin and sarcosine to 10-benzylideneanthracen-9(10H)-one as a dipolarophile in 1-butyl-3-methylimidazolium bromide([bmim]Br), an ionic liquid. This reaction proceeded regio- and diastereoselectively, in good to excellent yields.

One-dimensional growth of hexagonal rods of metastable h-MoO3 using one-pot, rapid and environmentally benign supercritical fluid processing

NASA Astrophysics Data System (ADS)

Thangasamy, Pitchai; Shanmugapriya, Vadivel; Sathish, Marappan

2018-05-01

A facile and one-pot supercritical fluid method was demonstrated for the synthesis of phase pure crystalline h-MoO3 microrods within a short reaction time of 5 min at 400 °C. The formation of h-MoO3 was confirmed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and Raman spectroscopic analysis. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) images clearly revealed the formation of hexagonal h-MoO3 rods. Further, photoluminescence emission peaks corresponding to band to band transition was observed in the h-MoO3 microrods. It was observed that when increasing the reaction time from 5 min to 30 min at 400 °C, h-MoO3 microrods undergoes disintegration to α-MoO3 thin nanorods. Interestingly, h-MoO3 microrods were also formed in a reaction time of 30 min at 400 °C when reducing the volume of nitric acid from 1 mL to ∼0.5 mL. The short reaction time and simple synthetic strategy makes this method can be suitable for the synthesis of other semiconductor nanomaterials for diverse applications.

Iodine-catalyzed Csp3-H functionalization of methylhetarenes: One-pot synthesis and cytotoxic evaluation of heteroarenyl-benzimidazoles and benzothiazole.

PubMed

Baig, Mirza Feroz; Shaik, Siddiq Pasha; Nayak, V Lakshma; Alarifi, Abdullah; Kamal, Ahmed

2017-09-01

An efficient one-pot synthetic procedure has been developed for the preparation of heteroarenyl-benzimidazoles via oxidative C sp3 -H functionalization with o-phenylenediamine using I 2 -DMSO in open air from easily available starting materials. Based on a logical plan a spectrum of multi fundamental reactions like iodination, Kornblum oxidation and amination were brought into one-pot. By using this simple method a library of heteroarenyl-benzimidazoles derivatives (3a-t and 5a-g) and heteroarenyl-benzothiazole (3u) have been synthesized in good to excellent yield and screened for their cytotoxicity against a group of four human cancer cell lines. Among them 3h, 3q and 5b showed significant cytotoxic activities with an IC 50 of 1.69, 1.62 and 2.81µM respectively against lung cancer (A549) cell line. Copyright © 2017 Elsevier Ltd. All rights reserved.

Catalytic asymmetric epoxidation of alpha,beta-unsaturated amides: efficient synthesis of beta-aryl alpha-hydroxy amides using a one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process.

PubMed

Nemoto, Tetsuhiro; Kakei, Hiroyuki; Gnanadesikan, Vijay; Tosaki, Shin-Ya; Ohshima, Takashi; Shibasaki, Masakatsu

2002-12-11

The catalytic asymmetric epoxidation of alpha,beta-unsaturated amides using Sm-BINOL-Ph3As=O complex was succeeded. Using 5-10 mol % of the asymmetric catalyst, a variety of amides were epoxidized efficiently, yielding the corresponding alpha,beta-epoxy amides in up to 99% yield and in more than 99% ee. Moreover, the novel one-pot tandem process, one-pot tandem catalytic asymmetric epoxidation-Pd-catalyzed epoxide opening process, was developed. This method was successfully utilized for the efficient synthesis of beta-aryl alpha-hydroxy amides, including beta-aryllactyl-leucine methyl esters. Interestingly, it was found that beneficial modifications on the Pd catalyst were achieved by the constituents of the first epoxidation, producing a more suitable catalyst for the Pd-catalyzed epoxide opening reaction in terms of chemoselectivity.

Concise total syntheses of (+/-)-strychnine and (+/-)-akuammicine.

PubMed

Sirasani, Gopal; Paul, Tapas; Dougherty, William; Kassel, Scott; Andrade, Rodrigo B

2010-05-21

Concise total syntheses of Strychnos alkaloids strychnine (1) and akuammicine (2) have been realized in 13 and 6 operations, respectively. Key steps include (1) the vinylogous Mannich reaction; (2) a novel, sequential one-pot spirocyclization/intramolecular aza-Baylis-Hillman reaction; and (3) a Heck cyclization. The synthesis of 1 proceeds via the Wieland-Gumlich aldehyde (26).

Cu-catalyzed formal methylative and hydrogenative carboxylation of alkynes with carbon dioxide: efficient synthesis of α,β-unsaturated carboxylic acids.

PubMed

Takimoto, Masanori; Hou, Zhaomin

2013-08-19

The sequential hydroalumination or methylalumination of various alkynes catalyzed by different catalyst systems, such those based on Sc, Zr, and Ni complexes, and the subsequent carboxylation of the resulting alkenylaluminum species with CO2 catalyzed by an N-heterocyclic carbene (NHC)-copper catalyst have been examined in detail. The regio- and stereoselectivity of the overall reaction relied largely on the hydroalumination or methylalumination reactions, which significantly depended on the catalyst and alkyne substrates. The subsequent Cu-catalyzed carboxylation proceeded with retention of the stereoconfiguration of the alkenylaluminum species. All the reactions could be carried out in one-pot to afford efficiently a variety of α,β-unsaturated carboxylic acids with well-controlled configurations, which are difficult to construct by previously reported methods. This protocol could be practically useful and attractive because of its high regio- and stereoselectivity, simple one-pot reaction operation, and the use of CO2 as a starting material. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A One-Pot/Single-Analysis Approach to Substrate Scope Investigations Using Comprehensive Two-Dimensional Gas Chromatography (GC×GC).

PubMed

O'Neil, Gregory W; Nelson, Robert K; Wright, Alicia M; Reddy, Christopher M

2016-05-06

A representative substrate scope investigation for an enantioselective catalytic ketone-reduction has been performed as a single reaction on a mixture containing equimolar amounts of nine (9) prototypical compounds. The resulting analyte pool containing 18 potential products from nine different reactions could all be completely resolved in a single chromatographic injection using comprehensive two-dimensional gas chromatography (GC×GC) with time-of-flight mass spectrometry, allowing for simultaneous determination of percent conversion and enantiomeric excess for each substrate. The results obtained for an enantioselective iron-catalyzed asymmetric transfer hydrogenation using this one-pot/single-analysis approach were similar to those reported for the individualized reactions, demonstrating the utility of this strategy for streamlining substrate scope investigations. Moreover, for this particular catalyst, activity and selectivity were not greatly affected by the presence of other ketones or enantioenriched reduced products. This approach allows for faster and greener analyses that are central to new reaction development, as well as an opportunity to gain further insights into other established transformations.

Copper-Catalyzed Sulfonyl Azide-Alkyne Cycloaddition Reactions: Simultaneous Generation and Trapping of Copper-Triazoles and -Ketenimines for the Synthesis of Triazolopyrimidines.

PubMed

Nallagangula, Madhu; Namitharan, Kayambu

2017-07-07

First simultaneous generation and utilization of both copper-triazole and -ketenimine intermediates in copper-catalyzed sulfonyl azide-alkyne cycloaddition reactions is achieved for the one-pot synthesis of triazolopyrimidines via a novel copper-catalyzed multicomponent cascade of sulfonyl azides, alkynes, and azirines. Significantly, the reaction proceeds under very mild conditions in good yields.

C-C cross-coupling reactions of O6-alkyl-2-haloinosine derivatives and a one-pot cross-coupling/O6-deprotection procedure.

PubMed

Gurram, Venkateshwarlu; Pottabathini, Narender; Garlapati, Ramesh; Chaudhary, Avinash B; Patro, Balaram; Lakshman, Mahesh K

2012-08-01

Reaction conditions for the CC cross-coupling of O(6)-alkyl-2-bromo- and 2-chloroinosine derivatives with aryl-, hetaryl-, and alkylboronic acids were studied. Optimization experiments with silyl-protected 2-bromo-O(6)-methylinosine led to the identification of [PdCl(2)(dcpf)]/K(3)PO(4) in 1,4-dioxane as the best conditions for these reactions (dcpf=1,1'-bis(dicyclohexylphosphino)ferrocene). Attempted O(6)-demethylation, as well as the replacement of the C-6 methoxy group by amines, was unsuccessful, which led to the consideration of Pd-cleavable groups such that C-C cross-coupling and O(6)-deprotection could be accomplished in a single step. Thus, inosine 2-chloro-O(6)-allylinosine was chosen as the substrate and, after re-evaluation of the cross-coupling conditions with 2-chloro-O(6)-methylinosine as a model substrate, one-step C-C cross-coupling/deprotection reactions were performed with the O(6)-allyl analogue. These reactions are the first such examples of a one-pot procedure for the modification and deprotection of purine nucleosides under C-C cross-coupling conditions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New method to access hyperbranched polymers with uniform structure via one-pot polymerization of inimer in microemulsion.

PubMed

Min, Ke; Gao, Haifeng

2012-09-26

A facile approach is presented for successful synthesis of hyperbranched polymers with high molecular weight and uniform structure by a one-pot polymerization of an inimer in a microemulsion. The segregated space in the microemulsion confined the inimer polymerization and particularly the polymer-polymer reaction within discrete nanoparticles. At the end of polymerization, each nanoparticle contained one hyperbranched polymer that had thousands of inimer units and low polydispersity. The hyperbranched polymers were used as multifunctional macroinitiators for synthesis of "hyper-star" polymers. When a degradable inimer was applied, the hyper-stars showed fast degradation into linear polymer chains with low molecular weight.

Traceless β-mercaptan-assisted activation of valinyl benzimidazolinones in peptide ligations† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc04148a

PubMed Central

Wang, Yinglu; Han, Lin; Yuan, Ning; Wang, Hanxuan; Li, Hongxing; Liu, Jinrong; Chen, Huan

2018-01-01

Peptidyl thioesters or their surrogates with C-terminal β-branched hydrophobic amino acid residues usually exhibit poor reactivities in ligation reactions. Thus, activation using exogenous additives is required to ensure an acceptable reaction efficiency. Herein, we report a traceless ligation at Val-Xaa sites under mild thiol additive-free reaction conditions, whereby the introduction of β-mercaptan on the C-terminal valine residue effectively activates the otherwise unreactive N-acyl-benzimidazolinone (Nbz), and enables the use of a one-pot ligation–desulfurization strategy to generate the desired peptide products. The orthogonality between β-thiovaline-Nbz and a conventional alkyl thioester, as well as the convenient access to the former from readily available penicillamine, also allowed expedited assembly of the peptidic hormone β-LPH and hPTH analogues, based on a kinetically controlled one-pot three-segment ligation and desulfurization strategy. PMID:29675240

l-Glutamic acid assisted eco-friendly one-pot synthesis of sheet-assembled platinum-palladium alloy networks for methanol oxidation and oxygen reduction reactions.

PubMed

Shi, Ya-Cheng; Mei, Li-Ping; Wang, Ai-Jun; Yuan, Tao; Chen, Sai-Sai; Feng, Jiu-Ju

2017-10-15

In this work, bimetallic platinum-palladium sheet-assembled alloy networks (PtPd SAANs) were facilely synthesized by an eco-friendly one-pot aqueous approach under the guidance of l-glutamic acid at room temperature, without any additive, seed, toxic or organic solvent involved. l-Glutamic acid was served as the green shape-director and weak-stabilizing agent. A series of characterization techniques were employed to examine the morphology, structure and formation mechanism of the product. The architectures exhibited improved electrocatalytic activity and durable ability toward methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) in contrast with commercial Pt black and Pd black catalysts. This is ascribed to the unique structures of the obtained PtPd SAANs and the synergistic effects of the bimetals. These results demonstrate the potential application of the prepared catalyst in fuel cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Unsaturated C3,5,7,9-Monocarboxylic Acids by Aqueous, One-Pot Carbon Fixation: Possible Relevance for the Origin of Life

PubMed Central

Scheidler, Christopher; Sobotta, Jessica; Eisenreich, Wolfgang; Wächtershäuser, Günter; Huber, Claudia

2016-01-01

All scientific approaches to the origin of life share a common problem: a chemical path to lipids as main constituents of extant cellular enclosures. Here we show by isotope-controlled experiments that unsaturated C3,5,7,9-monocarboxylic acids form by one-pot reaction of acetylene (C2H2) and carbon monoxide (CO) in contact with nickel sulfide (NiS) in hot aqueous medium. The primary products are toto-olefinic monocarboxylic acids with CO-derived COOH groups undergoing subsequent stepwise hydrogenation with CO as reductant. In the resulting unsaturated monocarboxylic acids the double bonds are mainly centrally located with mainly trans-configuration. The reaction conditions are compatible with an origin of life in volcanic-hydrothermal sub-seafloor flow ducts. PMID:27283227

Room-temperature transition-metal-free one-pot synthesis of 3-aryl imidazo[1,2-a]pyridines via iodo-hemiaminal intermediate.

PubMed

Lee, Seul Ki; Park, Jin Kyoon

2015-04-03

A mild and efficient one-pot synthesis of 3-aryl imidazo[1,2-a]pyridines in up to 88% yield was developed. An adduct was formed after the simple mixing of 2-amino-4-methylpyridine, 2-phenylacetaldehyde, and N-iodosuccinimide in CH2Cl2, and the structure of the adduct was characterized by 2D NMR, IR, and high-resolution mass analysis. The adduct was readily cyclized by treatment with a saturated aqueous solution of NaHCO3. The reactions proceeded to completion after several hours at room temperature.

An Efficient, Eco-friendly and Sustainable One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Directly from Alcohols Catalyzed by Heteropolyanion-Based Ionic Liquids.

PubMed

Fu, Renzhong; Yang, Yang; Ma, Xudong; Sun, Yu; Li, Jin; Gao, Hang; Hu, Huaxing; Zeng, Xiaojun; Yi, Jun

2017-09-11

Efficient, eco-friendly and sustainable access to 3,4-dihydropyrimidin-2(1 H )-ones directly from alcohols under microwave and solvent-free conditions has been reported. The practical protocol involves heteropolyanion-based catalyzed oxidation of alcohols to aldehydes with NaNO₃ as the oxidant followed by cyclocondensation with dicarbonyl compounds and urea or thiourea in a two-step, one-pot manner. Compatibility with different functional groups, good to excellent yields and reusable catalysts are the main highlights. The utilization of alcohols instead of aldehydes is a valid and green alternative to the classical Biginelli reaction.

One-pot multienzyme (OPME) systems for chemoenzymatic synthesis of carbohydrates.

PubMed

Yu, Hai; Chen, Xi

2016-03-14

Glycosyltransferase-catalyzed enzymatic and chemoenzymatic syntheses are powerful approaches for the production of oligosaccharides, polysaccharides, glycoconjugates, and their derivatives. Enzymes involved in the biosynthesis of sugar nucleotide donors can be combined with glycosyltransferases in one pot for efficient production of the target glycans from simple monosaccharides and acceptors. The identification of enzymes involved in the salvage pathway of sugar nucleotide generation has greatly facilitated the development of simplified and efficient one-pot multienzyme (OPME) systems for synthesizing major glycan epitopes in mammalian glycomes. The applications of OPME methods are steadily gaining popularity mainly due to the increasing availability of wild-type and engineered enzymes. Substrate promiscuity of these enzymes and their mutants allows OPME synthesis of carbohydrates with naturally occurring post-glycosylational modifications (PGMs) and their non-natural derivatives using modified monosaccharides as precursors. The OPME systems can be applied in sequence for synthesizing complex carbohydrates. The sequence of the sequential OPME processes, the glycosyltransferase used, and the substrate specificities of the glycosyltransferases define the structures of the products. The OPME and sequential OPME strategies can be extended to diverse glycans in other glycomes when suitable enzymes with substrate promiscuity become available. This Perspective summarizes the work of the authors and collaborators on the development of glycosyltransferase-based OPME systems for carbohydrate synthesis. Future directions are also discussed.

One-Pot Approach to Organo-Phosphorus-Chalcogen Macrocycles Incorporating Double OP(S)SCn or OP(Se)SeCn Scaffolds: A Synthetic and Structural Study.

PubMed

Hua, Guoxiong; Du, Junyi; Slawin, Alexandra M Z; Woollins, J Derek

2016-06-01

The development of new methodology for the preparation of functional macrocycles with practical applications is an important research area in macromolecular science. In this study, we report a new one-pot route for the synthesis of a series of macro-heterocycles by incorporating two phosphorus atoms and two chalcogen atoms and two oxygen atoms (double OP(S)SCn or OP(Se)SeCn scaffolds). The three-component condensation reactions of 2,4-diferrocenyl-1,3,2,4-diathiadiphosphetane 2,4-disulfide (FcLR, a ferrocene analogue of Lawesson's reagent) or 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (LR, Lawesson's reagent), or 2,4-diphenyl-1,3,2,4-diselenadiphosphetane 2,4-diselenide (WR, Woollins' reagent), disodium alkenyl-diols, and dihalogenated alkanes are performed, giving rise to soluble and air or moisture-stable macrocycles in good-to-excellent yields (up to 92 %). This is the first systemically preparative and readily scalable example of one-pot ring opening/ring extending reaction of three-components to prepare phosphorus-chalcogen containing macrocycles. We also provide a systematic crystallographic study. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemoselective synthesis of ketones and ketimines by addition of organometallic reagents to secondary amides

NASA Astrophysics Data System (ADS)

Bechara, William S.; Pelletier, Guillaume; Charette, André B.

2012-03-01

The development of efficient and selective transformations is crucial in synthetic chemistry as it opens new possibilities in the total synthesis of complex molecules. Applying such reactions to the synthesis of ketones is of great importance, as this motif serves as a synthetic handle for the elaboration of numerous organic functionalities. In this context, we report a general and chemoselective method based on an activation/addition sequence on secondary amides allowing the controlled isolation of structurally diverse ketones and ketimines. The generation of a highly electrophilic imidoyl triflate intermediate was found to be pivotal in the observed exceptional functional group tolerance, allowing the facile addition of readily available Grignard and diorganozinc reagents to amides, and avoiding commonly observed over-addition or reduction side reactions. The methodology has been applied to the formal synthesis of analogues of the antineoplastic agent Bexarotene and to the rapid and efficient synthesis of unsymmetrical diketones in a one-pot procedure.

Synthesis of aminocarbonyl N-acylhydrazones by a three-component reaction of isocyanides, hydrazonoyl chlorides, and carboxylic acids.

PubMed

Giustiniano, Mariateresa; Meneghetti, Fiorella; Mercalli, Valentina; Varese, Monica; Giustiniano, Francesco; Novellino, Ettore; Tron, Gian Cesare

2014-10-17

A novel one-pot multicomponent synthesis of α-aminocarbonyl N-acylhydrazones starting from readily available hydrazonoyl chlorides, isocyanides, and carboxylic acids is reported. The strategy exploits the ability of the carboxylic acid as a third component to suppress all competing reactions between nitrile imines and isocyanides, channeling the course of the reaction toward the formation of this novel class of compounds.

Synthesis and Evaluation of Cu/SAPO-34 Catalysts for NH3-SCR 2: Solid-state Ion Exchange and One-pot Synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Feng; Walter, Eric D.; Washton, Nancy M.

2015-01-01

Cu-SAPO-34 catalysts are synthesized using two methods: solid-state ion exchange (SSIE) and one-pot synthesis. SSIE is conducted by calcining SAPO-34/CuO mixtures at elevated temperatures. For the one-pot synthesis method, Cu-containing chemicals (CuO and CuSO4) are added during gel preparation. A high-temperature calcination step is also needed for this method. Catalysts are characterized with surface area/pore volume measurements, temperature programmed reduction (TPR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies, and scanning electron microscopy (SEM). Catalytic properties are examined using standard ammonia selective catalytic reduction (NH3-SCR) and ammonia oxidation reactions. In Cu-SAPO-34 samples formed using SSIE, Cu presents bothmore » as isolated Cu2+ ions and unreacted CuO. The former is highly active and selective in NH3-SCR, while the latter catalyzes a side reaction; notably, the non-selective oxidation of NH3 above 350 ºC. Using the one-pot method followed by a high-temperature aging treatment, it is possible to form Cu SAPO-34 samples with predominately isolated Cu2+ ions at low Cu loadings. However at much higher Cu loadings, isolated Cu2+ ions that bind weakly with the CHA framework and CuO clusters also form. These Cu moieties are very active in catalyzing non-selective NH3 oxidation above 350 ºC. Low-temperature reaction kinetics indicate that Cu-SAPO-34 samples formed using SSIE have core-shell structures where Cu is enriched in the shell layers; while Cu is more evenly distributed within the one-pot samples. Reaction kinetics also suggest that at low temperatures, the local environment next to Cu2+ ion centers plays little role on the overall catalytic properties. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed at the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle under contract number DE-AC05-76RL01830. The authors also thank Shari Li (PNNL) for surface area/pore volume measurements, and Bruce W. Arey (PNNL) for SEM measurements. Discussions with Drs. A. Yezerets, K. Kamasamudram, J.H. Li, N. Currier and J.Y. Luo from Cummins, Inc. and H.Y. Chen and H. Hess from Johnson-Matthey are greatly appreciated.« less

One-pot non-enzymatic formation of firefly luciferin in a neutral buffer from p-benzoquinone and cysteine

PubMed Central

Kanie, Shusei; Nishikawa, Toshio; Ojika, Makoto; Oba, Yuichi

2016-01-01

Firefly luciferin, the substrate for the bioluminescence reaction of luminous beetles, possesses a benzothiazole ring, which is rare in nature. Here, we demonstrate a novel one-pot reaction to give firefly luciferin in a neutral buffer from p-benzoquinone and cysteine without any synthetic reagents or enzymes. The formation of firefly luciferin was low in yield in various neutral buffers, whereas it was inhibited or completely prevented in acidic or basic buffers, in organic solvents, or under a nitrogen atmosphere. Labelling analysis of the firefly luciferin using stable isotopic cysteines showed that the benzothiazole ring was formed via the decarboxylation and carbon-sulfur bond rearrangement of cysteine. These findings imply that the biosynthesis of firefly luciferin can be developed/evolved from the non-enzymatic production of firefly luciferin using common primary biosynthetic units, p-benzoquinone and cysteine. PMID:27098929

One-pot non-enzymatic formation of firefly luciferin in a neutral buffer from p-benzoquinone and cysteine.

PubMed

Kanie, Shusei; Nishikawa, Toshio; Ojika, Makoto; Oba, Yuichi

2016-04-21

Firefly luciferin, the substrate for the bioluminescence reaction of luminous beetles, possesses a benzothiazole ring, which is rare in nature. Here, we demonstrate a novel one-pot reaction to give firefly luciferin in a neutral buffer from p-benzoquinone and cysteine without any synthetic reagents or enzymes. The formation of firefly luciferin was low in yield in various neutral buffers, whereas it was inhibited or completely prevented in acidic or basic buffers, in organic solvents, or under a nitrogen atmosphere. Labelling analysis of the firefly luciferin using stable isotopic cysteines showed that the benzothiazole ring was formed via the decarboxylation and carbon-sulfur bond rearrangement of cysteine. These findings imply that the biosynthesis of firefly luciferin can be developed/evolved from the non-enzymatic production of firefly luciferin using common primary biosynthetic units, p-benzoquinone and cysteine.

One-pot low-temperature green synthesis of magnetic graphene nanocomposite for the selective reduction of nitrobenzene

NASA Astrophysics Data System (ADS)

Haridas, Vijayasree; Sugunan, Sankaran; Narayanan, Binitha N.

2018-06-01

In the present study, a green one-pot low-temperature method is adopted for the synthesis of a novel magnetic graphene nanocomposite catalyst. Graphene preparation is performed without employing any oxidizing agents or corrosive chemicals, under mild sonication in isopropyl alcohol - water mixture. Monolayered nanoplatelets of graphene are obtained in the green solvent mixture and the composite material is found to be ferromagnetic in nature, obvious from the vibrating sample magnetometric measurements. Fe in the nanocomposite exists in two different forms i.e., α-Fe2O3 and α-FeOOH, as evident from the material characterization results. The graphene nanocomposite is found to be highly efficient in the selective reduction of nitrobenzene to aniline under solvent free reaction conditions and magnetic separation of this fine nanomaterial from the reaction mixture is successfully carried out. The catalyst is efficiently reusable till five repeated cycles.

Synthesis of Polyheterocyclic Pyrrolo[3,4-b]pyridin-5-ones via a One-Pot (Ugi-3CR/aza Diels-Alder/N-acylation/aromatization/SN2) Process. A Suitable Alternative towards Novel Aza-Analogues of Falipamil.

PubMed

Zamudio-Medina, Angel; García-González, Ailyn N; Herrera-Carrillo, Genesis K; Zárate-Zárate, Daniel; Benavides-Macías, Adriana; Tamariz, Joaquín; Ibarra, Ilich A; Islas-Jácome, Alejandro; González-Zamora, Eduardo

2018-03-27

We describe the one-pot synthesis of twenty polyheterocyclic pyrrolo[3,4- b ]pyridin-5-ones via a cascade process (Ugi-3CR/aza Diels-Alder/ N -acylation/aromatization) in 20 to 95% overall yields, as well as four pharmacologically promising analogues via an improved cascade process (Ugi-3CR/aza Diels-Alder/ N -acylation/aromatization/S N 2): two piperazine-linked pyrrolo[3,4- b ]pyridin-5-ones in 33 and 34%, and a couple of Falipamil aza-analogues in 30 and 35% overall yields. It is worth highlighting the good substrate scope found, because final products are furnished with alkyl, aryl, and heterocyclic substituents. The use of chain-ring tautomerizable isocyanides (as key reagents for the Ugi-type three component reaction) allowed for a rapid and efficient assembly of the polysubstituted oxindoles, which were used in situ toward the complex products, conferring features like robustness, sustainability, and the one-pot approach to this synthetic methodology.

Multicomponent Reactions in Ligation and Bioconjugation Chemistry.

PubMed

Reguera, Leslie; Méndez, Yanira; Humpierre, Ana R; Valdés, Oscar; Rivera, Daniel G

2018-05-25

Multicomponent reactions (MCRs) encompass an exciting class of chemical transformations that have proven success in almost all fields of synthetic organic chemistry. These convergent procedures incorporate three or more reactants into a final product in one pot, thus combining high levels of complexity and diversity generation with low synthetic cost. Striking applications of these processes are found in heterocycle, peptidomimetic, and natural product syntheses. However, their potential in the preparation of large macro- and biomolecular constructs has been realized just recently. This Account describes the most relevant results of our group in the utilization of MCRs for ligation/conjugation of biomolecules along with significant contributions from other laboratories that validate the utility of this special class of bioconjugation process. Thus, MCRs have proven to be efficient in the ligation of lipids to peptides and oligosaccharides as well as the ligation of steroids, carbohydrates, and fluorescent and affinity tags to peptides and proteins. In the field of glycolipids, we highlight the power of isocyanide-based MCRs with the one-pot double lipidation of glycan fragments functionalized as either the carboxylic acid or amine. In peptide chemistry, the versatility of the multicomponent ligation strategy is demonstrated in both solution-phase lipidation protocols and solid-phase procedures enabling the simultaneous lipidation and biotinylation of peptides. In addition, we show that MCRs are powerful methods for synchronized lipidation/labeling and macrocyclization of peptides, thus accomplishing in one step what usually requires long sequences. In the realm of protein bioconjugation, MCRs have also proven to be effective in labeling, site-selective modification, immobilization, and glycoconjugation processes. For example, we illustrate a successful application of multicomponent polysaccharide-protein conjugation with the preparation of multivalent glycoconjugate vaccine candidates by the ligation of two antigenic capsular polysaccharides of a pathogenic bacterium to carrier proteins. By highlighting the ability to join several biomolecules in only one synthetic operation, we hope to encourage the biomolecular chemistry community to apply this powerful chemistry to novel biomedicinal challenges.

5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones: Zinc triflate-catalyzed one-pot multi-component synthesis, X-ray crystal structure and anti-inflammatory activity

NASA Astrophysics Data System (ADS)

Essid, Idris; Lahbib, Karima; Kaminsky, Werner; Ben Nasr, Cherif; Touil, Soufiane

2017-08-01

Herein we report a simple and efficient one-pot three-component synthesis of 5-phosphonato-3,4-dihydropyrimidin-2(1H)-ones, through the zinc triflate-catalyzed Biginelli-type reaction of β-ketophosphonates, aldehydes and urea. The compounds obtained were characterized by various spectroscopic tools including IR, NMR (1H, 31P, 13C) spectroscopy, mass spectrometry and single crystal X-ray diffraction. All the synthesized compounds were screened, for the first time, for anti-inflammatory activity by carrageenan-induced hind paw edema method, using female Wister rats and they showed significant anti-inflammatory activity in some cases higher than the standard indomethacin.

Large scale fabrication of highly monodispersed rattle-type TiO2@void@SiO2 spheres via synthesis-cum-organization process.

PubMed

Wu, Liangzhuan; Yu, Yuan; Zhang, Yuan; Li, Yuzhen; Zhang, Yang; Zhi, Jinfang

2012-03-01

Architected nanostructures with interior space have attracted enormous attention due to both their esthetic beauty and their potential applications. It is a current dream to develop a template-free, one-pot and low-temperature synthetic routes for hetero-architecture in liquid media. In this manuscript, we develop a kind of template-free, low-temperature, and one-pot total synthetic strategy for synthesis of inorganic multi-component hetero-architecture. This synthetic strategy analogous to standard organic reactions used in total synthesis is an important breakthrough in inorganic chemical synthesis. We can achieve 1 kilogram (kg) yield of the TiO(2)@void@SiO(2) core-shell sphere one time by using this synthetic strategy, which may lead to practical applications of the sample. By embodying the new reaction and concept into future investigation, a more mature research field in synthetic architecture of nanomaterials can be anticipated. Copyright © 2011 Elsevier Inc. All rights reserved.

Copper catalyzed oxidative coupling reactions for trifluoromethylselenolations--synthesis of R-SeCF3 compounds using air stable tetramethylammonium trifluoromethylselenate.

PubMed

Lefebvre, Quentin; Pluta, Roman; Rueping, Magnus

2015-03-14

The aerobic, room-temperature coupling of tetramethylammonium trifluoromethylselenate with readily available boronic acids, boronic esters, and terminal alkynes has been developed. The method permits direct access to valuable trifluoromethylselenoarenes and alkynes under mild conditions. A convenient one-pot reaction, a scale up procedure as well as an extension to perfluoroalkylselenates are also presented to further demonstrate the synthetic utility of this reaction.

One-pot and efficient synthesis of triazolo[1,2-a]indazole-triones via reaction of arylaldehydes with urazole and dimedone catalyzed by silica nanoparticles prepared from rice husk.

PubMed

Hamidian, Hooshang; Fozooni, Samieh; Hassankhani, Asadollah; Mohammadi, Sayed Zia

2011-10-26

A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness.

A fully-automated one-pot synthesis of [18F]fluoromethylcholine with reduced dimethylaminoethanol contamination via [18F]fluoromethyl tosylate.

PubMed

Rodnick, Melissa E; Brooks, Allen F; Hockley, Brian G; Henderson, Bradford D; Scott, Peter J H

2013-08-01

A novel one-pot method for preparing [(18)F]fluoromethylcholine ([(18)F]FCH) via in situ generation of [(18)F]fluoromethyl tosylate ([(18)F]FCH2OTs), and subsequent [(18)F]fluoromethylation of dimethylaminoethanol (DMAE), has been developed. [(18)F]FCH was prepared using a GE TRACERlab FXFN, although the method should be readily adaptable to any other fluorine-(18) synthesis module. Initially ditosylmethane was fluorinated to generate [(18)F]FCH2OTs. DMAE was then added and the reaction was heated at 120 °C for 10 min to generate [(18)F]FCH. After this time, reaction solvent was evaporated, and the crude reaction mixture was purified by solid-phase extraction using C(18)-Plus and CM-Light Sep-Pak cartridges to provide [(18)F]FCH formulated in USP saline. The formulated product was passed through a 0.22 µm filter into a sterile dose vial, and submitted for quality control testing. Total synthesis time was 1.25 h from end-of-bombardment. Typical non-decay-corrected yields of [(18)F]FCH prepared using this method were 91 mCi (7% non-decay corrected based upon ~1.3 Ci [(18)F]fluoride), and doses passed all other quality control (QC) tests. A one-pot liquid-phase synthesis of [(18)F]FCH has been developed. Doses contain extremely low levels of residual DMAE (31.6 µg/10 mL dose or ~3 ppm) and passed all other requisite QC testing, confirming their suitability for use in clinical imaging studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Fully-automated One-pot Synthesis of [18F]Fluoromethylcholine with Reduced Dimethylaminoethanol Contamination via [18F]Fluoromethyl Tosylate

PubMed Central

Rodnick, Melissa E.; Brooks, Allen F.; Hockley, Brian G.; Henderson, Bradford D.; Scott, Peter J. H.

2013-01-01

Introduction A novel one-pot method for preparing [18F]fluoromethylcholine ([18F]FCH) via in situ generation of [18F]fluoromethyl tosylate ([18F]FCH2OTs), and subsequent [18F]fluoromethylation of dimethylaminoethanol (DMAE), has been developed. Methods [18F]FCH was prepared using a GE TRACERlab FXFN, although the method should be readily adaptable to any other fluorine-18 synthesis module. Initially ditosylmethane was fluorinated to generate [18F]FCH2OTs. DMAE was then added and the reaction was heated at 120°C for 10 min to generate [18F]FCH. After this time, reaction solvent was evaporated, and the crude reaction mixture was purified by solid-phase extraction using C18-Plus and CM-Light Sep-Pak cartridges to provide [18F]FCH formulated in USP saline. The formulated product was passed through a 0.22 μm filter into a sterile dose vial, and submitted for quality control testing. Total synthesis time was 1.25 hours from end-of-bombardment. Results Typical non-decay-corrected yields of [18F]FCH prepared using this method were 91 mCi (7% non-decay corrected based upon ~1.3 Ci [18F]fluoride), and doses passed all other quality control (QC) tests. Conclusion A one-pot liquid-phase synthesis of [18F]FCH has been developed. Doses contain extremely low levels of residual DMAE (31.6 μg / 10 mL dose or ~3 ppm) and passed all other requisite QC testing, confirming their suitability for use in clinical imaging studies. PMID:23665261

A One-Pot Self-Assembly Reaction to Prepare a Supramolecular Palladium(II) Cyclometalated Complex: An Undergraduate Organometallic Laboratory Experiment

ERIC Educational Resources Information Center

Fernandez, Alberto; Lopez-Torres, Margarita; Fernandez, Jesus J.; Vazquez-Garcia, Digna; Vila, Jose M.

2012-01-01

A laboratory experiment for students in advanced inorganic chemistry is described. Students prepare palladium(II) cyclometalated complexes. A terdentate [C,N,O] Schiff base ligand is doubly deprotonated upon reaction with palladium(II) acetate in a self-assembly process to give a palladacycle with a characteristic tetranuclear structure. This…

Supramolecular self-assembly of heterobimetallic complexes: a new N,P-based, selective heteroditopic ligand.

PubMed

Hutchinson, Daniel John; Clauss, Reike; Sárosi, Menyhárt-Botond; Hey-Hawkins, Evamarie

2018-01-23

Pyrimidine-hydrazone and phosphole architectures have been combined to create a new heteroditopic ligand capable of forming heterobimetallic Zn II /Pd II , Pb II /Pd II and Cu II /Pd II complexes in high yielding stepwise or one pot reactions. The catalytic activity of these complexes in Heck coupling and Miyaura borylation reactions was investigated.

IBX-mediated oxidation of unactivated cyclic amines: application in highly diastereoselective oxidative Ugi-type and aza-Friedel-Crafts reactions.

PubMed

de Graaff, C; Bensch, L; van Lint, Matthijs J; Ruijter, E; Orru, R V A

2015-10-28

The first o-iodoxybenzoic acid (IBX) mediated oxidation of unactivated amines to imines is described. A range of meso-pyrrolidines were shown to be suitable substrates. The chemical space was further explored with one-pot oxidative Ugi-type and aza-Friedel-Crafts reactions, which proved to be highly diastereoselective.

Efficient Three-Component Strecker Reaction of Aldehydes/Ketones via NHC-Amidate Palladium(II) Complex Catalysis

PubMed Central

Jarusiewicz, Jamie; Choe, Yvonne; Yoo, Kyung Soo; Park, Chan Pil

2009-01-01

A simple and efficient one-pot three-component method has been developed for the synthesis of α-aminonitriles. This Strecker reaction is applicable for aldehydes and ketones with aliphatic or aromatic amines and trimethyl siliyl cyanide in the presence of a palladium Lewis aid catalyst in dichloromethane solvent at room temperature. PMID:19265413

Presidential Green Chemistry Challenge: 2013 Greener Synthetic Pathways Award

EPA Pesticide Factsheets

Presidential Green Chemistry Challenge 2013 award winner, Life Technologies, developed a one-pot synthesis for polymerase chain reaction (PCR), which is a much more efficient process that prevents about 1.5 million pounds of hazardous waste a year.

One-pot conjugated linoleic acid production from castor oil by Rhizopus oryzae lipase and resting cells of Lactobacillus plantarum.

PubMed

Khaskheli, Abid Ali; Talpur, Farah Naz; Cebeci Aydin, Aysun; Jawaid, Sana; Surhio, Muhammad Ali; Afridi, Hassan Imran

2017-10-01

Conjugated linoleic acid (CLA) has attracted as novel type of fatty acids having unusual health-promoting properties such as anticarcinogenic and antiobesitic effects. The present work employed castor oil as substrate for one-pot production of CLA using washed cells of Lactobacillus plantarum (L. plantarum) and lipases as catalysts. Among the screened lipases, the lipase Rhizopus oryzae (ROL) greatly assisted resting cells to produce CLA. Mass spectral analysis of the product showed that two major isomers of CLA were produced in the reaction mixture i.e. cis-9, trans-11 56.55% and trans-10, cis-12 43.45%. Optimum factors for CLA synthesis were found as substrate concentration (8 mg/mL), pH (6.5), washed cell concentration (12% w/v), and incubation time of 20 h. Hence, the combination of ROL with L. plantarum offers one pot production of CLA selectively using castor oil as a cost-effective substrate.

Whole-cell based solvent-free system for one-pot production of biodiesel from waste grease.

PubMed

Li, Aitao; Ngo, Thao P N; Yan, Jinyong; Tian, Kaiyuan; Li, Zhi

2012-06-01

A whole-cell based solvent-free system was developed for efficient conversion of waste grease to biodiesel via one-pot esterification and transesterification. By isolation and screening of lipase-producing strains from soil, Serratia marcescens YXJ-1002 was discovered for the biotransformation of grease to biodiesel. The lipase (SML) from this strain was cloned and expressed in Escherichia coli as an intracellular enzyme, showing 6 times higher whole-cell based hydrolysis activity than that of wild type strain. The recombinant cells were used for biodiesel production from waste grease in one-pot reactions containing no solvent with the addition of methanol in several small portions, and 97% yield of biodiesel (FAME) was achieved under optimized conditions. In addition, the whole-cell biocatalysts showed excellent reusability, retaining 74% productivity after 4 cycles. The developed system, biocatalyst, and process enable the efficient, low-cost, and green production of biodiesel from waste grease, providing with a potential industrial application. Copyright © 2012 Elsevier Ltd. All rights reserved.

A facile, efficient, and sustainable chitosan/CaHAp catalyst and one-pot synthesis of novel 2,6-diamino-pyran-3,5-dicarbonitriles.

PubMed

Maddila, Suresh; Gangu, Kranthi Kumar; Maddila, Surya Narayana; Jonnalagadda, Sreekantha B

2017-02-01

A simple and versatile one-pot three-component synthetic protocol is devised for heterocycles, viz. 2,6-diamino-4-substituted-4H-pyran-3,5-dicarbonitrile derivatives, in short reaction times ([Formula: see text]30 min) at room temperature using ethanol as a solvent. This method involves the three-component reaction of malononitrile, substituted aldehydes, and cyanoacetamide catalyzed by chitosan-doped calcium hydroxyapatites (CS/CaHAps) giving good to excellent yields (86-96%). Twelve new pyran derivatives (4a-l) were synthesized and their structures were established and confirmed by different spectroscopic methods ([Formula: see text]H NMR, [Formula: see text]C NMR, [Formula: see text]N NMR, and HRMS). The heterogeneous catalyst, CS/CaHAp, was characterized by various instrumental techniques including XRD, TEM, SEM, and FT-IR and TGA spectroscopies. The catalyst was easily separable and reusable for up to six runs without any apparent loss of activity. The reported protocol has many benefits, such as ease of preparation, use of a green solvent, reduced reaction times, excellent product yields, and operational simplicity.

Molecular typing of methicillin-resistant Staphylococcus aureus: Comparison of PCR-based open reading frame typing, multilocus sequence typing, and Staphylococcus protein A gene typing.

PubMed

Ogihara, Shinji; Saito, Ryoichi; Sawabe, Etsuko; Kozakai, Takahiro; Shima, Mari; Aiso, Yoshibumi; Fujie, Toshihide; Nukui, Yoko; Koike, Ryuji; Hagihara, Michio; Tohda, Shuji

2018-04-01

The recently developed PCR-based open reading frame typing (POT) method is a useful molecular typing tool. Here, we evaluated the performance of POT for molecular typing of methicillin-resistant Staphylococcus aureus (MRSA) isolates and compared its performance to those of multilocus sequence typing (MLST) and Staphylococcus protein A gene typing (spa typing). Thirty-seven MRSA isolates were collected between July 2012 and May 2015. MLST, spa typing, and POT were performed, and their discriminatory powers were evaluated using Simpson's index analysis. The MRSA isolates were classified into 11, 18, and 33 types by MLST, spa typing, and POT, respectively. The predominant strains identified by MLST, spa typing, and POT were ST8 and ST764, t002, and 93-191-127, respectively. The discriminatory power of MLST, spa typing, and POT was 0.853, 0.875, and 0.992, respectively, indicating that POT had the highest discriminatory power. Moreover, the results of MLST and spa were available after 2 days, whereas that of POT was available in 5 h. Furthermore, POT is rapid and easy to perform and interpret. Therefore, POT is a superior molecular typing tool for monitoring nosocomial transmission of MRSA. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

One-Pot Synthesis of GeAs Ultrafine Particles from Coal Fly Ash by Vacuum Dynamic Flash Reduction and Inert Gas Condensation.

PubMed

Zhang, Lingen; Xu, Zhenming

2017-06-16

Ge-monopnictides (GeAs) plays critical role in high-tech industry, especially in the field of advanced optical devices and infrared. As a secondary material, coal fly ash could be further recycled to retrieve germanium and prepare GeAs material with high added values. Hence, the aim of this paper is to propose a one-pot synthesis that uses vacuum flash reduction and inert-gas consolidation method to prepare GeAs ultrafine particles. Germanium in coal fly ash can be successfully recycled; simultaneously, GeAs ultrafine particles were prepared. Separation principle and feasibility of this process was discussed. Temperature, carrier gas flow rate and system pressure were the major factors on formation, morphology and distribution of particle size of GeAs ultrafine particles. A three steps synthetic mechanism was clarified, namely, thermal rupture of coal fly ash and release of GeO 2 and As 2 O 3 , the gas-solid phase reaction of GeO 2 , As 2 O 3 and coke to generate metallic Ge and As in vacuum flash reduction. Meantime, GeAs were produced in the gas phase reaction. Finally, GeAs ultrafine particles were obtained by carrier gas condensation. In short, this research developed a practical and environment-friendly one-pot synthesis to recycle germanium in coal fly ash and prepare GeAs ultrafine particles with high added values.

Rare missense variants in POT1 predispose to familial cutaneous malignant melanoma

PubMed Central

Shi, Jianxin; Yang, Xiaohong R.; Ballew, Bari; Rotunno, Melissa; Calista, Donato; Fargnoli, Maria Concetta; Ghiorzo, Paola; Paillerets, Brigitte Bressac-de; Nagore, Eduardo; Avril, Marie Francoise; Caporaso, Neil E.; McMaster, Mary L.; Cullen, Michael; Wang, Zhaoming; Zhang, Xijun; Bruno, William; Pastorino, Lorenza; Queirolo, Paola; Banuls-Roca, Jose; Garcia-Casado, Zaida; Vaysse, Amaury; Mohamdi, Hamida; Riazalhosseini, Yasser; Foglio, Mario; Jouenne, Fanélie; Hua, Xing; Hyland, Paula L.; Yin, Jinhu; Vallabhaneni, Haritha; Chai, Weihang; Minghetti, Paola; Pellegrini, Cristina; Ravichandran, Sarangan; Eggermont, Alexander; Lathrop, Mark; Peris, Ketty; Scarra, Giovanna Bianchi; Landi, Giorgio; Savage, Sharon A.; Sampson, Joshua N.; He, Ji; Yeager, Meredith; Goldin, Lynn R.; Demenais, Florence; Chanock, Stephen J.; Tucker, Margaret A.; Goldstein, Alisa M.; Liu, Yie; Landi, Maria Teresa

2014-01-01

Although CDKN2A is the most frequent high-risk melanoma susceptibility gene, the underlying genetic factors for most melanoma-prone families remain unknown. Using whole exome sequencing, we identified a rare variant that arose as a founder mutation in the telomere shelterin POT1 gene (g.7:124493086 C>T, Ser270Asn) in five unrelated melanoma-prone families from Romagna, Italy. Carriers of this variant had increased telomere length and elevated fragile telomeres suggesting that this variant perturbs telomere maintenance. Two additional rare POT1 variants were identified in all cases sequenced in two other Italian families, yielding a frequency of POT1 variants comparable to that of CDKN2A mutations in this population. These variants were not found in public databases or in 2,038 genotyped Italian controls. We also identified two rare recurrent POT1 variants in American and French familial melanoma cases. Our findings suggest that POT1 is a major susceptibility gene for familial melanoma in several populations. PMID:24686846

Greener Synthesis of Organics and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Stereocontrolled total syntheses of (±)-fawcettimine, (±)-lycoflexine, and (±)-lycoflexine N-oxide.

PubMed

Xu, Ke; Cheng, Bin; Li, Yun; Xu, Tingting; Yu, Cunming; Zhang, Jun; Ma, Zhiqiang; Zhai, Hongbin

2014-01-03

New stereocontrolled total syntheses of (±)-fawcettimine, (±)-lycoflexine, and (±)-lycoflexine N-oxide have been accomplished. The highlights include a one-pot annulation to construct the enedione and a microwave-promoted Diels-Alder reaction.

