Microbial cyclosophoraose as a catalyst for the synthesis of diversified indolyl 4H-chromenes via one-pot three component reactions in water

Green Chem., 2016, 18,3620-3627
DOI: 10.1039/C6GC00137H, Paper
Someshwar D. Dindulkar, Daham Jeong, Eunae Cho, Dongjin Kim, Seunho Jung
A novel biosourced saccharide catalyst, microbial cyclosophoraose, a cyclic [small beta]-(1,2) glucan, was used for the synthesis of indolyl 4H-chromenes via a one pot three-component Knoevenagel-Michael addition-cyclization reaction in water under neutral conditions.

Microbial cyclosophoraose as a catalyst for the synthesis of diversified indolyl 4H-chromenes via one-pot three component reactions in water

 *corresponding authors

a
Institute for Ubiquitous Information Technology and Applications (UBITA) & Center for Biotechnology Research in UBITA (CBRU), Konkuk University, Seoul 143-701, South Korea
E-mail: shjung@konkuk.ac.kr
b
Nelson Mandela African Institution of Science and Technology, PO box 447, Arusha, Tanzania
c
Department of Bioscience and Biotechnology, Microbial Carbohydrate Resource Bank (MCRB), Konkuk University, Seoul 143-701, South Korea
Green Chem., 2016,18, 3620-3627

DOI: 10.1039/C6GC00137H

As a novel biosourced saccharide catalyst, microbial cyclosophoraose, a cyclic β-(1,2) glucan, was used for the synthesis of therapeutically important versatile indolyl 4H-chromenes via a one pot three-component Knoevenagel–Michael addition–cyclization reaction of salicylaldehyde, 1,3-cyclohexanedione/dimedone, and indoles in water under neutral conditions. A possible reaction mechanism through molecular complexation is suggested based on 2D ROESY NMR spectroscopic analysis. Moreover, green chemistry metric calculations were carried out for a model reaction, indicating the satisfactory greener approach of this method, with a low E-factor (0.18) and high atom economy (AE = 91.20%). The key features of this protocol are based on two critical factors where the first is to use a novel eco-friendly supramolecular carbohydrate catalyst and the second is its fine green properties such as compatibility with various substituted reactants, recyclability of the catalyst, chromatography-free purification, high product selectivity, and clean conversion with moderate to excellent yields in an aqueous medium.
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//////Microbial cyclosophoraose, catalyst,  synthesis , diversified indolyl 4H-chromenes , one-pot three component reactions, water

Selective reduction of aldehydes and ketones to alcohols with ammonia borane in neat water

Graphical abstract: Selective reduction of aldehydes and ketones to alcohols with ammonia borane in neat water

Chemoselective reduction of various carbonyl compounds to alcohols with ammonia borane (AB), a nontoxic, environmentally benign, and easily handled reagent, in neat water was achieved in quantitative conversions and high isolated yields. Interestingly, α- and β-keto esters were selectively reduced to corresponding hydroxyl esters by AB, while diols were obtained when sodium borohydride was used as a reducing agent. The procedure is also compatible with the presence of a variety of base-labile protecting groups, such as tosyl, acetyl, benzoyl, ester groups, and acid-labile protecting groups such as trityl and TBDMS groups, and others, such as the unsaturated double bond, nitro and cyano groups. Finally, a kilo scale reaction of methyl benzoylformate with AB was conducted in water and gave methyl mandelate in 94% yield.