Recent advances in the chemistry of Rh carbenoids: multicomponent reactions of diazocarbonyl compounds

NASA Astrophysics Data System (ADS)

Medvedev, J. J.; Nikolaev, V. A.

2015-07-01

Multicomponent reactions of diazo compounds catalyzed by RhII complexes become a powerful tool for organic synthesis. They enable three- or four-step processes to be carried out as one-pot procedures (actually as one step) with high stereoselectivity to give complex organic molecules, including biologically active compounds. This review addresses recent results in the chemistry of Rh-catalyzed multicomponent reactions of diazocarbonyl compounds with the intermediate formation of N-, O- and C=O-ylides. The diastereo- and enantioselectivity of these reactions and the possibility of using various co-catalysts to increase the efficiency of the processes under consideration are discussed. The bibliography includes 120 references.

Facile one-pot preparation of thermally and photochemically convertible soluble precursors of copper phthalocyanine and naphthalocyanine.

PubMed

Kikukawa, Yuu; Fukuda, Takamitsu; Fuyuhiro, Akira; Ishikawa, Naoto; Kobayashi, Nagao

2011-08-14

Soluble copper phthalocyanine (CuPc) and naphthalocyanine (CuNc) precursors which can be converted thermally and photochemically into insoluble CuPc and CuNc, respectively, have been synthesized by a one-step reaction using commercially available chemicals. This journal is © The Royal Society of Chemistry 2011

One-pot synthesis of keto thioethers by palladium/gold-catalyzed click and pinacol reactions.

PubMed

Cadu, Alban; Watile, Rahul A; Biswas, Srijit; Orthaber, Andreas; Sjöberg, Per J R; Samec, Joseph S M

2014-11-07

An atom-efficient synthesis of keto thioethers was devised via tandem gold/palladium catalysis. The reaction proceeds through a regioselective thiol attack at the β-position of the alcohol, followed by an alkyl, aryl, or benzyl 1,2-shift. Both acyclic and cyclic systems were studied, in the latter case leading to the ring expansion of cyclic substrates.

Microwave-assisted Stille-coupling of steroidal substrates.

PubMed

Skoda-Földes, Rita; Pfeiffer, Péter; Horváth, Judit; Tuba, Zoltán; Kollár, László

2002-07-01

Steroidal dienes were synthesised by Stille-coupling of the corresponding alkenyl iodides with vinyltributyltin under microwave irradiation in a domestic microwave oven in drastically reduced reaction times. Rate acceleration was observed also in the one-pot Stille-coupling-Diels-Alder reaction of 17-iodo-5alpha-androst-16-ene. Stereoselectivity of cycloaddition was slightly improved with diethyl maleate as the dienophile, compared to that achieved with thermal heating.

Nickel-catalyzed synthesis of diarylamines via oxidatively induced C-N bond formation at room temperature.

PubMed

Ilies, Laurean; Matsubara, Tatsuaki; Nakamura, Eiichi

2012-11-02

A nickel-catalyzed oxidative coupling of zinc amides with organomagnesium compounds selectively produces diarylamines under mild reaction conditions, with tolerance for chloride, bromide, hydroxyl, ester, and ketone groups. A diamine is bis-monoarylated. A bromoaniline undergoes N-arylation followed by Kumada-Tamao-Corriu coupling in one pot. The reaction may proceed via oxidatively induced reductive elimination of a nickel species.

Process for Preparing Epoxy-Reinforced Silica Aerogels

NASA Technical Reports Server (NTRS)

Meador, Mary Ann B (Inventor)

2016-01-01

One-pot reaction process for preparing epoxy-reinforced monolithic silica aerogels comprising the reaction of at least one silicon compound selected from the group consisting of alkoxysilanes, orthosilicates and combination thereof in any ratio with effective amounts of an epoxy monomer and an aminoalkoxy silane to obtain an epoxy monomer-silica sol in solution, subsequently preparing an epoxy-monomer silica gel from said silica sol solution followed by initiating polymerization of the epoxy monomer to obtain the epoxy-reinforced monolithic silica aerogel.

Efficient Syntheses of Organics and Nanomaterials Using Microwaves

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Green Synthetic Alternatives to Organic Compounds and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Green Synthetic Alternatives to Organic Molecules and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Greener Synthetic Alternatives to Organic Molecules and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Greener Synthetic Alternatives to Heterocycles, Nanomaterials and Nanocomposites

EPA Science Inventory

Microwave (MW) expedited reaction of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermediates via enamines or using hyp...

Use of Elemental Sulfur or Selenium in a Novel One-Pot Copper-Catalyzed Tandem Cyclization of Functionalized Ynamides Leading to Benzosultams.

PubMed

Siva Reddy, Alla; Kumara Swamy, K C

2015-06-19

A novel and efficient [Cu]-catalyzed one-pot regio- and stereospecific synthesis of benzo[1,4,2]dithiazine 1,1-dioxides and benzo[1,4,2]thiaselenazine 1,1-dioxides by cyclization of functionalized ynamides with elemental sulfur/selenium has been developed. Its generality is elegantly illustrated by extension to benzodithiazepines and benzothiaselenazepines. Involvement of water in the reaction is demonstrated by the incorporation of (2)D at the olefinic site by using D2O in place of water. Selective oxidation at sulfur in benzo[1,4,2]dithiazine 1,1-dioxide by using mCPBA as the oxidizing agent is also described.

Diversity-Oriented Synthesis of Coumarin-Linked Benzimidazoles via a One-Pot, Three-Step, Intramolecular Knoevenagel Cyclization.

PubMed

Yao, Po-Hsin Eric; Kumar, Sunil; Liu, Yu-Li; Fang, Chiu-Ping; Liu, Chia-Chen; Sun, Chung-Ming

2017-04-10

Diversity-oriented synthesis of coumarin-linked benzimidazoles from N-(2-aminophenyl)-2-cyanoacetamide was achieved via a one-pot, three-step sequential reaction in excellent yields. In situ intramolecular cyclization of the cyanoacetamide afforded benzimidazoles which subsequently underwent a Knoevenagel condensation of the 2-cyanomethylbenzimidazoles with salicylaldehydes promoted by triethylamine to reach the target compounds. An important intermediate, 2-(2-imino-2H-chromen-3-yl)-1H-benzimidazole was characterized by X-ray analysis and further hydrolyzed to 2-(coumarin-3-yl)benzimidazole in acidic condition. Among the synthesized compounds, some were found to be promising inhibitors of porcine kidney d-amino acid oxidase (pkDAO).

Ionic liquid catalyzed one-pot multi-component synthesis, characterization and antibacterial activity of novel chromeno[2,3-d]pyrimidin-8-amine derivatives

NASA Astrophysics Data System (ADS)

Kanakaraju, Sankari; Prasanna, Bethanamudi; Basavoju, Srinivas; Chandramouli, G. V. P.

2012-06-01

An efficient, simple and convenient method for the one-pot multi-component synthesis of novel chromeno[2,3-d]pyrimidin-8-amine derivatives has been accomplished by starting from α-naphthol, aryl aldehydes, malononitrile and NH4Cl. The reaction has been catalyzed by 1-butyl-3-methylimidazolium tetrafluoroborate [bmim]BF4 ionic liquid. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR, mass spectra, and elemental analysis. The structure of compound 4a was confirmed by single-crystal X-ray diffraction. All the synthesized compounds were evaluated for their in vitro antibacterial activity.

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P® activation of 3-arylpropiolic acids.

PubMed

Denißen, Melanie; Kraus, Alexander; Reiss, Guido J; Müller, Thomas J J

2017-01-01

In situ activation of 3-arylpropiolic acids with T3P ® ( n -propylphosphonic acid anhydride) initiates a domino reaction furnishing 4-arylnaphtho[2,3- c ]furan-1,3-diones in excellent yields. Upon employing these anhydrides as reactive intermediates blue-luminescent 4-aryl-1 H -benzo[ f ]isoindole-1,3(2 H )-diones are formed by consecutive pseudo three-component syntheses in a one-pot fashion. The Stokes shifts correlate excellently with the Hammett-Taft σ R parameter indicating an extended degree of resonance stabilization in the vibrationally relaxed excited singlet state.

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P® activation of 3-arylpropiolic acids

PubMed Central

Denißen, Melanie; Kraus, Alexander; Reiss, Guido J

2017-01-01

In situ activation of 3-arylpropiolic acids with T3P® (n-propylphosphonic acid anhydride) initiates a domino reaction furnishing 4-arylnaphtho[2,3-c]furan-1,3-diones in excellent yields. Upon employing these anhydrides as reactive intermediates blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones are formed by consecutive pseudo three-component syntheses in a one-pot fashion. The Stokes shifts correlate excellently with the Hammett–Taft σR parameter indicating an extended degree of resonance stabilization in the vibrationally relaxed excited singlet state. PMID:29181114

One-Pot Synthesis of N-Substituted β-Amino Alcohols from Aldehydes and Isocyanides.

PubMed

Cioc, Răzvan C; van der Niet, Daan J H; Janssen, Elwin; Ruijter, Eelco; Orru, Romano V A

2015-05-18

A practical two-stage one-pot synthesis of N-substituted β-amino alcohols using aldehydes and isocyanides as starting materials has been developed. This method features mild reaction conditions, broad scope, and general tolerance of functional groups. Based on a less common central carbon-carbon bond disconnection, this protocol complements traditional approaches that involve amines and various carbon electrophiles (epoxides, α-halo ketones, β-halohydrins). Medicinally relevant products can be prepared in a concise and efficient way from simple building blocks, as demonstrated in the synthesis of the antiasthma drug salbutamol. Upgrading the synthesis to an enantioselective variant is also feasible. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of the inoculation of Burkholderia vietnamensis and related endophytic diazotrophic bacteria on grain yield of rice.

PubMed

Govindarajan, Munusamy; Balandreau, Jacques; Kwon, Soon-Wo; Weon, Hang-Yeon; Lakshminarasimhan, Cunthipuram

2008-01-01

During a survey of endophytic diazotrophic bacteria associated with different rice varieties in Tamilnadu, some "endophytes" were obtained. Thirteen bacterial isolates from surface-sterilized roots and shoots were obtained in pure culture, which produced indole acetic acid (IAA) and reduced acetylene to ethylene. Polymerase chain reaction (PCR) amplification confirmed the presence of nif-H gene in all the isolates. Morphological, biochemical, and molecular characteristics indicated that all of them belonged to the genus Burkholderia One of them, MGK3, was consistently more active in reducing acetylene, and 16S rDNA sequences of isolate MGK3 confirmed its identification as Burkholderia vietnamiensis. Colonization of rice root was confirmed by strain MGK3 marked with gusA gene. The inoculated roots showed a blue color, which was most intense at the points of lateral root emergence and at the root tip. Transverse sections of roots, 15 days after inoculation, revealed beta-glucuronidase (GUS) activity within many of the cortical intercellular spaces next to the stele and within the aerenchyma. Nitrogen fixation was quantified by using (15)N isotope dilution method with two different cultivars grown in pot and field experiments. Higher nitrogen fixation was observed in variety Ponni than in ADT-43, where nearly 42% (field) and 40% (pot) of the nitrogen was derived from the atmosphere (% Ndfa). Isolate MGK3 was used to inoculate rice seedlings in a comparison with four other diazotrophs, viz., Gluconacetobacter diazotrophicus LMG7603, Herbaspirillum seropedicae LMG6513, Azospirillum lipoferum 4B LMG4348, and B. vietnamiensis LMG10929. They were used to conduct two pot and four field inoculation experiments. MGK3 alone, and combined with other diazotrophs, performed best under both pot and field conditions: combined inoculation produced yield increases between 9.5 and 23.6%, while MGK3 alone increased yield by 5.6 to 12.16% over the uninoculated control treatment.

Combi-metal organic framework (Combi-MOF) of α-amylase and glucoamylase for one pot starch hydrolysis.

PubMed

Salgaonkar, Manish; Nadar, Shamraja S; Rathod, Virendra K

2018-07-01

The multi-enzyme biocatalyst allows to run in vitro multi-step cascade reactions in single pot. An efficient combi-metal organic frameworks (combi-MOF) of α-amylase and glucoamylase for one pot starch hydrolysis was constructed by mixing zinc acetate and 2‑methylimmidazole with enzyme mixture in one pot under biocompatible conditions. The prepared combi-MOF was characterized and analyzed by powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Thermo-stability was evaluated for combi-MOF in the range of 55 to 75°C which showed three folds improved stability in terms of half-life. In kinetic parameter studies, rate of starch hydrolysis (V max ) of combi-MOF was found to be enhanced after co-immobilization. Further, combi-MOF was recycled in batch mode which retained up to 52% residual activity after five successive cycles of reuse. In addition to that, combi-MOF exhibited extraordinary storage stability till 24days. At the end, starch hydrolytic activity of combi-MOF was tested for different sources of starch (corn, rice, wheat and potato) which exhibited higher rate of hydrolysis than mixture of free enzymes due to spatially co-localized multi-enzymatic systems. Copyright © 2018 Elsevier B.V. All rights reserved.

Multi-enzymatic one-pot reduction of dehydrocholic acid to 12-keto-ursodeoxycholic acid with whole-cell biocatalysts.

PubMed

Sun, Boqiao; Kantzow, Christina; Bresch, Sven; Castiglione, Kathrin; Weuster-Botz, Dirk

2013-01-01

Ursodeoxycholic acid (UDCA) is a bile acid of industrial interest as it is used as an agent for the treatment of primary sclerosing cholangitis and the medicamentous, non-surgical dissolution of gallstones. Currently, it is prepared industrially from cholic acid following a seven-step chemical procedure with an overall yield of <30%. In this study, we investigated the key enzymatic steps in the chemo-enzymatic preparation of UDCA-the two-step reduction of dehydrocholic acid (DHCA) to 12-keto-ursodeoxycholic acid using a mutant of 7β-hydroxysteroid dehydrogenase (7β-HSDH) from Collinsella aerofaciens and 3α-hydroxysteroid dehydrogenase (3α-HSDH) from Comamonas testosteroni. Three different one-pot reaction approaches were investigated using whole-cell biocatalysts in simple batch processes. We applied one-biocatalyst systems, where 3α-HSDH, 7β-HSDH, and either a mutant of formate dehydrogenase (FDH) from Mycobacterium vaccae N10 or a glucose dehydrogenase (GDH) from Bacillus subtilis were expressed in a Escherichia coli BL21(DE3) based host strain. We also investigated two-biocatalyst systems, where 3α-HSDH and 7β-HSDH were expressed separately together with FDH enzymes for cofactor regeneration in two distinct E. coli hosts that were simultaneously applied in the one-pot reaction. The best result was achieved by the one-biocatalyst system with GDH for cofactor regeneration, which was able to completely convert 100 mM DHCA to >99.5 mM 12-keto-UDCA within 4.5 h in a simple batch process on a liter scale. Copyright © 2012 Wiley Periodicals, Inc.

Green Synthetic Alternatives to Organic Compounds and Nanomaterials-May 2008

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Greener Alternatives to Expedient Synthesis of Heterocycles and Nanomaterial

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds [1] from in situ generated reactive interm...

A modular synthesis of dithiocarbamate pendant unnatural α-amino acids

EPA Science Inventory

Unnatural α-amino acids containing dithiocarbamate side chains were synthesized by a one-pot reaction of in-situ generated dithiocarbamate anions with sulfamidates. A wide range of these anions participated in the highly regio- and stereo-selective ring opening of sulfamidates to...

Significant rate accelerated synthesis of glycosyl azides and glycosyl 1,2,3-triazole conjugates.

PubMed

Kumar, Rishi; Maulik, Prakas R; Misra, Anup Kumar

2008-10-01

An efficient and significantly rapid access of a series of glycosyl azides and glycosyl 1,2,3-triazole conjugates is reported using modified one-pot reaction conditions. In both cases yields were excellent and single diastereomers were obtained.

Recent Advances in the Catalytic One-Pot Synthesis of Flavonoids and Chromones.

PubMed

Mohadeszadeh, Manijeh; Iranshahi, Mehrdad

2017-01-01

Flavonoids and chromones are two important classes of natural products that have various biological properties. During the past 10 years, there has been a significant increase in studies on the one-pot synthesis of flavonoids and chromones as medicinal scaffolds in drug discovery. This review describes the scope, mechanistic properties and regio- and chemo-selectivity features of several recently developed one-pot procedures for the synthesis of substituted chromones and flavonoids that have recently been published. Special importance is placed on the most promising and exciting medicinal applications of flavonoids and chromones. In this review, we discuss the progress on the synthesis of flavonoid and chromone derivatives in the presence of metal catalysts, organocatalysts, solid surfaces, microwave irradiation, acid and base catalysis, etc. For example, flavones can be prepared via the catalytic coordination of palladium complexes in a short time and at a low temperature with a high yield. Additionally, the one-pot synthesis of 2-substituted chromones via metal triflate (Yb(OTf)3) has provided the best result for this type of reaction with a high yield and a high regio and chemoselectivity. Generally, this review proposes the first specific overview of this developing and rapidly expanding field of flavonoid synthesis. We also discuss the mechanisms and advantages and disadvantages of methods for the synthesis of flavonoids and chromones. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Facile synthesis of degradable and electrically conductive polysaccharide hydrogels.

PubMed

Guo, Baolin; Finne-Wistrand, Anna; Albertsson, Ann-Christine

2011-07-11

Degradable and electrically conductive polysaccharide hydrogels (DECPHs) have been synthesized by functionalizing polysaccharide with conductive aniline oligomers. DECPHs based on chitosan (CS), aniline tetramer (AT), and glutaraldehyde were obtained by a facile one-pot reaction by using the amine group of CS and AT under mild conditions, which avoids the multistep reactions and tedious purification involved in the synthesis of degradable conductive hydrogels in our previous work. Interestingly, these one-pot hydrogels possess good film-forming properties, electrical conductivity, and a pH-sensitive swelling behavior. The chemical structure and morphology before and after swelling of the hydrogels were verified by FT-IR, NMR, and SEM. The conductivity of the hydrogels was tuned by adjusting the content of AT. The swelling ratio of the hydrogels was altered by the content of tetraaniline and cross-linker. The hydrogels underwent slow degradation in a buffer solution. The hydrogels obtained by this facile approach provide new possibilities in biomedical applications, for example, biodegradable conductive hydrogels, films, and scaffolds for cardiovascular tissue engineering and controlled drug delivery.

An efficient one-pot two catalyst system in the construction of 2-substituted benzimidazoles: synthesis of benzimidazo[1,2-c]quinazolines.

PubMed

Cimarelli, Cristina; Di Nicola, Matteo; Diomedi, Simone; Giovannini, Riccardo; Hamprecht, Dieter; Properzi, Roberta; Sorana, Federico; Marcantoni, Enrico

2015-12-28

The benzimidazole core is a common moiety in a large number of natural products and pharmacologically active small molecules. The synthesis of novel benzimidazole derivatives remains a main focus in medicinal research. In continuation of the efforts towards Ce(III) catalysts for organic transformations, we observed for the first time the activity of the iodide ion and copper cation in activating CeCl3·7H2O in the selective formation of prototypical 2-substituted benzimidazoles. The one-pot CeCl3·7H2O-CuI catalytic system procedure includes the cyclo-dehydrogenation of aniline Schiff's bases, generated in situ from the condensation of 1,2-phenylenediamine and aldehydes, followed by the oxidation with iodine, which works as a hydrogen sponge. Mild reaction conditions, good to excellent yields, and clean reactions make the procedure a useful contribution to the synthesis of biologically active fused heterocycles containing benzimidazoquinazolines.

An alkaline one-pot reaction to synthesize luminescent Eu-BTC MOF nanorods, highly pure and water-insoluble, under room conditions

NASA Astrophysics Data System (ADS)

Medina-Velazquez, D. Y.; Alejandre-Zuniga, B. Y.; Loera-Serna, S.; Ortiz, E. M.; Morales-Ramirez, A. de J.; Garfias-Garcia, E.; Garcia-Murillo, A.; Falcony, C.

2016-12-01

The increasing demand for optoelectronic devices requires the development of luminescent materials with high luminescence efficiency and low energy demands, and the metalorganic frameworks (MOFs) with lanthanides ions offer great potential in this area. The metalorganic materials provide properties of flexibility, low density, low-cost methods of synthesis, and insolubility in water, which gives them an advantage over traditional phosphors. In this study, a benzenetricarboxylate ligand (BTC) with a Eu3+ MOF was synthesized, and its structural and luminescent properties were measured. The metalorganic compound was generated in a one-pot reaction from europium nitrate and trimesic acid precursors. Through characterization by X-ray diffraction powder, infrared spectroscopy, SEM structural characterization, and luminescent spectroscopy, the formation of Europium benzenetricarboxylate (Eu-BTC) MOF nanorods was tested and the calculated value was in the range of 30-60 nm. A red luminescent emission with high intensity was observed for all the procedures.

Discovery of core-structurally novel PTP1B inhibitors with specific selectivity containing oxindole-fused spirotetrahydrofurochroman by one-pot reaction.

PubMed

Dong, Suzhen; Lei, Yubing; Jia, Shikun; Gao, Lixin; Li, Jia; Zhu, Tong; Liu, Shunying; Hu, Wenhao

2017-02-15

Protein tyrosine phosphatase 1B (PTP1B) has been proposed to be an ideal target for treatment of type II diabetes and obesity. However, no druggable PTP1B inhibitor has been established and there is still an urgent demand for the development of structurally novel PTPIB inhibitor. Herein, we reported core-structurally novel PTP1B inhibitors with low micromole-ranged inhibitory activity by one-pot reaction from simple starting materials. Further studies demonstrated some of these active compounds had a specific selectivity over other PTPs. The structure and activity relationship was also described. The best active and selective compound 5e inhibited PTP1B activity with an IC 50 of 4.53μM. Molecular docking analysis further demonstrated that compound 5e bound to the active pocket of PTP1B. The results might provide some insights for further development of new drugs for type II diabetes and obesity. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fabrication and characterization of magnesium and calcium trimesate complexes via ion-exchange and one-pot self-assembly reaction

NASA Astrophysics Data System (ADS)

Ozer, Demet; Oztas, Nursen Altuntas; Köse, Dursun A.; Şahin, Onur

2018-03-01

Using two different synthesis methods, two diversified magnesium and calcium complexes were successfully prepared. When the ion exchange method was used, C9H14MgO11.H2O and C18H30Ca3O24 complexes were obtained. When the one-pot self-assembly reaction was used, C18H34Mg3O26.4H2O and C9H12CaO10 complexes were produced. The structural characterizations were performed by using X-ray diffraction, FT-IR and elemental analyses. Thermal behavior of complexes were also determined via TGA method. The both complexes of magnesium and calcium trimesate have micro and mesoporosity with low porosity because of hydrogen bonds. Then hydrogen storage capacities of complexes were also determined. The differences in synthesis method result in the differences on complexes structure, morphology (shape, particle size and specific surface area) and hydrogen storage capacities.

A one-pot strategy for biomimetic synthesis and self-assembly of gold nanoparticles

NASA Astrophysics Data System (ADS)

Wang, Yi; Chen, Li Qiang; Li, Yuan Fang; Zhao, Xi Juan; Peng, Li; Zhi Huang, Cheng

2010-07-01

A simple, one-pot and controllable strategy is reported in this contribution for biomimetic synthesis and self-assembly of gold nanoparticles (Au-NPs). It involves our synthesized polyaldehyde dextran (PAD), which has been proved to be a biomacromolecule with excellent biocompatibility and biodegradability, acting as both a reducing agent and a stabilizer. The morphology of the as-prepared Au-NP assemblies can be controlled by adjusting the reaction conditions, such as the concentration of aldehyde in PAD, the reaction time and the temperature. Investigations of the mechanism suggest that stabilizers may distribute on different crystal facets of NPs non-uniformly owing to the different binding forces, and dipole-dipole interaction of NPs could be the main driving force for the assembly of Au-NPs. In addition, intermolecular hydrogen bonding interaction of stabilizers could also act as a possible driving force. The excellent biocompatibility of the Au-NP assemblies makes them promising candidates for fabricating future optical nanodevices and application in biological systems.

A one-pot hydrothermal synthesis of 3D nitrogen-doped graphene aerogels-supported NiS2 nanoparticles as efficient electrocatalysts for the oxygen-reduction reaction

NASA Astrophysics Data System (ADS)

Yuan, Wen-Jing; Li, Ju-Chuan; Chen, Ping; Shen, Yu-Hua; Xie, An-Jian

2014-03-01

Nitrogen-doped graphene aerogels-supported NiS2 nanoparticles (NiS2/NG) were synthesized by a one-pot hydrothermal method. In the process, l-cysteine was used not only as the nitrogen source to form the nitrogen-doped graphene aerogels, but also the sulfur source to form NiS2. The nitrogen-doped graphene (NG) hybrids show an interconnected reticulation of NG sheets with uniform deposition of NiS2 NPs, and the NiS2 NPs are deposited on the NG layers. In studying the effects of the NG and NiS2/NG for the ORR, we found that NiS2/NG shows a more positive onset potential, higher current density, and higher electron transfer number (˜4) for the oxygen-reduction reaction (ORR) in alkaline media than NG. Furthermore, NiS2/NG shows better durability and methanol tolerance than the commercial Pt/C catalyst.

Fluorescence Aggregation-Caused Quenching versus Aggregation-Induced Emission: A Visual Teaching Technology for Undergraduate Chemistry Students

ERIC Educational Resources Information Center

Ma, Xiaofeng; Sun, Rui; Cheng, Jinghui; Liu, Jiaoyan; Gou, Fei; Xiang, Haifeng; Zhou, Xiangge

2016-01-01

A laboratory experiment visually exploring two opposite basic principles of fluorescence of aggregation-caused quenching (ACQ) and aggregation-induced emission (AIE) is demonstrated. The students would prepared two salicylaldehyde-based Schiff bases through a simple one-pot condensation reaction of one equiv of 1,2-diamine with 2 equiv of…

Chlorotrimethylsilane activation of acylcyanamides for the synthesis of mono-N-acylguanidines

PubMed Central

Haussener, Travis J.; Mack, James B. C.

2011-01-01

A simple and efficient one-pot method for the synthesis of mono-protected guanidines is presented. Treatment of an acylcyanamide with chlorotrimethylsilane generates a reactive N-silylcarbodiimide capable of guanylating a variety of amines. Typically the reaction is complete in 15 min for primary and secondary aliphatic amines at rt. Hindered amines and anilines are also competent nucleophiles but require extended reaction times. PMID:21732649

Antifungal activities of (E)-4-benzylidene-5-oxopyrrolidine- 2-carboxamides and 6-oxo-1,2,3,6-tetrahydropyridin-2- carboxamides synthezed via ugi reaction from baylis-hillman bromides

NASA Astrophysics Data System (ADS)

Zeng, X. H.; Xiang, L. C.; Li, H. L.; Wang, H. M.; Wang, X. B.

2016-08-01

The derivatives of N-containing heterocycles containing the pyrrolidone or pyridinone moiety are of high importance because they have extensive biological properties including antifungal, anti-muscarinic, anti-cancer, anti-viral and anti-HIV activities. In our previous work, we described an one-pot transition-metal-free, base-mediated synthesis of pyrrolidinones ((E)-4-benzylidene-5-oxopyrrolidine-2-carboxamides 6) and an one-pot regioselective synthesis of previously seldom reported pyridinones (6-oxo-1,2,3,6- tetrahydropyridin-2-carboxamides 9) via Ugi reaction from Baylis-Hillman Bromides. Herein, the growth inhibitory effect of one concentration (50mg/L) of compounds 6 and 9 against fungi (Gibberella zeae) in vitro was tested by the method of toxic medium. Ihe results showed that the inhibitory effects of compounds 6 against Gibberella zeae are not obvious, but compounds 9 showed moderate to good inhibitory effects against Gibberella zeae. Compound 9h showed the best inhibition rate against Gibberella zeae with 95%.

Rapid purification method for vitamin A-derived aging pigments A2E and iso-A2E using cation exchange resin.

PubMed

Jee, Eun Hye; Kim, So Ra; Jang, Young Pyo

2012-08-17

A2E, known to be involved in the pathogenesis of age-related macular degeneration (AMD), is one of the major compounds that accumulate as fluorescent pigments in retinal pigment epithelial (RPE) cells with age and in some retinal disorders. While the biomimetic synthesis of A2E and its cis-isomer, iso-A2E is as simple as 'one-pot' reaction, the purification of these amphiphillic compounds has been a bottleneck for the mass production of these pathophysiologically important eye pigments. In order to provide a new method of rapid purification of A2E and iso-A2E, we employed a cation exchange resin for the separation of these pigments from crude reaction mixture. The reaction mixture was loaded on a weak acid resin and was eluted with 80% methanol with sodium hydroxide (pH 12), 100% methanol, and 100% methanol with 0.1% trifluoroacetic acid (TFA) in sequence. A2E and isoA2E were eluted only with 100% methanol solution containing TFA. Most of unreacted starting materials and intermediates were removed with 80% methanol containing sodium hydroxide. The new method can be used as a relatively simple and economic way to purify A2E and iso-A2E compared to conventional HPLC technique. Copyright © 2012 Elsevier B.V. All rights reserved.

One-pot bioethanol production from cellulose by co-culture of Acremonium cellulolyticus and Saccharomyces cerevisiae

PubMed Central

2012-01-01

Background While the ethanol production from biomass by consolidated bioprocess (CBP) is considered to be the most ideal process, simultaneous saccharification and fermentation (SSF) is the most appropriate strategy in practice. In this study, one-pot bioethanol production, including cellulase production, saccharification of cellulose, and ethanol production, was investigated for the conversion of biomass to biofuel by co-culture of two different microorganisms such as a hyper cellulase producer, Acremonium cellulolyticus C-1 and an ethanol producer Saccharomyces cerevisiae. Furthermore, the operational conditions of the one-pot process were evaluated for maximizing ethanol concentration from cellulose in a single reactor. Results Ethanol production from cellulose was carried out in one-pot bioethanol production process. A. cellulolyticus C-1 and S. cerevisiae were co-cultured in a single reactor. Cellulase producing-medium supplemented with 2.5 g/l of yeast extract was used for productions of both cellulase and ethanol. Cellulase production was achieved by A. cellulolyticus C-1 using Solka-Floc (SF) as a cellulase-inducing substrate. Subsequently, ethanol was produced with addition of both 10%(v/v) of S. cerevisiae inoculum and SF at the culture time of 60 h. Dissolved oxygen levels were adjusted at higher than 20% during cellulase producing phase and at lower than 10% during ethanol producing phase. Cellulase activity remained 8–12 FPU/ml throughout the one-pot process. When 50–300 g SF/l was used in 500 ml Erlenmeyer flask scale, the ethanol concentration and yield based on initial SF were as 8.7–46.3 g/l and 0.15–0.18 (g ethanol/g SF), respectively. In 3-l fermentor with 50–300 g SF/l, the ethanol concentration and yield were 9.5–35.1 g/l with their yields of 0.12–0.19 (g/g) respectively, demonstrating that the one-pot bioethanol production is a reproducible process in a scale-up bioconversion of cellulose to ethanol. Conclusion A. cellulolyticus cells produce cellulase using SF. Subsequently, the produced cellulase saccharifies the SF, and then liberated reducing sugars are converted to ethanol by S. cerevisiae. These reactions were carried out in the one-pot process with two different microorganisms in a single reactor, which does require neither an addition of extraneous cellulase nor any pretreatment of cellulose. Collectively, the one-pot bioethanol production process with two different microorganisms could be an alternative strategy for a practical bioethanol production using biomass. PMID:22938388

Corona[5]arenes Accessed by a Macrocycle-to-Macrocycle Transformation Route and a One-Pot Three-Component Reaction.

PubMed

Wu, Zhi-Chen; Guo, Qing-Hui; Wang, Mei-Xiang

2017-06-12

Corona[5]arenes, a novel type of macrocyclic compound that is composed of alternating heteroatoms and para-arylenes, were synthesized efficiently by two distinct methods. In a macrocycle-to-macrocycle transformation approach, S 6 -corona[3]arene[3]tetrazine underwent sequential S N Ar reactions with HS-C 6 H 4 -X-C 6 H 4 -SH (X=S, CH 2 , CMe 2 , SO 2 , and O) to produce the corresponding corona[3]arene[2]tetrazines. Different corona[3]arene[2]tetrazine compounds were also constructed in a straightforward manner by a one-pot three-component reaction of HS-C 6 H 4 -X-C 6 H 4 -SH (X=S, CH 2 , CMe 2 , SO 2 , and O) with diethyl 2,5-dimercaptoterephthalate and 2 equiv of 3,6-dichlorotetrazine under very mild conditions. All corona[5]arenes adopted 1,2,4-alternate conformational structures in the crystalline state yielding similar nearly regular pentagonal cavities. Both the cavity size and the electronic property of the acquired macrocycles were fine-tuned by the nature of the bridging element X. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Generation of efficient mutants of endoglycosidase from Streptococcus pyogenes and their application in a novel one-pot transglycosylation reaction for antibody modification.

PubMed

Iwamoto, Mitsuhiro; Sekiguchi, Yukiko; Nakamura, Kensuke; Kawaguchi, Yoshirou; Honda, Takeshi; Hasegawa, Jun

2018-01-01

The fine structures of Fc N-glycan modulate the biological functions and physicochemical properties of antibodies. By remodeling N-glycan to obtain a homogeneous glycoform or chemically modified glycan, antibody characteristics can be controlled or modified. Such remodeling can be achieved by transglycosylation reactions using a mutant of endoglycosidase from Streptococcus pyogenes (Endo-S) and glycan oxazoline. In this study, we generated improved mutants of Endo-S by introducing additional mutations to the D233Q mutant. Notably, Endo-S D233Q/Q303L, D233Q/E350Q, and several other mutations resulted in transglycosylation efficiencies exceeding 90%, with a single-digit donor-to-substrate ratio of five, and D233Q/Y402F/D405A and several other mutations resulted in slightly reduced transglycosylation efficiencies accompanied by no detectable hydrolysis activity for 48 h. We further demonstrated that the combined use of mutants of Endo-S with Endo-M or Endo-CC, endoglycosidases from Mucor hiemalis and Coprinopsis cinerea, enables one-pot transglycosylation from sialoglycopeptide to antibodies. This novel reaction enables glycosylation remodeling of antibodies, without the chemical synthesis of oxazoline in advance or in situ.

MICROWAVE IRRADIATION IN BENIGN SYNTHESIS OF HETEROCYCLES, NOBLE NANOMETALS AND NANOCOMPOSITES

EPA Science Inventory

A brief historic account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds [1] from in situ generated reacti...

Greener Synthesis of N-Heterocycles via Sustainable Applications of Nano-Catalysts

EPA Science Inventory

A brief historic account of reactions involving microwave (MW) exposure of neat reactants or catalysis by mineral surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedi...

3,4-Dihydro-2H-pyrrole-2-carbonitriles: Useful Intermediates in the Synthesis of Fused Pyrroles and 2,2'-Bipyrroles.

PubMed

Nebe, Marco M; Kucukdisli, Murat; Opatz, Till

2016-05-20

Various heterocyclic structures containing the pyrrole moiety have been synthesized from easily accessible 3,4-dihydro-2H-pyrrole-2-carbonitriles in one-pot procedures. 5,6,7,8-Tetrahydroindolizines, 2,3-dihydro-1H-pyrrolizines as well as 6,7,8,9-tetrahydro-5H-pyrrolo[1,2-a]azepines were obtained from these precursors in high yields in an alkylation/annulation sequence. The same conditions were applied in the synthesis of a 5,8-dihydroindolizine, which could easily be transformed to the corresponding indolizine by dehydrogenation. Furthermore, oxidative couplings of 3,4-dihydro-2H-pyrrole-2-carbonitriles with copper(II)-salts furnished 2,2'-bipyrroles as well as 5,5'-bis(5-cyano-1-pyrrolines), depending on the reaction conditions. Overall, these methods give high yielding access to a variety of pyrrole-containing heterocyles in two steps from commercially available starting materials.

Scalable amplification of strand subsets from chip-synthesized oligonucleotide libraries

PubMed Central

Schmidt, Thorsten L.; Beliveau, Brian J.; Uca, Yavuz O.; Theilmann, Mark; Da Cruz, Felipe; Wu, Chao-Ting; Shih, William M.

2015-01-01

Synthetic oligonucleotides are the main cost factor for studies in DNA nanotechnology, genetics and synthetic biology, which all require thousands of these at high quality. Inexpensive chip-synthesized oligonucleotide libraries can contain hundreds of thousands of distinct sequences, however only at sub-femtomole quantities per strand. Here we present a selective oligonucleotide amplification method, based on three rounds of rolling-circle amplification, that produces nanomole amounts of single-stranded oligonucleotides per millilitre reaction. In a multistep one-pot procedure, subsets of hundreds or thousands of single-stranded DNAs with different lengths can selectively be amplified and purified together. These oligonucleotides are used to fold several DNA nanostructures and as primary fluorescence in situ hybridization probes. The amplification cost is lower than other reported methods (typically around US$ 20 per nanomole total oligonucleotides produced) and is dominated by the use of commercial enzymes. PMID:26567534

Domino reactions initiated by intramolecular hydride transfers from tri(di)arylmethane fragments to ketenimine and carbodiimide functions.

PubMed

Alajarin, Mateo; Bonillo, Baltasar; Ortin, Maria-Mar; Sanchez-Andrada, Pilar; Vidal, Angel; Orenes, Raul-Angel

2010-10-21

The ability of triarylmethane and diarylmethane fragments to behave as hydride donors participating in thermal [1,5]-H shift/6π-ERC tandem processes involving ketenimine and carbodiimide functions is disclosed. C-Alkyl-C-phenyl ketenimines N-substituted by a triarylmethane substructure convert into a variety of 3,3,4,4-tetrasubstituted-3,4-dihydroquinolines, as structurally related carbodiimides transform into 3,4,4-trisubstituted-3,4-dihydroquinazolines via transient ortho-azaxylylenes. The first step of these one-pot conversions, the [1,5]-H shift, is considered to be a hydride migration on the basis of the known hydricity of the tri(di)arylmethane fragment and the electrophilicity of the central heterocumulenic carbon atom, whereas the final electrocyclization involves the formation of a sterically congested C-C or C-N bond. In the cases of C,C-diphenyl substituted triarylmethane-ketenimines the usual 6π-ERC becomes prohibited by the presence of two phenyl rings at each end of the azatrienic system. This situation opens new reaction channels: (a) following the initial hydride shift, the tandem sequence continues with an alternative electrocyclization mode to give 9,10-dihydroacridines, (b) the full sequence is initiated by a rare 1,5 migration of an electron-rich aryl group, followed by a 6π-ERC which leads to 2-aryl-3,4-dihydroquinolines, or (c) a different [1,5]-H shift/6π-ERC sequence involving the initial migration of a hydrogen atom from a methyl group at the ortho position to the nitrogen atom of the ketenimine function. Diarylmethane-ketenimines bearing a methyl group at the benzylic carbon atom experience a tandem double [1,5]-H shift, the first one being the usual benzylic hydride transfer whereas the second one involves the methyl group at the initial benzylic carbon atom, the reaction products being 2-aminostyrenes. Diarylmethane-ketenimines lacking such a methyl group convert into 3,4-dihydroquinolines by the habitual tandem [1,5]-H shift/6π-ERC processes.

Preparation of Pd/Fe3O4 nanoparticles by use of Euphorbia stracheyi Boiss root extract: A magnetically recoverable catalyst for one-pot reductive amination of aldehydes at room temperature.

PubMed

Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad

2016-02-15

We describe a method for supporting palladium nanoparticles on magnetic nanoparticles using Euphorbia stracheyi Boiss root extract as the natural source of reducing and stabilizing agent. The progress of the reaction was monitored using UV-visible spectroscopy. The nanocatalyst was characterized by FE-SEM, TEM, XRD, EDS, FT-IR spectroscopy and ICP. The nanocatalyst was applied as an efficient, magnetically recoverable, highly reusable and heterogeneous catalyst for one-pot reductive amination of aldehydes at room temperature. The nanocatalyst was easily recovered by applying an external magnet and reused several times without considerable loss of activity. Copyright © 2015 Elsevier Inc. All rights reserved.

anti-Selective Asymmetric Henry Reaction Catalyzed by a Heterobimetallic Cu-Sm-Aminophenol Sulfonamide Complex.

PubMed

Li, Yang; Deng, Ping; Zeng, Youmao; Xiong, Yan; Zhou, Hui

2016-04-01

A novel heterobimetallic Cu/Sm/aminophenol sulfonamide complex has been developed by a convenient one-pot method for the anti-selective asymmetric Henry reaction. The corresponding anti-β-nitro alcohols are obtained in up to 99% yield, >30:1 dr, and 98% ee. The results of control experiments and ESI-MS analysis of the complex indicate that the monomeric bimetallic Cu/Sm/1 complex would be the active species.

Carbamoyl anion-initiated cascade reaction for stereoselective synthesis of substituted α-hydroxy-β-amino amides.

PubMed

Lin, Chao-Yang; Ma, Peng-Ju; Sun, Zhao; Lu, Chong-Dao; Xu, Yan-Jun

2016-01-18

A carbamoyl anion-initiated cascade reaction with acylsilanes and imines has been used to rapidly construct substituted α-hydroxy-β-amino amides. The Brook rearrangement-mediated cascade allows the formation of two C-C bonds and one O-Si bond in a single pot. Using this approach, a range of α-aryl α-hydroxy-β-amino amides has been synthesized in high yields with excellent diastereoselectivities.

Combining silver- and organocatalysis: an enantioselective sequential catalytic approach towards pyrano-annulated pyrazoles.

PubMed

Hack, Daniel; Chauhan, Pankaj; Deckers, Kristina; Mizutani, Yusuke; Raabe, Gerhard; Enders, Dieter

2015-02-11

A one-pot asymmetric Michael addition/hydroalkoxylation sequence, catalyzed by a sequential catalytic system consisting of a squaramide and a silver salt, provides a new series of chiral pyrano-annulated pyrazole derivatives in excellent yields (up to 95%) and high enantioselectivities (up to 97% ee).

Microwave-assisted Maillard reactions for the preparation of advanced glycation end products (AGEs).

PubMed

Visentin, Sonja; Medana, Claudio; Barge, Alessandro; Giancotti, Valeria; Cravotto, Giancarlo

2010-05-21

The application of microwaves as an efficient form of volumetric heating to promote organic reactions was recognized in the mid-1980 s. It has a much longer history in the food research and industry where microwave irradiation was studied in depth to optimize food browning and the development of desirable flavours from Maillard reactions. The microwave-promoted Maillard reaction is a challenging synthetic method to generate molecular diversity in a straightforward way. In this paper we present a new rapid and efficient one-pot procedure for the preparation of pentosidine and other AGEs under microwave irradiation.

MICROWAVE IRRADIATION IN BENIGN SYNTHESIS OF ORGANIC MOLECULES, NOBLE NANOMETALS AND NANOCOMPOSITES

EPA Science Inventory

A brief historic account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds [1] from in situ generated reacti...

N-formylation of amines via the aerobic oxidation of methanol over supported gold nanoparticles.

PubMed

Ishida, Tamao; Haruta, Masatake

2009-01-01

Dress code: formyl. Gold nanoparticles supported on NiO catalyze the one-pot N-formylation of amines with methanol and molecular oxygen to produce formamide at a selectivity of 90 %. This process generates methyl formate in situ, followed by reaction with amines.

One pot synthesis of some new substituted hexahydro 2H-1,3-benzoxazine derivatives.

PubMed

Safak, C; Simsek, R; Altas, Y; Erol, K; Boydag, S

1996-09-01

In this paper, we synthesized nineteen new compounds having 2,4-diaryl-5-oxohexahydro-2H-1,3-benzoxazine structure by the reaction of 1,3-cyclohexanedione, aromatic aldehyde and ammonium acetate. In addition, we evaluated calcium antagonistic activity of these compounds versus nicardipine.

Titanium isopropoxide as efficient catalyst for the aza-Baylis-Hillman reaction. Selective formation of alpha-methylene-beta-amino acid derivatives.

PubMed

Balan, Daniela; Adolfsson, Hans

2002-04-05

The direct formation of alpha-methylene-beta-amino acid derivatives is achieved using the aza version of the Baylis-Hillman protocol. The products are readily formed in a three-component one-pot reaction between arylaldehydes, sulfonamides, and alpha,beta-unsaturated carbonyl compounds. The reaction is efficiently catalyzed by titanium isopropoxide and 2-hydroxyquinuclidine in the presence of molecular sieves. The protocol allows for structural variation of the substrates, tolerating electron-poor and electron-rich arylaldehydes and various Michael acceptors.

Synthesis of oxazolidine-2,4-diones by a tandem phosphorus-mediated carboxylative condensation-cyclization reaction using atmospheric carbon dioxide.

PubMed

Zhang, Wen-Zhen; Xia, Tian; Yang, Xu-Tong; Lu, Xiao-Bing

2015-04-11

The oxazolidine-2,4-dione motif is found frequently in biologically important compounds. A tandem phosphorus-mediated carboxylative condensation of primary amines and α-ketoesters/base-catalyzed cyclization reaction have been developed. These processes provide a novel and convenient access to various oxazolidine-2,4-diones in a one-pot fashion using atmospheric carbon dioxide and readily available substrates under very mild and transition-metal-free conditions.

Ultrasound promoted one pot synthesis of novel fluorescent triazolyl spirocyclic oxindoles using DBU based task specific ionic liquids and their antimicrobial activity.

PubMed

Singh, Harjinder; Sindhu, Jayant; Khurana, Jitender M; Sharma, Chetan; Aneja, K R

2014-04-22

Spirocyclic oxindoles and triazolyl derivatives posses remarkable biological activities. In present work, we have described an efficient one pot four-component domino reaction of 1-(prop-2-ynyl)indoline-2,3-dione, cyclic 1,3-diketones, malononitrile and various aryl azides in DBU based ionic liquids [DBU-H]OAc and [DBU-Bu]OH under ultrasonic irradiation for the construction of heterocycles, comprising spiro-oxindole, 2-amino-4H-pyran, and 1,2,3-triazoles substructures. The antimicrobial activity of all compounds has been investigated against six microbial strains. All compounds showed good antimicrobial activity. All newly synthesized compounds exhibit fluorescence in methanol with large stoke shift. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Silylative Reductive Amination of α,β-Unsaturated Aldehydes: A Convenient Synthetic Route to β-Silylated Secondary Amines.

PubMed

Kim, Eunae; Park, Sehoon; Chang, Sukbok

2018-04-17

Described here is a reductive amination/hydrosilylation cascade of α,β-unsaturated aldehydes mediated by a Lewis acidic borane catalyst. The present reaction system provides an one-pot synthetic route towards β-silylated secondary amines that have not been accessible by other previous catalysis. Comparative 1 H NMR studies on the silylative reduction of enimines revealed that steric bulkiness of primary amine reactants strongly affects both catalytic efficiency and regioselectivity. This strategy was applicable to a broad range of substrates and amenable to one-pot gram-scale synthesis. Moreover, a diastereoselective introduction of the β-silyl group was also found to be feasible (d.r. up to 71:29). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

First application of core-shell Ag@Ni magnetic nanocatalyst for transfer hydrogenation reactions of aromatic nitro and carbonyl compounds

EPA Science Inventory

A magnetic separable core-shell Ag@Ni nanocatalyst was prepared by a simple one-pot synthetic route using oleylamine both as solvent and reducing agent and triphenylphosphine as surfactant. The synthesized nanoparticles were characterized by several techniques such as X-ray diffr...

Transamination at the Crossroad of the One-Pot Synthesis of N-Substituted Quinonediimines and C-Substituted Benzobisimidazoles.

PubMed

Andeme Edzang, Judicaelle; Chen, Zhongrui; Audi, Hassib; Canard, Gabriel; Siri, Olivier

2016-10-10

A green and very efficient synthesis of N-substituted benzoquinonediimines or C-substituted benzo-bis(imidazole) derivatives is described under similar conditions. The different reaction pathway is only controlled by the nature of the primary amines, which tunes the reactivity of the intermediates.

A facile and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles using click chemistry

EPA Science Inventory

The reaction of α-tosyloxy ketones, sodium azide and terminal alkynes in presence of copper(I) in aqueous polyethylene glycol afforded regioselectively 1,4-disubstituted 1,2,3-triazoles in good yield at ambient temperature. The one-pot exclusive formation of 1,4-disubstituted 1,2...

Accelerated Combinatorial High Throughput Star Polymer Synthesis via a Rapid One-Pot Sequential Aqueous RAFT (rosa-RAFT) Polymerization Scheme.

PubMed

Cosson, Steffen; Danial, Maarten; Saint-Amans, Julien Rosselgong; Cooper-White, Justin J

2017-04-01

Advanced polymerization methodologies, such as reversible addition-fragmentation transfer (RAFT), allow unprecedented control over star polymer composition, topology, and functionality. However, using RAFT to produce high throughput (HTP) combinatorial star polymer libraries remains, to date, impracticable due to several technical limitations. Herein, the methodology "rapid one-pot sequential aqueous RAFT" or "rosa-RAFT," in which well-defined homo-, copolymer, and mikto-arm star polymers can be prepared in very low to medium reaction volumes (50 µL to 2 mL) via an "arm-first" approach in air within minutes, is reported. Due to the high conversion of a variety of acrylamide/acrylate monomers achieved during each successive short reaction step (each taking 3 min), the requirement for intermediary purification is avoided, drastically facilitating and accelerating the star synthesis process. The presented methodology enables RAFT to be applied to HTP polymeric bio/nanomaterials discovery pipelines, in which hundreds of complex polymeric formulations can be rapidly produced, screened, and scaled up for assessment in a wide range of applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-pot synthesis of metal-organic framework@SiO2 core-shell nanoparticles with enhanced visible-light photoactivity.

PubMed

Li, Zong-Qun; Wang, Ai; Guo, Chun-Yan; Tai, Yan-Fang; Qiu, Ling-Guang

2013-10-14

This paper presents a novel strategy to prepare Cu3(BTC)2@SiO2 core-shell nanoparticles in the size range of 200-400 nm using a new one-pot strategy under ultrasonic irradiation at room temperature. In this approach, the silica shell thickness could be finely tuned in the size range of 12-60 nm for various reaction times. Nanocomposite thin films were fabricated on the glass substrates by Sol-Gel spin coating using the products for 1.5 h, 2 h and 2.5 h, respectively, and heat treated using an infrared lamp heating system in air. The photocatalytic degradation of phenol in aqueous solution using Cu2(BTC)3@SiO2 thin films was investigated under visible light irradiation at pH 4. After a 45 min reaction with phenol, the degradation rate was up to 93.1%. Moreover, the thin film photocatalysts could be reused 5 times without appreciable loss of photocatalytic activity for degradation of phenol. The present work clearly shows that the films as photocatalysts showed higher photocatalytic performance.

Generation of efficient mutants of endoglycosidase from Streptococcus pyogenes and their application in a novel one-pot transglycosylation reaction for antibody modification

PubMed Central

Sekiguchi, Yukiko; Nakamura, Kensuke; Kawaguchi, Yoshirou; Honda, Takeshi; Hasegawa, Jun

2018-01-01

The fine structures of Fc N-glycan modulate the biological functions and physicochemical properties of antibodies. By remodeling N-glycan to obtain a homogeneous glycoform or chemically modified glycan, antibody characteristics can be controlled or modified. Such remodeling can be achieved by transglycosylation reactions using a mutant of endoglycosidase from Streptococcus pyogenes (Endo-S) and glycan oxazoline. In this study, we generated improved mutants of Endo-S by introducing additional mutations to the D233Q mutant. Notably, Endo-S D233Q/Q303L, D233Q/E350Q, and several other mutations resulted in transglycosylation efficiencies exceeding 90%, with a single-digit donor-to-substrate ratio of five, and D233Q/Y402F/D405A and several other mutations resulted in slightly reduced transglycosylation efficiencies accompanied by no detectable hydrolysis activity for 48 h. We further demonstrated that the combined use of mutants of Endo-S with Endo-M or Endo-CC, endoglycosidases from Mucor hiemalis and Coprinopsis cinerea, enables one-pot transglycosylation from sialoglycopeptide to antibodies. This novel reaction enables glycosylation remodeling of antibodies, without the chemical synthesis of oxazoline in advance or in situ. PMID:29474426

CuI/Pd0 cooperative dual catalysis: tunable stereoselective construction of tetra-substituted alkenes.

PubMed

Vercruysse, Sébastien; Cornelissen, Loïc; Nahra, Fady; Collard, Laurent; Riant, Olivier

2014-02-10

This paper describes a tunable and stereoselective dual catalytic system that uses copper and palladium reagents. This cooperative silylcupration and palladium-catalyzed allylation readily affords trisubstituted alkenylsilanes. Fine-tuning the reaction conditions allows selective access to one stereoisomer over the other. This new methodology tolerates different substituents on both coupling partners with high levels of stereoselectivity. The one-pot reaction involving a Cu(I)/Pd(0) cooperative dual catalyst directly addresses the need to develop more time-efficient and less-wasteful synthetic pathways. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Allylic Amination and N-Arylation-Based Domino Reactions Providing Rapid Three-Component Strategies to Fused Pyrroles with Different Substituted Patterns

PubMed Central

Jiang, Bo; Li, Ying; Tu, Man-Su; Wang, Shu-Liang; Tu, Shu-Jiang; Li, Guigen

2012-01-01

New three-component domino reaction providing divergent approaches to multi-functionalized fused pyrroles with different substituted patterns have been established (40 examples). The direct C(sp3)–N bond formation was achieved through intermolecular allylic amination in a one-pot operation; and N-arylation of amines was realized by varying N-amino acid enaminones. The reaction is easy to perform simply by mixing three common reactants in acetic acid under microwave heating. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good chemical yields. PMID:22852549

Reductive alkylation of active methylene compounds with carbonyl derivatives, calcium hydride and a heterogeneous catalyst.

PubMed

Guyon, Carole; Duclos, Marie-Christine; Sutter, Marc; Métay, Estelle; Lemaire, Marc

2015-07-07

A one-pot two-step reaction (Knoevenagel condensation - reduction of the double bond) has been developed using calcium hydride as a reductant in the presence of a supported noble metal catalyst. The reaction between carbonyl compounds and active methylene compounds such as methylcyanoacetate, 1,3-dimethylbarbituric acid, dimedone and the more challenging dimethylmalonate, affords the corresponding monoalkylated products in moderate to good yields (up to 83%) with minimal reduction of the starting carbonyl compounds.

Metal-organic-framework-derived carbons: Applications as solid-base catalyst and support for Pd nanoparticles in tandem catalysis

DOE PAGES

Li, Xinle; Zhang, Biying; Fang, Yuhui; ...

2017-02-11

Here, the facile pyrolysis of a bipyridyl metal-organic framework, MOF-253, produces N-doped porous carbons (Cz-MOF-253), which exhibit excellent catalytic activity in the Knoevenagel condensation reaction and outperform other nitrogen-containing MOF-derived carbons. More importantly, by virtue of their high Lewis basicity and porous nature, Cz-MOF-253-supported Pd nanoparticles (Pd/Cz-MOF-253-800) show excellent performance in a one-pot sequential Knoevenagel condensation-hydrogenation reaction.

Synthesis of zwitterionic salts of pyridinium-Meldrum acid and barbiturate through unique four-component reactions.

PubMed

Wang, Qi-Fang; Hui, Li; Hou, Hong; Yan, Chao-Guo

2010-03-08

An efficient synthetic procedure for the preparation of the unusual charge-separated pyridinium-Meldrum acid and N,N-dimethylbarbiturate acid zwitterionic salts was developed though a unique one-pot four-component reaction involving pyridine, aromatic aldehyde, Meldrum acid or N,N-dimethylbarbituric acid, and p-nitrobenzyl bromide in acetonitrile. By varying combinations of four components involving nitrogen-containing heterocycles, we conveniently established reactive alpha-halomethylene compounds, aldehydes and beta-dicarbonyl compounds a library of zwitterionic salts.

Vinyl azides derived from allenes: thermolysis leading to multisubstituted 1,4-pyrazines and Mn(III)-catalyzed photochemical reaction leading to pyrroles.

PubMed

Sajna, K V; Kumara Swamy, K C

2012-10-05

Thermolysis of phosphorus-based vinyl azides under solvent- and catalyst-free conditions furnished a new route for 1,4-pyrazines. A simple one-pot, Mn(III)-catalyzed photochemical route has been developed for multisubstituted pyrroles starting from allenes and 1,3-dicarbonyls via in situ-generated vinyl azides. The utility of new phosphorus-based pyrroles is also demonstrated in the Horner reaction. The structures of key products are unequivocally confirmed by X-ray crystallography.

Synthesis of phenanthridinones from N-methoxybenzamides and arenes by multiple palladium-catalyzed C-H activation steps at room temperature.

PubMed

Karthikeyan, Jaganathan; Cheng, Chien-Hong

2011-10-10

Many steps make light work: substituted phenanthridinones can be obtained with high regioselectivity and in very good yields by palladium-catalyzed cyclization reactions of N-methoxybenzamides with arenes. The reaction proceeds through multiple oxidative C-H activation and C-C/C-N formation steps in one pot at room temperature, and thus provides a simple method for generating bioactive phenanthridinones. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rhodium-catalyzed NH insertion of pyridyl carbenes derived from pyridotriazoles: a general and efficient approach to 2-picolylamines and imidazo[1,5-a]pyridines.

PubMed

Shi, Yi; Gulevich, Anton V; Gevorgyan, Vladimir

2014-12-15

A general and efficient NH insertion reaction of rhodium pyridyl carbenes derived from pyridotriazoles was developed. Various NH-containing compounds, including amides, anilines, enamines, and aliphatic amines, smoothly underwent the NH insertion reaction to afford 2-picolylamine derivatives. The developed transformation was further utilized in a facile one-pot synthesis of imidazo[1,5-a]pyridines. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-pot facile synthesis of 4-amino-1,8-naphthalimide derived Tröger's bases via a nucleophilic displacement approach.

PubMed

Shanmugaraju, Sankarasekaran; McAdams, Deirdre; Pancotti, Francesca; Hawes, Chris S; Veale, Emma B; Kitchen, Jonathan A; Gunnlaugsson, Thorfinnur

2017-09-13

We report here a novel one-pot synthetic strategy for the synthesis of a family of N-alkyl-1,8-naphthalimide based Tröger's bases via a nucleophilic substitution reaction of a common 'precursor' (or a 'synthon') N-aryl-1,8-naphthalimide Tröger's base heated at 80 °C in neat aliphatic primary amine, in overall yield of 65-96%. This methodology provides an efficient and one-step facile route to design 1,8-naphthalimide derived Tröger's base structures in analytically pure form without the use of column chromatography purification, that can be used in medicinal chemistry and as supramolecular scaffolds. We also report the formation of the corresponding anhydride, and the crystallographic analysis of two of the resulting products, that of the N-phenyl-4-amino-1,8-naphthalimide and the anhydride derived Tröger's bases.

Influence of platform design of six different drug-eluting stents in provisional coronary bifurcation stenting by rePOT sequence: a comparative bench analysis.

PubMed

Derimay, François; Souteyrand, Geraud; Motreff, Pascal; Rioufol, Gilles; Finet, Gerard

2017-10-13

The rePOT (proximal optimisation technique) sequence proved significantly more effective than final kissing balloon (FKB) with two drug-eluting stents (DES) in a bench test. We sought to validate efficacy experimentally in a large range of latest-generation DES. On left main fractal coronary bifurcation bench models, five samples of each of the six main latest-generation DES (Coroflex ISAR, Orsiro, Promus PREMIER, Resolute Integrity, Ultimaster, XIENCE Xpedition) were implanted on rePOT (initial POT, side branch inflation, final POT). Proximal elliptical ratio, side branch obstruction (SBO), stent overstretch and strut malapposition were quantified on 2D and 3D OCT. Results were compared to FKB with Promus PREMIER. Whatever the design, rePOT maintained vessel circularity compared to FKB: elliptical ratio, 1.02±0.01 to 1.04±0.01 vs. 1.26±0.02 (p<0.05). Global strut malapposition was much lower: 2.6±1.4% to 0.1±0.2% vs. 40.4±8.4% for FKB (p<0.05). However, only Promus PREMIER and XIENCE Xpedition achieved significantly less SBO: respectively, 5.6±3.5% and 10.0±5.3% vs. 23.5±5.7% for FKB (p<0.05). Platform design differences had little influence on the excellent results of rePOT versus FKB. RePOT optimised strut apposition without proximal elliptical deformation in the six main latest-generation DES. Thickness and design characteristics seemed relevant for optimising SBO.

Ultrasonic activated efficient synthesis of chromenes using amino-silane modified Fe3O4 nanoparticles: A versatile integration of high catalytic activity and facile recovery

NASA Astrophysics Data System (ADS)

Safari, Javad; Zarnegar, Zohre

2014-08-01

An efficient synthesis of 2-amino-4H-chromenes is achieved by one pot three component coupling reaction of aldehyde, malononitrile, and resorcinol using amino-silane modified Fe3O4 nanoparticles (MNPs-NH2) heterogeneous nanocatalyst under sonic condition. The attractive advantages of the present process are mild reaction conditions, short reaction times, easy isolation of products, good yields and simple operational procedures. Combination of the advantages of ultrasonic irradiation and magnetic nanoparticles provides important methodology to carry out catalytic transformations.

Multi-catalysis cascade reactions based on the methoxycarbonylketene platform: diversity-oriented synthesis of functionalized non-symmetrical malonates for agrochemicals and pharmaceuticals.

PubMed

Ramachary, Dhevalapally B; Venkaiah, Chintalapudi; Reddy, Y Vijayendar; Kishor, Mamillapalli

2009-05-21

In this paper we describe new multi-catalysis cascade (MCC) reactions for the one-pot synthesis of highly functionalized non-symmetrical malonates. These metal-free reactions are either five-step (olefination/hydrogenation/alkylation/ketenization/esterification) or six-step (olefination/hydrogenation/alkylation/ketenization/esterification/alkylation), and employ aldehydes/ketones, Meldrum's acid, 1,4-dihydropyridine/o-phenylenediamine, diazomethane, alcohols and active ethylene/acetylenes, and involve iminium-, self-, self-, self- and base-catalysis, respectively. Many of the products have direct application in agricultural and pharmaceutical chemistry.

Dynamic mechanistic modeling of the multienzymatic one-pot reduction of dehydrocholic acid to 12-keto ursodeoxycholic acid with competing substrates and cofactors.

PubMed

Sun, Boqiao; Hartl, Florian; Castiglione, Kathrin; Weuster-Botz, Dirk

2015-01-01

Ursodeoxycholic acid (UDCA) is a bile acid which is used as pharmaceutical for the treatment of several diseases, such as cholesterol gallstones, primary sclerosing cholangitis or primary biliary cirrhosis. A potential chemoenzymatic synthesis route of UDCA comprises the two-step reduction of dehydrocholic acid to 12-keto-ursodeoxycholic acid (12-keto-UDCA), which can be conducted in a multienzymatic one-pot process using 3α-hydroxysteroid dehydrogenase (3α-HSDH), 7β-hydroxysteroid dehydrogenase (7β-HSDH), and glucose dehydrogenase (GDH) with glucose as cosubstrate for the regeneration of cofactor. Here, we present a dynamic mechanistic model of this one-pot reduction which involves three enzymes, four different bile acids, and two different cofactors, each with different oxidation states. In addition, every enzyme faces two competing substrates, whereas each bile acid and cofactor is formed or converted by two different enzymes. First, the kinetic mechanisms of both HSDH were identified to follow an ordered bi-bi mechanism with EBQ-type uncompetitive substrate inhibition. Rate equations were then derived for this mechanism and for mechanisms describing competing substrates. After the estimation of the model parameters of each enzyme independently by progress curve analyses, the full process model of a simple batch-process was established by coupling rate equations and mass balances. Validation experiments of the one-pot multienzymatic batch process revealed high prediction accuracy of the process model and a model analysis offered important insight to the identification of optimum reaction conditions. © 2015 American Institute of Chemical Engineers.

NEW IONIC LIQUIDS CONTAINING AN APPENDED HYDROXYL FUNCTIONALITY FROM THE ATOM-EFFICIENT, ONE-POT REACTION OF 1-METHYLIMIDAZOLE AND ACID WITH PROPYLENE OXIDE. (R828257)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

On-Line Synthesis and Analysis by Mass Spectrometry

ERIC Educational Resources Information Center

Bain, Ryan M.; Pulliam, Christopher J.; Raab, Shannon A.; Cooks, R. Graham

2015-01-01

In this laboratory experiment, students learn how to use ESI to accelerate chemical synthesis and to couple it with on-line mass spectrometry for structural analysis. The Hantzsch synthesis of symmetric 1,4-dihydropyridines is a classic example of a one-pot reaction in which multiple intermediates can serve to indicate the progress of the reaction…

Convergent synthesis of 13N-labelled Peptidic structures using aqueous [13N]NH3.

PubMed

Blower, Julia E; Cousin, Samuel F; Gee, Antony D

2017-01-01

Nitrogen-13 has a 10-min half-life which places time constraints on the complexity of viable synthetic methods for its incorporation into PET imaging agents. In exploring ways to overcome this limitation, we have used the Ugi reaction to develop a rapid one-pot method for radiolabelling peptidic molecules using [ 13 N]NH 3 as a synthetic precursor. Carrier-added [ 13 N]NH 3 (50 μL) was added to a solution of carboxylic acid, aldehyde, and isocyanide in 2,2,2-TFE (200 μL). The mixture was heated in a microwave synthesiser at 120 °C for 10 min. Reactions were analysed by radio-HPLC and radio-LCMS. Isolation of the target 13 N-labelled peptidic Ugi compound was achieved via semi-preparative radio-HPLC as demonstrated for Ugi 1. Radio-HPLC analysis of each reaction confirmed the formation of radioactive products co-eluting with their respective reference standards with radiochemical yields of the crude products ranging from 11% to 23%. Two cyclic γ-lactam structures were also achieved via intra-molecular reactions. Additional radioactive by-products observed in the radio-chromatogram were identified as 13 N-labelled di-imines formed from the reaction of [ 13 N]NH 3 with two isocyanide molecules. The desired 13 N-labelled Ugi product was isolated using semi-preparative HPLC. We have developed a one-pot method that opens up new routes to radiolabel complex, peptidic molecules with 13 N using aqueous [ 13 N]NH 3 as a synthetic precursor.

A comparison investigation of optical, structural and luminescence properties of CdOxTe1-x and CdTexSe1-x nanoparticles prepared by a simple one pot method

NASA Astrophysics Data System (ADS)

Kiprotich, Sharon; Onani, Martin O.; Dejene, Francis B.

2018-04-01

We present L-cysteine capped CdOXTe1-X and CdTeXSe1-X nanoparticles (NPs) prepared in one pot. The as-prepared CdOXTe1-X NPs were found to have a hexagonal crystal structure of CdTe with a cubic phase of CdO. There was, however, change in phase to cubic type when 2 mM of Se was introduced into the CdTe at 60 min of reaction time. The average crystallite sizes obtained from X-ray diffraction analysis for CdOXTe1-X and CdTeXSe1-X NPs were in the range of 10-36 nm. The diffraction peaks shifted to higher diffraction angle with longer growth time. Scanning electron microscope images display change in shape and size as reaction progress. Photoluminescence (PL) emission was observed to shift from 510-566 nm and 620-653 nm for CdOXTe1-X and CdTeXSe1-X NPs respectively followed by variation in the peak intensities. The emission spectra displayed a good symmetry and a narrow full width at half maximum ranging from 41 to 100 nm in both cases. The absorbance analysis of the as-prepared NPs displayed well-resolved absorption bands. The optical band gaps of the as-prepared NPs were found to decrease with increase in reaction time. Reaction parameters such as pH, reaction time, reaction temperature and the molar concentration could have major effects on the optical properties of the as-prepared nanoparticles hence their need to control them.

Forward design of a complex enzyme cascade reaction

PubMed Central

Hold, Christoph; Billerbeck, Sonja; Panke, Sven

2016-01-01

Enzymatic reaction networks are unique in that one can operate a large number of reactions under the same set of conditions concomitantly in one pot, but the nonlinear kinetics of the enzymes and the resulting system complexity have so far defeated rational design processes for the construction of such complex cascade reactions. Here we demonstrate the forward design of an in vitro 10-membered system using enzymes from highly regulated biological processes such as glycolysis. For this, we adapt the characterization of the biochemical system to the needs of classical engineering systems theory: we combine online mass spectrometry and continuous system operation to apply standard system theory input functions and to use the detailed dynamic system responses to parameterize a model of sufficient quality for forward design. This allows the facile optimization of a 10-enzyme cascade reaction for fine chemical production purposes. PMID:27677244

Synthesis of aryl thioethers through the N-chlorosuccinimide-promoted cross-coupling reaction of thiols with Grignard reagents.

PubMed

Cheng, Jun-Hao; Ramesh, Chintakunta; Kao, Hsin-Lun; Wang, Yu-Jen; Chan, Chien-Ching; Lee, Chin-Fa

2012-11-16

A convenient one-pot approach for the synthesis of aryl sulfides through the coupling of thiols with Grignard reagents in the presence of N-chlorosuccinimide is described. The sulfenylchlorides were formed when thiols were treated with N-chlorosuccinimide, and the resulting sulfenylchlorides were then directly reacted with Grignard reagents to provide aryl sulfides in good to excellent yields under mild reaction conditions. Functional groups including ester, fluoro, and chloro are tolerated by the reaction conditions employed. It is important to note that this method has a short reaction time (30 min in total) and represents an alternative approach for the synthesis of aryl sulfides over the existing protocols.

Direct Synthesis of Protoberberine Alkaloids by Rh-Catalyzed C-H Bond Activation as the Key Step.

PubMed

Jayakumar, Jayachandran; Cheng, Chien-Hong

2016-01-26

A one-pot reaction of substituted benzaldehydes with alkyne-amines by a Rh-catalyzed C-H activation and annulation to afford various natural and unnatural protoberberine alkaloids is reported. This reaction provides a convenient route for the generation of a compound library of protoberberine salts, which recently have attracted great attention because of their diverse biological activities. In addition, pyridinium salt derivatives can also be formed in good yields from α,β-unsaturated aldehydes and amino-alkynes. This reaction proceeds with excellent regioselectivity and good functional group compatibility under mild reaction conditions by using O2 as the oxidant. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methodology for in situ protection of aldehydes and ketones using trimethylsilyl trifluoromethanesulfonate and phosphines: selective alkylation and reduction of ketones, esters, amides, and nitriles.

PubMed

Yahata, Kenzo; Minami, Masaki; Yoshikawa, Yuki; Watanabe, Kei; Fujioka, Hiromichi

2013-01-01

A methodology for selective transformations of ketones, esters, Weinreb amides, and nitriles in the presence of aldehydes has been developed. The use of a combination of PPh(3)-trimethylsilyl trifluoromethanesulfonate (TMSOTf) promotes selective transformation of aldehydes to their corresponding, temporarily protected, O,P-acetal type phosphonium salts. Because, hydrolytic work-up following ensuing reactions of other carbonyl moieties in the substrates liberates the aldehyde moiety, a sequence involving aldehyde protection, transformation of other carbonyl groups, and deprotection can be accomplished in a one-pot manner. Furthermore, the use of PEt(3) instead of PPh(3) enables ketones to be converted in situ to their corresponding O,P-ketal type phosphonium salts and, consequently, selective transformations of esters, Weinreb amides, and nitriles in the presence of ketones can be performed. This methodology is applicable to various dicarbonyl compounds, including substrates that possess heteroaromatic skeletons and hydroxyl protecting groups.

Diastereoselective syntheses of 3-aryl-5-(arylalkyl)-6-methyl-1-(1-phenylethyl)thioxotetrahydropyrimidin-4(1H)-ones: a stereochemical perspective from endo and exocyclic chiral centres.

PubMed

Kumar, Varun; Raghavaiah, Pallepogu; Mobin, Shaikh M; Nair, Vipin A

2010-11-07

Diastereoselective syntheses of 3-aryl-(S/R)-6-methyl-1-[(S/R)-1-phenylethyl)]-2-thioxotetrahydro pyrimidin-4(1H)-ones were achieved in good yields by the condensation of aryl isothiocyanates with ethyl 3-(1-phenylethylamino)butanoate in a one-pot reaction. Benzylation of these substrates illustrated that the orientations of the exocylic and endocylic groups determine the stereochemical outcome of the product formed.

Unexpected formation of 2,1-benzisothiazol-3-ones from oxathiolano ketenimines: a rare tandem process.

PubMed

Alajarin, Mateo; Bonillo, Baltasar; Sanchez-Andrada, Pilar; Vidal, Angel; Bautista, Delia

2009-03-19

A rare one-pot reaction, a tandem [1,5]-H shift/1,5 electrocyclization/[3 + 2] cycloreversion process, leading from N-[2-(1,3-oxathiolan-2-yl)]phenyl ketenimines to 1-(beta-styryl)-2,1-benzisothiazol-3-ones and ethylene, is disclosed and mechanistically unraveled by means of a computational DFT study. The two latter stages of the tandem process are calculated to occur in a single mechanistic step via a transition structure of pseudopericyclic characteristics.

One-pot multienzyme (OPME) systems for chemoenzymatic synthesis of carbohydrates

PubMed Central

Yu, Hai; Chen, Xi

2016-01-01

Glycosyltransferase-catalyzed enzymatic and chemoenzymatic syntheses are powerful approaches for the production of oligosaccharides, polysaccharides, glycoconjugates, and their derivatives. Enzymes involved in the biosynthesis of sugar nucleotide donors can be combined with the glycosyltransferases in one pot for efficient production of target glycans from simple monosaccharides and accpetors. The identification of enzymes involved in the salvage pathway of sugar nucleotide generation has greatly facilitate the development of simplified and efficient one-pot multienzyme (OPME) systems for synthesizing major glycan epitopes in mammalian glycomes. The applications of OPME methods are steadily gaining popularity mainly due to the increasing availability of wild-type and engineered enzymes. Substrate promiscuity of these enzymes and their mutants allows OPME synthesis of carbohydrates with naturally occurring post-glycosylational modificiation (PGMs) and their non-natural derivatives using modified monosaccharides as precursors. The OPME systems can be applied in sequential for synthesizing complex carbohydrates. The sequence of the sequential OPME processes, the glycosyltransferase used, and the substrate specificities of glycosyltransferasese define the structures of the products. The OPME and sequential OPME strategies can be extended to diverse glycans in other glycomes when suitable enzymes with substrate promiscuity become available. The Perspective summariezes the work of the authors and collaborators on the development of glycosyltransferase-based OPME systems for carbohydrate synthesis. Future directions are also discussed. PMID:26881499

One-pot aldol condensation and hydrodeoxygenation of biomass-derived carbonyl compounds for biodiesel synthesis.

PubMed

Faba, Laura; Díaz, Eva; Ordóñez, Salvador

2014-10-01

Integrating reaction steps is of key interest in the development of processes for transforming lignocellulosic materials into drop-in fuels. We propose a procedure for performing the aldol condensation (reaction between furfural and acetone is taken as model reaction) and the total hydrodeoxygenation of the resulting condensation adducts in one step, yielding n-alkanes. Different combinations of catalysts (bifunctional catalysts or mechanical mixtures), reaction conditions, and solvents (aqueous and organic) have been tested for performing these reactions in an isothermal batch reactor. The results suggest that the use of bifunctional catalysts and aqueous phase lead to an effective integration of both reactions. Therefore, selectivities to n-alkanes higher than 50% were obtained using this catalyst at typical hydrogenation conditions (T=493 K, P=4.5 MPa, 24 h reaction time). The use of organic solvent, carbonaceous supports, or mechanical mixtures of monofunctional catalysts leads to poorer results owing to side effects; mainly, hydrogenation of reactants and adsorption processes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential effect of ultrasound on carbohydrates.

PubMed

Bera, Smritilekha; Mondal, Dhananjoy; Martin, Jacob T; Singh, Man

2015-06-17

The use of ultrasound has emerged as one of the most useful alternative energy sources for the synthesis of carbohydrate-derived biologically and pharmaceutically potential compounds. Spectacular advances have been made in the field of sonication-assisted organic reactions, which are known for producing superior yields, enhanced reactivity of the reactant, improved stereoselectivity, and shortened reaction times. Orthogonal protection-deprotection reactions and/or modification and manipulation of functional groups in carbohydrates are common synthetic steps in carbohydrate chemistry. These reaction steps can be driven by the ultrasonic energy generated by acoustic cavitation via the formation and subsequent collapse of ultrasound-induced bubbles. The ultrasound-assisted synthesis of differently functionalised monosaccharides is useful in a wide variety of applications of carbohydrate chemistry such as the glycosylation of oligosaccharides, one pot domino reactions, thioglycoside syntheses, azidoglycoside syntheses, 1,3-dipolar cycloaddition reactions, and syntheses of natural products. This review article covers ultrasound-mediated reactions on carbohydrates that have been described in the literature since 2000. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis and Characterization of 9-Hydroxyphenalenone Using 2D NMR Techniques

ERIC Educational Resources Information Center

Caes, Benjamin; Jensen, Dell, Jr.

2008-01-01

9-Hydroxyphenalenone is a planar multicyclic [beta]-keto-enol, which is synthesized via a Friedel-Crafts acylation followed by acid-catalyzed intramolecular Michael addition with the loss of a phenyl group in a one-pot reaction during a four-hour lab period. Tautomerization of the [beta]-keto-enol results in C[subscript 2v] symmetry on the NMR…

Asymmetric Synthesis of Spiropyrazolones by Sequential Organo- and Silver Catalysis

PubMed Central

Hack, Daniel; Dürr, Alexander B; Deckers, Kristina; Chauhan, Pankaj; Seling, Nico; Rübenach, Lukas; Mertens, Lucas; Raabe, Gerhard; Schoenebeck, Franziska; Enders, Dieter

2016-01-01

A stereoselective one-pot synthesis of spiropyrazolones through an organocatalytic asymmetric Michael addition and a formal Conia-ene reaction has been developed. Depending on the nitroalkene, the 5-exo-dig-cyclization could be achieved by silver-catalyzed alkyne activation or by oxidation of the intermediate enolate. The mechanistic pathways have been investigated using computational chemistry and mechanistic experiments. PMID:26676875

Oxidative tandem nitrosation/cyclization of N-aryl enamines with nitromethane toward 3-(trifluoromethyl)quinoxalines.

PubMed

Yang, Zhi-Jun; Liu, Chuan-Zhuo; Hu, Bo-Lun; Deng, Chen-Liang; Zhang, Xing-Guo

2014-12-04

A novel one-pot strategy for the synthesis of 3-trifluoromethylquinoxalines from N-aryl enamines and nitromethane was developed. The tandem reaction is achieved through nitrosation of alkenes, tautomerization and cyclization, which can be applicable to a wide range of enamines with excellent functional group tolerance and afford quinoxalines in moderate to good yields.

Base-catalyzed bicyclization of dialkyl glutaconates with cinnamoylacetamides: a synthetic strategy for isoquinolinedione derivatives.

PubMed

Li, Lei; Zhao, Yu-Long; Wang, He; Li, Yi-Jin; Xu, Xianxiu; Liu, Qun

2014-06-21

We report here that polysubstituted dihydroisoquinolones and isoquinolones can be constructed by the one-pot reaction of the readily available acyclic α,β-unsaturated carbonyl precursors and dialkyl glutaconates under mild basic conditions (1-45 min for the former vs. 1-6 h for the latter) via the domino process involving [3+3] annulation/intramolecular aza-cyclization.

C-Terminal Protein Characterization by Mass Spectrometry: Isolation of C-Terminal Fragments from Cyanogen Bromide-Cleaved Protein

PubMed Central

Nika, Heinz; Hawke, David H.; Angeletti, Ruth Hogue

2014-01-01

A sample preparation method for protein C-terminal peptide isolation from cyanogen bromide (CNBr) digests has been developed. In this strategy, the analyte was reduced and carboxyamidomethylated, followed by CNBr cleavage in a one-pot reaction scheme. The digest was then adsorbed on ZipTipC18 pipette tips for conjugation of the homoserine lactone-terminated peptides with 2,2′-dithiobis (ethylamine) dihydrochloride, followed by reductive release of 2-aminoethanethiol from the derivatives. The thiol-functionalized internal and N-terminal peptides were scavenged on activated thiol sepharose, leaving the C-terminal peptide in the flow-through fraction. The use of reversed-phase supports as a venue for peptide derivatization enabled facile optimization of the individual reaction steps for throughput and completeness of reaction. Reagents were replaced directly on the support, allowing the reactions to proceed at minimal sample loss. By this sequence of solid-phase reactions, the C-terminal peptide could be recognized uniquely in mass spectra of unfractionated digests by its unaltered mass signature. The use of the sample preparation method was demonstrated with low-level amounts of a whole, intact model protein. The C-terminal fragments were retrieved selectively and efficiently from the affinity support. The use of covalent chromatography for C-terminal peptide purification enabled recovery of the depleted material for further chemical and/or enzymatic manipulation. The sample preparation method provides for robustness and simplicity of operation and is anticipated to be expanded to gel-separated proteins and in a scaled-up format to high-throughput protein profiling in complex biological mixtures. PMID:24688319

Zinc-oxide-silica-silver nanocomposite: Unique one-pot synthesis and enhanced catalytic and anti-bacterial performance.

PubMed

Kokate, Mangesh; Garadkar, Kalyanrao; Gole, Anand

2016-12-01

We describe herein a unique approach to synthesize zinc oxide-silica-silver (ZnO-SiO2-Ag) nanocomposite, in a simple, one-pot process. The typical process for ZnO synthesis by alkaline precipitation of zinc salts has been tweaked to replace alkali by alkaline sodium silicate. The free acid from zinc salts helps in the synthesis of silica nanoparticles, whereas the alkalinity of sodium silicate precipitates the zinc salts. Addition of silver ions into the reaction pot prior to addition of sodium silicate, and subsequent reduction by borohydride, gives additional functionality of metallic centres for catalytic applications. The synthesis strategy is based on our recent work typically involving acid-base type of cross-reactions and demonstrates a novel strategy to synthesize nanocomposites in a one-pot approach. Each component in the composite offers a unique feature. ZnO besides displaying mild catalytic and anti-bacterial behaviour is an excellent and a cheap 3-D support for heterogeneous catalysis. Silver nanoparticles enhance the catalytic & anti-bacterial properties of ZnO. Silica is an important part of the composite; which not only "glues" the two nanoparticles thereby stabilizing the nanocomposite, but also significantly enhances the surface area of the composite; which is an attractive feature of any catalyst composite. The nanocomposite is found to show excellent catalytic performance with very high turnover frequencies (TOFs) when studied for catalytic reduction of Rhodamine B (RhB) and 4-Nitrophenol (4-NP). Additionally, the composite has been tested for its anti-bacterial properties on three different bacterial strains i.e. E. coli, B. Cereus and Bacillus firmus. The mechanism for enhancement of catalytic performance has been probed by understanding the role of silica in offering accessibility to the catalyst via its porous high surface area network. The nanocomposite has been characterized by a host of different analytical techniques. The uniqueness of our product and process stems from the novel synthesis strategy, the choice and combination of the three moieties, increased surface area offered by silica, and cost effectiveness, thereby making our product and process commercially viable and sustainable for industrial applications. Copyright © 2016 Elsevier Inc. All rights reserved.

One-pot pseudomorphic crystallization of mesoporous porous silica to hierarchical porous zeolites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xing, Jun-Ling; Jiang, Shu-Hua; Pang, Jun-Ling

2015-09-15

Hierarchically porous silica with mesopore and zeolitic micropore was synthesized via pseudomorphic crystallization under high-temperature hydrothermal treatment in the presence of cetyltrimethylammonium tosylate and tetrapropylammonium ions. A combined characterization using small-angle X-ray diffraction (XRD), nitrogen adsorption, high-resolution transmission electron microscopy (TEM), thermogravimetric analysis (TG), and elemental analysis showed that dual templates, CTA{sup +} and TPA{sup +} molecules, can work in a cooperative manner to synthesize mesoporous zeolite in a one-pot system by precisely tuning the reaction conditions, such as reaction time and temperature, and type and amount of heterometal atoms. It is found that the presence of Ti precursor ismore » critical to the successful synthesis of such nanostructure. It not only retards the nucleation and growth of crystalline MFI domains, but also acts as nano-binder or nano-glue to favor the assembly of zeolite nanoblocks. - Graphical abstract: Display Omitted - Highlights: • A facile method to synthesize mesoporous zeolites with hierarchical porosity was presented. • It gives a new insight into keeping the balance between mesoscopic and molecular ordering in hierarchical porous materials. • A new understanding on the solid–solid transformation mechanism for the synthesis of titanosilicate zeolites was proposed.« less

Single-step One-pot Synthesis of TiO2 Nanosheets Doped with Sulfur on Reduced Graphene Oxide with Enhanced Photocatalytic Activity.

PubMed

Wang, Weilin; Wang, Zhaofeng; Liu, Jingjing; Luo, Zhu; Suib, Steven L; He, Peng; Ding, Guqiao; Zhang, Zhengguo; Sun, Luyi

2017-04-21

A hybrid photocatalyst based on anatase TiO 2 was designed by doping TiO 2 with sulfur and incorporating reduced graphene oxide (TiO 2 -S/rGO hybrid), with an aim to narrow the band gap to potentially make use of visible light and decrease the recombination of excitons, respectively. This TiO 2 -S/rGO hybrid was successfully synthesized using a one-pot hydrothermal method via single-step reaction. The structure and morphology of the TiO 2 -S/rGO hybrid catalyst was carefully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Its photocatalytic reactivity was evaluated by the degradation of methyl blue. The results showed that both the doping of sulfur and the introduction of rGO worked as designed, and the TiO 2 -S/rGO hybrid exhibited high photocatalytic activity under simulated sunlight. Considering both the facile and scalable reaction to synthesize TiO 2 -S/rGO hybrid, and its excellent photocatalytic performance, such TiO 2 -S/rGO hybrids are expect to find practical applications in environmental and energy sectors.

Single-step One-pot Synthesis of TiO2 Nanosheets Doped with Sulfur on Reduced Graphene Oxide with Enhanced Photocatalytic Activity

NASA Astrophysics Data System (ADS)

Wang, Weilin; Wang, Zhaofeng; Liu, Jingjing; Luo, Zhu; Suib, Steven L.; He, Peng; Ding, Guqiao; Zhang, Zhengguo; Sun, Luyi

2017-04-01

A hybrid photocatalyst based on anatase TiO2 was designed by doping TiO2 with sulfur and incorporating reduced graphene oxide (TiO2-S/rGO hybrid), with an aim to narrow the band gap to potentially make use of visible light and decrease the recombination of excitons, respectively. This TiO2-S/rGO hybrid was successfully synthesized using a one-pot hydrothermal method via single-step reaction. The structure and morphology of the TiO2-S/rGO hybrid catalyst was carefully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Its photocatalytic reactivity was evaluated by the degradation of methyl blue. The results showed that both the doping of sulfur and the introduction of rGO worked as designed, and the TiO2-S/rGO hybrid exhibited high photocatalytic activity under simulated sunlight. Considering both the facile and scalable reaction to synthesize TiO2-S/rGO hybrid, and its excellent photocatalytic performance, such TiO2-S/rGO hybrids are expect to find practical applications in environmental and energy sectors.

A novel mesoporous sulfated zirconium solid acid catalyst for Friedel-Crafts benzylation reaction

NASA Astrophysics Data System (ADS)

Miao, Zhichao; Zhou, Jin; Zhao, Jinping; Liu, Dandan; Bi, Xu; Chou, Lingjun; Zhuo, Shuping

2017-07-01

In this paper, a novel mesoporous sulfated zirconium (M-ZrO2/SO42-) has been gotten by one-pot evaporation-induced self-assembly (one-pot EISA) strategy. The SXRD, N2-physisorption and TEM characterization techniques indicated that M-ZrO2/SO42- possessed distinct mesostructure with big specific surface area (133.5 m2 g-1), large pore volume (0.18 cm3 g-1) and narrow pore size distribution (4.90 nm). Moreover, the existing states and the influence in mesostructure of introduced S species were detailedly investigated by the XRD, N2-physisorption, TEM, TG-DSC, FT-IR and XPS techniques and the results showed that the S species, which existed as the type of SO42-, improved the textural properties of prepared materials. In addition, the NH3-TPD and IR spectra of adsorbed pyridine indicated the existence of strong Brønsted and Lewis acid sites in M-ZrO2/SO42- even evacuated at 400 °C. Furthermore, the M-ZrO2/SO42- was used as a promise solid acid catalyst and displayed excellent catalytic performance and reusability in Friedel-Crafts benzylation reaction.

From biomass to chemicals: synthesis of precursors of biodegradable surfactants from 5-hydroxymethylfurfural.

PubMed

Arias, K S; Al-Resayes, Saud I; Climent, Maria J; Corma, Avelino; Iborra, Sara

2013-01-01

The selective acetalization of 5-hydroxymethylfurfural (HMF) with long-chain alkyl alcohols has been performed to obtain precursors of molecules with surfactant properties. If direct acetalization of HMF with n-octanol is performed in the presence of strong acids (homogeneous and heterogeneous catalysts), an increase in etherification versus acetalization occurs. Beta zeolite catalyzes both reactions. However, if the acidity of a zeolite (Beta) was controlled by partial exchange of H(+) with Na(+), the dioctyl acetal of HMF can be achieved in 95% yield by transacetalization. It is possible to achieve a high yield in a very short reaction time through a two-step one-pot process, which includes the synthesis of the dimethyl acetal of HMF followed by transacetalization with n-octanol. The one-pot process could be extended to other alcohols that contain 6-12 carbon atoms to afford 87-98% yield of the corresponding dialkyl acetal with a selectivity higher than 96%. The optimized catalyst with an adequate Na content (1.5NaBeta) could be recycled without loss of activity or selectivity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physicochemical fabrication of antibacterial calcium phosphate submicrospheres with dispersed silver nanoparticles via coprecipitation and photoreduction under laser irradiation.

PubMed

Nakamura, Maki; Oyane, Ayako; Shimizu, Yoshiki; Miyata, Saori; Saeki, Ayumi; Miyaji, Hirofumi

2016-12-01

We achieved rapid, surfactant-free, and one-pot fabrication of antibacterial calcium phosphate (CaP) submicrospheres containing silver nanoparticles by combining physical laser and chemical coprecipitation processes. In this physicochemical process, weak pulsed laser irradiation (20min) was performed on a labile CaP reaction mixture supplemented with silver ions as a light-absorbing agent. The silver content in the submicrospheres was controlled for a wide range (Ag/P elemental ratio varied from 0.60 to 62.0) by tuning the initial concentration of silver ions (from 5 to 20mM) in the CaP reaction mixture. At the silver concentration of 5mM, we obtained unique nanocomposite particles: CaP submicrospheres (average diameter of approximately 500nm) containing metallic silver nanoparticles dispersed throughout, as a result of CaP and silver coprecipitation with simultaneous photoreduction of silver ions and spheroidization of the coprecipitates. These CaP submicrospheres containing silver nanoparticles (ca. 0.3mg silver per 1mg submicrospheres) exhibited antibacterial activity against major pathogenic oral bacteria, i.e., Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. Moreover, the CaP submicrospheres dissolved and neutralized the acidic environment generated by Streptococcus mutans, demonstrating their potential as acid-neutralizing and remineralizing agents. The present process and resulting antibacterial CaP-based submicrospheres are expected to be useful in dental healthcare and infection control. Nano- and microsized spheres of calcium phosphate (CaP) containing silver nanoparticles have great potential in dental applications. Conventional fabrication processes were time-consuming or weak regarding the size/shape control of the spheres. In this study, we achieved a simple (one-pot), rapid (20-min irradiation), and surfactant-free fabrication of CaP submicrospheres containing silver nanoparticles by pulsed laser irradiation to a mixture of calcium, phosphate, and silver ion solutions. The resulting CaP submicrospheres contained metallic silver nanoparticles dispersed throughout in a sequence of reactions: CaP and silver coprecipitation, laser-induced melting and spheroidization of the coprecipitates, and photoreduction of silver ions. These submicrospheres showed antibacterial activity against oral bacteria and acid-neutralizing property in the bacterial suspension, and hence are worth considering for dental applications. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A convenient synthesis of 1,1-disubstituted 1,2,3,4-tetrahydroisoquinolines via Pictet-Spengler reaction using titanium(IV) isopropoxide and acetic-formic anhydride.