Selective reduction of aldehydes and ketones to alcohols with ammonia borane in neat water

*Corresponding authors
aKey Laboratory of Green Chemical Media and Reactions, Ministry of Education, College of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007, China
E-mail: zgs@htu.cn
Tel: +86 373 3325250
Green Chem., 2012,14, 1372-1375

DOI: 10.1039/C2GC00006G

 

http://pubs.rsc.org/en/content/articlelanding/2012/gc/c2gc00006g#!divAbstract

 

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////////Selective reduction, aldehydes and ketones, alcohols,  ammonia borane, neat water

Domino Hydrogenation−Reductive Amination of Phenols, a Simple Process To Access Substituted Cyclohexylamines

 

Domino Hydrogenation−Reductive Amination of Phenols, a Simple Process To Access Substituted Cyclohexylamines
Org. Lett. 2015, 17, 3990−3993   DOI: 10.1021/acs.orglett.5b01842

 

Abstract Image

Phenols can be efficiently reduced by sodium formate and Pd/C as the catalyst in water and in the presence of amines to give the corresponding cyclohexylamines. This reaction works at rt for 12 h or at 60 °C under microwave dielectric heating for 20 min. With the exception of aniline, primary, secondary amines, amino alcohols, and even amino acids can be used as nucleophiles. The reductive process is based on a sustainable hydrogen source and a catalyst that can be efficiently recovered and reused. The protocol was developed into a continuous-flow production of cyclohexylamines in gram scale achieving very efficient preliminary results (TON 32.7 and TOF 5.45 h–1).

Domino Hydrogenation–Reductive Amination of Phenols, a Simple Process To Access Substituted Cyclohexylamines

Dipartimento di Biotecnologie, Chimica e Farmacia, Università degli Studi di Siena, Via A. Moro 2, 53100 Siena, Italy
Laboratory of Green Synthetic Organic Chemistry, CEMIN − Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
Org. Lett., 2015, 17 (16), pp 3990–3993
DOI: 10.1021/acs.orglett.5b01842
Publication Date (Web): July 31, 2015
Copyright © 2015 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/acs.orglett.5b01842

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/////Domino Hydrogenation, Reductive Amination of Phenols, Simple Process ,  Access Substituted Cyclohexylamines

Mechanisms and reactivity differences of proline-mediated catalysis in water and organic solvents

ORGANIC CHEMISTRY SELECT

Catal. Sci. Technol., 2016, 6,3378-3385
DOI: 10.1039/C6CY00033A, Paper
Gang Yang, Lijun Zhou
Several key issues regarding the mechanisms of proline catalysis are unravelled by first-principles calculations that can guide future catalyst design.

Mechanisms and reactivity differences of proline-mediated catalysis in water and organic solvents

Gang Yang*a and  Lijun Zhoua  
*Corresponding authors
aCollege of Resource and Environment & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing, PR China
E-mail: theobiochem@gmail.com
Fax: +86 023 68250444
Tel: +86 023 68251545
Catal. Sci. Technol., 2016,6, 3378-3385

DOI: 10.1039/C6CY00033A

Proline is an efficient and versatile catalyst for organic reactions while a number of issues remain controversial. Here, ab initio and density functional calculations were used to unravel a few key issues of catalytic mechanisms in water and…

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Intensified biocatalytic production of enantiomerically pure halophenylalanines from acrylic acids using ammonium carbamate as the ammonia source

ORGANIC CHEMISTRY SELECT

Catal. Sci. Technol., 2016, Advance Article
DOI: 10.1039/C6CY00855K, Communication
Nicholas J. Weise, Syed T. Ahmed, Fabio Parmeggiani, Elina Siirola, Ahir Pushpanath, Ursula Schell, Nicholas J. Turner
An industrial-scale method employing a phenylalanine ammonia lyase enzyme

Intensified biocatalytic production of enantiomerically pure halophenylalanines from acrylic acids using ammonium carbamate as the ammonia source

*Corresponding authors
aManchester Institute of Biotechnology & School of Chemistry, University of Manchester, 131 Princess Street, Manchester, UK
E-mail: nicholas.turner@manchester.ac.uk
bJohnson Matthey Catalysts and Chiral Technologies, 28 Cambridge Science Park, Milton Road, Cambridge, UK
Catal. Sci. Technol., 2016, Advance…

View original post 69 more words