PubMed

Horiguchi, Yoshie; Kodama, Hirokazu; Nakamura, Masayoshi; Yoshimura, Tsuyoshi; Hanezi, Kaori; Hamada, Hiroko; Saitoh, Toshiaki; Sano, Takehiro

2002-02-01

A synthesis of 1,1-disubstituted 1,2,3,4-tetrahydroisoquinolines (6) was achieved in a highly efficient manner via Pictet-Spengler reaction of arylethylamines (1) and acyclic and cyclic ketones (2) using titanium (IV) isopropoxide and acetic-formic anhydride. The cyclization of the in situ formed acyliminium ion (4) to N-formyl 1,2,3,4-tetrahydroisoquinoline (5) was greatly facilitated by using trifluoroacetic acid as an additional reagent. The Pictet-Spengler reaction was carried out by one pot procedure, providing a convenient and effective method for preparing various 1,2,3,4-tetrahydroisoquinolines.

Silica functionalized Cu(II) acetylacetonate Schiff base complex: An efficient catalyst for the oxidative condensation reaction of benzyl alcohol with amines

NASA Astrophysics Data System (ADS)

Anbarasu, G.; Malathy, M.; Karthikeyan, P.; Rajavel, R.

2017-09-01

Silica functionalized Cu(II) acetylacetonate Schiff base complex via the one pot reaction of silica functionalized 3-aminopropyltriethoxysilane with acetyl acetone and copper acetate has been reported. The synthesized material was well characterized by analytical techniques such as FT-IR, UV-DRS, XRD, SEM-EDX, HR-TEM, EPR, ICP-AES and BET analysis. The characterization results confirmed the grafting of Cu(II) Schiff base complex on the silica surface. The catalytic activity of synthesized silica functionalized Cu(II) acetylacetonate Schiff base complex was evaluated through the oxidative condensation reaction of benzyl alcohol to imine.

One-Pot Silver Nanoring Synthesis

NASA Astrophysics Data System (ADS)

Drogat, Nicolas; Granet, Robert; Sol, Vincent; Krausz, Pierre

2010-03-01

Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV-vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation.

One-pot silver nanoring synthesis.

PubMed

Drogat, Nicolas; Granet, Robert; Sol, Vincent; Krausz, Pierre

2009-12-16

Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV-vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation.

One-Pot Silver Nanoring Synthesis

PubMed Central

2010-01-01

Silver colloidal nanorings have been synthesized by reducing silver ions with NaBH4 in trisodium citrate buffers. pH increase, by addition of NaOH, was used to speed up reduction reaction. The UV–vis absorption spectra of resulting silver nanorings showed two peaks accounting for transverse and longitudinal surface plasmon resonance, at ≈400 nm, and between 600 and 700 nm, respectively. The shapes of these silver nanoparticles (nanorings) depended on AgNO3/NaBH4 ratio, pH and reaction temperature. Particles were analysed by transmission electron microscopy, scanning electron microscopy and X-ray diffraction. A reaction pathway is proposed to explain silver nanoring formation. PMID:20672109

Copper-promoted sandmeyer difluoromethylthiolation of aryl and heteroaryl diazonium salts.

PubMed

Wu, Jiang; Gu, Yang; Leng, Xuebing; Shen, Qilong

2015-06-22

An efficient copper-promoted difluoromethylthiolation of aryl and heteroaryl diazonium salts is described. The reaction is conducted under mild reaction conditions and various functional groups were compatible. In addition, reactions of heteroaryl diazonium salts such as pyridyl, quinolinyl, benzothiazolyl, thiophenyl, carbazolyl, and pyrazolyl diazonium salts occurred smoothly to afford the medicinally important difluoromethylthiolated heteroarenes. Furthermore, a more practical one-pot direct diazotization and difluoromethylthiolation protocol was developed, and it converts the aniline derivatives into difluoromethylthiolated arenes. The utility of the method is demonstrated by difluoromethylthiolation of a number of natural products and drug molecules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid Construction of Complex 2-Pyrrolines through Lewis Acid-Catalyzed, Sequential Three-Component Reactions via in Situ-Generated 1-Azaallyl Cations.

PubMed

Schlegel, Marcel; Schneider, Christoph

2018-05-09

The first Sc(OTf) 3 -catalyzed dehydration of 2-hydroxy oxime ethers to generate benzylic stabilized 1-azaallyl cations, which are captured by 1,3-carbonyls, is described. A subsequent addition of primary amines in a sequential three-component reaction affords highly substituted and densely functionalized tetrahydroindeno[2,1- b]pyrroles as single diastereomers with up to quantitative yield. Thus, three new σ-bonds and two vicinal quaternary stereogenic centers are generated in a one-pot operation.

Copper-free route to triazole-modified peptidomimetic by the combination of two multicomponent reactions in one pot.

PubMed

Niu, Teng-fei; Gu, Lin; Yi, Wen-bin; Cai, Chun

2012-05-14

An efficient copper-free protocol for the synthesis of 5-methyl-1H-1,2,3-triazole-modified peptidomimetics through the combination of Ugi four-component reaction with a three-component cycloaddition, has been developed. The copper-free straightforward process is suitable for drug discovery. The chemoselective preparation of 1,4-disubstituted, triazole-modified peptidomimetics by using alkynyl substituted amines may have potential biological and synthetic application. At last, a "Lapinski type" analysis of the physical properties was performed, which is expected to help drug discovery.

Preparation of 3,5-disubstituted pyrazoles and isoxazoles from terminal alkynes, aldehydes, hydrazines, and hydroxylamine.

PubMed

Harigae, Ryo; Moriyama, Katsuhiko; Togo, Hideo

2014-03-07

The reaction of terminal alkynes with n-BuLi, and then with aldehydes, followed by the treatment with molecular iodine, and subsequently hydrazines or hydroxylamine provided the corresponding 3,5-disubstituted pyrazoles or isoxazoles in good yields with high regioselectivity, through the formations of propargyl secondary alkoxides and α-alkynyl ketones. The present reactions are one-pot preparation of 3,5-disubstituted pyrazoles from terminal alkynes, aldehydes, molecular iodine, and hydrazines, and 3,5-disubstituted isoxazoles from terminal alkynes, aldehydes, molecular iodine, and hydroxylamine.

A one-pot, microwave-influenced synthesis of diverse small molecules by multicomponent reaction cascades.

PubMed

Santra, Soumava; Andreana, Peter R

2007-11-22

Small molecule diversity can be achieved in a single synthetic operation from bifunctional substrates in the absence of additives and under the influence of microwaves with complete control of pathway selectivity. The preliminary Ugi four-component coupling products give rise to three structurally distinct scaffolds that are dependent on solvent effects and sterics. 2,5-Diketopiperazines (Type A), 2-azaspiro[4.5]deca-6,9-diene-3,8-diones (Type B), and thiophene-derived Diels-Alder tricyclic lactams (Type C) predominate in this reaction cascade.

A one-pot synthesis of bis(phenylimino)thiazolidines from ketene N,S-acetals and [Formula: see text],[Formula: see text]-diphenyloxalimidoyl dichloride.

PubMed

Yavari, Issa; Zahedi, Nooshin; Baoosi, Leila; Skoulika, Stavroula

2018-02-01

A synthesis of functionalized 4,5-bis(phenylimino)-1,3-thiazolidine-2-ylidenes via a simple reaction between ketene [Formula: see text]-acetals (derived from isothiocyanates and acetonitrile derivatives) with N,[Formula: see text]-diphenyloxalimidoyl dichloride in the presence of KOH in DMF is described. When CS[Formula: see text] was used as the heterocumulene component, the reaction led to the formation of 4,5-bis(phenylimino)-1,3-dithiolan-2-ylidene derivatives, in moderate to good yields.

RPA and POT1: friends or foes at telomeres?

PubMed

Flynn, Rachel Litman; Chang, Sandy; Zou, Lee

2012-02-15

Telomere maintenance in cycling cells relies on both DNA replication and capping by the protein complex shelterin. Two single-stranded DNA (ssDNA)-binding proteins, replication protein A (RPA) and protection of telomere 1 (POT1) play critical roles in DNA replication and telomere capping, respectively. While RPA binds to ssDNA in a non-sequence-specific manner, POT1 specifically recognizes singlestranded TTAGGG telomeric repeats. Loss of POT1 leads to aberrant accumulation of RPA at telomeres and activation of the ataxia telangiectasia and Rad3-related kinase (ATR)-mediated checkpoint response, suggesting that POT1 antagonizes RPA binding to telomeric ssDNA. The requirement for both POT1 and RPA in telomere maintenance and the antagonism between the two proteins raises the important question of how they function in concert on telomeric ssDNA. Two interesting models were proposed by recent studies to explain the regulation of POT1 and RPA at telomeres. Here, we discuss how these models help unravel the coordination, and also the antagonism, between POT1 and RPA during the cell cycle.

One-pot palladium-catalyzed synthesis of sulfonyl fluorides from aryl bromides† †Electronic supplementary information (ESI) available: Experimental details and supporting characterisation data. See DOI: 10.1039/c6sc03924c Click here for additional data file.

PubMed Central

Davies, Alyn T.; Curto, John M.

2017-01-01

A mild, efficient synthesis of sulfonyl fluorides from aryl and heteroaryl bromides utilizing palladium catalysis is described. The process involves the initial palladium-catalyzed sulfonylation of aryl bromides using DABSO as an SO2 source, followed by in situ treatment of the resultant sulfinate with the electrophilic fluorine source NFSI. This sequence represents the first general method for the sulfonylation of aryl bromides, and offers a practical, one-pot alternative to previously described syntheses of sulfonyl fluorides, allowing rapid access to these biologically important molecules. Excellent functional group tolerance is demonstrated, with the transformation successfully achieved on a number of active pharmaceutical ingredients, and their precursors. The preparation of peptide-derived sulfonyl fluorides is also demonstrated. PMID:28451264

Elucidation of the structure-property relationship of p-type organic semiconductors through rapid library construction via a one-pot, Suzuki-Miyaura coupling reaction.

PubMed

Fuse, Shinichiro; Matsumura, Keisuke; Wakamiya, Atsushi; Masui, Hisashi; Tanaka, Hiroshi; Yoshikawa, Susumu; Takahashi, Takashi

2014-09-08

The elucidation of the structure-property relationship is an important issue in the development of organic electronics. Combinatorial synthesis and the evaluation of systematically modified compounds is a powerful tool in the work of elucidating structure-property relationships. In this manuscript, D-π-A structure, 32 p-type organic semiconductors were rapidly synthesized via a one-pot, Suzuki-Miyaura coupling with subsequent Knoevenagel condensation. Evaluation of the solubility and photovoltaic properties of the prepared compounds revealed that the measured solubility was strongly correlated with the solubility parameter (SP), as reported by Fedors. In addition, the SPs were correlated with the Jsc of thin-film organic solar cells prepared using synthesized compounds. Among the evaluated photovoltaic properties of the solar cells, Jsc and Voc had strong correlations with the photoconversion efficiency (PCE).

One-pot synthesis of hierarchical Cu{sub 2}O/Cu hollow microspheres with enhanced visible-light photocatalytic activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Tianjie; Tao, Feifei, E-mail: feifeitao@usx.edu.cn; Lin, Jiudong

2015-08-15

The hierarchical Cu{sub 2}O/Cu hollow microspheres have been fabricated by the one-pot solvothermal redox method, which is one-step approach without any surfactant and template. By using the HRTEM, XRD, XPS and UV–vis spectroscopy, the as-prepared product is composed of Cu{sub 2}O and Cu with energy band gap of 1.72 eV. Based on the time-dependent experiments, the content of Cu{sub 2}O and Cu compositions can be effectively controlled by adjusting the reaction time and a possible mechanism is proposed. In addition, using various dye molecules to stimulate pollutants, the hierarchical Cu{sub 2}O/Cu hollow microspheres reacted for 8 h exhibit excellent visible-lightmore » photocatalytic activities, which is much higher than those of the Cu{sub 2}O/Cu catalysts formed at the shorter reaction time, commercial Cu{sub 2}O powder and the mixture of alone Cu{sub 2}O and Cu. This enhanced photocatalytic performance makes these hierarchical Cu{sub 2}O/Cu hollow microspheres a kind of efficient visible-light photocatalyst in removing some organic compounds in wastewater. - Graphical abstract: The hierarchical Cu{sub 2}O/Cu hollow microspheres with adjustable components have been synthesized by one-step solvothermal redox approach. The special structures and composition lead to the excellent visible-light photocatalytic activity. - Highlights: • The hierarchical Cu{sub 2}O/Cu hollow microspheres are fabricated by one-step approach. • The content of Cu{sub 2}O and Cu can be controlled by adjusting the reaction time. • The material exhibits a better visible-light photocatalytic activity and stability. • Degradation kinetics of MO by Cu{sub 2}O/Cu fits the pseudo first-order model.« less

Gold-nanoparticle-catalyzed synthesis of propargylamines: the traditional A3-multicomponent reaction performed as a two-step flow process.

PubMed

Abahmane, Lahbib; Köhler, J Michael; Gross, G Alexander

2011-03-01

The alkyne, aldehyde, amine A(3)-coupling reaction, a traditional multicomponent reaction (MCR), has been investigated as a two-step flow process. The implicated aminoalkylation reaction of phenylacetylene with appropriate aldimine intermediates was catalyzed by gold nanoparticles impregnated on alumina. The aldimine formation was catalyzed by Montmorillonite K10 beforehand. The performance of the process has been investigated with respect to different reaction regimes. Usually, the A(3)-multicomponent reaction is performed as a "one-pot" process. Diversity-oriented syntheses using MCRs often have the shortcoming that only low selectivity and low yields are achieved. We have used a flow-chemistry approach to perform the A(3)-MCR in a sequential manner. In this way, the reaction performance was significantly enhanced in terms of shortened reaction time, and the desired propargylamines were obtained in high yields. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Titanocene(III)-Catalyzed Three-Component Reaction of Secondary Amides, Aldehydes, and Electrophilic Alkenes.

PubMed

Zheng, Xiao; He, Jiang; Li, Heng-Hui; Wang, Ao; Dai, Xi-Jie; Wang, Ai-E; Huang, Pei-Qiang

2015-11-09

An umpolung Mannich-type reaction of secondary amides, aliphatic aldehydes, and electrophilic alkenes has been disclosed. This reaction features the one-pot formation of C-N and C-C bonds by a titanocene-catalyzed radical coupling of the condensation products, from secondary amides and aldehydes, with electrophilic alkenes. N-substituted γ-amido-acid derivatives and γ-amido ketones can be efficiently prepared by the current method. Extension to the reaction between ketoamides and electrophilic alkenes allows rapid assembly of piperidine skeletons with α-amino quaternary carbon centers. Its synthetic utility has been demonstrated by a facile construction of the tricyclic core of marine alkaloids such as cylindricine C and polycitorol A. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Alkanes from Bioderived Furans by using Metal Triflates and Palladium-Catalyzed Hydrodeoxygenation of Cyclic Ethers.

PubMed

Song, Hai-Jie; Deng, Jin; Cui, Min-Shu; Li, Xing-Long; Liu, Xin-Xin; Zhu, Rui; Wu, Wei-Peng; Fu, Yao

2015-12-21

Using a metal triflate and Pd/C as catalysts, alkanes were prepared from bioderived furans in a one-pot hydrodeoxygenation (HDO) process. During the reaction, the metal triflate plays a crucial role in the ring-opening HDO of furan compounds. The entire reaction process has goes through two major phases: at low temperatures, saturation of the exocyclic double bond and furan ring are catalyzed by Pd/C; at high temperatures, the HDO of saturated furan compounds is catalyzed by the metal triflate. The reaction mechanism was verified by analyzing the changes of the intermediates during the reaction. In addition, different metal triflates, solvents, and catalyst recycling were also investigated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concurrent extraction and reaction for the production of biodiesel from wet microalgae.

PubMed

Im, Hanjin; Lee, HanSol; Park, Min S; Yang, Ji-Won; Lee, Jae W

2014-01-01

This work addresses a reliable in situ transesterification process which integrates lipid extraction from wet microalgae, and its conversion to biodiesel, with a yield higher than 90 wt.%. This process enables single-step production of biodiesel from microalgae by mixing wet microalgal cells with solvent, methanol, and acid catalyst; and then heating them in one pot. The effects of reaction parameters such as reaction temperature, wet cell weight, reaction time, and catalyst volume on the conversion yield are investigated. This simultaneous extraction and transesterification of wet microalgae may enable a significant reduction in energy consumption by eliminating the drying process of algal cells and realize the economic production of biodiesel using wet microalgae. Copyright © 2013 Elsevier Ltd. All rights reserved.

Preparation of a N-Heterocyclic Carbene Nickel(II) Complex: Synthetic Experiments in Current Organic and Organometallic Chemistry

ERIC Educational Resources Information Center

Ritleng, Vincent; Brenner, Eric; Chetcuti, Michael J.

2008-01-01

A four-part experiment that leads to the synthesis of a cyclopentadienyl chloro-nickel(II) complex bearing a N-heterocyclic carbene (NHC) ligand is presented. In the first part, the preparation of 1,3-bis-(2,4,6-trimethylphenyl)imidazolium chloride (IMes[middle dot]HCl) in a one-pot procedure by reaction of 2,4,6-trimethylaniline with…

Metal-free one-pot oxidative amination of aldehydes to amides.

PubMed

Ekoue-Kovi, Kekeli; Wolf, Christian

2007-08-16

Metal-free oxidative amination of aromatic aldehydes in the presence of TBHP provides convenient access to amides in 85-99% under mild reaction conditions within 5 h. This method avoids free carboxylic acid intermediates and integrates aldehyde oxidation and amide bond formation, which are usually accomplished separately, into a single operation. Proline-derived amides can be prepared in excellent yields without noticeable racemization.

Recent advances in heterobimetallic palladium(II)/copper(II) catalyzed domino difunctionalization of carbon-carbon multiple bonds.

PubMed

Beccalli, Egle M; Broggini, Gianluigi; Gazzola, Silvia; Mazza, Alberto

2014-09-21

The double functionalization of carbon-carbon multiple bonds in one-pot processes has emerged in recent years as a fruitful tool for the rapid synthesis of complex molecular scaffolds. This review covers the advances in domino reactions promoted by the couple palladium(ii)/copper(ii), which was proven to be an excellent catalytic system for the functionalization of substrates.

Sandwich-type tetrakis(phthalocyaninato) dysprosium-cadmium quadruple-decker SMM.

PubMed

Wang, Hailong; Qian, Kang; Wang, Kang; Bian, Yongzhong; Jiang, Jianzhuang; Gao, Song

2011-09-14

Homoleptic tetrakis[2,3,9,10,16,17,23,24-octa(butyloxy)phthalocyaninato] dysprosium-cadmium quadruple-decker complex 1 was isolated in relatively good yield of 43% from a simple one-pot reaction. This compound represents the first sandwich-type tetrakis(phthalocyaninato) rare earth-cadmium quadruple-decker SMM that has been structurally characterized. This journal is © The Royal Society of Chemistry 2011

A hydrogen fuel cell for rapid, enzyme-catalysed organic synthesis with continuous monitoring.

PubMed

Wan, Lei; Megarity, Clare F; Siritanaratkul, Bhavin; Armstrong, Fraser A

2018-01-23

A one-pot fuel cell for specific, enzyme-catalysed organic synthesis, with continuous monitoring of rate and reaction progress, combines an electrode catalysing rapid, reversible and diffusion-controlled interconversion of NADP + and NADPH with a Pt electrode catalysing 2H + /H 2 interconversion. This Communication demonstrates its performance and characteristics using the reductive amination of 2-oxoglutarate as a test system.

Spent Pot Lining Characterization Framework

NASA Astrophysics Data System (ADS)

Ospina, Gustavo; Hassan, Mohamed I.

2017-09-01

Spent pot lining (SPL) management represents a major concern for aluminum smelters. There are two key elements for spent pot lining management: recycling and safe storage. Spent pot lining waste can potentially have beneficial uses in co-firing in cement plants. Also, safe storage of SPL is of utmost importance. Gas generation of SPL reaction with water and ignition sensitivity must be studied. However, determining the feasibility of SPL co-firing and developing the required procedures for safe storage rely on determining experimentally all the necessary SPL properties along with the appropriate test methods, recognized by emissions standards and fire safety design codes. The applicable regulations and relevant SPL properties for this purpose are presented along with the corresponding test methods.

A multiple multicomponent approach to chimeric peptide-peptoid podands.

PubMed

Rivera, Daniel G; León, Fredy; Concepción, Odette; Morales, Fidel E; Wessjohann, Ludger A

2013-05-10

The success of multi-armed, peptide-based receptors in supramolecular chemistry traditionally is not only based on the sequence but equally on an appropriate positioning of various peptidic chains to create a multivalent array of binding elements. As a faster, more versatile and alternative access toward (pseudo)peptidic receptors, a new approach based on multiple Ugi four-component reactions (Ugi-4CR) is proposed as a means of simultaneously incorporating several binding and catalytic elements into organizing scaffolds. By employing α-amino acids either as the amino or acid components of the Ugi-4CRs, this multiple multicomponent process allows for the one-pot assembly of podands bearing chimeric peptide-peptoid chains as appended arms. Tripodal, bowl-shaped, and concave polyfunctional skeletons are employed as topologically varied platforms for positioning the multiple peptidic chains formed by Ugi-4CRs. In a similar approach, steroidal building blocks with several axially-oriented isocyano groups are synthesized and utilized to align the chimeric chains with conformational constrains, thus providing an alternative to the classical peptido-steroidal receptors. The branched and hybrid peptide-peptoid appendages allow new possibilities for both rational design and combinatorial production of synthetic receptors. The concept is also expandable to other multicomponent reactions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A phosphine mediated sequential annulation process of 2-tosylaminochalcones with MBH carbonates to construct functionalized aza-benzobicyclo[4.3.0] derivatives.

PubMed

Zhang, Qinglong; Zhu, Yannan; Jin, Hongxing; Huang, You

2017-04-04

A novel phosphine mediated sequential annulation process to construct functionalized aza-benzobicyclo[4.3.0] derivatives has been developed involving a one-pot sequential catalytic and stoichiometric process, which generates a series of benzobicyclo[4.3.0] compounds containing one quaternary center with up to 94% yield and 20 : 1 dr value. In this reaction, MBH carbonates act as 1,2,3-C 3 synthons.

One-pot synthesis of 4,8-dibromobenzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole.

PubMed

Tam, Teck Lip; Li, Hairong; Wei, Fengxia; Tan, Ke Jie; Kloc, Christian; Lam, Yeng Ming; Mhaisalkar, Subodh G; Grimsdale, Andrew C

2010-08-06

A one-step synthesis of 4,8-dibromobenzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole with use of 1,2,4,5-tetraaminobenzene tetrahydrobromide and thionyl bromide in good yield is reported. This unit can then be used in the synthesis of low bandgap materials via palladium-catalyzed coupling reactions. The approach offers a quick and easy way to prepare low bandgap materials as compared to the current literature methods.

One-Pot Synthesis of Mesoporous Ni-Ti-Al Ternary Oxides: Highly Active and Selective Catalysts for Steam Reforming of Ethanol.

PubMed

Gonçalves, Alexandre A S; Faustino, Patrícia B; Assaf, José M; Jaroniec, Mietek

2017-02-22

One-pot synthesis of nanostructured ternary oxides of Ni, Al, and Ti was designed and performed via evaporation induced self-assembly (EISA). For the purpose of comparison, analogous oxides were also prepared by the impregnation method. The resulting materials were applied in two catalytic reactions: steam reforming of ethanol (SRE) for H 2 production (subjected to prior activation with H 2 ) and ethanol dehydration (ED; used without prior activation), to in situ analyze carbon accumulation by ethylene depletion when ethanol interacts with acidic sites present on the support. Modification of Ni-Al mixed oxides with titania was shown to have several benefits. CO 2 , NH 3 , and propylamine sorption data indicate a decrease in the strength of acidic and basic sites after addition of titania, which in turn slowed down the carbon accumulation during the ED reaction. These changes in interactions between ethanol and byproducts with the support led to different reaction pathways in SRE, indicating that the catalysts obtained by EISA with titania addition showed higher ethylene selectivity and CO 2 /CO ratios. The opposite was observed for the impregnated catalysts, which were less coke-stable during ED reactions and showed no ethylene selectivity in SRE. Carbon formed during ED reactions was shown to be thermodynamically less favorable and easier to decompose in the presence of titania. All catalysts studied displayed similar and high selectivities (∼80%) and yields (∼5.3 mol H2 /mol ethanol ) toward H 2 , which place them among the most active and selective catalysts for SRE. These results indicate the importance of tailoring the support surface acidity to achieve high reforming performance and higher selectivity toward SRE, one of the key processes to produce cleaner and efficient fuels. For an efficient reforming process, the yield of byproducts is low but still they affect the catalyst stability in the long-run, thus this work may impact future studies toward development of near-zero coke catalysts.

Divergent reaction pathways for one-pot, three-component synthesis of novel 4H-pyrano[3,2-h]quinolines under ultrasound irradiation.

PubMed

Al-Bogami, Abdullah S; Saleh, Tamer S; Zayed, Ehab M

2013-09-01

The present paper deal with the multi-component condensation of 8-hydroxy quinoline, aromatic aldehydes, and sulfone derivatives catalyzed by p-toluenesulfonic acid for the synthesis of a series of 4H-pyrano[3,2-h]quinoline derivatives in ethanol under ultrasonic irradiations. We provide a series of quinoline derivatives containing sulfone moiety interesting for biological screening tests. The reactions were carried out under both conventional and ultrasonic irradiation conditions. In general, improvement in rates and yields were observed when reactions were carried out under sonication compared with classical silent conditions. Also, also, sonochemical reaction give different reaction pathway other than silent reaction. These remarkable effects appeared in sonicated reactions can be reasonably interpreted in terms of acoustic cavitation phenomenon. Structures of the products were established on analytical and spectral data. Copyright © 2013 Elsevier B.V. All rights reserved.

Chemistry with spatial control using particles and streams†

PubMed Central

Kalinin, Yevgeniy V.; Murali, Adithya

2012-01-01

Spatial control of chemical reactions, with micro- and nanometer scale resolution, has important consequences for one pot synthesis, engineering complex reactions, developmental biology, cellular biochemistry and emergent behavior. We review synthetic methods to engineer this spatial control using chemical diffusion from spherical particles, shells and polyhedra. We discuss systems that enable both isotropic and anisotropic chemical release from isolated and arrayed particles to create inhomogeneous and spatially patterned chemical fields. In addition to such finite chemical sources, we also discuss spatial control enabled with laminar flow in 2D and 3D microfluidic networks. Throughout the paper, we highlight applications of spatially controlled chemistry in chemical kinetics, reaction-diffusion systems, chemotaxis and morphogenesis. PMID:23145348

One-pot synthesis of biologically active 1,2,3-trisubstituted pyrrolo[2,3-b]quinoxalines through a palladium-catalyzed reaction with internal alkyne moieties.

PubMed

Keivanloo, Ali; Besharati-Seidani, Tayebeh; Kaboudin, Babak; Yoshida, Akihiro; Yokomatsu, Tsutomu

2018-06-16

Synthesis of 2,3-disubstituted 1-alkylpyrrolo[2,3-b]quinoxalines was accomplished through the reaction of 3-chloroquinoxalin-2-amines with internal alkynes in the presence of Pd(OAc)[Formula: see text], NaOAc, and KOtBu in DMSO. This method afforded desired pyrrolo[2,3-b]quinoxalines in 65-92% reaction yields. The minimum inhibition concentration and minimum bactericidal concentration determinations against Micrococcus luteus and Pseudomonas aeruginosa revealed that some of the synthesized compounds showed the same values compared to tetracycline. These compounds could be used in the future research for the development of new antibiotics.

Ultrasound mediated, iodine catalyzed green synthesis of novel 2-amino-3-cyano-4H-pyran derivatives.

PubMed

Tabassum, Sumaiya; Govindaraju, Santhosh; Khan, Riyaz-ur-Rahaman; Pasha, Mohamed Afzal

2015-05-01

An efficient synthesis of a novel series of twelve substituted 2-amino-3-cyano-4H-pyran derivatives was achieved by a one-pot three-component cyclocondensation reaction of heteroaryl aldehydes, malononitrile and active methylene compounds catalyzed by iodine in aqueous medium under ultrasound irradiation. In comparison with conventional methods, our protocol is convenient and offers several advantages, such as shorter reaction time, higher yields, milder conditions and environmental friendliness. We have herein successfully demonstrated the synergistic outcome of multi-component reaction (MCR) and sonication to offer a facile route for the design of these derivatives. Copyright © 2014 Elsevier B.V. All rights reserved.

Convenient stereocontrolled amidoglycosylation of alcohols with acetylated glycals and trichloroethoxysulfonamide.

PubMed

Murakami, Teiichi; Sato, Yukari; Yoshioka, Kyoko; Tanaka, Mutsuo

2016-11-03

A regio- and stereo-controlled, rhodium(II)-catalyzed amidoglycosylation of alcohols has been developed using O-acetylated glycals, trichloroethoxysulfonamide, and iodosobenzene. This one-pot amidoglycosylation was applied to a variety of primary and secondary alcohols to afford the β-O-glycosides with acceptable yields up to 84%. The reaction would proceed via stereoselective intermolecular aziridination of the glycal from the α-face followed by S N 2 reaction with alcohol at C-1 from the β-face to give 1,2:2,3-di-trans-substituted isomer only. Copyright © 2016 Elsevier Ltd. All rights reserved.

(CF3CO)2O/CF3SO3H-mediated synthesis of 1,3-diketones from carboxylic acids and aromatic ketones

PubMed Central

Kim, JungKeun; Shokova, Elvira; Tafeenko, Victor

2014-01-01

Summary A very simple and convenient reaction for 1,3-diketone preparation from carboxylic acids and aromatic ketones in TFAA/TfOH system is described. When the β-phenylpropionic acids were used as starting materials, they initially gave 1-indanones and then underwent further acylation with the formation of 2-(β-phenylpropionyl)-1-indanones as the main reaction products. In addition, the application of the proposed protocol allowed for the synthesis of selected polysubstituted pyrazoles in a one-pot procedure directly from acids and ketones. PMID:25298794

A thermoresponsive nanorattle containing two different catalysts for controllable one-pot tandem catalysis

NASA Astrophysics Data System (ADS)

Niu, Chengrong; Hu, Jie; Li, Yinfeng; Leng, Jinghang; Li, Songjun

2018-03-01

In the present work, a thermoresponsive nanorattle with a Ag nanoparticle (NP) core (one catalyst in the nanorattle), and a poly(N-isopropylacrylamide) shell was developed. An imidazole group was grafted on the polymer shell by copolymerization as the other catalyst. Owing to the catalytic activities of the imidazole group and Ag NP with regards to hydrolysis and reduction, respectively, this nanorattle exhibited tandem-reaction catalytic abilities. In addition, because of the shrinkage of the poly(N-isopropylacrylamide) shell at high temperatures, the tandem reaction could be controlled to stop at the first reaction step. That is to say, only the hydrolysis reaction was catalyzed by the imidazole group being grafted on the surface of the shell. The reduction step in the tandem reaction catalyzed by the Ag particle, however, was switched off by the shrinkage of the poly(N-isopropylacrylamide) shell. This protocol opens up an opportunity to develop controllable catalysts for complicated chemical processes.

A facile one-pot hydrothermal approach for the preparation of CuO/rGO nanocomposites with different morphologies

NASA Astrophysics Data System (ADS)

Ajit, Akshata V.; Gawli, Yogesh P.; Ethiraj, Anita Sagadevan

2018-05-01

Graphene-based metal oxides such as Cu2O, SnO2, CuO, Fe3O4, MnO2 are promising candidates for many applications because of their advantageous properties. Amongst all, CuO has been widely studied because of its excellent electrocatalytic activity. Although many methodologies have been developed for the synthesis of CuO/graphene nanostructures with different morphologies including nanorods, nanoparticles, nanosheets, flower, urchin; not many investigations have been done on one pot synthesis method for CuO/reduced graphene oxide (rGO) nanocomposites to achieve different morphologies. Therefore in the present work effort has been made to synthesize various CuO-rGO nanocomposites via surfactant (CTAB) assisted hydrothermal method. Detailed study was performed to monitor the effect of various reaction parameters like temperature, reaction time, reactant concentration on the synthesized nanocomposites. Several analytical tools, including XRD, SEM, FTIR and UV-Vis spectroscopy have been utilized to characterize the samples. XRD results showed formation of monoclinic structure of CuO along with presence of rGO. Calculated optical bandgap studies indicate decrease in the bandgap of synthesized CuO (Eg=4.5eV-4.34eV) with increase in temperature from 120°C to 180°C. Our results clearly demonstrate that reaction parameters play a key role to bring out the optical and morphological changes in the CuO-rGO nanocomposites.

Recent biocatalytic oxidation–reduction cascades

PubMed Central

Schrittwieser, Joerg H; Sattler, Johann; Resch, Verena; Mutti, Francesco G; Kroutil, Wolfgang

2011-01-01

The combination of an oxidation and a reduction in a cascade allows performing transformations in a very economic and efficient fashion. The challenge is how to combine an oxidation with a reduction in one pot, either by running the two reactions simultaneously or in a stepwise fashion without isolation of intermediates. The broader availability of various redox enzymes nowadays has triggered the recent investigation of various oxidation–reduction cascades. PMID:21130024

Cyanide-bridged decanuclear cobalt-iron cage.

PubMed

Shiga, Takuya; Tetsuka, Tamaki; Sakai, Kanae; Sekine, Yoshihiro; Nihei, Masayuki; Newton, Graham N; Oshio, Hiroki

2014-06-16

A cyanide-bridged decanuclear [Co6Fe4] cluster was synthesized by a one-pot reaction, and the magnetic properties and electronic configuration were investigated. The complex displayed thermally controlled electron-transfer-coupled spin transition (ETCST) behavior between Co(III) low-spin-NC-Fe(II) low-spin and Co(II) high-spin-NC-Fe(III) low-spin states, as confirmed by single-crystal X-ray, magnetic, and Mössbauer analyses.

Single-step One-pot Synthesis of TiO 2 Nanosheets Doped with Sulfur on Reduced Graphene Oxide with Enhanced Photocatalytic Activity

DOE PAGES

Wang, Weilin; Wang, Zhaofeng; Liu, Jingjing; ...

2017-04-21

A hybrid photocatalyst based on anatase TiO 2 was designed by doping TiO 2 with sulfur and incorporating reduced graphene oxide (TiO 2-S/rGO hybrid), with an aim to narrow the band gap to potentially make use of visible light and decrease the recombination of excitons, respectively. This TiO 2-S/rGO hybrid was successfully synthesized using a one-pot hydrothermal method via single-step reaction. The structure and morphology of the TiO 2-S/rGO hybrid catalyst was carefully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Its photocatalytic reactivity was evaluated by the degradation ofmore » methyl blue. The results showed that both the doping of sulfur and the introduction of rGO worked as designed, and the TiO 2-S/rGO hybrid exhibited high photocatalytic activity under simulated sunlight. Finally, considering both the facile and scalable reaction to synthesize TiO 2-S/rGO hybrid, and its excellent photocatalytic performance, such TiO 2-S/rGO hybrids are expect to find practical applications in environmental and energy sectors.« less

Synthesis, molecular docking, antimicrobial, antioxidant and toxicity assessment of quinoline peptides.

PubMed

Thangaraj, Muthu; Gengan, Robert Moonsamy; Ranjan, Bibhuti; Muthusamy, Ramesh

2018-01-01

A series of quinoline based peptides were synthesized by a one-pot reaction through Ugi-four component condensation of lipoic acid, cyclohexyl isocyanide, aniline derivatives and 2-methoxy quinoline-3-carbaldehyde derivatives under microwave irradiation. The products were obtained in excellent yields and high purity. Solvent optimization and the effect of microwave irradiation with various powers were also observed. All the synthesized compounds were characterized by FTIR, NMR spectral data and elemental analysis. A total of eight peptides were subjected to antimicrobial, antioxidant and toxicity evaluation. Among them, four peptides showed potential towards antibacterial screening with Bacillus cereus, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Candida albicans, Candida utilis and three peptides showed antioxidant test positive (DPPH). Besides, toxicity of all the peptides were evaluated by using brine shrimp and it was observed that four peptides showed mortality rate less than 50% up to 48h. Molecular docking studies revealed that the higher binding affinity of the two peptides toward DNA gyrase than ciprofloxacin based on Libdock score. The described chemistry represents a facile tool to synthesize complex heterocycles of pharmaceutical relevance in a highly efficient and one-pot fashion. The advantages of this method are its green approach, inexpensive solvent, shorter reaction times and excellent yields. Copyright © 2017 Elsevier B.V. All rights reserved.

One-Pot Anchoring of Pd Nanoparticles on Nitrogen-Doped Carbon through Dopamine Self-Polymerization and Activity in the Electrocatalytic Methanol Oxidation Reaction.

PubMed

Li, Xin; Niu, Xiangheng; Zhang, Wenchi; He, Yanfang; Pan, Jianming; Yan, Yongsheng; Qiu, Fengxian

2017-03-09

Exploration of advanced electrocatalysts to promote the sluggish methanol oxidation reaction (MOR) is of vital importance for developing high efficiency and low-cost direct methanol fuel cells. Highly dispersed palladium nanoparticles (Pd NPs) anchored on a nitrogen-doped carbon support were fabricated using a facile one-pot dopamine self-polymerization mediated redox strategy, in which dopamine not only acted as a moderate reductant to induce the formation of Pd NPs during self-polymerization but was also the precursor of the nitrogen-doped carbon support for Pd. The synthesized hybrid features the following characteristics: 1) High dispersity of Pd NPs, which exposed a high abundance of active surfaces and sites for heterogeneous electrocatalysis; 2) metal-support interactions, which may affect the surface chemistry and electron distribution of active Pd NPs; 3) the Pd NPs were partially imbedded or encapsulated into the support, thus reducing the possible agglomeration of Pd NPs during cyclic measurements. The electrocatalyst with such favorable features provided higher mass activity (2.2 times that of commercial Pd/C) and better durability (reduced loss of activity during simulated frequent startup-shutdown operations) for the MOR in alkaline media. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Single-step One-pot Synthesis of TiO2 Nanosheets Doped with Sulfur on Reduced Graphene Oxide with Enhanced Photocatalytic Activity

PubMed Central

Wang, Weilin; Wang, Zhaofeng; Liu, Jingjing; Luo, Zhu; Suib, Steven L.; He, Peng; Ding, Guqiao; Zhang, Zhengguo; Sun, Luyi

2017-01-01

A hybrid photocatalyst based on anatase TiO2 was designed by doping TiO2 with sulfur and incorporating reduced graphene oxide (TiO2-S/rGO hybrid), with an aim to narrow the band gap to potentially make use of visible light and decrease the recombination of excitons, respectively. This TiO2-S/rGO hybrid was successfully synthesized using a one-pot hydrothermal method via single-step reaction. The structure and morphology of the TiO2-S/rGO hybrid catalyst was carefully characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Its photocatalytic reactivity was evaluated by the degradation of methyl blue. The results showed that both the doping of sulfur and the introduction of rGO worked as designed, and the TiO2-S/rGO hybrid exhibited high photocatalytic activity under simulated sunlight. Considering both the facile and scalable reaction to synthesize TiO2-S/rGO hybrid, and its excellent photocatalytic performance, such TiO2-S/rGO hybrids are expect to find practical applications in environmental and energy sectors. PMID:28429736

One-pot synthesis of GDP-l-fucose by a four-enzyme cascade expressed in Lactococcus lactis.

PubMed

Li, Ling; Kim, Seul-Ah; Heo, Ji Eun; Kim, Tae-Jip; Seo, Jin-Ho; Han, Nam Soo

2017-12-20

GDP-l-fucose is an l-fucose donor to synthesize fucosylated compounds such as human milk oligosaccharides or Lewis antigen. In this study, we used Lactococcus lactis subsp. cremoris NZ9000 to express 4 enzymes, ManB, ManC, Gmd, and WcaG and produced GDP-l-fucose by using one-pot synthesis method with mannose-6-phosphate as substrate and the enzymes as biocatalyst. For preparation of enzyme mixture, 4 genes (manB, manC, gmd, and wcaG) cloned from Escherichia coli were transformed into L. lactis strains using pNZ8008 and the recombinant cell lysates were obtained after cultivation. When mannose-6-phosphate was used as the substrate, the consecutive reactions with ManB, ManC, Gmd, and WcaG resulted in the successful production of GDP-l-fucose (0.13mM). When GDP-d-mannose was used as the substrate, it was entirely converted to GDP-l-fucose (0.2mM; 0.12g/L) via 2 enzymatic reactions mediated by Gmd and WcaG. This is the first report of GDP-l-fucose production by using multiple enzymes expressed in lactic acid bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation of stable magnetic nanofluids containing Fe3O4@PPy nanoparticles by a novel one-pot route

PubMed Central

2011-01-01

Stable magnetic nanofluids containing Fe3O4@Polypyrrole (PPy) nanoparticles (NPs) were prepared by using a facile and novel method, in which one-pot route was used. FeCl3·6H2O was applied as the iron source, and the oxidizing agent to produce PPy. Trisodium citrate (Na3cit) was used as the reducing reagent to form Fe3O4 NPs. The as-prepared nanofluid can keep long-term stability. The Fe3O4@PPy NPs can still keep dispersing well after the nanofluid has been standing for 1 month and no sedimentation is found. The polymerization reaction of the pyrrole monomers took place with Fe3+ ions as the initiator, in which these Fe3+ ions remained in the solution adsorbed on the surface of the Fe3O4 NPs. Thus, the core-shell NPs of Fe3O4@PPy were obtained. The particle size of the as-prepared Fe3O4@PPy can be easily controlled from 7 to 30 nm by the polymerization reaction of the pyrrole monomers. The steric stabilization and weight of the NPs affect the stability of the nanofluids. The as-prepared Fe3O4@PPy NPs exhibit superparamagnetic behavior. PMID:21711771

Ni xWO 2.72 nanorods as an efficient electrocatalyst for oxygen evolution reaction

DOE PAGES

Xi, Zheng; Mendoza-Garcia, Adriana; Zhu, Huiyuan; ...

2017-01-13

Ni xWO 2.72 nanorods (NRs) are synthesized by a one-pot reaction of Ni(acac) 2 and WCl 4. In the rod structure, Ni(II) intercalates in the defective perovskite-type WO 2.72 and is stabilized. The Ni xWO 2.72 NRs show the x-dependent electrocatalysis for the oxygen evolution reaction (OER) in 0.1M KOH with Ni 0.78WO 2.72 being the most efficient, even outperforming the commercial Ir-catalyst. Lastly, the synthesis is not limited to Ni xWO 2.72 but can be extended to M xWO 2.72 (M = Co, Fe) as well, providing a new class of oxide-based catalysts for efficient OER and other energymore » conversion reactions.« less

FOXP2 promotes the nuclear translocation of POT1, but FOXP2(R553H), mutation related to speech-language disorder, partially prevents it.

PubMed

Tanabe, Yuko; Fujita, Eriko; Momoi, Takashi

2011-07-08

FOXP2 is a forkhead box-containing transcription factor with several recognizable sequence motifs. However, little is known about the FOXP2-associated proteins except for C-terminal binding protein (CtBP). In the present study, we attempted to isolate the FOXP2-associated protein with a yeast two-hybrid system using the C-terminal region, including the forkhead domain, as a bait probe, and identified protection of telomeres 1 (POT1) as a FOXP2-associated protein. Immunoprecipitation assay confirmed the association with FOXP2 and POT1. POT1 alone localized in the cytoplasm but co-localized with FOXP2 and the forkhead domain of FOXP2 in nuclei. However, both FOXP2 with mutated nuclear localization signals and (R553H) mutated forkhead, which is associated with speech-language disorder, prevented the nuclear translocation of POT1. These results suggest that FOXP2 is a binding partner for the nuclear translocation of POT1. As loss of POT1 function induces the cell arrest, the impaired nuclear translocation of POT1 in the developing neuronal cells may be associated with the pathogenesis of speech-language disorder with FOXP2(R553H) mutation. Copyright © 2011 Elsevier Inc. All rights reserved.

G-quadruplex formation in telomeres enhances POT1/TPP1 protection against RPA binding

PubMed Central

Ray, Sujay; Bandaria, Jigar N.; Qureshi, Mohammad H.; Yildiz, Ahmet; Balci, Hamza

2014-01-01

Human telomeres terminate with a single-stranded 3′ G overhang, which can be recognized as a DNA damage site by replication protein A (RPA). The protection of telomeres (POT1)/POT1-interacting protein 1 (TPP1) heterodimer binds specifically to single-stranded telomeric DNA (ssTEL) and protects G overhangs against RPA binding. The G overhang spontaneously folds into various G-quadruplex (GQ) conformations. It remains unclear whether GQ formation affects the ability of POT1/TPP1 to compete against RPA to access ssTEL. Using single-molecule Förster resonance energy transfer, we showed that POT1 stably loads to a minimal DNA sequence adjacent to a folded GQ. At 150 mM K+, POT1 loading unfolds the antiparallel GQ, as the parallel conformation remains folded. POT1/TPP1 loading blocks RPA’s access to both folded and unfolded telomeres by two orders of magnitude. This protection is not observed at 150 mM Na+, in which ssTEL forms only a less-stable antiparallel GQ. These results suggest that GQ formation of telomeric overhangs may contribute to suppression of DNA damage signals. PMID:24516170

Flexible polyimides through one-pot synthesis as water-soluble binders for silicon anodes in lithium ion batteries

NASA Astrophysics Data System (ADS)

Yao, Dahua; Yang, Yu; Deng, Yonghong; Wang, Chaoyang

2018-03-01

A series of polyimides, which contain polyethylene glycol (PEG) segments with different molecular weight in the polymer chains, are synthesized through a facile one-pot method and characterized by Fourier transform infrared spectroscopy and hydrogen nuclear magnetic resonance spectroscopy. The main part of polyimides is originated from trimellitic anhydride chloride (TMAC) and 4,4‧-methylenedianiline, onto which PEG segments are introduced through an esterification reaction with TMAC. These obtained polyimides, which acquire excellent water solubility after being neutralized by triethylamine, are applied as water-soluble binders to silicon negative electrodes for lithium ion batteries, and significantly improve the electrochemical performance of silicon anodes. Specially, the PI-200 (polyimide copolymerized with PEG-200) based silicon electrode exhibits a high initial discharge capacity of 2989.7 mAh g-1 and remains about 2235.5 mAh g-1 after 200 cycles at the current density of 0.1 C (420 mA g-1).

One-Pot Synthesis of Hierarchical Flower-Like Pd-Cu Alloy Support on Graphene Towards Ethanol Oxidation

NASA Astrophysics Data System (ADS)

Zhang, Jingyi; Feng, Anni; Bai, Jie; Tan, Zhibing; Shao, Wenyao; Yang, Yang; Hong, Wenjing; Xiao, Zongyuan

2017-09-01

The synergetic effect of alloy and morphology of nanocatalysts play critical roles towards ethanol electrooxidation. In this work, we developed a novel electrocatalyst fabricated by one-pot synthesis of hierarchical flower-like palladium (Pd)-copper (Cu) alloy nanocatalysts supported on reduced graphene oxide (Pd-Cu(F)/RGO) for direct ethanol fuel cells. The structures of the catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrometer (XPS). The as-synthesized Pd-Cu(F)/RGO nanocatalyst was found to exhibit higher electrocatalytic performances towards ethanol electrooxidation reaction in alkaline medium in contrast with RGO-supported Pd nanocatalyst and commercial Pd black catalyst in alkaline electrolyte, which could be attributed to the formation of alloy and the morphology of nanoparticles. The high performance of nanocatalyst reveals the great potential of the structure design of the supporting materials for the future fabrication of nanocatalysts.

One-Pot Synthesis of Hierarchical Flower-Like Pd-Cu Alloy Support on Graphene Towards Ethanol Oxidation.

PubMed

Zhang, Jingyi; Feng, Anni; Bai, Jie; Tan, Zhibing; Shao, Wenyao; Yang, Yang; Hong, Wenjing; Xiao, Zongyuan

2017-09-02

The synergetic effect of alloy and morphology of nanocatalysts play critical roles towards ethanol electrooxidation. In this work, we developed a novel electrocatalyst fabricated by one-pot synthesis of hierarchical flower-like palladium (Pd)-copper (Cu) alloy nanocatalysts supported on reduced graphene oxide (Pd-Cu (F) /RGO) for direct ethanol fuel cells. The structures of the catalysts were characterized by using scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectrometer (XPS). The as-synthesized Pd-Cu (F) /RGO nanocatalyst was found to exhibit higher electrocatalytic performances towards ethanol electrooxidation reaction in alkaline medium in contrast with RGO-supported Pd nanocatalyst and commercial Pd black catalyst in alkaline electrolyte, which could be attributed to the formation of alloy and the morphology of nanoparticles. The high performance of nanocatalyst reveals the great potential of the structure design of the supporting materials for the future fabrication of nanocatalysts.

One-pot synthesis of triangular Ag nanoplates with tunable edge length.

PubMed

Zhang, Yulan; Yang, Ping; Zhang, Lipeng

2012-11-01

Triangular Ag nanoplates were prepared via a one-pot synthesis method by using citrate and poly (vinyl pyrolidone) (PVP). The edge length of the nanoplates was changed from 30 nm to 100 nm with increasing the concentration of PVP and the amount of sodium borohydride in aqueous solutions during preparation. The molar ratio of PVP to Ag nitrate affected the morphologies of the nanoplates. PVP plays an important role for determining the final morphologies and edge length of resulting nanoplates because the amount of PVP affected the viscosity of solutions. The viscosity of solutions kinetically controlled the nucleation and growth of Ag nanoplates. Furthermore, Ag nanoplates were not created in the case of without PVP. After adding sodium chloride, irregular Ag nanoparticles (NPs) instead of nanoplates were fabricated because of a Cl-/O2 etching process. Stacking fault was a key for the growth of triangular nanostructures. Reaction temperature and aging time also affected the formation of Ag nanoplates.

A microwave assisted one-pot route synthesis of bimetallic PtPd alloy cubic nanocomposites and their catalytic reduction for 4-nitrophenol

NASA Astrophysics Data System (ADS)

Zhang, Jian; Gan, Wei; Fu, Xucheng; Hao, Hequn

2017-10-01

We herein report a simple, rapid, and eco-friendly chemical route to the one-pot synthesis of bimetallic PtPd alloy cubic nanocomposites under microwave irradiation. During this process, water was employed as an environmentally benign solvent, while dimethylformamide served as a mild reducing agent, and polyvinylpyrrolidone was used as both a dispersant and a stabilizer. The structure, morphology, and composition of the resulting alloy nanocomposites were examined by x-ray diffraction, transmission electron microscopy, and energy dispersive x-ray spectroscopy. A detailed study was then carried out into the catalytic activity of the PtPd nanocomposites with a Pt:Pd molar ratio of 50:50 in the reduction of 4-nitrophenol (4-NP) by sodium borohydride as a model reaction. Compared with pristine Pt and Pd monometallic nanoparticles (PtNPs and PdNPs), the bimetallic PtPd alloy nanocomposites exhibited enhanced catalytic activities and were readily recyclable in the reduction of 4-NP due to synergistic effects.

Three-component, one-pot synthesis of anthranilamide Schiff bases bearing 4-aminoquinoline moiety as Mycobacterium tuberculosis gyrase inhibitors.

PubMed

Salve, Preeti S; Alegaon, Shankar G; Sriram, Dharmarajan

2017-04-15

An efficient three-component, one-pot protocol is described for the synthesis of biologically interesting 2-(benzylideneamino)-N-(7-chloroquinolin-4-yl)benzohydrazide derivatives from isatoic anhydride, 7-chloro-4-hydrazinylquinoline and aromatic and/or hetero aromatic aldehydes under catalyst free condensation by using water as reaction media. All synthesized compounds were evaluated for their antimycobacterial activity against Mycobacterium tuberculosis (MTB) and cytotoxicity activity against normal VERO cell lines. The synthesized compounds exhibited minimum inhibitory concentration (MIC) ranging from 0.78 to 25μM. Among the tested compounds 4c, 4o, 4r, and 4u exhibited promising inhibitory activity (MIC=3.12μM). Compounds 4h and 4i stand out, showing MIC values of 0.78 and 1.56μM respectively. Both compounds were further screened for their Mycobacterium tuberculosis DNA gyrase inhibitory assay which suggested that these compounds have a great potential for further optimization and development as antitubercular agents. Copyright © 2017 Elsevier Ltd. All rights reserved.

One-pot hydrothermal synthesis of an assembly of magnetite nanoneedles on a scaffold of cyclic-diphenylalanine nanorods

NASA Astrophysics Data System (ADS)

Togashi, Takanari; Umetsu, Mitsuo; Naka, Takashi; Ohara, Satoshi; Hatakeyama, Yoshiharu; Adschiri, Tadafumi

2011-09-01

The assembly of metal oxide nanoparticles (NPs) on a biomolecular template by a one-pot hydrothermal synthesis method is achieved for the first time. Magnetite (Fe3O4) nanoneedles (length: 100 nm; width: 10 nm) were assembled on cyclic-diphenylalanine (cFF) nanorods (length: 2-10 μm; width: 200 nm). The Fe3O4 nanoneedles and cFF nanorods were simultaneously synthesized from FeSO4 and l-phenylalanine by hydrothermal synthesis (220 °C and 22 MPa), respectively. The samples were analyzed by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (IR), transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) magnetometry. Experimental results indicate that Fe3O4 nanoneedles were assembled on cFF nanorods during the hydrothermal reaction. The composite contained 3.3 wt% Fe3O4 nanoneedles without any loss of the original magnetic properties of Fe3O4.

One-Pot Evolution of Ageladine A through a Bio-Inspired Cascade towards Selective Modulators of Neuronal Differentiation.

PubMed

Iwata, Takayuki; Otsuka, Satoshi; Tsubokura, Kazuki; Kurbangalieva, Almira; Arai, Daisuke; Fukase, Koichi; Nakao, Yoichi; Tanaka, Katsunori

2016-10-04

A bio-inspired cascade reaction has been developed for the construction of the marine natural product ageladine A and a de novo array of its N1-substituted derivatives. This cascade features a 2-aminoimidazole formation that is modeled after an arginine post-translational modification and an aza-electrocyclization. It can be effectively carried out in a one-pot procedure from simple anilines or guanidines, leading to structural analogues of ageladine A that had been otherwise synthetically inaccessible. We found that some compounds out of this structurally novel library show a significant activity in modulating the neural differentiation. Namely, these compounds selectively activate or inhibit the differentiation of neural stem cells to neurons, while being negligible in the differentiation to astrocytes. This study represents a successful case in which the native biofunction of a natural product could be altered by structural modifications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Facile One-Pot Synthesis of Au/Cu2O Nanocomposites for Nonenzymatic Detection of Hydrogen Peroxide

NASA Astrophysics Data System (ADS)

Chen, Ting; Tian, Liangliang; Chen, Yuan; Liu, Bitao; Zhang, Jin

2015-06-01

Au/Cu2O nanocomposites were successfully synthesized by a facile one-pot redox reaction without additional reducing agent under room temperature. The morphologies and structures of the as-prepared products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The electrocatalytic performance of Au/Cu2O nanocomposites towards hydrogen peroxide was evaluated by cyclic voltammetry (CV) and chronoamperometry (CA). The prepared Au/Cu2O nanocomposite electrode showed a wide linear range from 25 to 11.2 mM ( R = 0.9989) with a low detection limit of 1.05 μM ( S/ N = 3) and high sensitivity of 292.89 mA mM-1 cm-2. The enhanced performance for H2O2 detection can be attributed to the introduction of Au and the synergistic effect between Au and Cu2O. It is demonstrated that the Au/Cu2O nanocomposites material could be a promising candidate for H2O2 detection.

Selective Cell Adhesion and Biosensing Applications of Bio-Active Block Copolymers Prepared by CuAAC/Thiol-ene Double Click Reactions.

PubMed

Oyman Eyrilmez, Gizem; Doran, Sean; Murtezi, Eljesa; Demir, Bilal; Odaci Demirkol, Dilek; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf

2015-09-01

N-Acetyl-l-cysteine (NAC)-capped poly(methyl methacrylate)-b-polycaprolactone block copolymer (PMMA-b-PCL-NAC) was prepared using the previously described one-pot photoinduced sequential CuAAC/thiol-ene double click procedure. PMMA-b-PCL-NAC had previously shown good applicability as a matrix for cell adhesion of cells from the Vero cell line (African green monkey kidney epithelial). Here, in this work, PMMA-b-PCL-NAC served as an excellent immobilization matrix for biomolecule conjugation. Covalent binding of RGD (R: arginine, G: glycine, and D: aspartic acid) peptide sequence onto the PMMA-b-PCL-NAC-coated surface was performed via EDC chemistry. RGD-modified PMMA-b-PCL-NAC (PMMA-b-PCL-NAC-RGD) as a non-toxic cell proliferation platform was used for selective "integrin αvβ3-mediated cell adhesion and biosensing studies. Both optical and electrochemical techniques were used to monitor the adhesion differences between "integrin αvβ3" receptor positive and negative cell lines on to the designed biofunctional surfaces. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

FOXP2 promotes the nuclear translocation of POT1, but FOXP2(R553H), mutation related to speech-language disorder, partially prevents it

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanabe, Yuko; Fujita, Eriko; Department of Pediatrics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498

Highlights: {yields} We isolated protection of telomeres 1 (POT1) as a FOXP2-associated protein by a yeast two-hybrid. {yields} FOXP2 associated and co-localized with POT1 in the nuclei. {yields} FOXP2(R553H) also co-localized with POT1 in both the cytoplasm and nuclei. {yields} FOXP2(R553H) partially prevented the nuclear translocation of POT1. {yields} FOXP2(R553H) mutation may be associated with the pathogenesis of speech-language disorder. -- Abstract: FOXP2 is a forkhead box-containing transcription factor with several recognizable sequence motifs. However, little is known about the FOXP2-associated proteins except for C-terminal binding protein (CtBP). In the present study, we attempted to isolate the FOXP2-associated protein withmore » a yeast two-hybrid system using the C-terminal region, including the forkhead domain, as a bait probe, and identified protection of telomeres 1 (POT1) as a FOXP2-associated protein. Immunoprecipitation assay confirmed the association with FOXP2 and POT1. POT1 alone localized in the cytoplasm but co-localized with FOXP2 and the forkhead domain of FOXP2 in nuclei. However, both FOXP2 with mutated nuclear localization signals and (R553H) mutated forkhead, which is associated with speech-language disorder, prevented the nuclear translocation of POT1. These results suggest that FOXP2 is a binding partner for the nuclear translocation of POT1. As loss of POT1 function induces the cell arrest, the impaired nuclear translocation of POT1 in the developing neuronal cells may be associated with the pathogenesis of speech-language disorder with FOXP2(R553H) mutation.« less

A novel one-pot room-temperature synthesis route to produce very small photoluminescent silicon nanocrystals

NASA Astrophysics Data System (ADS)

Douglas-Gallardo, Oscar A.; Burgos-Paci, Maxi A.; Mendoza-Cruz, Rubén; Putnam, Karl G.; Josefina Arellano-Jiménez, M.; José-Yacamán, Miguel; Mariscal, Marcelo M.; Macagno, Vicente A.; Sánchez, Cristián G.; Pérez, Manuel A.

2018-03-01

A novel strategy to synthesize photoluminescent silicon nanocrystals (SiNCs) from a reaction between tetraethylorthosilicate (TEOS) and trimethyl-hexadecyl-ammonium borohydride (CTABH4) in organic solvent is presented. The formation reaction occurs spontaneously at room temperature in homogeneous phase. The produced silicon nanocrystals are characterized by using their photoluminescent properties and via HRTEM. In addition, theoretical calculations of the optical absorption spectrum of silicon quantum dots in vacuum with different sizes and surface moieties were performed in order to compare with the experimental findings. The new chemical reaction is simple and can be implemented to produce silicon nanocrystal with regular laboratory materials by performing easy and safe procedures. [Figure not available: see fulltext.

Asymmetric Synthesis of Spiropyrazolones by Sequential Organo- and Silver Catalysis.

PubMed

Hack, Daniel; Dürr, Alexander B; Deckers, Kristina; Chauhan, Pankaj; Seling, Nico; Rübenach, Lukas; Mertens, Lucas; Raabe, Gerhard; Schoenebeck, Franziska; Enders, Dieter

2016-01-26

A stereoselective one-pot synthesis of spiropyrazolones through an organocatalytic asymmetric Michael addition and a formal Conia-ene reaction has been developed. Depending on the nitroalkene, the 5-exo-dig-cyclization could be achieved by silver-catalyzed alkyne activation or by oxidation of the intermediate enolate. The mechanistic pathways have been investigated using computational chemistry and mechanistic experiments. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Synthesis of jet fuel range branched cycloalkanes with mesityl oxide and 2-methylfuran from lignocellulose

NASA Astrophysics Data System (ADS)

Li, Shanshan; Li, Ning; Wang, Wentao; Li, Lin; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

2016-09-01

Jet fuel range branched cycloalkanes with high density (0.82 g mL-1) and low freezing point (217-219 K) was first prepared by the solvent-free intramolecular aldol condensation of the trione from the hydrolysis of the alkylation product of mesityl oxide and 2-methylfuran (or the one-pot reaction of mesityl oxide, 2-methylfuran and water), followed by hydrodeoxygenation (HDO).

[Development and application of practical synthetic methods of imidazolines].

PubMed

Murai, Kenichi

2010-08-01

This review describes the first method to prepare imidazolines from aldehydes and 1,2-diamines by condensation and successive oxidation using NBS in one-pot operation. The reaction proceeds under mild conditions and can be applied to various aromatic and aliphatic aldehydes and 1,2-diamines. The utility of this method is also demonstrated in the total synthesis of spongotine A and the preparation of a newly designed organocatalyst, C3-symmetric trisimidazoline 7.

SNAr-Based, facile synthesis of a library of Benzothiaoxazepine-1,1’-dioxides

PubMed Central

Rolfe, Alan; Samarakoon, Thiwanka B.; Klimberg, Sarra V.; Brzozowski, Marek; Neuenswander, Benjamin; Lushington, Gerald H.

2011-01-01

The construction of a library of benzothiaoxazepine-1,1’-dioxides utilizing a one-pot, SNAr diversification – ODCT50 scavenging protocol is reported. This protocol combines microwave irradiation to facilitate the reaction, in conjunction with a soluble ROMP-derived scavenger (ODCT) to afford the desired products in good overall purity. Utilizing this protocol, a 78-member library was successfully synthesized and submitted for biological evaluation. PMID:20879738

Synthesis of jet fuel range branched cycloalkanes with mesityl oxide and 2-methylfuran from lignocellulose.

PubMed

Li, Shanshan; Li, Ning; Wang, Wentao; Li, Lin; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

2016-09-01

Jet fuel range branched cycloalkanes with high density (0.82 g mL(-1)) and low freezing point (217-219 K) was first prepared by the solvent-free intramolecular aldol condensation of the trione from the hydrolysis of the alkylation product of mesityl oxide and 2-methylfuran (or the one-pot reaction of mesityl oxide, 2-methylfuran and water), followed by hydrodeoxygenation (HDO).

Synthesis of jet fuel range branched cycloalkanes with mesityl oxide and 2-methylfuran from lignocellulose

PubMed Central

Li, Shanshan; Li, Ning; Wang, Wentao; Li, Lin; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

2016-01-01

Jet fuel range branched cycloalkanes with high density (0.82 g mL−1) and low freezing point (217–219 K) was first prepared by the solvent-free intramolecular aldol condensation of the trione from the hydrolysis of the alkylation product of mesityl oxide and 2-methylfuran (or the one-pot reaction of mesityl oxide, 2-methylfuran and water), followed by hydrodeoxygenation (HDO). PMID:27582417

Copper-catalyzed aerobic oxidative synthesis of α-ketoamides from methyl ketones, amines and NIS at room temperature.

PubMed

Zhang, Juan; Wei, Ying; Lin, Shaoxia; Liang, Fushun; Liu, Pengjun

2012-12-14

A simple, efficient and practical copper-catalyzed aerobic oxidative synthesis of α-ketoamides from aryl methyl ketones, aliphatic amines and N-iodosuccinimide (NIS) has been developed. The one-pot reaction may proceed smoothly at room temperature in the open air. The possible mechanism for the formation of α-ketoamides was proposed. Molecular oxygen in air functions as both an oxidant and an oxygen source.

A facile one-pot hydrothermal synthesis of β-MnO{sub 2} nanopincers and their catalytic degradation of methylene blue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Gao; Yu, Lin, E-mail: gych@gdut.edu.cn; Lin, Ting

2014-09-15

Branched β-MnO{sub 2} bipods with novel nanopincer morphology were prepared by a facile one-pot hydrothermal method via a redox reaction between NaClO{sub 3} and MnSO{sub 4} in sulfuric acid solution without using any surfactants or templates. The products were characterized in detail by various techniques including X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, surface area analyzer, field emission scanning electron microscopy and transmission electron microscopy. Results show that the obtained β-MnO{sub 2} nanopincers consist of two sharp nanorods with a diameter of 100–200 nm and a length of 1–2 μm. The concentration of H{sub 2}SO{sub 4} solution plays anmore » important role in controlling the crystal phase and morphology of the final product. A possible formation mechanism for the β-MnO{sub 2} nanopincers was proposed. Moreover, these β-MnO{sub 2} nanostructures exhibited better catalytic performance than the commercial MnO{sub 2} particles to decompose methyl blue (MB) in the presence of H{sub 2}O{sub 2}. - Graphical abstract: Branched β-MnO{sub 2} bipods with novel nanopincer morphology were prepared by a facile one-pot hydrothermal method through oxidizing MnSO{sub 4} with NaClO{sub 3} in H2SO{sub 4} condition without using any surfactants or templates. - Highlights: {sup •} Branched β-MnO{sub 2} nanopincers were prepared by a facile one-pot hydrothermal method. {sup •} Morphology and crystal phase of MnO{sub 2} were controlled by the H{sub 2}SO{sub 4} concentration. {sup •} A possible formation mechanism for the obtained β-MnO{sub 2} nanopincers was proposed. {sup •} The products showed great catalytic performance in degradation of methylene blue.« less

Preparation of magnetic resonance probes using one-pot method for detection of hepatocellular carcinoma.

PubMed

Li, You-Wei; Chen, Zheng-Guang; Zhao, Zhou-She; Li, Hong-Li; Wang, Ji-Chen; Zhang, Zong-Ming

2015-04-14

To prepare the specific magnetic resonance (MR) probes for detection of hepatocellular carcinoma (HCC) using one-pot method. The carboxylated dextran-coated nanoparticles were conjugated with anti-α-fetoprotein (anti-AFP) or anti-glypican 3 (anti-GPC3) antibodies through 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS)-mediated reaction to synthesize the probes. The physical and chemical properties of the probes were determined by transmission electron microscopy (TEM) and dynamic light scattering, and the relaxivity was compared to uncombined ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs) using a 1.5T clinical MR scanner. The binding efficiency of the antibodies to nanoparticles was measured with an ultraviolet-visible spectrophotometer. In addition, the probes were incubated with targetable cells in vitro. The superparamagnetic MR probes (anti-GPC3-USPION probe and anti-AFP-USPION probe) were synthesized using one-pot method. Their mean hydrodynamic diameter was 47 nm with a broader slight size distribution. The coupling efficiency of carboxylated dextran-coated ultrasmall superparamagnetic iron oxide (USPIO) with anti-GPC3 or anti-AFP antibody was 15.9% and 88.8%, respectively. Each of the USPIO nanoparticles may bind 3 GPC3 antibodies or 12 AFP antibodies. The statistical analysis showed no significance (P > 0.05) in shortening the T1 and T2 values when comparing the USPIO-AFP or USPIO-GPC3 to USPIO. Analysis of TEM images revealed that anti-GPC3-USPION probes and anti-AFP-USPION probes could specifically enter into the HepG2 cell by combining with the GPC3 receptors or AFP receptors, whereas the HepG2 cell sample incubated with USPIONs showed no or few nanoparticles in the cytoplasm. The synthesized probes using one-pot method can be used for in vitro experimental study and have potential clinical application in MR imaging for detection of hepatocellular carcinomas.

Synthesis of Diverse Nitrogen-Enriched Heterocyclic Scaffolds Using a Suite of Tunable One-Pot Multicomponent Reactions

PubMed Central

2015-01-01

Five elegant and switchable three-component reactions which enable access to a new series of nitrogen-containing heterocycles are reported. A novel one-step addition of an isocyanide to a hydrazine derived Schiff base affords unique six-membered pyridotriazine scaffolds (A and E). With slight modification of reaction conditions and replacement of the nucleophilic isocyanide moiety with different electrophiles (i.e., isocyanates, isothiocyanates, cyclic anhydrides, and acyl chlorides) five-membered triazolopyridine scaffolds (B, D, F, G) are generated in a single step. Furthermore, the use of phenyl hydrazine enables access to dihydroindazole-carboxamides, devoid of a bridge-head nitrogen (C). All protocols are robust and tolerate a diverse collection of reactants, and as such, it is expected that the new scaffolds and associated chemistry will garner high interest from medicinal chemists involved in either file enhancement or specific target-related drug discovery campaigns. PMID:24788091

Towards bulk syntheses of nanomaterials: a homeostatically supersaturated synthesis of polymer-like Bi 2S 3 nanowires with nearly 100% yield and no injection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Bin; Iowa State Univ. of Science and Technology, Ames, IA; Brandt, Jordan Aaron

This article reports the implementation of a one-pot strategy for the synthesis of polymer-like Bi 2S 3 nanowires from supersaturated precursors. These conditions result in (i) a homeostatically regulated supersaturation of the growing phase during most of the reaction, (ii) a nearly 100% conversion of the limiting reagent, and (iii) an improved colloidal stability and polydispersity of the product (when compared to the hot-injection product) that allows the identification of three new exciton transitions in the absorption spectrum (one of them, importantly, being a weakly absorbing ground state at 1.64 eV). Three different commercial sources of ligands do not yieldmore » significantly different conversion rates. Scalability is further improved by lack of stirring after the initial stage of reaction and a lower reaction temperature (90 °C).« less

Towards bulk syntheses of nanomaterials: a homeostatically supersaturated synthesis of polymer-like Bi 2S 3 nanowires with nearly 100% yield and no injection

DOE PAGES

Yuan, Bin; Iowa State Univ. of Science and Technology, Ames, IA; Brandt, Jordan Aaron; ...

2016-11-25

This article reports the implementation of a one-pot strategy for the synthesis of polymer-like Bi 2S 3 nanowires from supersaturated precursors. These conditions result in (i) a homeostatically regulated supersaturation of the growing phase during most of the reaction, (ii) a nearly 100% conversion of the limiting reagent, and (iii) an improved colloidal stability and polydispersity of the product (when compared to the hot-injection product) that allows the identification of three new exciton transitions in the absorption spectrum (one of them, importantly, being a weakly absorbing ground state at 1.64 eV). Three different commercial sources of ligands do not yieldmore » significantly different conversion rates. Scalability is further improved by lack of stirring after the initial stage of reaction and a lower reaction temperature (90 °C).« less

Quick and clean cloning.

PubMed

Thieme, Frank; Marillonnet, Sylvestre

2014-01-01

Identification of unknown sequences that flank known sequences of interest requires PCR amplification of DNA fragments that contain the junction between the known and unknown flanking sequences. Since amplified products often contain a mixture of specific and nonspecific products, the quick and clean (QC) cloning procedure was developed to clone specific products only. QC cloning is a ligation-independent cloning procedure that relies on the exonuclease activity of T4 DNA polymerase to generate single-stranded extensions at the ends of the vector and insert. A specific feature of QC cloning is the use of vectors that contain a sequence called catching sequence that allows cloning specific products only. QC cloning is performed by a one-pot incubation of insert and vector in the presence of T4 DNA polymerase at room temperature for 10 min followed by direct transformation of the incubation mix in chemo-competent Escherichia coli cells.

Highly efficient regioselective synthesis, spectroscopic characterizations and DFT calculations of novel hydroxymethylated 1,4-disubstituted-1,2,3-triazole-based sulfonamides

NASA Astrophysics Data System (ADS)

Taheri, Elmira; Mirjafary, Zohreh; Saeidian, Hamid

2018-04-01

The novel hydroxymethylated 1,4-disubstituted-1,2,3-triazole-based sulfonamides were synthesized in excellent yields and high regioselectivity via a one-pot, two-step, three-component reaction of N-propargylsulfonamides, sodium azide, and epoxide derivatives under green conditions. Green and mild reaction condition, commercially readily available and inexpensive starting materials, wide scope and easy work-up are the key features of the present method. The Li+ and Na+ ion affinities of the model structure have been also investigated by density functional theory (DFT) studies to find the applicability of these products as ligand in coordination chemistry.

A facile and regioselective one-pot synthesis of novel pyrazolo[1[Formula: see text],5[Formula: see text]:1,2]pyrrolo[3,4-b]quinoline-2,3-dicarboxylate hybrids via intramolecular Wittig reaction.

PubMed

Largani, Tahere Hosseyni; Imanzadeh, Gholamhasan; Pesyan, Nader Noroozi; Şahin, Ertan; Shamkhali, Amir Nasser; Notash, Behrouz

2018-02-01

The regioselective syntheses of novel pyrazolo[1[Formula: see text],5[Formula: see text]:1,2]pyrrolo[3,4-b]quinoline-2,3-dicarboxylates (6a-l) from pyrrolo([3,4-b]quinolin-2(3H)-yl)benzamides through an intramolecular Wittig reaction are described. This protocol takes advantages of mild conditions, simple workup and high yield which make this method attractive for the synthesis of these hybrid of pyrazolo[1[Formula: see text],5[Formula: see text]:1,2]pyrrolo[3,4-b]quinolines.

One-Pot Preparation of Dimethyl Isosorbide from d-Sorbitol via Dimethyl Carbonate Chemistry.

PubMed

Aricò, F; Aldoshin, A S; Tundo, P

2017-01-10

Direct synthesis of dimethyl isosorbide (DMI) from d-sorbitol via dimethyl carbonate (DMC) chemistry is herein first reported. High yield of DMI was achieved using the nitrogen superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as catalyst and performing the reaction in a stainless steel autoclave by increasing the temperature from 90 to 200 °C. In this procedure, DMC features its full capacity acting in the different steps of the process as carboxymethylating, leaving-group (cyclization), and methylating agent; DMC is also employed as the reaction media. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A combination of directing groups and chiral anion phase-transfer catalysis for enantioselective fluorination of alkenes

PubMed Central

Wu, Jeffrey; Wang, Yi-Ming; Drljevic, Amela; Rauniyar, Vivek; Phipps, Robert J.; Toste, F. Dean

2013-01-01

We report a catalytic enantioselective electrophilic fluorination of alkenes to form tertiary and quaternary C(sp3)-F bonds and generate β-amino- and β-aryl-allylic fluorides. The reaction takes advantage of the ability of chiral phosphate anions to serve as solid–liquid phase transfer catalysts and hydrogen bond with directing groups on the substrate. A variety of heterocyclic, carbocyclic, and acyclic alkenes react with good to excellent yields and high enantioselectivities. Further, we demonstrate a one-pot, tandem dihalogenation–cyclization reaction, using the same catalytic system twice in series, with an analogous electrophilic brominating reagent in the second step. PMID:23922394

α-Unsubstituted Pyrroles by NHC-Catalyzed Three-Component Coupling: Direct Synthesis of a Versatile Atorvastatin Derivative.

PubMed

Fleige, Mirco; Glorius, Frank

2017-08-10

A practical one-pot cascade reaction protocol provides direct access to valuable 1,2,4-trisubstituted pyrroles. The process involves an N-heterocyclic carbene (NHC)-catalyzed Stetter-type hydroformylation using glycolaldehyde dimer as a novel C1 building-block, followed by a Paal-Knorr condensation with primary amines. The reaction makes use of simple and commercially available starting-materials and catalyst, an important feature regarding applicability and utility. Low catalyst loading under mild reaction conditions afforded a variety of 1,2,4-substituted pyrroles in a transition-metal-free reaction with high step economy and good yields. This methodology is applied in the synthesis of a versatile Atorvastatin precursor, in which a variety of modifications at the pyrrole core structure are possible. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-pot fabrication of NiFe2O4 nanoparticles on α-Ni(OH)2 nanosheet for enhanced water oxidation

NASA Astrophysics Data System (ADS)

Chen, Hong; Yan, Junqing; Wu, Huan; Zhang, Yunxia; Liu, Shengzhong (Frank)

2016-08-01

Water splitting has been intensively investigated as a promising solution to resolve the future environmental and energy crises. The oxygen evolution reaction (OER) of the photo- and electric field-induced water splitting limits the development of other reactions, including hydrogen evolution reaction (HER). Fe, Ni and NiFe (hydro) oxide-based catalysts are generally acknowledged among the best candidates of OER catalysts for water splitting. Herein, we developed a one-pot simple hydrothermal process to assemble NiFe2O4 nanoparticles onto the α-Ni(OH)2 nanosheets. The first formed NiFe2O4 under high temperature and pressure environment induces and assists the α-Ni(OH)2 formation without any further additives, because the distance between the neighboring Ni atoms in the cubic NiFe2O4 is similar to that in the α-Ni(OH)2 {003} facets. We have synthesized a series of NiFe2O4/α-Ni(OH)2 compounds and find that the overpotential decreases with the increase of Ni(OH)2 content while the OER kinetics stays unchanged, suggesting that Ni(OH)2 plays a major role in overpotential while NiFe2O4 mainly affects the OER kinetics. The obtained NiFe2O4/α-Ni(OH)2 compounds is also found to be a promising co-catalyst for the photocatalytic water oxidation. In fact, it is even more active than the noble PtOx with acceptable stability for the oxygen generation.

Interactions of DNA binding proteins with G-Quadruplex structures at the single molecule level

NASA Astrophysics Data System (ADS)

Ray, Sujay

Guanine-rich nucleic acid (DNA/RNA) sequences can form non-canonical secondary structures, known as G-quadruplex (GQ). Numerous in vivo and in vitro studies have demonstrated formation of these structures in telomeric and non-telomeric regions of the genome. Telomeric GQs protect the chromosome ends whereas non-telomeric GQs either act as road blocks or recognition sites for DNA metabolic machinery. These observations suggest the significance of these structures in regulation of different metabolic processes, such as replication and repair. GQs are typically thermodynamically more stable than the corresponding Watson-Crick base pairing formed by G-rich and C-rich strands, making protein activity a crucial factor for their destabilization. Inside the cell, GQs interact with different proteins and their enzymatic activity is the determining factor for their stability. We studied interactions of several proteins with GQs to understand the underlying principles of protein-GQ interactions using single-molecule FRET and other biophysical techniques. Replication Protein-A (RPA), a single stranded DNA (ssDNA) binding protein, is known to posses GQ unfolding activity. First, we compared the thermal stability of three potentially GQ-forming DNA sequences (PQS) to their stability against RPA-mediated unfolding. One of these sequences is the human telomeric repeat and the other two, located in the promoter region of tyrosine hydroxylase gene, are highly heterogeneous sequences that better represent PQS in the genome. The thermal stability of these structures do not necessarily correlate with their stability against protein-mediated unfolding. We conclude that thermal stability is not necessarily an adequate criterion for predicting the physiological viability of GQ structures. To determine the critical structural factors that influence protein-GQ interactions we studied two groups of GQ structures that have systematically varying loop lengths and number of G-tetrad layers. We observed a linear increase in the steady-state stability of the GQ against RPA-mediated unfolding with increasing number of layers or decreasing loop length. The stability demonstrated by different GQ structures varied by at least three orders of magnitude. Finally, we studied another protein-GQ system where a protein complex works synergistically with a GQ to suppress DNA damage signals by preventing RPA to bind to telomeric DNA. Human telomeres that terminate with a single-stranded 3' G-overhang can be recognized as a DNA damage site by RPA. The protection of telomere-1 (POT1) and POT1-interacting protein (TPP1) heterodimer, binds specifically to telomeric DNA and protects it against RPA binding. Using model telomeric DNA, we studied the competition between POT1/TPP1 and RPA to access telomeric GQs in vitro. Under physiological salt and pH conditions, POT1/TPP1 stably load to a minimal DNA sequence adjacent to a folded GQ and unfolds the anti-parallel GQ as the parallel conformation remains folded. We showed that GQ formation of telomeres enhances the ability of POT1/TPP1 to block RPA's access to telomeres by two orders of magnitude and contributes to suppress DNA damage signals.

Transition metal-free one-pot cascade synthesis of 7-oxa-2-azatricyclo[7.4.0.0(2,6)]trideca-1(9),10,12-trien-3-ones from biomass-derived levulinic acid under mild conditions.

PubMed

Jha, Amitabh; Naidu, Ajaya B; Abdelkhalik, Ashraf M

2013-11-21

An efficient, environmentally benign, transition-metal free, tandem C-N, C-O bond formation reaction is developed for the synthesis of tricyclic 7-oxa-2-azatricyclo[7.4.0.0(2,6)]trideca-1(9),10,12-trien-3-ones and their homologs from easily available starting materials, including renewable levulinic acid, a keto acid. The reaction of keto acids with methyl chloroformate and variously substituted o-aminobenzyl alcohols using triethylamine as a base in toluene at room temperature gave good to excellent yields. This newly developed protocol was successfully utilized for the synthesis of a variety of polycyclic 7-oxa-2-azatricyclo[7.4.0.0(2,6)]trideca-1(9),10,12-trien-3-ones and related compounds.

Production of DNA minicircles less than 250 base pairs through a novel concentrated DNA circularization assay enabling minicircle design with NF-κB inhibition activity

PubMed Central

Thibault, Thomas; Degrouard, Jeril; Baril, Patrick; Pichon, Chantal; Midoux, Patrick

2017-01-01

Abstract Double-stranded DNA minicircles of less than 1000 bp in length have great interest in both fundamental research and therapeutic applications. Although minicircles have shown promising activity in gene therapy thanks to their good biostability and better intracellular trafficking, minicircles down to 250 bp in size have not yet been investigated from the test tube to the cell for lack of an efficient production method. Herein, we report a novel versatile plasmid-free method for the production of DNA minicircles comprising fewer than 250 bp. We designed a linear nicked DNA double-stranded oligonucleotide blunt-ended substrate for efficient minicircle production in a ligase-mediated and bending protein-assisted circularization reaction at high DNA concentration of 2 μM. This one pot multi-step reaction based-method yields hundreds of micrograms of minicircle with sequences of any base composition and position and containing or not a variety of site-specifically chemical modifications or physiological supercoiling. Biochemical and cellular studies were then conducted to design a 95 bp minicircle capable of binding in vitro two NF-κB transcription factors per minicircle and to efficiently inhibiting NF-κB-dependent transcriptional activity in human cells. Therefore, our production method could pave the way for the design of minicircles as new decoy nucleic acids. PMID:27899652

Sugar analog synthesis by in vitro biocatalytic cascade: A comparison of alternative enzyme complements for dihydroxyacetone phosphate production as a precursor to rare chiral sugar synthesis

PubMed Central

French, Nigel G.; Scoble, Judith A.; Williams, Charlotte C.; Churches, Quentin I.; Frazer, Andrew R.; Taylor, Matthew C.; Coia, Greg; Simpson, Gregory; Turner, Nicholas J.; Scott, Colin

2017-01-01

Carbon-carbon bond formation is one of the most challenging reactions in synthetic organic chemistry, and aldol reactions catalysed by dihydroxyacetone phosphate-dependent aldolases provide a powerful biocatalytic tool for combining C-C bond formation with the generation of two new stereo-centres, with access to all four possible stereoisomers of a compound. Dihydroxyacetone phosphate (DHAP) is unstable so the provision of DHAP for DHAP-dependent aldolases in biocatalytic processes remains complicated. Our research has investigated the efficiency of several different enzymatic cascades for the conversion of glycerol to DHAP, including characterising new candidate enzymes for some of the reaction steps. The most efficient cascade for DHAP production, comprising a one-pot four-enzyme reaction with glycerol kinase, acetate kinase, glycerophosphate oxidase and catalase, was coupled with a DHAP-dependent fructose-1,6-biphosphate aldolase enzyme to demonstrate the production of several rare chiral sugars. The limitation of batch biocatalysis for these reactions and the potential for improvement using kinetic modelling and flow biocatalysis systems is discussed. PMID:29112947

Sugar analog synthesis by in vitro biocatalytic cascade: A comparison of alternative enzyme complements for dihydroxyacetone phosphate production as a precursor to rare chiral sugar synthesis.

PubMed

Hartley, Carol J; French, Nigel G; Scoble, Judith A; Williams, Charlotte C; Churches, Quentin I; Frazer, Andrew R; Taylor, Matthew C; Coia, Greg; Simpson, Gregory; Turner, Nicholas J; Scott, Colin

2017-01-01

Carbon-carbon bond formation is one of the most challenging reactions in synthetic organic chemistry, and aldol reactions catalysed by dihydroxyacetone phosphate-dependent aldolases provide a powerful biocatalytic tool for combining C-C bond formation with the generation of two new stereo-centres, with access to all four possible stereoisomers of a compound. Dihydroxyacetone phosphate (DHAP) is unstable so the provision of DHAP for DHAP-dependent aldolases in biocatalytic processes remains complicated. Our research has investigated the efficiency of several different enzymatic cascades for the conversion of glycerol to DHAP, including characterising new candidate enzymes for some of the reaction steps. The most efficient cascade for DHAP production, comprising a one-pot four-enzyme reaction with glycerol kinase, acetate kinase, glycerophosphate oxidase and catalase, was coupled with a DHAP-dependent fructose-1,6-biphosphate aldolase enzyme to demonstrate the production of several rare chiral sugars. The limitation of batch biocatalysis for these reactions and the potential for improvement using kinetic modelling and flow biocatalysis systems is discussed.

In vitro synthesis of linear α-1,3-glucan and chemical modification to ester derivatives exhibiting outstanding thermal properties

PubMed Central

Puanglek, Sakarin; Kimura, Satoshi; Enomoto-Rogers, Yukiko; Kabe, Taizo; Yoshida, Makoto; Wada, Masahisa; Iwata, Tadahisa

2016-01-01

Bio-based polymer is considered as one of potentially renewable materials to reduce the consumption of petroleum resources. We report herein on the one-pot synthesis and development of unnatural-type bio-based polysaccharide, α-1,3-glucan. The synthesis can be achieved by in vitro enzymatic polymerization with GtfJ enzyme, one type of glucosyltransferase, cloned from Streptococcus salivarius ATCC 25975 utilizing sucrose, a renewable feedstock, as a glucose monomer source, via environmentally friendly one-pot water-based reaction. The structure of α-1,3-glucan is completely linear without branches with weight-average molecular weight (Mw) of 700 kDa. Furthermore, acetate and propionate esters of α-1,3-glucan were synthesized and characterized. Interestingly, α-1,3-glucan acetate showed a comparatively high melting temperature at 339 °C, higher than that of commercially available thermoplastics such as PET (265 °C) and Nylon 6 (220 °C). Thus, the discovery of crystalline α-1,3-glucan esters without branches with high thermal stability and melting temperature opens the gate for further researches in the application of thermoplastic materials. PMID:27469976

One-pot synthesis, quantum chemical calculations and X-ray diffraction studies of thiazolyl-coumarin hybrid compounds

NASA Astrophysics Data System (ADS)

Saeed, Aamer; Arif, Mubeen; Erben, Mauricio F.; Flörke, Ulrich; Simpson, Jim

2018-06-01

Two closely related hybrid species containing both, thiazolyl and coumarin groups, were synthesized by using two different one-pot procedures from a common precursor. The reaction of α-bromoacetylcoumarin with thioacetamide in methanol furnished 3‑(2‑methylthiazol‑4‑yl)‑2H‑chromen‑2‑one (2), whereas refluxing α‑bromoacetylcoumarin with potassium thiocyanate in ethanol afforded 3‑(2‑ethoxythiazol‑4‑yl)‑2H‑chromen‑2‑one (3). Both derivatives were fully characterized by spectroscopic methods, elemental analysis and X-ray diffraction studies. Intramolecular C4sbnd H⋯N and C5‧sbnd H⋯Odbnd C hydrogen bonds between the heterocycles determine the conformational behavior. The co-planarity of the coumarin and thiazolyl rings favors the occurrence of two remote orbital interactions involving the oxygen and nitrogen lone pairs and the corresponding σ*Csbnd H electron acceptor, as demonstrated by Natural Bond Orbital population analysis. The 2-substitution of the thiazol‑4‑yl group has little effect on the molecular structures but causes significant differences in the crystal packing of the two compounds.

In vitro synthesis of linear α-1,3-glucan and chemical modification to ester derivatives exhibiting outstanding thermal properties

NASA Astrophysics Data System (ADS)

Puanglek, Sakarin; Kimura, Satoshi; Enomoto-Rogers, Yukiko; Kabe, Taizo; Yoshida, Makoto; Wada, Masahisa; Iwata, Tadahisa

2016-07-01

Bio-based polymer is considered as one of potentially renewable materials to reduce the consumption of petroleum resources. We report herein on the one-pot synthesis and development of unnatural-type bio-based polysaccharide, α-1,3-glucan. The synthesis can be achieved by in vitro enzymatic polymerization with GtfJ enzyme, one type of glucosyltransferase, cloned from Streptococcus salivarius ATCC 25975 utilizing sucrose, a renewable feedstock, as a glucose monomer source, via environmentally friendly one-pot water-based reaction. The structure of α-1,3-glucan is completely linear without branches with weight-average molecular weight (Mw) of 700 kDa. Furthermore, acetate and propionate esters of α-1,3-glucan were synthesized and characterized. Interestingly, α-1,3-glucan acetate showed a comparatively high melting temperature at 339 °C, higher than that of commercially available thermoplastics such as PET (265 °C) and Nylon 6 (220 °C). Thus, the discovery of crystalline α-1,3-glucan esters without branches with high thermal stability and melting temperature opens the gate for further researches in the application of thermoplastic materials.

Mesoporous TiO2 Yolk-Shell Microspheres for Dye-sensitized Solar Cells with a High Efficiency Exceeding 11%

PubMed Central

Li, Zhao-Qian; Chen, Wang-Chao; Guo, Fu-Ling; Mo, Li-E; Hu, Lin-Hua; Dai, Song-Yuan

2015-01-01

Yolk-shell TiO2 microspheres were synthesized via a one-pot template-free solvothermal method building on the aldol condensation reaction of acetylacetone. This unique structure shows superior light scattering ability resulting in power conversion efficiency as high as 11%. This work provided a new synthesis system for TiO2 microspheres from solid to hollow and a novel material platform for high performance solar cells. PMID:26384004

Palladium-Catalyzed Nitromethylation of Aryl Halides: An Orthogonal Formylation Equivalent

PubMed Central

Walvoord, Ryan R.; Berritt, Simon; Kozlowski, Marisa C.

2012-01-01

An efficient cross-coupling reaction of aryl halides and nitromethane was developed with the use of parallel microscale experimentation. The arylnitromethane products are precursors for numerous useful synthetic products. An efficient method for their direct conversion to the corresponding oximes and aldehydes in a one-pot operation has been discovered. The process exploits inexpensive nitromethane as a carbonyl equivalent, providing a mild and convenient formylation method that is compatible with many functional groups. PMID:22839593

Synthesis of Cyano-Containing Phenanthridine Derivatives via Catalyst-, Base-, and Oxidant-Free Direct Cyanoalkylarylation of Isocyanides.

PubMed

Song, Weihong; Yan, Peipei; Shen, Dan; Chen, Zhangtao; Zeng, Xiaofei; Zhong, Guofu

2017-04-21

An efficient catalyst-, base-, and oxidant-free direct cyanoalkylarylation of isocyanides with AIBN has been developed under mild conditions. This strategy provides an elusive and rapid access to a wide range of cyano-containing phenanthridine derivatives in good yields via a one-pot alkylation/cyclization radical-cascade process. The mild reaction conditions together with no need of any catalyst, base, or oxidant make this protocol environmentally benign and practical.

Reversible sympathetic vasomotor dysfunction in POTS patients.

PubMed

Freitas, J; Santos, R; Azevedo, E; Costa, O; Carvalho, M; de Freitas, A F

2000-11-01

Orthostatic intolerance refers to the development upon assuming an upright posture of disabling symptoms, which are partly relieved by resuming the supine position. Postural tachycardia syndrome (POTS) is an orthostatic intolerance syndrome characterized by palpitations due to excessive orthostatic sinus tachycardia, lightheadedness, tremor, and near-syncope. Patients usually undergo extensive medical, cardiac, endocrine, neurological and psychiatric evaluation, which usually fails to identify a specific abnormality. We investigated the autonomic and hemodynamic profile of POTS patients and the efficacy of bisoprolol and or fludrocortisone. We evaluated eleven female patients with POTS before and after medical treatment with a cardio-selective beta blocker (bisoprolol) and/or fludrocortisone, and eleven age-matched controls. Variability of heart rate and systolic blood pressure was assessed by Fast Fourier Transform, and spontaneous baroreceptor gain by temporal sequences slope and alpha index. Modelflow was used to quantify hemodynamics. All patients improved greatly after medication. The autonomic and hemodynamic impairment observed in patients with POTS, particularly after orthostatic stress, is treated effectively with bisoprolol and/or fludrocortisone. These results need further confirmation in a controlled double-blind study. Proper medical treatment dramatically improves the clinical and autonomic/hemodynamic disturbances observed in patients with POTS. The data support the hypothesis that POTS is due to a hyperadrenergic activation and/or hypovolemia during orthostasis.

One-pot synthesis of La0.7Sr0.3MnO3 supported on flower-like CeO2 as electrocatalyst for oxygen reduction reaction in aluminum-air batteries

NASA Astrophysics Data System (ADS)

Xue, Yejian; Huang, Heran; Miao, He; Sun, Shanshan; Wang, Qin; Li, Shihua; Liu, Zhaoping

2017-08-01

A novel La0.7Sr0.3MnO3-CeO2 (LSM-CeO2) hybrid catalyst for oxygen reduction reaction (ORR) has been synthesized by a facile one-pot method. The flower-like CeO2 with the diameter of about 3 μm is formed by the agglomeration of nanosheets with the thickness of about 40 nm. The LSM particles with the diameter of about 150 nm are well distributed on the flower-like CeO2, thus the interaction between LSM and CeO2 is built. Therefore, the LSM-CeO2 composite catalyst exhibits the much higher catalytic activity toward ORR with the direct four-electron transfer mechanism in alkaline solution than LSM or CeO2. Furthermore, the stability of LSM-CeO2 is superior to that of Pt/C, and the current retention is 93% after 100000 s. The maximum power density of the aluminum-air battery using LSM-CeO2 as the ORRC can reach 238 mW cm-2, which is about 29% higher than that with LSM (184 mW cm-2). It indicates that LSM-CeO2 composite material is a promising cathodic electrocatalyst for metal-air batteries.

One-pot synthesis, biological evaluation, and docking study of new chromeno-annulated thiopyrano[2,3-c]pyrazoles.

PubMed

Parmar, Bhagyashri D; Sutariya, Tushar R; Brahmbhatt, Gaurangkumar C; Parmar, Narsidas J; Kant, Rajni; Gupta, Vivek K; Murumkar, Prashant R; Sharma, Mayank Kumar; Yadav, Mange Ram

2016-08-01

A one-pot synthesis of new chromeno-annulated thiopyrano[2,3-c]pyrazoles has been achieved through a domino-Knoevenagel-hetero-Diels-Alder reaction after combining various pyrazol-5-thiones with O-alkenyloxy/alkynyloxy-salicylaldehydes/naphthaldehydes in a Brønsted acidic ionic liquid, [Hmim]HSO[Formula: see text], methylimidazolium hydrogen sulphate, under microwave irradiation. The method is simple and in many cases the isolated products did not require further purification. The central pyranothiopyranyl cis-fusion was confirmed by 2D NMR NOESY and single-crystal X-ray analysis suggesting that the endo-E-Syn transition state would be the most favored pathway of the reaction. Many heterocycles of this new series were found active against six bacterial and two fungal strains. In addition, all the compounds possess good anti-oxidant activity with the ferric reducing anti-oxidant power value [Formula: see text]. All new structures were docked into active site of angiotensin I converting enzyme (ACE), assuming that the compounds possessed the anti-hypertensive activity potential on the basis of prediction of activity spectra of substances prediction results. Pyranyl ring oxygen in compound 9a forms two hydrogen bonds with HIS353 and HIS513 residues in the active site of the ACE having good G score ([Formula: see text]) of this compound, comparable to that of the reference drug captopril ([Formula: see text]).

A One-Pot, Asymmetric Robinson Annulation in the Organic Chemistry Majors Laboratory

ERIC Educational Resources Information Center

Lazarski, Kiel E.; Rich, Alan A.; Mascarenhas, Cheryl M.

2008-01-01

The Robinson annulation is a topic of importance in the second-year organic curriculum. A one-pot, enantioselective Robinson annulation is described. The experiment is completed in two lab periods and is geared towards the second-year organic chemistry major. To our knowledge, this is the first example of a one-pot enantioselective Robinson…

Preparation and characterization of conjugated polymers made by postpolymerization reactions of alternating polyketones.

PubMed

Cheng, Chen; Guironnet, Damien; Barborak, James; Brookhart, Maurice

2011-06-29

Conjugated polymers possessing a poly(2,5-dimethylene-2,5-dihydrofuran) backbone were prepared through postpolymerization reaction of styrenic polyketones with bromine in one-pot reactions. The modification is proposed to proceed via condensation of two repeating units to form a fully characterized polymer with a poly(2,5-dimethylenetetrahydrofuran) backbone. Subsequent bromination and elimination of HBr yield a polymer with a fully conjugated carbon backbone. The new conjugated polymers were characterized by NMR, IR, and UV-vis spectroscopies and by CV. These polymers have strong absorption in the visible region, with the absorption peaks shifted to the NIR region upon doping with acids. The ease of the synthesis of the starting polyketone and of the modifications allows large-scale preparation of those conjugated polymers.

Sequence-Independent Cloning and Post-Translational Modification of Repetitive Protein Polymers through Sortase and Sfp-Mediated Enzymatic Ligation.

PubMed

Ott, Wolfgang; Nicolaus, Thomas; Gaub, Hermann E; Nash, Michael A

2016-04-11

Repetitive protein-based polymers are important for many applications in biotechnology and biomaterials development. Here we describe the sequential additive ligation of highly repetitive DNA sequences, their assembly into genes encoding protein-polymers with precisely tunable lengths and compositions, and their end-specific post-translational modification with organic dyes and fluorescent protein domains. Our new Golden Gate-based cloning approach relies on incorporation of only type IIS BsaI restriction enzyme recognition sites using PCR, which allowed us to install ybbR-peptide tags, Sortase c-tags, and cysteine residues onto either end of the repetitive gene polymers without leaving residual cloning scars. The assembled genes were expressed in Escherichia coli and purified using inverse transition cycling (ITC). Characterization by cloud point spectrophotometry, and denaturing polyacrylamide gel electrophoresis with fluorescence detection confirmed successful phosphopantetheinyl transferase (Sfp)-mediated post-translational N-terminal labeling of the protein-polymers with a coenzyme A-647 dye (CoA-647) and simultaneous sortase-mediated C-terminal labeling with a GFP domain containing an N-terminal GG-motif in a one-pot reaction. In a further demonstration, we installed an N-terminal cysteine residue into an elastin-like polypeptide (ELP) that was subsequently conjugated to a single chain poly(ethylene glycol)-maleimide (PEG-maleimide) synthetic polymer, noticeably shifting the ELP cloud point. The ability to straightforwardly assemble repetitive DNA sequences encoding ELPs of precisely tunable length and to post-translationally modify them specifically at the N- and C- termini provides a versatile platform for the design and production of multifunctional smart protein-polymeric materials.

Nanoreactors for green catalysis

PubMed Central

De Martino, M Teresa; Abdelmohsen, Loai K E A; Rutjes, Floris P J T

2018-01-01

Sustainable and environmentally benign production are key drivers for developments in the chemical industrial sector, as protecting our planet has become a significant element that should be considered for every industrial breakthrough or technological advancement. As a result, the concept of green chemistry has been recently defined to guide chemists towards minimizing any harmful outcome of chemical processes in either industry or research. Towards greener reactions, scientists have developed various approaches in order to decrease environmental risks while attaining chemical sustainability and elegancy. Utilizing catalytic nanoreactors for greener reactions, for facilitating multistep synthetic pathways in one-pot procedures, is imperative with far-reaching implications in the field. This review is focused on the applications of some of the most used nanoreactors in catalysis, namely: (polymer) vesicles, micelles, dendrimers and nanogels. The ability and efficiency of catalytic nanoreactors to carry out organic reactions in water, to perform cascade reaction and their ability to be recycled will be discussed. PMID:29719570

Efficient Synthesis and Antimicrobial Evaluation of Pyrazolopyranopyrimidines in the Presence of SBA-Pr-SO3H as a Nanoporous Acid Catalyst

PubMed Central

Mohammadi Ziarani, Ghodsi; Aleali, Faezeh; Lashgari, Negar; Badiei, Alireza; Abolhasani Soorki, Ali

2018-01-01

A simple, efficient, and environmentally friendly method has been developed for the synthesis of a series of tricyclic fused pyrazolopyranopyrimidines via a one-pot three-component reaction of barbituric acids, aromatic aldehydes, and 3-methyl-5-pyrazolone in the presence of SBA-Pr-SO3H. SBA-15 mesoporous silica material functionalized with propyl sulfonic acid groups was used as a heterogeneous Brønsted acid catalyst with hexagonal structure, high surface area, thick walls, and large uniform pores. All reactions were performed under reflux conditions in water in the presence of a catalytic amount of SBA-Pr-SO3H. High yields, mild reaction conditions, short reaction times, and simple work-up procedures are some advantages of this method. The antimicrobial activities of the synthesized compounds were also evaluated and some products exhibited significant antibacterial activities at low concentrations. PMID:29881410

Stereo-, Regio-, and Chemoselective [3 + 2]-Cycloaddition of (2E,4E)-Ethyl 5-(Phenylsulfonyl)penta-2,4-dienoate with Various Azomethine Ylides, Nitrones, and Nitrile Oxides: Synthesis of Pyrrolidine, Isoxazolidine, and Isoxazoline Derivatives and a Computational Study.

PubMed

Sankar, Ulaganathan; Surya Kumar, Ch Venkata; Subramanian, V; Balasubramanian, K K; Mahalakshimi, S

2016-03-18

One-pot chemo-, regio-, and stereoselective synthesis of series of heterocyclic and spiroheterocyclic compounds was accomplished through mono- and bis[3 + 2]-cycloaddition reactions of (2E,4E)-ethyl 5-(phenylsulfonyl)penta-2,4-dienoate as a dipolarophile with azomethine ylides, nitrones, and nitrile oxides in good yields. The structures of the products were established by spectroscopic techniques as well as by single-crystal XRD study, and DFT calculations were performed to further understand the mechanism of this [3 + 2]-cycloaddition reaction.

Mechanistic insights into the one-pot synthesis of propargylamines from terminal alkynes and amines in chlorinated solvents catalyzed by gold compounds and nanoparticles.

PubMed

Aguilar, David; Contel, Maria; Urriolabeitia, Esteban P

2010-08-09

Propargylamines can be obtained from secondary amines and terminal alkynes in chlorinated solvents by a three- and two-component synthesis catalyzed by gold compounds and nanoparticles (Au-NP) under mild conditions. The use of dichloromethane allows for the activation of two C-Cl bonds and a clean transfer of the methylene fragment to the final product. The scope of the reaction as well as the influence of different gold(III) cycloaurated complexes and salts has been investigated. The involvement of gold nanoparticles generated in situ in the process is discussed and a plausible reaction mechanism is proposed on the basis of the data obtained.

Cucurbit[7]uril as a tool in the green synthesis of gold nanoparticles.

PubMed

Premkumar, Thathan; Geckeler, Kurt E

2010-12-03

A simple, green, one-pot synthesis of gold nanoparticles was achieved through the reaction of an aqueous mixture of potassium tetrachloroaurate(III) and the macrocycle cucurbit[7]uril in the presence of sodium hydroxide at room temperature without introducing any kind of traditional reducing agents and/or external energy. The as-prepared gold nanoparticles showed catalytic activity for the reduction reaction of 4-nitrophenol in the presence of NaBH(4), which has been established by visual inspection and UV/Vis spectroscopy. This report is the first for the preparation of gold nanoparticles using cucurbit[7]uril in aqueous media through chemical reduction without employing conventional reducing agents and/or external energy.

The antioxidant effect of derivatives pyroglutamic lactam

NASA Astrophysics Data System (ADS)

Rohadi, Atisya; Lazim, Azwani Mat; Hasbullah, Siti Aishah

2013-11-01

Diphenylpicrylhydrazyl (DPPH) is widely used for quickly accessing the ability of polyphenols to transfer labile H atoms to radicals. The antioxidant activity of all the synthesized compounds was screened by DPPH method. Compound (4) showed 54% antioxidant potential while all other compounds were found to have moderate to have moderate to mild antioxidant activity ranging from 47-52%. Pyroglutamic lactams have been synthesized stereoselectively in racemic form from levulinic acid as bifunctional adduct using convertible isocyanide in one-pot Ugi 4-center-3-component condensation reaction (U-4C-3CR). The product formed provides biologically interesting products in excellent yields in a short reaction time. The structures of the synthesized compounds were elucidated using spectroscopic data and elemental analysis.

A novel copper complex supported on magnetic reduced graphene oxide: an efficient and green nanocatalyst for the synthesis of 1-amidoalkyl-2-naphthol derivatives

NASA Astrophysics Data System (ADS)

Kooti, M.; Karimi, M.; Nasiri, E.

2018-02-01

A new Cu(II) complex supported on magnetic reduced graphene oxide was prepared and characterized by various techniques, such as FT-IR, XRD, SEM, EDX, TEM, TGA, BET, ICP, and VSM. The synthesized nanocomposite, which has size distribution of 25-30 nm, was employed as catalyst in one-pot synthesis of 1-amidoalkyl-2-naphthols via three-component condensation reaction of amides, aromatic aldehydes, and 2-naphthol, under solvent-free conditions. The introduced catalysis procedure for the synthesis of 1-amidoalkyl-2-naphthol derivatives offers several advantages namely, short reaction times, high yields, facile recyclability, and cost effectiveness. [Figure not available: see fulltext.

An Unconventional Redox Cross Claisen Condensation-Aromatization of 4-Hydroxyprolines with Ketones.

PubMed

Tang, Mi; Sun, Rengwei; Li, Hao; Yu, Xinhong; Wang, Wei

2017-08-18

Reaction of α-amino acids, particularly prolines and their derivatives with carbonyl compounds via decarboxylative redox process, is a viable strategy for synthesis of structurally diverse nitrogen centered heterocyclics. In these processes, the decarboxylation is the essential driving force for the processes. The realization of the redox process without decarboxylation may offer an opportunity to explore new reactions. Herein, we report the discovery of an unprecedented redox Claisen-type condensation aromatization cascade reaction of 4-substituted 4-hydroxyproline and its esters with unreactive ketones. We found that the use of propionic acid as a catalyst and a co-solvent can change the reaction course. The commonly observed redox decarboxylation and aldol condensation reactions are significantly minimized. Moreover, unreactive ketones can effectively participate in the Claisen condensation reaction. The new reactivity enables a redox cyclization via an unconventional Claisen-type condensation reaction of in situ formed enamine intermediates from ketone precursors with 4-substituted 4-hydroxyproline and its esters as electrophilic acylation partners. Under the reaction conditions, the cascade process proceeds highly regio- and stereoselectively to afford highly synthetically and biologically valued cis-2,3-dihydro-1H-pyrrolizin-1-ones with a broad substrate scope in efficient 'one-pot' operation, whereas such structures generally require multiple steps.

Automated synthesis of a library of triazolated 1,2,5-thiadiazepane 1,1-dioxides via a double aza-Michael strategy.

PubMed

Zang, Qin; Javed, Salim; Hill, David; Ullah, Farman; Bi, Danse; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H; Santini, Conrad; Organ, Michael G; Hanson, Paul R

2012-08-13

The construction of a 96-member library of triazolated 1,2,5-thiadiazepane 1,1-dioxides was performed on a Chemspeed Accelerator (SLT-100) automated parallel synthesis platform, culminating in the successful preparation of 94 out of 96 possible products. The key step, a one-pot, sequential elimination, double-aza-Michael reaction, and [3 + 2] Huisgen cycloaddition pathway has been automated and utilized in the production of two sets of triazolated sultam products.

Automated Synthesis of a Library of Triazolated 1,2,5-Thiadiazepane 1,1-Dioxides via a Double aza-Michael Strategy

PubMed Central

Zang, Qin; Javed, Salim; Hill, David; Ullah, Farman; Bi, Danse; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H.; Santini, Conrad; Organ, Michael G.; Hanson, Paul R.

2013-01-01

The construction of a 96-member library of triazolated 1,2,5-thiadiazepane 1,1-dioxides was performed on a Chemspeed Accelerator (SLT-100) automated parallel synthesis platform, culminating in the successful preparation of 94 out of 96 possible products. The key step, a one-pot, sequential elimination, double-aza-Michael reaction, and [3+2] Huisgen cycloaddition pathway has been automated and utilized in the production of two sets of triazolated sultam products. PMID:22853708

One-Pot Synthesis of Allylic Sulfones, Ketosulfones, and Trifylallylic Alcohols from Domino Reactions of Allylic Alcohols with Sulfinic Acid under Metal-Free Conditions.

PubMed

Chu, Xue-Qiang; Meng, Hua; Xu, Xiao-Ping; Ji, Shun-Jun

2015-08-03

Invited for the cover of this issue is the group of Shun-Jun Ji and co-workers at Soochow University, (China). The image depicts a cheaper, low-toxic, eco-friendly benign and metal-free methodology incorporating the both aryl and trifyl sulfonyl functionality from allylic alcohols. Read the full text of the article at 10.1002/chem.201500469. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct one-pot reductive amination of aldehydes with nitroarenes in a domino fashion: catalysis by gum-acacia-stabilized palladium nanoparticles.

PubMed

Sreedhar, B; Reddy, P Surendra; Devi, D Keerthi

2009-11-20

This note describes the direct reductive amination of carbonyl compounds with nitroarenes using gum acacia-palladium nanoparticles, employing molecular hydrogen as the reductant. This methodology is found to be applicable to both aliphatic and aromatic aldehydes and a wide range of nitroarenes. The operational simplicity and the mild reaction conditions add to the value of this method as a practical alternative to the reductive amination of carbonyl compounds.

One-pot production of 18F-biotin by conjugation with 18F-FDG for pre-targeted imaging: synthesis and radio-labelling of a PEGylated precursor.

PubMed

Simpson, Michael; Trembleau, Laurent; Cheyne, Richard W; Smith, Tim A D

2011-02-01

The biotin-avidin affinity system is exploited in pre-targeted imaging using avidin-conjugated antibodies. (18)F-FDG is available at all PET centres. (18)F-FDG forms oximes by reaction with oxyamine. Herein we describe the synthesis of oxyamine-funtionalised biotin, its (18)F-labelling by conjugation with (18)F-FDG and confirm its ability to interact with avidin. Copyright © 2010 Elsevier Ltd. All rights reserved.

One-pot synthesis of transition metal ion-chelating ordered mesoporous carbon/carbon nanotube composites for active and durable fuel cell catalysts

NASA Astrophysics Data System (ADS)

Dombrovskis, Johanna K.; Palmqvist, Anders E. C.

2017-07-01

Development of non-precious metal catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells with high activity and durability and with optimal water management properties is of outmost technological importance and highly challenging. Here we study the possibilities offered through judicious selection of small molecular precursors used for the formation of ordered mesoporous carbon-based non-precious metal ORR catalysts. By combining two complementary precursors, we present a one-pot synthesis that leads to a composite material consisting of transition metal ion-chelating ordered mesoporous carbon and multi-walled carbon nanotubes (TM-OMC/CNT). The resulting composite materials show high specific surface areas and a carbon structure that exhibits graphitic signatures. The synthesis procedure allows for tuning of the carbon structure, the surface area, the pore volume and the ratio of the two components of the composite. The TM-OMC/CNT composites were processed into membrane electrode assemblies and evaluated in single cell fuel cell measurements where they showed a combination of good ORR activity and very high durability.

An efficient one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles at room temperature by green synthesized Cu NPs using Otostegia persica leaf extract.

PubMed

Nasrollahzadeh, Mahmoud; Sajadi, S Mohammad; Mirzaei, Yousef

2016-04-15

In this study, copper nanoparticles (Cu NPs) were synthesized using a rapid, single step and completely green biosynthetic method by reduction of CuCl2 · 2H2O solution with aqueous extract of leaves of Otostegia persica containing flavonoid and other phenolics as a main factor which acts as reducing agent and efficient stabilizer. UV-vis spectra gave surface plasmon resonance (SPR) at 560 nm. The Cu NPs were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). A possible synthesis mechanism of Cu NPs was presented. In addition, we investigated the catalytic activity of Cu NPs for the one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles under mild reaction conditions with good to excellent yields. The catalyst could be easily recovered by centrifugation and reused at least five recycles with no significant decreases in the yields. Copyright © 2016 Elsevier Inc. All rights reserved.

One-pot synthesis of redox-responsive polymers-coated mesoporous silica nanoparticles and their controlled drug release.

PubMed

Sun, Jiao-Tong; Piao, Ji-Gang; Wang, Long-Hai; Javed, Mohsin; Hong, Chun-Yan; Pan, Cai-Yuan

2013-09-01

A versatile one-pot strategy for the preparation of reversibly cross-linked polymer-coated mesoporous silica nanoparticles (MSNs) via surface reversible addition-fragmentation chain transfer (RAFT) polymerization is presented for the first time in this paper. The less reactive monomer oligo(ethylene glycol) acrylate (OEGA) and the more reactive cross-linker N,N'-cystaminebismethacrylamide (CBMA) are chosen to be copolymerized on the external surfaces of RAFT agent-functionalized MSNs to form the cross-linked polymer shells. Owing to the reversible cleavage and restoration of disulfide bonds via reduction/oxidation reactions, the polymer shells can control the on/off switching of the nanopores and regulate the drug loading and release. The redox-responsive release of doxorubicin (DOX) from this drug carrier is realized. The protein adsorption, in vitro cytotoxicity assays, and endocytosis studies demonstrate that this biocompatible vehicle is a potential candidate for delivering drugs. It is expected that this versatile grafting strategy may help fabricate satisfying MSN-based drug delivery systems for clinical application. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-pot, one-step synthesis of 2,5-diformylfuran from carbohydrates over Mo-containing Keggin heteropolyacids.

PubMed

Liu, Yu; Zhu, Liangfang; Tang, Jinqiang; Liu, Mingyang; Cheng, Ruodi; Hu, Changwei

2014-12-01

In this work, a one-pot strategy for directly converting fructose into 2,5-diformylfuran (DFF) over Mo-containing Keggin heteropolyacids (HPAs) in open air is developed. H3 PMo12 O40 HPA is found to show high activity and selectivity to the formation of DFF owing to its higher Brønsted acidity and moderate redox potential. The partial substitution of the H(+) in H3 PMo12 O40 with Cs(+) leads to the heterogenization of the HPA by forming its cesium salts Csx H3-x PMo12 (x=0.5, 1.5, and 2.5). A satisfactory yield of 69.3% to DFF is obtained over Cs0.5 H2.5 PMo12 polyoxometalate after deliberate optimization of the reaction conditions. The heterogenized polyoxometalate could be recycled and reused without significant loss of catalytic activity for five runs. The produced DFF could be separated from the resulting mixture by an adsorption-desorption method using activated carbon as the adsorbent and furfural as the desorbent. A highest isolated yield of 58.2% is obtained. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-Pot Synthesis, Spectroscopic and Physicochemical Studies of Quinoline Based Blue Emitting Donor-Acceptor Chromophores with Their Biological Application.

PubMed

Asiri, Abdullah M; Khan, Salman A; Al-Thaqafya, Saad H

2015-09-01

Blue emitting cyano substituted isoquinoline dyes were synthesized by one-pot multicomponent reactions (MCRs) of aldehydes, malononitrile, 6-methoxy-1,2,3,4-tetrahydro-naphthalin-1-one and ammonium acetate. Results obtained from spectroscopic (FT-IR, (1)H-NMR, (13)C-NMR, EI-MS) and elemental analysis of synthesized compounds was in good agreement with their chemical structures. UV-vis and fluorescence spectroscopy measurements proved that all compounds are good absorbent and fluorescent. Fluorescence polarity study demonstrated that these compounds were sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including electronic absorption, excitation coefficient, stokes shift, oscillator strength, transition dipole moment and fluorescence quantum yield were investigated in order to explore the analytical potential of synthesized compounds. The anti-bacterial activity of these compounds were first studied in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria then the minimum inhibitory concentration (MIC) was determined with the reference of standard drug chloramphenicol. The results displayed that compound 3 was better inhibitors of both types of the bacteria (Gram-positive and Gram-negative) than chloramphenicol. Graphical Abstract ᅟ.

Organic-Inorganic Hybrid Materials: Multi-Functional Solids for Multi-Step Reaction Processes.

PubMed

Díaz, Urbano; Corma, Avelino

2018-03-15

The design of new hybrid materials with tailored properties at the nano-, meso-, and macro-scale, with the use of structural functional nanobuilding units, is carried out to obtain specific multi-functional materials. Organization into controlled 1D, 2D, and 3D architectures with selected functionalities is key for developing advanced catalysts, but this is hardly accomplished using conventional synthesis procedures. The use of pre-formed nanostructures, derived either from known materials or made with specific innovative synthetic methodologies, has enormous potential in the generation of multi-site catalytic materials for one-pot processes. The present concept article introduces a new archetype wherein self-assembled nanostructured builder units are the base for the design of multifunctional catalysts, which combine catalytic efficiency with fast reactant and product diffusion. The article addresses a new generation of versatile hybrid organic-inorganic multi-site catalytic materials for their use in the production of (chiral) high-added-value products within the scope of chemicals and fine chemicals production. The use of those multi-reactive solids for more nanotechnological applications, such as sensors, due to the inclusion of electron donor-acceptor structural arrays is also considered, together with the adsorption-desorption capacities due to the combination of hydrophobic and hydrophilic sub-domains. The innovative structured hybrid materials for multipurpose processes here considered, can allow the development of multi-stage one-pot reactions with industrial applications, using the materials as one nanoreactor systems, favoring more sustainable production pathways with economic, environmental and energetic advantages. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of 4'-Selenoribonucleosides, the Building Blocks of 4'-SelenoRNA, Using a Hypervalent Iodine.

PubMed

Saito-Tarashima, Noriko; Ota, Masashi; Minakawa, Noriaki

2017-09-18

Herein is described a detailed protocol for the synthesis of 4'-selenoribonucleoside derivatives that involves the use of a hypervalent iodine species. These derivatives are versatile units for the preparation of 4'-selenoRNA. Large-scale synthesis of a 4-selenosugar starting from D-ribose is achieved in eight steps, including a final chromatographic purification. The resulting 4-selenosugar is then subjected to the one-pot Pummerer-like reaction using hypervalent iodine in the presence of silylated nucleobases. The reaction with silylated uracil affords the desired 4'-selenouridine derivatives with excellent β-selectivity and in good yield. Conversely, when purine nucleobases are used in the Pummerer-like reaction, N7 4'-selenoribonucleoside isomers are obtained alongside the desired N9 isomers. However, the undesired N7 isomers can be converted to the desired N9 ones under acidic conditions. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Efficiency of extraction and conversion of pseudoephedrine to methamphetamine from tamper-resistant and non-tamper-resistant formulations.

PubMed

Presley, Brandon; Bianchi, Bob; Coleman, John; Diamond, Fran; McNally, Gerry

2018-07-15

Clandestine chemists have demonstrated an ability to convert commercially available pseudoephedrine formulations to methamphetamine. Some of these formulations have properties that manufacturers claim limit or block the extraction of pseudoephedrine and its direct conversion to methamphetamine. In this study, 3 commercially available pseudoephedrine formulations were evaluated for ease of extraction and conversion to methamphetamine using a common chemistry technique called the one-pot method that is frequently employed by clandestine chemists. Two marketed pseudoephedrine formulations with claimed tamper-resistant properties - Zephrex-D ® and Nexafed ® - were compared to Sunmark ® , a comparator formulation of pseudoephedrine without tamper-resistant properties. Particle size reduction was conducted using 8 readily available tools; solubility was assessed using 2 common aqueous solutions and various reaction conditions (e.g., temperature, stirring); extractability was evaluated using 8 common organic solvents. The one-pot (single vessel) method commonly used in clandestine processes was employed; chemicals and equipment were purchased locally on the open market. Quantities and addition times of the chemicals used to carry out the procedure and the duration of the reaction were varied to determine the effect on methamphetamine yield. The procedure was appropriately scaled and conducted in a controlled environment to reduce risk and maximize yields. Pseudoephedrine and methamphetamine were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Standard quantitative procedures were used to determine the quantities of pseudoephedrine and methamphetamine recovered and produced, respectively. Particle size reduction resulted in some loss of material of each pseudoephedrine formulation; Zephrex-D tablets were broken down to a coarse material; Nexafed and Sunmark tablets were reduced to a fine powder. The solubility rates of intact and ground tablets varied by product; Zephrex-D was most resistant to solubilizing while Nexafed and Sunmark were comparable and dissolved completely, demonstrating no solubility-resistant properties. Conditions of the one-pot method were modified throughout the studies to increase methamphetamine yield. Using optimal parameters identified in these studies and allowing the reaction to proceed for 90 min, average percent conversions were similar for the 3 formulations: 43.3% for Zephrex-D, 46.4% for Nexafed, and 48.6% for Sunmark. The greatest conversion occurred with a 150 min reaction time and resulted in 44.8%-48.4% conversion of Zephrex-D, 54.1%-66.4% conversion of Nexafed, and 58.6%-71.8% conversion of Sunmark. This series of methodological evaluations demonstrated that clandestine chemists can readily produce similar yields of methamphetamine using pseudoephedrine products with and without claimed tamper-resistant technology. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf)3 catalyst in the reaction selectivity

PubMed Central

Herrera Cano, Natividad; Uranga, Jorge G; Nardi, Mónica; Procopio, Antonio; Wunderlin, Daniel A

2016-01-01

An improved and greener protocol for the synthesis of benzimidazole derivatives, starting from o-phenylenediamine, with different aldehydes is reported. Double-condensation products were selectively obtained when Er(OTf)3 was used as the catalyst in the presence of electron-rich aldehydes. Conversely, the formation of mono-condensation products was the preferred path in absence of this catalyst. One of the major advantages of these reactions was the formation of a single product, avoiding extensive isolation and purification of products, which is frequently associated with these reactions. Theoretical calculations helped to understand the different reactivity established for these reactions. Thus, we found that the charge density on the oxygen of the carbonyl group has a significant impact on the reaction pathway. For instance, electron-rich aldehydes better coordinate to the catalyst, which favours the addition of the amine group to the carbonyl group, therefore facilitating the formation of double-condensation products. Reactions with aliphatic or aromatic aldehydes were possible, without using organic solvents and in a one-pot procedure with short reaction time (2–5 min), affording single products in excellent yields (75–99%). This convenient and eco-friendly methodology offers numerous benefits with respect to other protocols reported for similar compounds. PMID:28144309

Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf)3 catalyst in the reaction selectivity.

PubMed

Herrera Cano, Natividad; Uranga, Jorge G; Nardi, Mónica; Procopio, Antonio; Wunderlin, Daniel A; Santiago, Ana N

2016-01-01

An improved and greener protocol for the synthesis of benzimidazole derivatives, starting from o -phenylenediamine, with different aldehydes is reported. Double-condensation products were selectively obtained when Er(OTf) 3 was used as the catalyst in the presence of electron-rich aldehydes. Conversely, the formation of mono-condensation products was the preferred path in absence of this catalyst. One of the major advantages of these reactions was the formation of a single product, avoiding extensive isolation and purification of products, which is frequently associated with these reactions. Theoretical calculations helped to understand the different reactivity established for these reactions. Thus, we found that the charge density on the oxygen of the carbonyl group has a significant impact on the reaction pathway. For instance, electron-rich aldehydes better coordinate to the catalyst, which favours the addition of the amine group to the carbonyl group, therefore facilitating the formation of double-condensation products. Reactions with aliphatic or aromatic aldehydes were possible, without using organic solvents and in a one-pot procedure with short reaction time (2-5 min), affording single products in excellent yields (75-99%). This convenient and eco-friendly methodology offers numerous benefits with respect to other protocols reported for similar compounds.

Solution-phase parallel synthesis of hexahydro-1H-isoindolone libraries via tactical combination of Cu-catalyzed three-component coupling and Diels-Alder reactions.

PubMed

Zhang, Lei; Lushington, Gerald H; Neuenswander, Benjamin; Hershberger, John C; Malinakova, Helena C

2008-01-01

Parallel solution-phase synthesis of combinatorial libraries of hexahydro-1 H-isoindolones exploiting a novel "tactical combination" of Cu-catalyzed three-component coupling and Diels-Alder reactions was accomplished. Three distinct libraries consisting of 24 members (library I), 60 members (library II), and 32 members (library III) were constructed. Variation of three substituents on the isoindolone scaffold in library I was exclusively achieved by the choice of the building blocks. In the syntheses of libraries II and III, sublibraries of isoindolone scaffolds were prepared initially in a one-pot/two-step process and were further diversified via Pd-catalyzed Suzuki cross-coupling reaction with boronic acids at two different diversification points. The Lipinski profiles and calculated ADME properties of the compounds are also reported.

In-vitro evaluation of copper nanoparticles cytotoxicity on prostate cancer cell lines and their antioxidant, sensing and catalytic activity: One-pot green approach.

PubMed

Prasad, P Reddy; Kanchi, S; Naidoo, E B

2016-08-01

In this study, Broccoli green extract was reported as a green and environmental friendly precursor for the one-pot biosynthesis of copper nanoparticles. The synthesized nanoparticles were characterized by UV-vis, FTIR, TEM, DLS, XRD and cyclic voltammetry. The TEM and DLS results showed that the NPs are in spherical and monodispersed with an average particle size of ~4.8nm. The FTIR results confirmed the occurrence of bioactive functional groups that are responsible for reducing cupric sulphate to copper ions. The UV-vis spectrophotometry was used for catalytic reduction of 4-nitrophenol and its dynamic reaction in Britton-Robinson buffer solution. This catalytic activity was further supported with methylene blue and methyl red dyes degradation. The nanocatalyst can be recovered from the reaction mixture and reused many times with none vital loss of catalytic activity. The Broccoli green extract modified copper nanoparticles coated on screen printing electrode laid a new sensing platform and has an excellent electrocatalytic activity. Furthermore, surface modified CuNPs with Broccoli green extract exhibited no cytotoxicity at the concentration ranging from 0.5 to 1.5μM on the prostate cancer (PC-3) cell lines. The maximum scavenging % of Broccoli green extract modified CuNPs was found to be >70.50% at the concentration of 0.25mM against 1,1-diphenyl-2-picrylhydrazyl. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrathin ZnSe nanowires: one-pot synthesis via a heat-triggered precursor slow releasing route, controllable Mn doping and application in UV and near-visible light detection.

PubMed

Li, Dong; Xing, Guanjie; Tang, Shilin; Li, Xiaohong; Fan, Louzhen; Li, Yunchao

2017-10-12

We report herein a heat-triggered precursor slow releasing route for the one-pot synthesis of ultrathin ZnSe nanowires (NWs), which relies on the gradual dissolving of Se powder into oleylamine containing a soluble Zn precursor under heating. This route allows the reaction system to maintain a high monomer concentration throughout the entire reaction process, thus enabling the generation of ZnSe NWs with diameter down to 2.1 nm and length approaching 400 nm. The size-dependent optical properties and band-edge energy levels of the ZnSe NWs were then explored in depth by UV-visible spectroscopy and cyclic voltammetry, respectively. Considering their unique absorption properties, these NWs were specially utilized for fabricating photoelectrochemical-type photodetectors (PDs). Impressively, the PDs based on the ZnSe NWs with diameters of 2.1 and 4.5 nm exhibited excellent responses to UVA and near-visible light, respectively: both possessed ultrahigh on/off ratios (5150 for UVA and 4213 for near-visible light) and ultrawide linear response ranges (from 2.0 to 9000 μW cm -2 for UVA and 5.0 to 8000 μW cm -2 for near-visible light). Furthermore, these ZnSe NWs were selectively doped with various amounts of Mn 2+ to tune their emission properties. As a result, ZnSe NW film-based photochromic cards were creatively developed for visually detecting UVA and near-visible radiation.

One-pot synthesis of MoS2/In2S3 ultrathin nanoflakes with mesh-shaped structure on indium tin oxide as photocathode for enhanced photo-and electrochemical hydrogen evolution reaction

NASA Astrophysics Data System (ADS)

Sun, Baoliang; Shan, Fei; Jiang, Xinxin; Ji, Jing; Wang, Feng

2018-03-01

A bifunctional MoS2/In2S3 hybrid composite that has both photo- and electrocatalytic activity toward hydrogen evolution reaction (HER) is prepared by a facile one pot hydrothermal method. The characterizations by scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM) and Photoluminescence (PL) shows that the MoS2/In2S3 hybrid exhibits ultrathin nanoflakes with mesh-shaped structure on transparent conductive substrates, and the as prepared catalyst composite obviously improves the separation of electro-hole pairs. The as prepared hybrid nanosheets with Mo:In of 1/2 integrate In-doped MoS2 to reduce the stacking and increase the active surface area. The novel mesh-shaped nanostructure with a moderate degree of disorder provides not only simultaneously intrinsic conductivity and defects but also higher electrochemically active surface area (ECSA). By electrochemical measurements, such as linear sweep voltammetry (LSV), electrochemical impedance spectroscope (EIS) and cyclic voltammetry (CV), we find that the MoS2/In2S3 hybrid possesses much better photo/electrochemical activity than pristine MoS2 or In2S3. MoS2/In2S3 ultrathin nanoflaks are anticipated to be a superior photoelectrocatalyst for PEC cells, and the rational use of the MoS2/In2S3 cathode offers a new avenue toward achieving effective photo-assistant electrocatalytic activity.

Amavadin and other vanadium complexes as remarkably efficient catalysts for one-pot conversion of ethane to propionic and acetic acids.

PubMed

Kirillova, Marina V; Kuznetsov, Maxim L; da Silva, José A L; Guedes da Silva, Maria Fátima C; Fraústo da Silva, João J R; Pombeiro, Armando J L

2008-01-01

Synthetic amavadin Ca[V{ON[CH(CH(3))COO](2)}(2)] and its models Ca[V{ON(CH(2)COO)(2)}(2)] and [VO{N(CH(2)CH(2)O)(3)}], in the presence of K(2)S(2)O(8) in trifluoroacetic acid (TFA), exhibit remarkable catalytic activity for the one-pot carboxylation of ethane to propionic and acetic acids with the former as the main product (overall yields up to 93 %, catalyst turnover numbers (TONs) up to 2.0 x 10(4)). The simpler V complexes [VO(CF(3)SO(3))(2)], [VO(acac)(2)] and VOSO(4) are less active. The effects of various factors, namely, C(2)H(6) and CO pressures, time, temperature, and amounts of catalyst, TFA and K(2)S(2)O(8), have been investigated, and this allowed optimisation of the process and control of selectivity. (13)C-labelling experiments indicated that the formation of acetic acid follows two pathways, the dominant one via oxidation of ethane with preservation of the C--C bond, and the other via rupture of this bond and carbonylation of the methyl group by CO; the C--C bond is retained in the formation of propionic acid upon carbonylation of ethane. The reactions proceed via both C- and O-centred radicals, as shown by experiments with radical traps. On the basis of detailed DFT calculations, plausible reaction mechanisms are discussed. The carboxylation of ethane in the presence of CO follows the sequential formation of C(2)H(5) (*), C(2)H(5)CO(*), C(2)H(5)COO(*) and C(2)H(5)COOH. The C(2)H(5)COO(*) radical is easily formed on reaction of C(2)H(5)CO(*) with a peroxo V catalyst via a V{eta(1)-OOC(O)C(2)H(5)} intermediate. In the absence of CO, carboxylation proceeds by reaction of C(2)H(5) (*) with TFA. For the oxidation of ethane to acetic acid, either with preservation or cleavage of the C-C bond, metal-assisted and purely organic pathways are also proposed and discussed.

A general strategy for stereoselective glycosylations.

PubMed

Kim, Jin-Hwan; Yang, Hai; Park, Jin; Boons, Geert-Jan

2005-08-31

The principal challenge that the synthesis of oligosaccharides of biological importance presents is the development of a general approach for the stereoselective introduction of a glycosidic linkage. It is shown here that a (1S)-phenyl-2-(phenylsulfanyl)ethyl moiety at C-2 of a glycosyl donor can perform neighboring group participation to give a quasi-stable anomeric sulfonium ion. Due to steric and electronic factors, the sulfonium ion is formed as a trans-decalin ring system. Displacement of the sulfonium ion by a hydroxyl leads to the stereoselective formation of alpha-glycosides. NMR experiments were employed to show convincingly the presence of the beta-linked sulfonium ion intermediate. The (1S)-phenyl-2-(phenylsulfanyl)ethyl moiety could be introduced by reaction of a sugar alcohol with acetic acid (1S)-phenyl-2-(phenylsulfanyl)ethyl ester in the presence of BF(3)-OEt(2). Furthermore, it could be removed by conversion into acetate by treatment with BF(3)-OEt(2) in acetic anhydride. The introduction as well as the cleavage reaction proceeds through the formation of an intermediate episulfonium ion. The use of the new methodology in combination with traditional neighboring group participation by esters to introduce beta-glycosides makes it possible, for the first time, to synthesize a wide variety of oligosaccharides by routine procedures. The latter was demonstrated by the synthesis of the Galili trisaccharide, which has been identified as an epitope that can trigger acute rejections in xeno-transplantations, by the one-pot two-step glycosylation sequence.

Production of DNA minicircles less than 250 base pairs through a novel concentrated DNA circularization assay enabling minicircle design with NF-κB inhibition activity.

PubMed

Thibault, Thomas; Degrouard, Jeril; Baril, Patrick; Pichon, Chantal; Midoux, Patrick; Malinge, Jean-Marc

2017-03-17

Double-stranded DNA minicircles of less than 1000 bp in length have great interest in both fundamental research and therapeutic applications. Although minicircles have shown promising activity in gene therapy thanks to their good biostability and better intracellular trafficking, minicircles down to 250 bp in size have not yet been investigated from the test tube to the cell for lack of an efficient production method. Herein, we report a novel versatile plasmid-free method for the production of DNA minicircles comprising fewer than 250 bp. We designed a linear nicked DNA double-stranded oligonucleotide blunt-ended substrate for efficient minicircle production in a ligase-mediated and bending protein-assisted circularization reaction at high DNA concentration of 2 μM. This one pot multi-step reaction based-method yields hundreds of micrograms of minicircle with sequences of any base composition and position and containing or not a variety of site-specifically chemical modifications or physiological supercoiling. Biochemical and cellular studies were then conducted to design a 95 bp minicircle capable of binding in vitro two NF-κB transcription factors per minicircle and to efficiently inhibiting NF-κB-dependent transcriptional activity in human cells. Therefore, our production method could pave the way for the design of minicircles as new decoy nucleic acids. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Fabrication of modified GIC: GIC-nanoSiO2-HA-ZrO2 using two different mixing methods

NASA Astrophysics Data System (ADS)

Ghazali, Nor Ainon Maziah; Bakar, Wan Zaripah Wan; Rahman, Ismail Ab; Masudi, Sam'an Malik

2017-12-01

Conventional glass ionomer cement (GIC) is among the mostly used material in dentistry but some modifications were needed due to its deficiencies such as low mechanical strength and opacity. In this study, a new nanocomposite, GIC-nanoSiO2-HA-ZrO2 was fabricated whereby zirconia is added to improve the hardness. The nanocomposite of SiO2-HA-ZrO2 was synthesized using two different mixing methods which are one pot and spatulation methods. One pot method involved the addition of zirconia nanopowder during the one pot synthesis of nanoSiO2-HA and spatulation method involved the addition of zirconia nanopowder by controlled grinding process using mortar and pestle. Different weight percentage from 1-20 % of nanoSiO2-HA-ZrO2 was added to GIC and the hardness was analyzed using Vickers Tester. The one pot method recorded the highest and significant hardness value at 3 % addition which is ˜75.27 HV (± 2.48) compared to spatulation method ˜69.53 HV (± 7.78) at p < 0.05. Scanning Electron Microscope image from one pot method showed less agglomeration of the nanopowder and nanozirconia is uniformly distributed. Within the limitation of this study, one pot method produced better GIC-nanoSiO2-HA-ZrO2 composite.

Repressor-mediated tissue-specific gene expression in plants

DOEpatents

Meagher, Richard B [Athens, GA; Balish, Rebecca S [Oxford, OH; Tehryung, Kim [Athens, GA; McKinney, Elizabeth C [Athens, GA

2009-02-17

Plant tissue specific gene expression by way of repressor-operator complexes, has enabled outcomes including, without limitation, male sterility and engineered plants having root-specific gene expression of relevant proteins to clean environmental pollutants from soil and water. A mercury hyperaccumulation strategy requires that mercuric ion reductase coding sequence is strongly expressed. The actin promoter vector, A2pot, engineered to contain bacterial lac operator sequences, directed strong expression in all plant vegetative organs and tissues. In contrast, the expression from the A2pot construct was restricted primarily to root tissues when a modified bacterial repressor (LacIn) was coexpressed from the light-regulated rubisco small subunit promoter in above-ground tissues. Also provided are analogous repressor operator complexes for selective expression in other plant tissues, for example, to produce male sterile plants.

Direct synthesis of acid-base bifunctionalized hexagonal mesoporous silica and its catalytic activity in cascade reactions.

PubMed

Shang, Fanpeng; Sun, Jianrui; Wu, Shujie; Liu, Heng; Guan, Jingqi; Kan, Qiubin

2011-03-01

A series of efficient acid-base bifunctionalized hexagonal mesoporous silica (HMS) catalysts contained aminopropyl and propanesulfonic acid have been synthesized through a simple co-condensation by protection of amino group. The results of small-angle XRD, TEM, and N(2) adsorption-desorption measurements show that the resultant materials have mesoscopic structures. X-ray photoelectron spectroscopies, elemental analysis (EA), back titration, (29)Si NMR and (13)C NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The resultant catalysts exhibit excellent acid-basic properties, which make them possess high activity for one-pot deacetalization-Knoevenagel and deacetalization-nitroaldol (Henry) reactions. Copyright © 2010 Elsevier Inc. All rights reserved.

The antioxidant effect of derivatives pyroglutamic lactam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rohadi, Atisya; Lazim, Azwani Mat; Hasbullah, Siti Aishah

Diphenylpicrylhydrazyl (DPPH) is widely used for quickly accessing the ability of polyphenols to transfer labile H atoms to radicals. The antioxidant activity of all the synthesized compounds was screened by DPPH method. Compound (4) showed 54% antioxidant potential while all other compounds were found to have moderate to have moderate to mild antioxidant activity ranging from 47–52%. Pyroglutamic lactams have been synthesized stereoselectively in racemic form from levulinic acid as bifunctional adduct using convertible isocyanide in one-pot Ugi 4-center-3-component condensation reaction (U-4C-3CR). The product formed provides biologically interesting products in excellent yields in a short reaction time. The structures ofmore » the synthesized compounds were elucidated using spectroscopic data and elemental analysis.« less

Multicomponent Synthesis and Evaluation of New 1,2,3-Triazole Derivatives of Dihydropyrimidinones as Acidic Corrosion Inhibitors for Steel.

PubMed

González-Olvera, Rodrigo; Román-Rodríguez, Viridiana; Negrón-Silva, Guillermo E; Espinoza-Vázquez, Araceli; Rodríguez-Gómez, Francisco Javier; Santillan, Rosa

2016-02-22

An efficient one-pot synthesis of 1,2,3-triazole derivatives of dihydropyrimidinones has been developed using two multicomponent reactions. The aldehyde-1,2,3-triazoles were obtained in good yields from in situ-generated organic azides and O-propargylbenzaldehyde. The target heterocycles were synthesized through the Biginelli reaction in which the aldehyde-1,2,3-triazoles reacted with ethyl acetoacetate and urea in the presence of Ce(OTf)₃ as the catalyst. The corrosion inhibition of steel grade API 5 L X52 in 1 M HCl by the synthesized compounds was investigated using the electrochemical impedance spectroscopy technique. The measurements revealed that these heterocycles are promising candidates to inhibit acidic corrosion of steel.

An innovative pot system for monitoring the effects of water stress on grapevines and grape quality

NASA Astrophysics Data System (ADS)

Puccioni, Sergio; Leprini, Marco; Mocali, Stefano; Perria, Rita; Priori, Simone; Storchi, Paolo; Zombardo, Alessandra; Costantini, Edoardo

2016-04-01

The advantage of a pot system is the possibility to control many variables and factors with a large number of replicates, obtaining statistically significant results in only one year of experimentation. An innovative pot system for the monitoring of grapevine water stress was set up. The system consists of 99 pots of 70 liters, filled by 3 different soils collected from premium vineyards of the Chianti Classico district (Tuscany). The soils showed different texture (clay-loam, loam and sandy-loam), different gravel and carbonate content, and different available water capacity (AWC). The same soils had been field monitored for grapevine water stress; therefore it was possible to compare the grapevine behaviour both in pot and in field conditions. The grapevine cultivar was Pinot noir clone ENTAV 115, which can be used to investigate the genetic expression in response to environmental factors, since its genome has been sequenced. Different rootstocks theses were compared: not grafted, 1103 Paulsen and M101-14. Each combination rootstock-soil was repeated 9 times. Every pot was equipped for drip irrigation and with electrodes for soil moisture determination by TDR. A non-stop automated control unit recorded meteorological data (temperature and rainfalls), soil temperature and water potential on 9 selected pots. These 9 selected pots were also used to calibrate a model for soil water volume/tension curve. Soil, leaves and grapes samples from each pot were collected for microbial community determination, through NGS analysis. A preliminary study was based on testing the ability of the system to simulate the natural growing conditions of the grapevines. Therefore the grape performances of the potted plants were compared to those of plants cultivated in the vineyards where the soils were taken. In July 2015 three levels of water supply were tested during 5 weeks (up to veraison) in order to study the effects of water stress on the plants and the grape. Later, all the pots were irrigated abundantly until the full ripening of the grapes. The results revealed that a period of water stress during the early stages of bunches growth can induce irreversible changes in the physiology of the plant. Even if the leaf water potential was restored after abundant irrigations, the photosynthetic capacity was compromised, provoking remarkable effects on the composition of the grape. Although the plants produced similar amounts of grape, the water stress reduced the average berry weight. The plants with higher water availability synthesized more sugars and organic acids, while a strong water stress promoted the accumulation of anthocyanins and phenolic compounds. Soil typology and AWC influenced water stress and physiology of plants, and grape yield and quality. As expected, the plants grafted on 1103 Paulsen resulted more productive, while on the 110-14 they showed similar response to water stress that non-grafted vines. The results in the pots confirmed the effect of soil type that was monitored in the field, and highlighted a strong interaction between rootstock, soil, and microbial community. Acknowledgements: Financial support for this project was provided by the Italy - Israel Cooperation in Agricultural Research.

Heteropoly acid-catalyzed microwave-assisted three-component aza-Diels-Alder cyclizations: diastereoselective synthesis of potential drug candidates for Alzheimer's disease.

PubMed

Borkin, Dmitry; Morzhina, Elena; Datta, Silpi; Rudnitskaya, Aleksandra; Sood, Abha; Török, Marianna; Török, Béla

2011-03-07

A highly diastereoselective microwave-assisted three component synthesis of azabicyclo[2.2.2]octan-5-ones by a silicotungstic acid-catalyzed aza-Diels-Alder cyclization is described. The one-pot process involves the formation of the in situ generated Schiff base and its immediate cyclization with cyclohex-2-enone. The short reaction times, good yields and excellent diastereoselectivity make this annulation a practical and environmentally attractive method for the synthesis of the target compounds. Preliminary assays were carried out to determine the activity of the products in AChE as well as in amyloid β fibrillogenesis inhibition.

One-pot strategy for on-site enzyme production, biomass hydrolysis, and ethanol production using the whole solid-state fermentation medium of mixed filamentous fungi.

PubMed

Maehara, Larissa; Pereira, Sandra C; Silva, Adilson J; Farinas, Cristiane S

2018-02-01

The efficient use of renewable lignocellulosic feedstocks to obtain biofuels and other bioproducts is a key requirement for a sustainable biobased economy. This requires novel and effective strategies to reduce the cost contribution of the cellulolytic enzymatic cocktails needed to convert the carbohydrates into simple sugars, in order to make large-scale commercial processes economically competitive. Here, we propose the use of the whole solid-state fermentation (SSF) medium of mixed filamentous fungi as an integrated one-pot strategy for on-site enzyme production, biomass hydrolysis, and ethanol production. Ten different individual and mixed cultivations of commonly used industrial filamentous fungi (Aspergillus niger, Aspergillus oryzae, Trichoderma harzianum, and Trichoderma reesei) were performed under SSF and the whole media (without the extraction step) were used in the hydrolysis of pretreated sugarcane bagasse. The cocultivation of T. reesei with A. oryzae increased the amount of glucose released by around 50%, compared with individual cultivations. The release of glucose and reducing sugars achieved using the whole SSF medium was around 3-fold higher than obtained with the enzyme extract. The addition of soybean protein (0.5% w/w) during the hydrolysis reaction further significantly improved the saccharification performance by blocking the lignin and avoiding unproductive adsorption of enzymes. The results of the alcoholic fermentation validated the overall integrated process, with a volumetric ethanol productivity of 4.77 g/L.h, representing 83.5% of the theoretical yield. These findings demonstrate the feasibility of the proposed one-pot integrated strategy using the whole SSF medium of mixed filamentous fungi for on-site enzymes production, biomass hydrolysis, and ethanol production. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018. © 2018 American Institute of Chemical Engineers.

Facile one-pot synthesis of cellulose nanocrystal-supported hollow CuFe2O4 nanoparticles as efficient catalyst for 4-nitrophenol reduction

NASA Astrophysics Data System (ADS)

Zhang, Sufeng; Zhao, Dongyan; Hou, Chen; Liang, Chen; Li, Hao

2018-06-01

A facile and efficient one-pot method for the synthesis of well-dispersed hollow CuFe2O4 nanoparticles (H-CuFe2O4 NPs) in the presence of cellulose nanocrystals (CNC) as the support was described. Based on the one-pot solvothermal condition control, magnetic H-CuFe2O4 NPs were in-situ grown on the CNC surface uniformly. TEM images indicated good dispersity of H-CuFe2O4 NPs with uniform size of 300 nm. The catalytic activity of H-CuFe2O4/CNC was tested in the catalytic reduction of 4-nitrophenol (4-NP) in aqueous solution. Compared with most CNC-based ferrite catalysts, H-CuFe2O4/CNC catalyst exhibited an excellent catalytic activity toward the reduction of 4-NP. The catalytic performance of H-CuFe2O4/CNC catalyst was remarkably enhanced with the rate constant of 3.24 s-1 g-1, which was higher than H-CuFe2O4 NPs (0.50 s-1 g-1). The high catalytic activity was attributed to the introduction of CNC and the special hollow mesostructure of H-CuFe2O4 NPs. In addition, the H-CuFe2O4/CNC catalyst promised good conversion efficiency without significant decrease even after 10 cycles, confirming relatively high stability. Because of its environmental sustainability and magnetic separability, H-CuFe2O4/CNC catalyst was shown to indicate that the ferrite nanoparticles supported on CNC were acted as a promising catalyst and exhibited potential applications in numerous ferrite based catalytic reactions.

Automated three-component synthesis of a library of γ-lactams

PubMed Central

Fenster, Erik; Hill, David; Reiser, Oliver

2012-01-01

Summary A three-component method for the synthesis of γ-lactams from commercially available maleimides, aldehydes, and amines was adapted to parallel library synthesis. Improvements to the chemistry over previous efforts include the optimization of the method to a one-pot process, the management of by-products and excess reagents, the development of an automated parallel sequence, and the adaption of the method to permit the preparation of enantiomerically enriched products. These efforts culminated in the preparation of a library of 169 γ-lactams. PMID:23209515

Emittance formula for slits and pepper-pot measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, M.

1996-10-01

In this note, a rigid formula for slits and pepper-pot emittance measurement is derived. The derivation is based on the one- dimensional slit measurement setup. A mathematical generalization of the slit emittance formula to the pepper-pot measurement is discussed.

Identification of Striga hermonthica-Resistant Upland Rice Varieties in Sudan and Their Resistance Phenotypes.

PubMed

Samejima, Hiroaki; Babiker, Abdel G; Mustafa, Ahmed; Sugimoto, Yukihiro

2016-01-01

Rice has become a major staple cereal in sub-Saharan Africa. Currently, upland rice cultivation is expanding particularly in rainfed areas where the root parasitic weed Striga hermonthica, a major constraint to cereal production, is endemic. Laboratory, pot, and semi-controlled open air experiments were performed to evaluate resistance of selected rice varieties in Sudan to a resident S. hermonthica population. In the laboratory, 27 varieties were screened for post-attachment resistance using the rhizotron technique. Varieties displaying high post-attachment resistance, Umgar, NERICA5, and NERICA13 together with NERICA4, NERICA18, and Nipponbare, a lowland rice variety, were further evaluated for performance and Striga resistance in pot and semi-controlled open air experiments and for germination inducing activity in a laboratory. In addition, comparative studies on reaction of Umgar, Kosti1 and Kosti2, released varieties for commercial production in Sudan, to the parasite were performed in two pot experiments. In the pot experiments Umgar and NERICA5, consistently, sustained the lowest Striga emergence (<2.2 Striga plants per pot), while NERICA13 and NERICA4 supported 1.8-5.7 and 8.7-16.4 Striga plants per pot, respectively. In an artificially Striga-infested field, number of emergent Striga plants per 10 rice hills, at harvest, was 2.0, 2.0, 4.8, 13.5, 13.3, and 18.3 on Umgar, NERICA5, NERICA13, NERICA4, NERICA18, and Nipponbare, respectively. Striga had no adverse effects on total above-ground parts and panicle dry weight in Umgar and NERICA5. Germination-inducing activity of root exudates, at 14 days after sowing onward, was markedly lower for Umgar than for NERICA5, NERICA13, NERICA4, and NERICA18. Based on these findings, Umgar has both pre and post-attachment resistance to a resident Striga population in Sudan. Kosti1 and Kosti2 did not exhibit Striga-resistance at the same level as Umgar. Further the resistance of NERICA5, a variety reported to be endowed with a broad spectrum resistance to Striga species and ecotypes, at least to one resident Striga population in Sudan was clearly indicated.

Identification of Striga hermonthica-Resistant Upland Rice Varieties in Sudan and Their Resistance Phenotypes

PubMed Central

Samejima, Hiroaki; Babiker, Abdel G.; Mustafa, Ahmed; Sugimoto, Yukihiro

2016-01-01

Rice has become a major staple cereal in sub-Saharan Africa. Currently, upland rice cultivation is expanding particularly in rainfed areas where the root parasitic weed Striga hermonthica, a major constraint to cereal production, is endemic. Laboratory, pot, and semi-controlled open air experiments were performed to evaluate resistance of selected rice varieties in Sudan to a resident S. hermonthica population. In the laboratory, 27 varieties were screened for post-attachment resistance using the rhizotron technique. Varieties displaying high post-attachment resistance, Umgar, NERICA5, and NERICA13 together with NERICA4, NERICA18, and Nipponbare, a lowland rice variety, were further evaluated for performance and Striga resistance in pot and semi-controlled open air experiments and for germination inducing activity in a laboratory. In addition, comparative studies on reaction of Umgar, Kosti1 and Kosti2, released varieties for commercial production in Sudan, to the parasite were performed in two pot experiments. In the pot experiments Umgar and NERICA5, consistently, sustained the lowest Striga emergence (<2.2 Striga plants per pot), while NERICA13 and NERICA4 supported 1.8–5.7 and 8.7–16.4 Striga plants per pot, respectively. In an artificially Striga-infested field, number of emergent Striga plants per 10 rice hills, at harvest, was 2.0, 2.0, 4.8, 13.5, 13.3, and 18.3 on Umgar, NERICA5, NERICA13, NERICA4, NERICA18, and Nipponbare, respectively. Striga had no adverse effects on total above-ground parts and panicle dry weight in Umgar and NERICA5. Germination-inducing activity of root exudates, at 14 days after sowing onward, was markedly lower for Umgar than for NERICA5, NERICA13, NERICA4, and NERICA18. Based on these findings, Umgar has both pre and post-attachment resistance to a resident Striga population in Sudan. Kosti1 and Kosti2 did not exhibit Striga-resistance at the same level as Umgar. Further the resistance of NERICA5, a variety reported to be endowed with a broad spectrum resistance to Striga species and ecotypes, at least to one resident Striga population in Sudan was clearly indicated. PMID:27242837

Rhodium-Catalyzed Regioselective Synthesis of Isocoumarins through Benzothiadiazine-Fused Frameworks.

PubMed

Dalvi, Prashant B; Lin, Kuang-Ling; Kulkarni, Manohar V; Sun, Chung-Ming

2016-08-05

An unprecedented two-step, one-pot synthesis of benzimidazothiadiazine 5,5-dioxides is presented. Reaction condition based regioselectivity has been achieved where fused benzimidazo[1,2-b][1,2,4]thiadiazines are exclusively formed under thermal conditions, whereas benzimidazo[2,1-c][1,2,4]thiadiazines were created only under microwave irradiation. The salient features of this protocol include a regioselective sulfonylation of 2-aminobenzimidazole with o-halo sulfonyl chlorides followed by N-C bond formation. The acid forms of these fused regioisomers have been used to introduce novel guanidine-containing isocoumarin frameworks.

Method of Cross-Linking Aerogels Using a One-Pot Reaction Scheme

NASA Technical Reports Server (NTRS)

Meador, Ann B.; Capadona, Lynn A.

2008-01-01

A document discusses a new, simplified method for cross-linking silica and other oxide aerogels, with a polymeric material to increase strength of such materials without adversely affecting porosity or low density. This innovation introduces the polymer precursor into the sol before gelation either as an agent, which co-reacts with the oxide gel, or as soluble polymer precursors, which do not interact with the oxide gel in any way. Subsequent exposure to heat, light, catalyst or other method of promoting polymerization causes cross-linking without any additional infiltration steps.

Chiral Brønsted Base-Promoted Nitroalkane Alkylation: Enantioselective Synthesis of sec-Alkyl-3-Substituted Indoles

PubMed Central

Dobish, Mark C.; Johnston, Jeffrey N.

2010-01-01

A Brønsted base-catalyzed reaction of nitroalkanes with alkyl electrophiles provides indole heterocycles substituted at C3 bearing a sec-alkyl group with good enantioselectivity (up to 90% ee). Denitration by hydrogenolysis provides a product with equally high ee. An indolenine intermediate is implicated in the addition step, and surprisingly, water cosolvent was found to have a beneficial effect in this step, leading to a one-pot protocol for elimination/enantioselective addition using PBAM, a bis(amidine) chiral nonracemic base. PMID:21090654

Nucleophilic addition of Grignard reagents to 3-acylindoles: stereoselective synthesis of highly substituted indoline scaffolds.

PubMed

Wang, Lu; Shao, Yushang; Liu, Yuanhong

2012-08-03

3-Acylindoles undergo nucleophilic-type reactions with Grignard reagents to efficiently afford either cis- or trans-substituted indolines, depending on the different quenching procedures. The enolate intermediate could be trapped by aryl acyl chlorides to provide indolines bearing a quaternary carbon center with high stereoselectivity. In contrast, the use of benzyl bromide as an electrophile results in the fragmentation of the indole ring. The indoline products could be easily transformed into indoles through oxidation with DDQ in a one-pot manner.

Catalyst-free dehydrative α-alkylation of ketones with alcohols: green and selective autocatalyzed synthesis of alcohols and ketones.

PubMed

Xu, Qing; Chen, Jianhui; Tian, Haiwen; Yuan, Xueqin; Li, Shuangyan; Zhou, Chongkuan; Liu, Jianping

2014-01-03

Direct dehydrative α-alkylation reactions of ketones with alcohols are now realized under simple, practical, and green conditions without using external catalysts. These catalyst-free autocatalyzed alkylation methods can efficiently afford useful alkylated ketone or alcohol products in a one-pot manner and on a large scale by CC bond formation of the in situ generated intermediates with subsequent controllable and selective Meerwein-Pondorf-Verley-Oppenauer-type redox processes. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One recognition sequence, seven restriction enzymes, five reaction mechanisms

PubMed Central

Gowers, Darren M.; Bellamy, Stuart R.W.; Halford, Stephen E.

2004-01-01

The diversity of reaction mechanisms employed by Type II restriction enzymes was investigated by analysing the reactions of seven endonucleases at the same DNA sequence. NarI, KasI, Mly113I, SfoI, EgeI, EheI and BbeI cleave DNA at several different positions in the sequence 5′-GGCGCC-3′. Their reactions on plasmids with one or two copies of this sequence revealed five distinct mechanisms. These differ in terms of the number of sites the enzyme binds, and the number of phosphodiester bonds cleaved per turnover. NarI binds two sites, but cleaves only one bond per DNA-binding event. KasI also cuts only one bond per turnover but acts at individual sites, preferring intact to nicked sites. Mly113I cuts both strands of its recognition sites, but shows full activity only when bound to two sites, which are then cleaved concertedly. SfoI, EgeI and EheI cut both strands at individual sites, in the manner historically considered as normal for Type II enzymes. Finally, BbeI displays an absolute requirement for two sites in close physical proximity, which are cleaved concertedly. The range of reaction mechanisms for restriction enzymes is thus larger than commonly imagined, as is the number of enzymes needing two recognition sites. PMID:15226412

Emergent Properties of Giant Vesicles Formed by a Polymerization-Induced Self-Assembly (PISA) Reaction

NASA Astrophysics Data System (ADS)

Albertsen, Anders N.; Szymański, Jan K.; Pérez-Mercader, Juan

2017-01-01

Giant micrometer sized vesicles are of obvious interest to the natural sciences as well as engineering, having potential application in fields ranging from drug delivery to synthetic biology. Their formation often requires elaborate experimental techniques and attempts to obtain giant vesicles from chemical media in a one-pot fashion have so far led to much smaller nanoscale structures. Here we show that a tailored medium undergoing controlled radical polymerization is capable of forming giant polymer vesicles. Using a protocol which allows for an aqueous reaction under mild conditions, we observe the macroscale consequences of amphiphilic polymer synthesis and the resulting molecular self-assembly using fluorescence microscopy. The polymerization process is photoinitiated by blue light granting complete control of the reaction, including on the microscope stage. The self-assembly process leads to giant vesicles with radii larger than 10 microns, exhibiting several emergent properties, including periodic growth and collapse as well as phototaxis.

A comparative study: Greener vs conventional synthesis of 4H-pyrimido[2,1-b]benzothiazoles via Biginelli reaction

NASA Astrophysics Data System (ADS)

Agarwal, Shikha; Agarwal, Dinesh Kr.; Kalal, Priyanka; Gandhi, Divyani

2018-05-01

Multicomponent reactions (MCRs) have been discovered as a powerful method for the synthesis of organic molecules, since the products are formed in a single step and the building blocks with diverse range of complexity can be obtained from easily available precursors. This strategy has become important in drug designing and discovery in the context of synthesis of biologically active compounds. In the today's scenario, MCRs are influenced by greener conditions as a powerful alternative over the conventional synthesis. In the last few years, a number of scientific publications have been appeared in the literature depicting the synthesis of pyrimidobenzothiazoles via greener routes which clearly states its importance in pharmaceutical chemistry for the drug development. Our article describes the synthesis of substituted pyrimidobenzothiazoles via one pot multicomponent reaction with structural diversity through conventional and greener pathways using different catalysts, ionic liquids, agar, resins etc.

Polyethyleneimine-modified superparamagnetic Fe3O4 nanoparticles: An efficient, reusable and water tolerance nanocatalyst

NASA Astrophysics Data System (ADS)

Khoobi, Mehdi; Delshad, Tayebeh Modiri; Vosooghi, Mohsen; Alipour, Masoumeh; Hamadi, Hosein; Alipour, Eskandar; Hamedani, Majid Pirali; Sadat ebrahimi, Seyed Esmaeil; Safaei, Zahra; Foroumadi, Alireza; Shafiee, Abbas

2015-02-01

A novel magnetically separable catalyst was prepared based on surface modification of Fe3O4 magnetic nanoparticle (MNPs) with polyethyleneimine (PEI) via covalent bonding. [3-(2,3-Epoxypropoxy)propyl]trimethoxysilane (EPO) was used as cross linker to bond PEI on the surface of MNPs with permanent stability in contrast to PEI coating via electrostatic interactions. The synthesized catalyst was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The catalyst show high efficiency for one-pot synthesis of 2-amino-3-cyano-4H-pyran derivatives via multi-component reaction (MCR). This procedure offers the advantages of green reaction media, high yield, short reaction time, easy purification of the products and simple recovery and reuse of the catalyst by simple magnetic decantation without significant loss of catalytic activity.

AgI /TMG-Promoted Cascade Reaction of Propargyl Alcohols, Carbon Dioxide, and 2-Aminoethanols to 2-Oxazolidinones.

PubMed

Li, Xue-Dong; Song, Qing-Wen; Lang, Xian-Dong; Chang, Yao; He, Liang-Nian

2017-11-17

Chemical valorization of CO 2 to access various value-added compounds has been a long-term and challenging objective from the viewpoint of sustainable chemistry. Herein, a one-pot three-component reaction of terminal propargyl alcohols, CO 2 , and 2-aminoethanols was developed for the synthesis of 2-oxazolidinones and an equal amount of α-hydroxyl ketones promoted by Ag 2 O/TMG (1,1,3,3-tetramethylguanidine) with a TON (turnover number) of up to 1260. By addition of terminal propargyl alcohol, the thermodynamic disadvantage of the conventional 2-aminoethanol/CO 2 coupling was ameliorated. Mechanistic investigations including control experiments, DFT calculation, kinetic and NMR studies suggest that the reaction proceeds through a cascade pathway and TMG could activate propargyl alcohol and 2-aminoethanol through the formation of hydrogen bonds and also activate CO 2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bio-waste corn-cob cellulose supported poly(hydroxamic acid) copper complex for Huisgen reaction: Waste to wealth approach.

PubMed

Mandal, Bablu Hira; Rahman, Md Lutfor; Yusoff, Mashitah Mohd; Chong, Kwok Feng; Sarkar, Shaheen M

2017-01-20

Corn-cob cellulose supported poly(hydroxamic acid) Cu(II) complex was prepared by the surface modification of waste corn-cob cellulose through graft copolymerization and subsequent hydroximation. The complex was characterized by IR, UV, FESEM, TEM, XPS, EDX and ICP-AES analyses. The complex has been found to be an efficient catalyst for 1,3-dipolar Huisgen cycloaddition (CuAAC) of aryl/alkyl azides with a variety of alkynes as well as one-pot three-components reaction in the presence of sodium ascorbate to give the corresponding cycloaddition products in up to 96% yield and high turn over number (TON 18,600) and turn over frequency (TOF 930h -1 ) were achieved. The complex was easy to recover from the reaction mixture and reused six times without significant loss of its catalytic activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

The long underestimated carbonyl function of carbohydrates – an organocatalyzed shot into carbohydrate chemistry.

PubMed

Mahrwald, R

2015-09-21

The aggressive and strong development of organocatalysis provides several protocols for the convenient utilization of the carbonyl function of unprotected carbohydrates in C-C-bond formation processes. These amine-catalyzed mechanisms enable multiple cascade-protocols for the synthesis of a wide range of carbohydrate-derived compound classes. Several, only slightly different protocols, have been developed for the application of 1,3-dicarbonyl compounds in the stereoselective chain-elongation of unprotected carbohydrates and the synthesis of highly functionalized C-glycosides of defined configuration. In addition, C-glycosides can also be accessed by amine-catalyzed reactions with methyl ketones. By a one-pot cascade reaction of isocyanides with unprotected aldoses and amino acids access to defined configured glycopeptide mimetics is achieved. Depending on the reaction conditions different origins to control the installation of configuration during the bond-formation process were observed.

Clinical improvement in patients with orthostatic intolerance after treatment with bisoprolol and fludrocortisone.

PubMed

Freitas, J; Santos, R; Azevedo, E; Costa, O; Carvalho, M; de Freitas, A F

2000-10-01

Orthostatic intolerance is the development of disabling symptoms upon assuming an upright posture that are relieved partially by resuming the supine position. Postural tachycardia syndrome (POTS) is an orthostatic intolerance syndrome characterized by palpitations because of excessive orthostatic sinus tachycardia, lightheadedness, tremor, and near-syncope. Patients usually undergo extensive medical, cardiac, endocrine, neurologic, and psychiatric evaluation, which usually fails to identify a specific abnormality. The authors investigated the autonomic and hemodynamic profile of patients with POTS and the effectiveness of bisoprolol and fludrocortisone. The authors evaluated 11 female patients with POTS before and after medical treatment with a cardioselective bisoprolol beta-blocker or fludrocortisone, or both, and 11 age-matched control patients. Variability of heart rate and systolic blood pressure was assessed by fast Fourier transform, and spontaneous baroreceptor gain was assessed by use of the temporal sequences slope and alpha index. Modelflow was used to quantify hemodynamics. Symptoms in all patients improved greatly after medication. The autonomic and hemodynamic impairment observed in patients with POTS, particularly after orthostatic stress, is treated effectively with bisoprolol or fludrocortisone or both. These results need further confirmation in a controlled double-blind study. Proper medical treatment improves dramatically the clinical and autonomic-hemodynamic disturbances observed in patients with POTS. The data support the hypothesis that POTS is the result of a hyperadrenergic activation or hypovolemia during orthostasis.

Improved 18F Labeling of Peptides with a Fluoride-Aluminum-Chelate Complex

PubMed Central

McBride, William J.; D’Souza, Christopher A.; Sharkey, Robert M.; Karacay, Habibe; Rossi, Edmund A.; Chang, Chien-Hsing; Goldenberg, David M.

2010-01-01

We reported previously the feasibility to radiolabel peptides with fluorine-18 (18F) using a rapid, one-pot, method that first mixes 18F− with Al3+, and then binds the (Al18F)2+ complex to a NOTA ligand on the peptide. In this report, we examined several new NOTA ligands and determined how temperature, reaction time, and reagent concentration affected the radiolabeling yield. Four structural variations of the NOTA ligand had isolated radiolabeling yields ranging from 5.8% to 87% under similar reaction conditions. All of the Al18F NOTA complexes were stable in vitro in human serum and those that were tested in vivo also were stable. The radiolabeling reactions were performed at 100°C and the peptides could be labeled in as little as five minutes. The IMP467 peptide could be labeled up to 115 GBq/μmol (3100 Ci/mmol), with a total reaction and purification time of 30 min without chromatographic purification. PMID:20540570

Rapid, chemical-free breaking of microfluidic emulsions with a hand-held antistatic gun

PubMed Central

Shahi, Payam; Abate, Adam R.

2017-01-01

Droplet microfluidics can form and process millions of picoliter droplets with speed and ease, allowing the execution of huge numbers of biological reactions for high-throughput studies. However, at the conclusion of most experiments, the emulsions must be broken to recover and analyze their contents. This is usually achieved with demulsifiers, like perfluorooctanol and chloroform, which can interfere with downstream reactions and harm cells. Here, we describe a simple approach to rapidly and efficiently break microfluidic emulsions, which requires no chemicals. Our method allows one-pot multi-step reactions, making it useful for large scale automated processing of reactions requiring demulsification. Using a hand-held antistatic gun, we pulse emulsions with the electric field, coalescing ∼100 μl of droplets in ∼10 s. We show that while emulsions broken with chemical demulsifiers exhibit potent PCR inhibition, the antistatic-broken emulsions amplify efficiently. The ability to break emulsions quickly without chemicals should make our approach valuable for most demulsification needs in microfluidics. PMID:28794817

Biotransformation of caffeoyl quinic acids from green coffee extracts by Lactobacillus johnsonii NCC 533.

PubMed

Bel-Rhlid, Rachid; Thapa, Dinesh; Kraehenbuehl, Karin; Hansen, Carl Erik; Fischer, Lutz

2013-01-01

The potential of Lactobacillus johnsonii NCC 533 to metabolize chlorogenic acids from green coffee extract was investigated. Two enzymes, an esterase and a hydroxycinnamate decarboxylase (HCD), were involved in this biotransformation. The complete hydrolysis of 5-caffeoylquinic acid (5-CQA) into caffeic acid (CA) by L. johnsonii esterase occurred during the first 16 h of reaction time. No dihydrocaffeic acid was identified in the reaction mixture. The decarboxylation of CA into 4-vinylcatechol (4-VC) started only when the maximum concentration of CA was reached (10 μmol/ml). CA was completely transformed into 4-VC after 48 h of incubation. No 4-vinylphenol or other derivatives could be identified in the reaction media. In this study we demonstrate the capability of L. johnsonii to transform chlorogenic acids from green coffee extract into 4-VC in two steps one pot reaction. Thus, the enzymatic potential of certain lactobacilli might be explored to generate flavor compounds from plant polyphenols.

One-step instant synthesis of protein-conjugated quantum dots at room temperature.

PubMed

He, Xuewen; Gao, Li; Ma, Nan

2013-10-02

We present a new general facile strategy for the preparation of protein-functionalized QDs in a single step at ambient conditions. We demonstrated that highly luminescent red to near-infrared (NIR) protein-functionalized QDs could be synthesized at room temperature in one second through a one-pot reaction that proceeds in aqueous solution. Herein protein-functionalized QDs were successfully constructed for a variety of proteins with a wide range of molecular weights and isoelectric points. The as-prepared protein-conjugated QDs exhibited high quantum yield, high photostabiliy and colloidal stability, and high functionalization efficiency. Importantly, the proteins attached to the QDs maintain their biological activities and are capable of catalyzing reactions and biotargeting. In particular, the as-prepared transferrin-QDs could be used to label cancer cells with high specificity. Moreover, we demonstrated that this synthetic strategy could be extended to prepare QDs functionalized with folic acids and peptides, which were also successfully applied to cancer cell imaging.

One-Pot Approach to Prepare Organo-silica Hybrid Capillary Monolithic Column with Intact Mesoporous Silica Nanoparticle as Building Block.

PubMed

Liu, Shengju; Peng, Jiaxi; Liu, Zheyi; Liu, Zhongshan; Zhang, Hongyan; Wu, Ren'an

2016-10-04

A facile "one-pot" approach to prepare organo-silica hybrid capillary monolithic column with intact mesoporous silica nanoparticle (IMSN) as crosslinker and building block was described. An IMSN crosslinked octadecyl-silica hybrid capillary monolithic column (IMSN-C18 monolithic column) was successfully prepared, and the effects of fabrication conditions (e.g. concentration of intact mesoporous silica nanoparticle, polycondensation temperature, content of vinyltrimethoxysilane and stearyl methacrylate) on the structures of the IMSN-C18 monolithic column were studied in detail. The IMSN-C18 hybrid monolithic column possessed uniform morphology, good mechanical and pH stability (pH 1.1-11), which was applied to the separations of alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), as well as proteins. The minimum plate height of 10.5 μm (corresponding to 95000 N m -1 ) for butylbenzene and high reproducibility were achieved. The analysis of tryptic digest of bovine serum albumin (BSA) was carried out on the IMSN-C18 monolithic column by cLC coupled mass spectrometry (cLC-MS/MS), with the protein sequence coverage of 87.5% for BSA, demonstrating its potential application in proteomics.

Synthesis of Curcumin Glycosides with Enhanced Anticancer Properties Using One-Pot Multienzyme Glycosylation Technique.

PubMed

Gurung, Rit Bahadur; Gong, So Youn; Dhakal, Dipesh; Le, Tuoi Thi; Jung, Na Rae; Jung, Hye Jin; Oh, Tae Jin; Sohng, Jae Kyung

2017-09-28

Curcumin is a natural polyphenolic compound, widely acclaimed for its antioxidant, antiinflammatory, antibacterial, and anticancerous properties. However, its use has been limited due to its low-aqueous solubility and poor bioavailability, rapid clearance, and low cellular uptake. In order to assess the effect of glycosylation on the pharmacological properties of curcumin, one-pot multienzyme (OPME) chemoenzymatic glycosylation reactions with UDP- α-D-glucose or UDP-α-D-2-deoxyglucose as donor substrate were employed. The result indicated significant conversion of curcumin to its glycosylated derivatives: curcumin 4'- O -β- glucoside, curcumin 4',4''-di- O -β-glucoside, curcumin 4'- O -β-2-deoxyglucoside, and curcumin 4',4''-di- O -β-2-deoxyglucoside. The products were characterized by ultra-fast performance liquid chromatography, high-resolution quadruple-time-of-flight electrospray ionization-mass spectrometry, and NMR analyses. All the products showed improved water solubility and comparable antibacterial activities. Additionally, the curcumin 4'- O -β-glucoside and curcumin 4'- O -β-2-deoxyglucoside showed enhanced anticancer activities compared with the parent aglycone and diglycoside derivatives. This result indicates that glycosylation can be an effective approach for enhancing the pharmaceutical properties of different natural products, such as curcumin.

Facile one-pot multicomponent synthesis and molecular docking studies of steroidal oxazole/thiazole derivatives with effective antimicrobial, antibiofilm and hemolytic properties.

PubMed

Ansari, Anam; Ali, Abad; Asif, Mohd; Rauf, Mohd Ahmar; Owais, Mohammad; Shamsuzzaman

2018-06-01

A series of steroidal oxazole and thiazole derivatives have been synthesized employing thiosemicarbazide/semicarbazide hydrochloride and ethyl 2-chloroacetoacetate with a simple and facile one-pot multicomponent reaction pathway. The antimicrobial activity of newly synthesized compounds were evaluated against four bacterial strains namely Gram-negative (Escherichia coliand Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) in addition to pathogenic fungi (Candida albicans and Cryptococcus neoformans). Bioactivity assay manifested that most of the compounds exhibited good antimicrobial activity. To provide additional insight into antimicrobial activity, the compounds were also tested for their antibiofilm activity against S. aureus biofilm. Moreover, molecular docking study shows binding of compounds with amino acid residues of DNA gyrase and glucosamine-6-phosphate synthase (promising antimicrobial target) through hydrogen bonding interactions. Hemolytic activity have been also investigated to ascertain the effect of compounds over RBC lysis and results indicate good prospects for biocompatibility. The expedient synthesis of steroidal heterocycles, effective antibacterial and antifungal behavior against various clinically relevant human pathogens, promising biocompatibility offer opportunities for further modification and potential applications as therapeutic agents. Copyright © 2018 Elsevier Inc. All rights reserved.

One-Pot Parallel Synthesis of Lipid Library via Thiolactone Ring Opening and Screening for Gene Delivery.

PubMed

Molla, Mijanur R; Böser, Alexander; Rana, Akshita; Schwarz, Karina; Levkin, Pavel A

2018-04-18

Efficient delivery of nucleic acids into cells is of great interest in the field of cell biology and gene therapy. Despite a lot of research, transfection efficiency and structural diversity of gene-delivery vectors are still limited. A better understanding of the structure-function relationship of gene delivery vectors is also essential for the design of novel and intelligent delivery vectors, efficient in "difficult-to-transfect" cells and in vivo clinical applications. Most of the existing strategies for the synthesis of gene-delivery vectors require multiple steps and lengthy procedures. Here, we demonstrate a facile, three-component one-pot synthesis of a combinatorial library of 288 structurally diverse lipid-like molecules termed "lipidoids" via a thiolactone ring opening reaction. This strategy introduces the possibility to synthesize lipidoids with hydrophobic tails containing both unsaturated bonds and reducible disulfide groups. The whole synthesis and purification are convenient, extremely fast, and can be accomplished within a few hours. Screening of the produced lipidoids using HEK293T cells without addition of helper lipids resulted in identification of highly stable liposomes demonstrating ∼95% transfection efficiency with low toxicity.

One-pot solvothermal synthesis of graphene wrapped rice-like ferrous carbonate nanoparticles as anode materials for high energy lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zhang, Fan; Zhang, Ruihan; Feng, Jinkui; Ci, Lijie; Xiong, Shenglin; Yang, Jian; Qian, Yitai; Li, Lifei

2014-11-01

Well dispersed rice-like FeCO3 nanoparticles were produced and combined with reduced graphene oxide (RGO) via a one-pot solvothermal route. SEM characterization shows that rice-like FeCO3 nanoparticles are homogeneously anchored on the surface of the graphene nanosheets; the addition of RGO is helpful to form a uniform morphology and reduce the particle size of FeCO3 to nano-grade. As anode materials for lithium-ion batteries, the FeCO3/RGO nanocomposites exhibit significantly improved lithium storage properties with a large reversible capacity of 1345 mA h g-1 for the first cycle and a capacity retention of 1224 mA h g-1 after 50 cycles with a good rate capability compared with pure FeCO3 particles. The superior electrochemical performance of the FeCO3/RGO nanocomposite electrode compared to the pure FeCO3 electrode can be attributed to the well dispersed RGO which enhances the electronic conductivity and accommodates the volume change during the conversion reactions. Our study shows that the FeCO3/RGO nanocomposite could be a suitable candidate for high capacity lithium-ion batteries.

Biocatalytic, one-pot diterminal oxidation and esterification of n-alkanes for production of α,ω-diol and α,ω-dicarboxylic acid esters.

PubMed

van Nuland, Youri M; de Vogel, Fons A; Scott, Elinor L; Eggink, Gerrit; Weusthuis, Ruud A

2017-11-01

Direct and selective terminal oxidation of medium-chain n-alkanes is a major challenge in chemistry. Efforts to achieve this have so far resulted in low specificity and overoxidized products. Biocatalytic oxidation of medium-chain n-alkanes - with for example the alkane monooxygenase AlkB from P. putida GPo1- on the other hand is highly selective. However, it also results in overoxidation. Moreover, diterminal oxidation of medium-chain n-alkanes is inefficient. Hence, α,ω-bifunctional monomers are mostly produced from olefins using energy intensive, multi-step processes. By combining biocatalytic oxidation with esterification we drastically increased diterminal oxidation upto 92mol% and reduced overoxidation to 3% for n-hexane. This methodology allowed us to convert medium-chain n-alkanes into α,ω-diacetoxyalkanes and esterified α,ω-dicarboxylic acids. We achieved this in a one-pot reaction with resting-cell suspensions of genetically engineered Escherichia coli. The combination of terminal oxidation and esterification constitutes a versatile toolbox to produce α,ω-bifunctional monomers from n-alkanes. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

One-pot template-free synthesis of porous CdMoO4 microspheres and their enhanced photocatalytic activity

NASA Astrophysics Data System (ADS)

Madhusudan, Puttaswamy; Zhang, Jinfeng; Yu, Jiaguo; Cheng, Bei; Xu, Difa; Zhang, Jun

2016-11-01

The optical and catalytic performances of materials strongly depend on their size, morphology, dimensionality and structure. Herein, we demonstrate a facile one-pot template free synthesis of hierarchical CdMoO4 porous microspheres via a simple low temperature oil bath method. The photoactivity of the as-prepared samples was evaluated by photocatalytic decolorization of Methyl Orange (MO) and Methylene Blue (MB) mixed dye aqueous solutions at ambient temperature under full solar spectrum. The results indicated that the concentration of ammonium molybdate and reaction time greatly influence the diameter, average crystallite size, specific surface area, pore structure and photocatalytic activity of the prepared samples. Especially, under the suitable conditions the prepared hierarchical CdMoO porous microspheres exhibited enhanced photocatalytic activity and high stability. Furthermore, it is found that the photocatalytic activity and formation rate of hydroxyl radicals greatly depend on the particle sizes and morphology of as-prepared samples. This work not only demonstrates a simple way to fabricate the hierarchical CdMoO4 porous microspheres but also shows a possibility for utilization of CdMoO4 porous microspheres for the photocatalytic treatment of waste water pollutants.

One pot synthesis, X-ray crystal structure of 2-(2‧-hydroxyphenyl)oxazolo[4,5-b]pyridine derivatives and studies of their optical properties

NASA Astrophysics Data System (ADS)

Briseño-Ortega, Horacio; Juárez-Guerra, Lizbeth; Rojas-Lima, Susana; Mendoza-Huizar, Luis Humberto; Vázquez-García, Rosa A.; Farfán, Norberto; Arcos-Ramos, Rafael; Santillan, Rosa; López-Ruiz, Heralio

2018-04-01

A series of five 2-(2-hydroxyphenyl)oxazolo [4,5-b]pyridines (HPOP) (3a-e), where four are novel, were synthesized by a mild, one pot, phenylboronic acid-NaCN catalyzed reaction. Spectroscopic characterization and photophysical properties of these compounds are reported. Absorption and excitation spectra of the compounds were dependent on the substituents in the phenyl ring. Fluorescence quantum yields (0.009-0.538) were associated with the donor strength and the position of the substituents. Also, DFT analysis allowed us to determine the contribution of diethylamino and methoxy moieties to the π-system, which is in agreement with the experimental data analyzed in solution and by cyclic voltammetry. The results obtained in the solid state by single-crystal X-ray diffraction experiments indicate that, the quasi-planarity envisioned for the explored compounds is present, supporting the hypothesis that both the H-bonding of a hydroxyl group to the Cdbnd N moiety and a donor groups such as diethylamino and methoxy moieties favor an electronic communication. Due to the facile synthesis and their photophysical properties, the novel HPOP 3a-e have potential application as organic semiconductors.

One-Pot Soft-Template Synthesis of Nanostructured Copper-Supported Mesoporous Carbon FDU-15 Electrocatalysts for Efficient CO2 Reduction.

PubMed

Şahin, Nihat Ege; Comminges, Clément; Le Valant, Anthony; Kiener, Julien; Parmentier, Julien; Napporn, Teko W; Melinte, Georgian; Ersen, Ovidiu; Kokoh, Kouakou B

2018-03-14

Copper-supported mesoporous carbon nanocatalysts (Cu/FDU-15) were synthesized using an easy and convenient one-pot soft-template method for low-overvoltage CO 2 electroreduction. TEM imaging revealed the presence of large Cu nanoparticles (diameter 140 nm) with Cu 2 O nanoparticles (16 nm) as an additional phase. From the electron tomography observations, we found that the copper particles were placed inside and on the exterior surface of the porous FDU-15 support, providing an accessible surface for electrocatalytic reactions. CO 2 electrolyses showed that the mesostructured Cu/FDU-15-350 cathode materials were active towards CO 2 conversion to formic acid with 22 % Faradaic efficiency at a remarkably low overpotential of 290 mV, hydrogen being the only side-product. The catalyst's activity correlates to the calculated metallic surface area, as determined from a geometrical model, confirming that the mesoporous channels act as a diffusion path for the CO 2 molecule, and that the whole Cu surface is accessible to CO 2 , even if particles are entrapped in the carbon matrix. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and self-organization of zinc β-(dialkoxyphosphoryl)porphyrins in the solid state and in solution.

PubMed

Vinogradova, Ekaterina V; Enakieva, Yulia Y; Nefedov, Sergey E; Birin, Kirill P; Tsivadze, Aslan Y; Gorbunova, Yulia G; Bessmertnykh Lemeune, Alla G; Stern, Christine; Guilard, Roger

2012-11-19

The first synthesis and self-organization of zinc β-phosphorylporphyrins in the solid state and in solution are reported. β-Dialkoxyphosphoryl-5,10,15,20-tetraphenylporphyrins and their Zn(II) complexes have been synthesized in good yields by using Pd- and Cu-mediated carbon-phosphorous bond-forming reactions. The Cu-mediated reaction allowed to prepare the mono-β-(dialkoxyphosphoryl)porphyrins 1 Zn-3 Zn starting from the β-bromo-substituted zinc porphyrinate ZnTPPBr (TPP = tetraphenylporphyrin) and dialkyl phosphites HP(O)(OR)(2) (R = Et, iPr, nBu). The derivatives 1 Zn-3 Zn were obtained in good yields by using one to three equivalents of CuI. When the reaction was carried out in the presence of catalytic amounts of palladium complexes in toluene, the desired zinc derivative 1 Zn was obtained in up to 72% yield. The use of a Pd-catalyzed C-P bond-forming reaction was further extended to the synthesis of β-poly(dialkoxyphosphoryl)porphyrins. An unprecedented one-pot sequence involving consecutive reduction and phosphorylation of H(2)TPPBr(4) led to the formation of a mixture of the 2,12- and 2,13-bis(dialkoxy)phosphorylporphyrins 5 H(2) and 6 H(2) in 81% total yield. According to the X-ray diffraction studies, 1 Zn and 3 Zn are partially overlapped cofacial dimers formed through the coordination of two Zn centers by two phosphoryl groups belonging to the adjacent molecules. The equilibrium between the monomeric and the dimeric species exists in solutions of 1 Zn and 3 Zn in weakly polar solvents according to spectroscopic data (UV/Vis absorption and NMR spectroscopy). The ratio of each form is dependent on the concentration, temperature, and traces of water or methanol. These features demonstrated that zinc β-phosphorylporphyrins can be regarded as new model compounds for the weakly coupled chlorophyll pair in the photosynthesis process. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Valorization of starchy, cellulosic, and sugary food waste into hydroxymethylfurfural by one-pot catalysis.

PubMed

Yu, Iris K M; Tsang, Daniel C W; Yip, Alex C K; Chen, Season S; Ok, Yong Sik; Poon, Chi Sun

2017-10-01

This study aimed to produce a high-value platform chemical, hydroxymethylfurfural (HMF), from food waste and evaluate the catalytic performance of trivalent and tetravalent metals such as AlCl 3 , CrCl 3 , FeCl 3 , Zr(O)Cl 2 , and SnCl 4 for one-pot conversion. Starchy food waste, e.g., cooked rice and penne produced 4.0-8.1 wt% HMF and 46.0-64.8 wt% glucose over SnCl 4 after microwave heating at 140 °C for 20 min. This indicated that starch hydrolysis was effectively catalyzed but subsequent glucose isomerization was rate-limited during food waste valorization, which could be enhanced by 40-min reaction to achieve 22.7 wt% HMF from cooked rice. Sugary food waste, e.g., kiwifruit and watermelon, yielded up to 13 wt% HMF over Sn catalyst, which mainly resulted from naturally present fructose. Yet, organic acids in fruits may hinder Fe-catalyzed dehydration by competing for the Lewis sites. In contrast, conversion of raw mixed vegetables as cellulosic food waste was limited by marginal hydrolysis at the studied conditions (120-160 °C and 20-40 min). It is interesting to note that tetravalent metals enabled HMF production at a lower temperature and shorter time, while trivalent metals could achieve a higher HMF selectivity at an elevated temperature. Further studies on kinetics, thermodynamics, and reaction pathways of food waste valorization are recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Influence of Mineralogy on Recovering Organic Acids from Mars Analogue Materials Using the One-Pot Derivatization Experiment on the Sample Analysis at Mars(SAM) Instrument Suite

NASA Technical Reports Server (NTRS)

Stalport, Fabien; Glavin, Daniel P.; Eigenbrode, J. L.; Bish, D.; Blake, D.; Coll, P.; Szopa, C.; Buch, A.; McAdam, A.; Dworkin, J. P.;

Structural diversification of the aminobicyclo[4.3.0]nonane skeleton using alkynylsilyl-derived allylic trichloroacetimidates.

PubMed

Mostafa, Mohamed A B; McMillan, Angus E; Sutherland, Andrew

2017-04-05

The amino substituted bicyclo[4.3.0]nonane is a molecular scaffold found in a wide range of natural products and medicinal agents. Despite this, synthetic methods for the general preparation of this structural motif are sparse. Here we evaluate a diastereoselective approach for the preparation of vinylsilyl derived aminobicyclo[4.3.0]nonanes using a one-pot multi-bond forming process involving a Pd(ii)-catalysed Overman rearrangement, a Ru(ii)-catalysed ring closing enyne metathesis reaction, followed by a hydrogen bonding directed Diels-Alder reaction. We show that a benzyldimethylsilyl-substituted alkene analogue is amenable to further functionalisation and the late stage generation of diverse sp 3 -rich, drug-like aminobicyclo[4.3.0]nonane scaffolds with up to six stereogenic centres.

Sequential Dy(OTf)3 -Catalyzed Solvent-Free Per-O-Acetylation and Regioselective Anomeric De-O-Acetylation of Carbohydrates.

PubMed

Yan, Yi-Ling; Guo, Jiun-Rung; Liang, Chien-Fu

2017-09-19

Dysprosium(III) trifluoromethanesulfonate-catalyzed per-O-acetylation and regioselective anomeric de-O-acetylation of carbohydrates can be tuned by adjusting the reaction medium. In this study, the per-O-acetylation of unprotected sugars by using a near-stoichiometric amount of acetic anhydride under solvent-free conditions resulted in the exclusive formation of acetylated saccharides as anomeric mixtures, whereas anomeric de-O-acetylation in methanol resulted in a moderate-to-excellent yield. Reactions with various unprotected monosaccharides or disaccharides followed by a semi-one-pot sequential conversion into the corresponding acetylated glycosyl hemiacetal also resulted in high yields. Furthermore, the obtained hemiacetals could be successfully transformed into trichloroimidates after Dy(OTf) 3 -catalyzed glycosylation. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent efforts directed to the development of more sustainable asymmetric organocatalysis.

PubMed

Hernández, José G; Juaristi, Eusebio

2012-06-04

In line with the principles of "green" chemistry, organocatalysis seeks to reduce energy consumption and to optimize the use of the available resources, aiming to become a sustainable strategy in chemical transformations. Nevertheless, during the last decade diverse experimental protocols have made organocatalysis an even "greener" alternative by the use of friendlier reaction conditions, or via the application of solvent-free methodologies, or through the design and synthesis of more selective catalysts, or via the development of multicomponent one-pot organocatalytic reactions, or by the recycling and reuse of organocatalysts, or by means of the application of more energy-efficient activation techniques, among other approaches. In this feature article we review some of the remarkable advancements that have made it possible to develop even more sustainable asymmetric organocatalyzed methodologies.

Facile synthesis and antibacterial, antitubercular, and anticancer activities of novel 1,4-dihydropyridines.

PubMed

Sirisha, Kalam; Achaiah, Garlapati; Reddy, Vanga Malla

2010-06-01

A series of twenty new 4-substituted-2,6-dimethyl-3,5-bis-N-(heteroaryl)-carbamoyl-1,4-dihydropyridines have been prepared from a three-component one-pot condensation reaction of N-heteroaryl acetoacetamide, an aromatic/heteroaromatic aldehyde, and ammonium acetate under four different experimental conditions. Except for the conventional method, all the experimental conditions were simple, eco-friendly, economical, and the reactions were rapid and high-yielding. The methods employed have been compared in terms of yields, cost, and simplicity. The synthesized compounds were characterized by different spectroscopic techniques and evaluated for their in-vitro anticancer, antibacterial, and antitubercular activities. Amongst the compounds tested, compound 25 exhibited the highest anticancer activity while compounds 14 and 18 exhibited significant antibacterial and antitubercular activities.

Synthesis and biological evaluation of some novel thiazole compounds as potential anti-inflammatory agents.

PubMed

Helal, M H M; Salem, M A; El-Gaby, M S A; Aljahdali, M

2013-07-01

In the present investigation, furo[2,3-d]thiazol-5(2H)-one 5 was obtained from reaction of thiosemicarbazone derivative 2 with diethyl acetylene dicarboxylate. A series of newly synthesized 2-(hydrazinyl)thiazol-4(5H)-one 6, 7 &8 and 2-(4-(substituted)-thiazol-2-yl)hydrazono derivatives 9a, b &10 were synthesized from treatment of thiosemicarbazone derivative 2 with appropriate α-halogenated compounds. Also, a one pot synthesis of thiazole derivatives 13 &15 was achieved from three components reaction of hydrazone derivative 11 with phenyl isothiocyanate and α-halogenated compounds catalyzed by DMF/KOH. 4-(4-Morpholino phenyl) thiazol-2-amino 17 was obtained via the reaction of acetophenone derivative 1 with thiourea in presence of iodine. The reactivity of 2-aminothiazole 17 toward some electrophilic reagents was investigated. The structure of the newly compounds was confirmed on the basis of elemental analysis and spectral data. The antibacterial activity towards two Gram negative (Proteus mirabilis &Serratia marcesens) and two Gram positive (Staphylococcus aureus &Bacillus cereus) bacteria was investigated. The anti-inflammatory activity was also investigated and the inhibition of the carrageenin-induced oedema by these compounds was established. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Enhanced N-Transfer from a Soybean to Maize by Vesicular Arbuscular Mycorrhizal (VAM) Fungi.

PubMed

van Kessel, C; Singleton, P W; Hoben, H J

1985-10-01

Using a split-root technique, roots of soybean plants were divided between two pots. In one of the two pots, two maize plants were grown and half of those pots were inoculated with the vesicular arbuscular mycorrhizal (VAM) fungus, Glomus fasciculatus. Fifty-two days after planting, (15)N-labeled ammonium sulfate was applied to the pots which contained only soybean roots. Forty-eight hours after application, significantly higher values for atom per cent (15)N excess were found in roots and leaves of VAM-infected maize plants as compared with the non-VAM-infected maize plants. Results indicated that VAM fungi did enhance N transfer from one plant to another.

A One-Pot Synthesis of Dibenzofurans from 6-Diazo-2-cyclohexenones.

PubMed

Zhao, Hua; Yang, Ke; Zheng, Hongyan; Ding, Ruichao; Yin, Fangjie; Wang, Ning; Li, Yun; Cheng, Bin; Wang, Huifei; Zhai, Hongbin

2015-12-04

A novel and efficient protocol for the rapid construction of dibenzofuran motifs from 6-diazo-2-cyclohexenone and ortho-haloiodobenzene has been developed. The process involves one-pot Pd-catalyzed cross-coupling/aromatization and Cu-catalyzed Ullmann coupling.

PhI(OAc)2-mediated one-pot oxidative decarboxylation and aromatization of tetrahydro-β-carbolines: synthesis of norharmane, harmane, eudistomin U and eudistomin I.

PubMed

Kamal, Ahmed; Tangella, Yellaiah; Manasa, Kesari Lakshmi; Sathish, Manda; Srinivasulu, Vunnam; Chetna, Jadala; Alarifi, Abdullah

2015-08-28

Iodobenzene diacetate was employed as a mild and efficient reagent for one-pot oxidative decarboxylation of tetrahydro-β-carboline acids and dehydrogenation of tetrahydro-β-carbolines to access the corresponding aromatic β-carbolines. To the best of our knowledge this is the first synthesis of β-carbolines via a one-pot oxidative decarboxylation at ambient temperature. The utility of this protocol has been demonstrated in the synthesis of β-carboline alkaloids norharmane (2o), harmane (2p), eudistomin U (9) and eudistomin I (12).

Assessing effects of the entomopathogenic fungus Metarhizium brunneum on soil microbial communities in Agriotes spp. biological pest control.

PubMed

Mayerhofer, Johanna; Eckard, Sonja; Hartmann, Martin; Grabenweger, Giselher; Widmer, Franco; Leuchtmann, Adrian; Enkerli, Jürg

2017-10-01

The release of large quantities of microorganisms to soil for purposes such as pest control or plant growth promotion may affect the indigenous soil microbial communities. In our study, we investigated potential effects of Metarhizium brunneum ART2825 on soil fungi and prokaryota in bulk soil using high-throughput sequencing of ribosomal markers. Different formulations of this strain, and combinations of the fungus with garlic as efficacy-enhancing agent, were tested over 4 months in a pot and a field experiment carried out for biological control of Agriotes spp. in potatoes. A biocontrol effect was observed only in the pot experiment, i.e. the application of FCBK resulted in 77% efficacy. Colony counts combined with genotyping and marker sequence abundance confirmed the successful establishment of the applied strain. Only the formulated applied strain caused small shifts in fungal communities in the pot experiment. Treatment effects were in the same range as the effects caused by barley kernels, the carrier of the FCBK formulation and temporal effects. Garlic treatments and time affected prokaryotic communities. In the field experiment, only spatial differences affected fungal and prokaryotic communities. Our findings suggest that M. brunneum may not adversely affect soil microbial communities. © FEMS 2017.

Regio- and Stereoselective Cascades via Aldol Condensation and 1,3-Dipolar Cycloaddition for Construction of Functional Pyrrolizidine Derivatives.

PubMed

Mao, Zhuo-Ya; Liu, Yi-Wen; Han, Pan; Dong, Han-Qing; Si, Chang-Mei; Wei, Bang-Guo; Lin, Guo-Qiang

2018-02-16

An efficient and step-economical approach to access functionalized pyrrolizidine derivatives by a one-pot tandem sequence, including an aldol condensation and subsequent 1,3-dipolar cycloaddition process, has been developed, starting from acetone, aldehyde, and proline. A number of substituted aromatic aldehydes were amenable to this transformation, and the desired products, racemic 7a-7w and chiral 9a-9m, were obtained with excellent regioselectivities and outstanding diastereoselectivities. Moreover, in situ NMR studies revealed MgSO 4 could effectively promote the aldol condensation pathway in this tandem process.

Concerto catalysis--harmonising [NiFe]hydrogenase and NiRu model catalysts.

PubMed

Ichikawa, Koji; Nonaka, Kyoshiro; Matsumoto, Takahiro; Kure, Bunsho; Yoon, Ki-Seok; Higuchi, Yoshiki; Yagi, Tatsuhiko; Ogo, Seiji

2010-03-28

This communication reports the successful merging of the chemical properties of a natural [NiFe]hydrogenase (Desulfovibrio vulgaris Miyazaki F) and our previously reported [NiRu] hydrogenase-mimic. The catalytic activity of both the natural enzyme and the mimic is almost identical, with the exception of working pH ranges, and this allows us to use them simultaneously in the same reaction flask. In such a manner, isotope exchange between D(2) and H(2)O could be conducted over an extended pH range (about 2-10) in one pot under mild conditions at ambient temperature and pressure.

Palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate: A practical synthesis of unsymmetrical ureas

PubMed Central

Vinogradova, Ekaterina V.; Fors, Brett P.; Buchwald, Stephen L.

2012-01-01

An efficient method for palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate is reported. The protocol allows for the synthesis of unsymmetrical N,N'-di- and N,N,N'-trisubstituted ureas in one pot, and is tolerant of a wide range of functional groups. Insight into the mechanism of aryl isocyanate formation is gleaned through studies of the transmetallation and reductive elimination steps of the reaction, including the first demonstration of reductive elimination from an arylpalladium isocyanate complex to produce an aryl isocyanate. PMID:22716197

Multicomponent click synthesis of new 1,2,3-triazole derivatives of pyrimidine nucleobases: promising acidic corrosion inhibitors for steel.

PubMed

González-Olvera, Rodrigo; Espinoza-Vázquez, Araceli; Negrón-Silva, Guillermo E; Palomar-Pardavé, Manuel E; Romero-Romo, Mario A; Santillan, Rosa

2013-12-06

A series of new mono-1,2,3-triazole derivatives of pyrimidine nucleobases were synthesized by one-pot copper(I)-catalyzed 1,3-dipolar cycloaddition reactions between N-1-propargyluracil and thymine, sodium azide and several benzyl halides. The desired heterocyclic compounds were obtained in good yields and characterized by NMR, IR, and high resolution mass spectrometry. These compounds were investigated as corrosion inhibitors for steel in 1 M HCl solution, using electrochemical impedance spectroscopy (EIS) technique. The results indicate that these heterocyclic compounds are promising acidic corrosion inhibitors for steel.

Heteromultimetallic catalysis for sustainable organic syntheses.

PubMed

Lorion, Mélanie M; Maindan, Karan; Kapdi, Anant R; Ackermann, Lutz

2017-12-07

Fully complementary bimetallic catalysis has been identified as an increasingly powerful tool for molecular transformations, which was largely inspired by early examples of sequential catalytic transformations. Thus, energy-efficient one-pot reactions involving different metal catalysts orchestrated in concert constitute an attractive alternative to multi-step protocols, with major recent progress through the elegant ligand design in heterobimetallic catalysis as well as sustainable photo-induced C-H transformations, among others. This review provides a critical assessment of the state of the art in heterobimetallic catalysis for sustainable organic syntheses (SOS), highlighting key advances and representative examples until summer 2017.

Redox Catalysis Facilitates Lignin Depolymerization

PubMed Central

2017-01-01

Lignin is a recalcitrant and underexploited natural feedstock for aromatic commodity chemicals, and its degradation generally requires the use of high temperatures and harsh reaction conditions. Herein we present an ambient temperature one-pot process for the controlled oxidation and depolymerization of this potent resource. Harnessing the potential of electrocatalytic oxidation in conjugation with our photocatalytic cleavage methodology, we have developed an operationally simple procedure for selective fragmentation of β-O-4 bonds with excellent mass recovery, which provides a unique opportunity to expand the existing lignin usage from energy source to commodity chemicals and synthetic building block source. PMID:28691074

UGT74AN1, a Permissive Glycosyltransferase from Asclepias curassavica for the Regiospecific Steroid 3-O-Glycosylation.

PubMed

Wen, Chao; Huang, Wei; Zhu, Xue-Lin; Li, Xiao-San; Zhang, Fan; Jiang, Ren-Wang

2018-02-02

A permissive steroid glycosyltransferase (UGT74AN1) from Asclepias curassavica exhibited robust capabilities for the regiospecific C3 glycosylation of cardiotonic steroids and C 21 steroid precursors, and unprecedented promiscuity toward 53 structurally diverse natural and unnatural compounds to form O-, N-, and S-glycosides, along with the catalytic reversibility for a one-pot transglycosylation reaction. These findings highlight UGT74AN1 as the first regiospecific catalyst for cardiotonic steroid C3 glycosylation and exhibit significant potential for glycosylation of diverse bioactive molecules in drug discovery.

Electrolytic oxidation of anthracite

USGS Publications Warehouse

Senftle, F.E.; Patton, K.M.; Heard, I.

1981-01-01

An anthracite slurry can be oxidized only with difficulty by electrolytic methods in which aqueous electrolytes are used if the slurry is confined to the region of the anode by a porous pot or diaphragm. However, it can be easily oxidized if the anthracite itself is used as the anode. No porous pot or diaphragm is needed. Oxidative consumption of the coal to alkali-soluble compounds is found to proceed preferentially at the edges of the aromatic planes. An oxidation model is proposed in which the chief oxidants are molecular and radical species formed by the electrolytic decomposition of water at the coal surface-electrolyte interface. The oxidation reactions proposed account for the opening of the aromatic rings and the subsequent formation of carboxylic acids. The model also explains the observed anisotropic oxidation and the need for the porous pot or diaphragm used in previous studies of the oxidation of coal slurries. ?? 1981.

The CanOE strategy: integrating genomic and metabolic contexts across multiple prokaryote genomes to find candidate genes for orphan enzymes.

PubMed

Smith, Adam Alexander Thil; Belda, Eugeni; Viari, Alain; Medigue, Claudine; Vallenet, David

2012-05-01

Of all biochemically characterized metabolic reactions formalized by the IUBMB, over one out of four have yet to be associated with a nucleic or protein sequence, i.e. are sequence-orphan enzymatic activities. Few bioinformatics annotation tools are able to propose candidate genes for such activities by exploiting context-dependent rather than sequence-dependent data, and none are readily accessible and propose result integration across multiple genomes. Here, we present CanOE (Candidate genes for Orphan Enzymes), a four-step bioinformatics strategy that proposes ranked candidate genes for sequence-orphan enzymatic activities (or orphan enzymes for short). The first step locates "genomic metabolons", i.e. groups of co-localized genes coding proteins catalyzing reactions linked by shared metabolites, in one genome at a time. These metabolons can be particularly helpful for aiding bioanalysts to visualize relevant metabolic data. In the second step, they are used to generate candidate associations between un-annotated genes and gene-less reactions. The third step integrates these gene-reaction associations over several genomes using gene families, and summarizes the strength of family-reaction associations by several scores. In the final step, these scores are used to rank members of gene families which are proposed for metabolic reactions. These associations are of particular interest when the metabolic reaction is a sequence-orphan enzymatic activity. Our strategy found over 60,000 genomic metabolons in more than 1,000 prokaryote organisms from the MicroScope platform, generating candidate genes for many metabolic reactions, of which more than 70 distinct orphan reactions. A computational validation of the approach is discussed. Finally, we present a case study on the anaerobic allantoin degradation pathway in Escherichia coli K-12.

Synthesis and pharmacological investigation of 2-(4-dimethylaminophenyl)-3,5-disubstituted thiazolidin-4-ones as anticonvulsants.

PubMed

Senthilraja, Manavalan; Alagarsamy, Veerachamy

2012-10-01

A new series of 2-(4-dimethylaminophenyl)-3-substituted thiazolidin-4-one-5-yl-acetyl acetamides/benzamides were synthesized by the nucleophilic substitution of 3-substituted-2-(4-dimethylaminophenyl)-thiazolidin-4-one-5-yl-acetylchloride with acetamide and benzamide. The starting material 3-substituted-2-(4-dimethylaminophenyl)-thiazolidin-4-one-5-yl-acetylchloride was synthesized from 3-substituted-2-(4-dimethylaminophenyl)-thiazolidin-4-one-5-yl-acetic acid, which in turn was prepared by one-pot reaction of amino component, p-dimethylamino benzaldehyde and mercapto succinic acid. The title compounds were investigated for their anticonvulsant activities; among the test compounds, compound 2-(4-dimethylaminophenyl)-3-phenylamino-thiazolidine-4-one-5-yl-acetylbenzamide (14) emerged as the most active compound of the series and as moderately more potent than the reference standard diazepam. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Automated one-step DNA sequencing based on nanoliter reaction volumes and capillary electrophoresis.

PubMed

Pang, H M; Yeung, E S

2000-08-01

An integrated system with a nano-reactor for cycle-sequencing reaction coupled to on-line purification and capillary gel electrophoresis has been demonstrated. Fifty nanoliters of reagent solution, which includes dye-labeled terminators, polymerase, BSA and template, was aspirated and mixed with the template inside the nano-reactor followed by cycle-sequencing reaction. The reaction products were then purified by a size-exclusion chromatographic column operated at 50 degrees C followed by room temperature on-line injection of the DNA fragments into a capillary for gel electrophoresis. Over 450 bases of DNA can be separated and identified. As little as 25 nl reagent solution can be used for the cycle-sequencing reaction with a slightly shorter read length. Significant savings on reagent cost is achieved because the remaining stock solution can be reused without contamination. The steps of cycle sequencing, on-line purification, injection, DNA separation, capillary regeneration, gel-filling and fluidic manipulation were performed with complete automation. This system can be readily multiplexed for high-throughput DNA sequencing or PCR analysis directly from templates or even biological materials.

One pot synthesis of nanosized anion doped TiO2: Effect of irradiation of sound waves on surface morphology and optical properties

NASA Astrophysics Data System (ADS)

Sharotri, Nidhi; Sud, Dhiraj

2015-08-01

Commercialization of AOP's for remediation of pollutants from environmental matrix required the process to be operated by solar light. Semiconductor TiO2 has emerged as an effective and preferred photocatalyst in the field of environmental photocatalysis due to its; (i) biological and chemical inertness (ii) resistance to chemical and photo corrosion, (iii) can absorb natural UV light due to appropriate energetic separation between its valence and conduction band. However, unfortunately the optical band gap of TiO2 (3.0-3.23 eV) with absorption cut off ˜ 380 nm, enables it to harness only a small fraction (˜ 5%) of the entire solar spectrum. One of the current areas of research is modification of TiO2 photocatalyst. In present paper one pot greener synthesis from titanium isopropoxide and hydroxylamine hydrochloride has been used as titanium and nitrogen precursor under ultrasonic waves. The as synthesized TiO2 nanomaterials were dried at 100°C and further calcinated at different temperatures. The effect of reaction parameters such as ultrasonication time on the yield, surface morphology, spectroscopic data and optical properties was also investigated. The results confirm that the anatase phase is a main phase with a crystallite size of 35-77 nm and the calculated band gap of nanomaterials varies from 2.10-3.1 eV.

High Glass Transition Temperature Renewable Polymers via Biginelli Multicomponent Polymerization.

PubMed

Boukis, Andreas C; Llevot, Audrey; Meier, Michael A R

2016-04-01

A novel and straightforward one-pot multicomponent polycondensation method was established in this work. The Biginelli reaction is a versatile multicomponent reaction of an aldehyde, a β-ketoester (acetoacetate) and urea, which can all be obtained from renewable resources, yielding diversely substituted 3,4-dihydropyrimidin-2(1H)-ones (DHMPs). In this study, renewable diacetoacetate monomers with different spacer chain lengths (C3, C6, C10, C20) were prepared via simple transesterification of renewable diols and commercial acetoacetates. The diacetoacetate monomers were then reacted with renewable dialdehydes, i.e., terephthalaldehyde and divanillin in a Biginelli type step-growth polymerization. The obtained DHMP polymers (polyDHMPs) displayed high molar masses, high glass transition temperatures (Tg) up to 203 °C and good thermal stability (Td5%) of 280 °C. The Tg of the polyDHMPs could be tuned by variation of the structure of the dialdehyde or the diacetoacetate component. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Green approach for synthesis of bioactive Hantzsch 1,4-dihydropyridine derivatives based on thiophene moiety via multicomponent reaction

NASA Astrophysics Data System (ADS)

Sharma, M. G.; Rajani, D. P.; Patel, H. M.

2017-06-01

A novel green and efficient one-pot multicomponent reaction of dihydropyridine derivatives was reported as having good to excellent yield. In the presence of the catalyst ceric ammonium nitrate (CAN), different 1,3-diones and same starting materials as 5-bromothiophene-2-carboxaldehyde and ammonium acetate were used at room temperature under solvent-free condition for the Hantzsch pyridine synthesis within a short period of time. All compounds were evaluated for their in vitro antibacterial and antifungal activity and, interestingly, we found that 5(b-f) show excellent activity compared with Ampicillin, whereas only the 5e compound shows excellent antifungal activity against Candida albicans compared with griseofulvin. The cytotoxicity of all compounds has been assessed against breast tumour cell lines (BT-549), but no activity was found. The X-ray structure of one such compound, 5a, viewed as a colourless block crystal, corresponded accurately to a primitive monoclinic cell.

A Feasible One-Step Synthesis of Hierarchical Zeolite Beta with Uniform Nanocrystals via CTAB

PubMed Central

Zhang, Weimin; Hu, Sufang; Qin, Bo; Li, Ruifeng

2018-01-01

A hierarchical zeolite Beta has been prepared by a feasible one-pot and one-step method, which is suitable for application in industrial production. The synthesis is a simple hydrothermal process with low-cost raw materials, without adding alcohol or adding seeds, and without aging, recrystallization, and other complex steps. The hierarchical zeolite Beta is a uniform nanocrystal (20–50 nm) aggregation with high external surface area (300 m2/g) and mesoporous volume (0.50 cm3/g), with the mesoporous structure composed of intercrystal and intracrystal pores. As an acid catalyst in benzylation of naphthalene with benzyl chloride, the hierarchical zeolite Beta has shown high activity in the bulky molecule reaction due to its introduction of mesostructure. PMID:29695044

Polyallylamine-Rh nanosheet nanoassemblies-carbon nanotubes organic-inorganic nanohybrids: A electrocatalyst superior to Pt for the hydrogen evolution reaction

NASA Astrophysics Data System (ADS)

Bai, Juan; Xing, Shi-Hui; Zhu, Ying-Ying; Jiang, Jia-Xing; Zeng, Jing-Hui; Chen, Yu

2018-05-01

Rationally tailoring the surface/interface structures of noble metal nanostructures emerges as a highly efficient method for improving their electrocatalytic activity, selectivity, and long-term stability. Recently, hydrogen evolution reaction is attracting more and more attention due to the energy crisis and environment pollution. Herein, we successfully synthesize polyallylamine-functionalized rhodium nanosheet nanoassemblies-carbon nanotube nanohybrids via a facile one-pot hydrothermal method. Three-dimensionally branched rhodium nanosheet nanoassemblies are consisted of two dimensionally atomically thick ultrathin rhodium nanosheets. The as-prepared polyallylamine-functionalized rhodium nanosheet nanoassemblies-carbon nanotube nanohybrids show the excellent electrocatalytic activity for the hydrogen evolution reaction in acidic media, with a low onset reduction potential of -1 mV, a small overpotential of 5 mV at 10 mA cm-2, which is much superior to commercial platinum nanocrystals. Two dimensionally ultrathin morphology of rhodium nanosheet, particular rhodium-polyallylamine interface, and three-dimensionally networks induced by carbon nanotube are the key factors for the excellent hydrogen evolution reaction activity in acidic media.

Rapid Grafting of Azido-labeled Oligo(ethylene glycol)s onto an Alkynyl-terminated Monolayer on Non-oxidized Silicon via Microwave-assisted “Click” Reaction

PubMed Central

Li, Yan; Wang, Jun; Cai, Chengzhi

2011-01-01

Microwave (MW) irradiation was used for the grafting of azido-labeled oligo(ethylene oxide) (OEG) on alkynyl-terminated non-oxidized silicon substrates via copper-catalyzed “click” reaction. The “clickable” monolayers were prepared by photografting of an α,ω-alkynene, where the alkynyl terminus was protected by a trimethylgermanyl (TMG) group, onto hydrogen-terminated Si(111) surfaces. X-ray photoelectron spectroscopy (XPS) was primarily employed to characterize the monolayers, and the data obtained were utilized to calculate the surface density of the TMG-alkynyl-functionalized substrate. MW-assisted one-pot deprotection/click reaction was optimized on the surfaces using azido-tagged OEG derivatives. Using MW instead of conventional heating led to a substantial improvement on the rate of the reaction while suppressing the oxidation of the silicon interface and OEG degradation. The antifouling property of the resulting substrates was evaluated using fibrinogen as a model protein. Results show that the OEG-modification reduced the protein adsorption by >90%. PMID:21306165

Indium-mediated asymmetric Barbier-type propargylations: additions to aldehydes and ketones and mechanistic investigation of the organoindium reagents.

PubMed

Haddad, Terra D; Hirayama, Lacie C; Buckley, Jannise J; Singaram, Bakthan

2012-01-20

We report a simple, efficient, and general method for the indium-mediated enantioselective propargylation of aromatic and aliphatic aldehydes under Barbier-type conditions in a one-pot synthesis affording the corresponding chiral alcohol products in very good yield (up to 90%) and enantiomeric excess (up to 95%). The extension of this methodology to ketones demonstrated the need for electrophilic ketones more reactive than acetophenone as the reaction would not proceed with just acetophenone. Using the Lewis acid indium triflate [In(OTf)(3)] induced regioselective formation of the corresponding homoallenic alcohol product from acetophenone. However, this methodology demonstrated excellent chemoselectivity in formation of only the corresponding secondary homopropargylic alcohol product in the presence of a ketone functionality. Investigation of the organoindium intermediates under our reaction conditions shows the formation of allenylindium species, and we suggest that these species contain an indium(III) center. In addition, we have observed the presence of a shiny, indium(0) nugget throughout the reaction, irrespective of the stoichiometry, indicating disproportionation of indium halide byproduct formed during the reaction.

One-Pot Green Synthesis of Ag-Decorated SnO2 Microsphere: an Efficient and Reusable Catalyst for Reduction of 4-Nitrophenol.

PubMed

Hu, Min; Zhang, Zhenwei; Luo, Chenkun; Qiao, Xiuqing

2017-12-01

In this paper, hierarchical Ag-decorated SnO 2 microspheres were synthesized by a facile one-pot hydrothermal method. The resulting composites were characterized by XRD, SEM, TEM, XPS, BET, and FTIR analysis. The catalytic performances of the samples were evaluated with the reduction of 4-nitrophenol to 4-aminophenol by potassium borohydride (KBH 4 ) as a model reaction. Time-dependent experiments indicated that the hierarchical microspheres assembled from SnO 2 and Ag nanoparticles can be formed when the react time is less than 10 h. With the increase of hydrothermal time, SnO 2 nanoparticles will self-assemble into SnO 2 nanosheets and Ag nanoparticles decorated SnO 2 nanosheets were obtained. When evaluated as catalyst, the obtained Ag-decorated SnO 2 microsphere prepared for 36 h exhibited excellent catalytic performance with normalized rate constant (κ nor ) of 6.20 min -1 g -1 L, which is much better than that of some previous reported catalysts. Moreover, this Ag-decorated SnO 2 microsphere demonstrates good reusability after the first five cycles. In addition, we speculate the formation mechanism of the hierarchical Ag-decorated SnO 2 microsphere and discussed the possible origin of the excellent catalytic activity.

One-pot synthesis of a PtPd dendritic nanocube cage superstructure on graphenes as advanced catalysts for oxygen reduction

NASA Astrophysics Data System (ADS)

Zheng, Yuanyuan; Qiao, Junhua; Yuan, Junhua; Shen, Jianfeng; Wang, Ai-Jun; Gong, Peijun

2018-03-01

How to use Pt economically and efficiently in the oxygen reduction reaction (ORR) is of theoretical and practical significance for the industrialization of the proton-exchange membrane fuel cells. In order to minimize Pt consumption and optimize the ORR performance, the ORR catalysts are recommended to be designed as a porous nanostructure. Herein, we report a one-pot solvothermal strategy to prepare PtPd dendritic nanocube cages via a galvanic replacement mechanism triggered by an I- ion. These PtPd alloy crystals are nanoporous, and uniformly dispersed on reduced graphene oxides (RGOs). The size of the PtPd dendritic nanocube cages can be easily tuned from 20-80 nm by controlling their composition. Their composition is optimized to be 1:5 Pt/Pd atomic ratio for these RGO-supported PtPd dendritic nanocages. This catalyst shows superior ORR performance with a specific activity of 2.01 mA cm-2 and a mass activity of 4.45 A mg-1 Pt, far above those for Pt/C catalysts (0.288 mA cm-2 for specific activity, and 0.21 A mg-1 Pt for mass activity). In addition to ORR activity, it also exhibits robust durability with almost negligible decay in ORR mass activity after 10 000 voltammetric cycling.

One-pot synthesis of CdS nanocrystals hybridized with single-layer transition-metal dichalcogenide nanosheets for efficient photocatalytic hydrogen evolution.

PubMed

Chen, Junze; Wu, Xue-Jun; Yin, Lisha; Li, Bing; Hong, Xun; Fan, Zhanxi; Chen, Bo; Xue, Can; Zhang, Hua

2015-01-19

Exploration of low-cost and earth-abundant photocatalysts for highly efficient solar photocatalytic water splitting is of great importance. Although transition-metal dichalcogenides (TMDs) showed outstanding performance as co-catalysts for the hydrogen evolution reaction (HER), designing TMD-hybridized photocatalysts with abundant active sites for the HER still remains challenge. Here, a facile one-pot wet-chemical method is developed to prepare MS2-CdS (M=W or Mo) nanohybrids. Surprisedly, in the obtained nanohybrids, single-layer MS2 nanosheets with lateral size of 4-10 nm selectively grow on the Cd-rich (0001) surface of wurtzite CdS nanocrystals. These MS2-CdS nanohybrids possess a large number of edge sites in the MS2 layers, which are active sites for the HER. The photocatalytic performances of WS2-CdS and MoS2-CdS nanohybrids towards the HER under visible light irradiation (>420 nm) are about 16 and 12 times that of pure CdS, respectively. Importantly, the MS2-CdS nanohybrids showed enhanced stability after a long-time test (16 h), and 70% of catalytic activity still remained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-Pot Production of l-threo-3-Hydroxyaspartic Acid Using Asparaginase-Deficient Escherichia coli Expressing Asparagine Hydroxylase of Streptomyces coelicolor A3(2)

PubMed Central

Nakano, Masashi; Kino, Kuniki

2015-01-01

We developed a novel process for efficient synthesis of l-threo-3-hydroxyaspartic acid (l-THA) using microbial hydroxylase and hydrolase. A well-characterized mutant of asparagine hydroxylase (AsnO-D241N) and its homologous enzyme (SCO2693-D246N) were adaptable to the direct hydroxylation of l-aspartic acid; however, the yields were strictly low. Therefore, the highly stable and efficient wild-type asparagine hydroxylases AsnO and SCO2693 were employed to synthesize l-THA. By using these recombinant enzymes, l-THA was obtained by l-asparagine hydroxylation by AsnO followed by amide hydrolysis by asparaginase via 3-hydroxyasparagine. Subsequently, the two-step reaction was adapted to one-pot bioconversion in a test tube. l-THA was obtained in a small amount with a molar yield of 0.076% by using intact Escherichia coli expressing the asnO gene, and thus, two asparaginase-deficient mutants of E. coli were investigated. A remarkably increased l-THA yield of 8.2% was obtained with the asparaginase I-deficient mutant. When the expression level of the asnO gene was enhanced by using the T7 promoter in E. coli instead of the lac promoter, the l-THA yield was significantly increased to 92%. By using a combination of the E. coli asparaginase I-deficient mutant and the T7 expression system, a whole-cell reaction in a jar fermentor was conducted, and consequently, l-THA was successfully obtained from l-asparagine with a maximum yield of 96% in less time than with test tube-scale production. These results indicate that asparagine hydroxylation followed by hydrolysis would be applicable to the efficient production of l-THA. PMID:25795668

Highly efficient and recyclable basic mesoporous zeolite catalyzed condensation, hydroxylation, and cycloaddition reactions.

PubMed

Sarmah, Bhaskar; Satpati, Biswarup; Srivastava, Rajendra

2017-05-01

Crystalline mesoporous ZSM-5 zeolite was prepared in the presence of 1,4-diazabicyclo[2.2.2]octane derived multi-cationic structure directing agent. The calcined form of the mesoprous zeolite was treated with NH 4 OH to obtain basic mesoporous ZSM-5. Catalyst was characterized by the complementary combination of X-ray diffraction, N 2 -adsorption, electron microscopes, and temperature programme desorption techniques. Catalytic activity of the basic mesoporous ZSM-5 was systematically assessed using Knoevenagel condensation reaction for the synthesis a wide range of substituted styrene. Applications of the catalyst were investigated in the benzamide hydroxylation for the synthesis of carbinolamides and one-pot, multi-component condensation reaction for the synthesis of naphthopyrans. Finally, the catalyst was evaluated in the cycloaddition of CO 2 to epoxide for the synthesis of cyclic carbonates. Recycling study shows that no significant decrease in the catalytic activity was observed after five recycles. Copyright © 2017. Published by Elsevier Inc.

Quantitative synthesis of genetically encoded glycopeptide libraries displayed on M13 phage.

PubMed

Ng, Simon; Jafari, Mohammad R; Matochko, Wadim L; Derda, Ratmir

2012-09-21

Phage display is a powerful technology that enables the discovery of peptide ligands for many targets. Chemical modification of phage libraries have allowed the identification of ligands with properties not encountered in natural polypeptides. In this report, we demonstrated the synthesis of 2 × 10(8) genetically encoded glycopeptides from a commercially available phage-displayed peptide library (Ph.D.-7) in a two-step, one-pot reaction in <1.5 h. Unlike previous reports, we bypassed genetic engineering of phage. The glycan moiety was introduced via an oxime ligation following oxidation of an N-terminal Ser/Thr; these residues are present in the peptide libraries at 20-30% abundance. The construction of libraries was facilitated by simple characterization, which directly assessed the yield and regioselectivity of chemical reactions performed on phage. This quantification method also allowed facile yield determination of reactions in 10(9) distinct molecules. We envision that the methodology described herein will find broad application in the synthesis of custom chemically modified phage libraries.

Production of furfural from xylose, xylan and corncob in gamma-valerolactone using FeCl3·6H2O as catalyst.

PubMed

Zhang, Luxin; Yu, Hongbing; Wang, Pan; Li, Yong

2014-01-01

An efficient and simple one-pot monophasic reaction system with small carbon footprint for converting xylose, xylan and corncob into furfural was developed in gamma-valerolactone (GVL, an ideal sustainable solvent derived from lignocelluloses) by using FeCl3·6H2O as catalyst. Good yields of furfural from xylose were obtained, and the system was shown to work for xylan and corncob as well. A surprisingly high furfural yield of 79.6% from untreated corncob was achieved at 458 K for 100 min. Contrary to what was generally believed, the addition of water, reduced the rate of the reactions, but showed positive effect on preventing the furfural from degradation in GVL. Besides, the C6 sugars (glucose and cellulose) afforded 11.4-24.5% furfural yields when employing this catalytic approach. The reaction system proposed in this manuscript showed great potential for optimizing the catalytic process in furfural production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Active and stable Ir@Pt core–shell catalysts for electrochemical oxygen reduction

DOE PAGES

Strickler, Alaina L.; Jackson, Ariel; Jaramillo, Thomas F.

2016-12-28

Electrochemical oxygen reduction is an important reaction for many sustainable energy technologies, such as fuel cells and metal–air batteries. Kinetic limitations of this reaction, expensive electrocatalysts, and catalyst instability, however, limit the commercial viability of such devices. Herein, we report an active Ir@Pt core–shell catalyst that combines platinum overlayers with nanostructure effects to tune the oxygen binding to the Pt surface, thereby achieving enhanced activity and stability for the oxygen reduction reaction. Ir@Pt nanoparticles with several shell thicknesses were synthesized in a scalable, inexpensive, one-pot polyol method. Electrochemical analysis demonstrates the activity and stability of the Ir@Pt catalyst, with specificmore » and mass activities increasing to 2.6 and 1.8 times that of commercial Pt/C (TKK), respectively, after 10 000 stability cycles. Furthermore, activity enhancement of the Ir@Pt catalyst is attributed to weakening of the oxygen binding to the Pt surface induced by the Ir core.« less

Light-Induced C-H Arylation of (Hetero)arenes by In Situ Generated Diazo Anhydrides.

PubMed

Cantillo, David; Mateos, Carlos; Rincon, Juan A; de Frutos, Oscar; Kappe, C Oliver

2015-09-07

Diazo anhydrides (Ar-N=N-O-N=N-Ar) have been known since 1896 but have rarely been used in synthesis. This communication describes the development of a photochemical catalyst-free C-H arylation methodology for the preparation of bi(hetero)aryls by the one-pot reaction of anilines with tert-butyl nitrite and (hetero)arenes under neutral conditions. The key step in this procedure is the in situ formation and subsequent photochemical (>300 nm) homolytic cleavage of a transient diazo anhydride intermediate. The generated aryl radical then efficiently reacts with a (hetero)arene to form the desired bi(hetero)aryls producing only nitrogen, water, and tert-butanol as byproducts. The scope of the reaction for several substituted anilines and (hetero)arenes was investigated. A continuous-flow protocol increasing selectivity and safety has been developed enabling the experimentally straightforward preparation of a variety of substituted bi(hetero)aryls within 45 min of reaction time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tandem catalysis by palladium nanoclusters encapsulated in metal–organic frameworks

DOE PAGES

Li, Xinle; Guo, Zhiyong; Xiao, Chaoxian; ...

2014-08-25

A bifunctional Zr-MOF catalyst containing palladium nanoclusters (NCs) has been developed. The formation of Pd NCs was confirmed by transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS). Combining the oxidation activity of Pd NCs and the acetalization activity of the Lewis acid sites in UiO-66-NH 2, this catalyst (Pd@UiO-66-NH 2) exhibits excellent catalytic activity and selectivity in a one-pot tandem oxidation-acetalization reaction. This catalyst shows 99.9% selectivity to benzaldehyde ethylene acetal in the tandem reaction of benzyl alcohol and ethylene glycol at 99.9% conversion of benzyl alcohol. We also examined various substituted benzyl alcohols and found thatmore » alcohols with electron-donating groups showed better conversion and selectivity compared to those with electron-withdrawing groups. As a result, we further proved that there was no leaching of active catalytic species during the reaction and the catalyst can be recycled at least five times without significant deactivation.« less

Alkaline earth metallocenes coordinated with ester pendants: synthesis, structural characterization, and application in metathesis reactions.

PubMed

Li, Heng; Zhang, Wen-Xiong; Xi, Zhenfeng

2013-09-16

A variety of ester-substituted cyclopentadiene derivatives have been synthesized by one-pot reactions of 1,4-dilithio-1,3-butadienes, CO, and acid chlorides. Direct deprotonation of the ester-substituted cyclopentadienes with Ae[N(SiMe3 )2 ]2 (Ae=Ca, Sr, Ba) efficiently generated members of a new class of heavier alkaline earth (Ca, Sr, Ba) metallocenes in good to excellent yields. Single-crystal X-ray structural analysis demonstrated that these heavier alkaline earth metallocenes incorporated two intramolecularly coordinated ester pendants and multiply-substituted cyclopentadienyl ligands. The corresponding transition metal metallocenes, such as ferrocene derivatives and half-sandwich cyclopentadienyl tricarbonylrhenium complexes, could be generated highly efficiently by metathesis reactions. The multiply-substituted cyclopentadiene ligands bearing an ester pendant, and the corresponding heavier alkaline earth and transition-metal metallocenes, may have further applications in coordination chemistry, organometallic chemistry, and organic synthesis. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of carboxylic acids, esters, alcohols and ethers containing a tetrahydropyran ring derived from 6-methyl-5-hepten-2-one.

PubMed

Hanzawa, Yohko; Hashimoto, Kahoko; Kasashima, Yoshio; Takahashi, Yoshiko; Mino, Takashi; Sakamoto, Masami; Fujita, Tsutomu

2012-01-01

3-hydroxy acids, 3-hydroxy-3,7-dimethyloct-6-enoic acid (1) and 3-hydroxy-2,2,3,7-tetramethyloct-6-enoic acid (2), were prepared from 6-methyl-5-hepten-2-one, and they were subsequently used to prepare (2,6,6-trimethyltetrahydropyran-2-yl)acetic acid (3) and 2-methyl-2-(2,6,6-trimethyltetrahydropyran-2-yl)propanoic acid (4), respectively, via cyclization with an acidic catalyst such as boron trifluoride diethyl etherate or iodine. The reaction of carboxylic acids 3 and 4 with alcohols, including methanol, ethanol, and 1-propanol, produced the corresponding methyl, ethyl, and propyl esters, which all contained a tetrahydropyran ring. Reduction of carboxylic acids 3 and 4 afforded the corresponding alcohols. Subsequent reactions of these alcohols with several acyl chlorides produced novel esters. The alcohols also reacted with methyl iodide and sodium hydride to provide novel ethers. A one-pot cyclization-esterification of 1 to produce esters containing a tetrahydropyran ring, using iodine as a catalyst, was also investigated.

One-pot preparation of unsaturated polyester nanocomposites containing functionalized graphene sheets via a novel solvent-exchange method

USDA-ARS?s Scientific Manuscript database

This paper reports a convenient one-pot method integrating a novel solvent-exchange method into in situ melt polycondensation to fabricate unsaturated polyester nanocomposites containing functionalized graphene sheets (FGS). A novel solvent-exchange method was first developed to prepare graphene oxi...