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Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins.

ABSTRACT: A number of per-6-substituted cyclodextrin derivative syntheses have been effectively carried out in a planetary ball mill under solvent-free conditions. The preparation of Bridion^® and important per-6-amino/thiocyclodextrin intermediates without polar aprotic solvents, a source of byproducts and persistent impurities, could be performed. Isolation and purification processes could also be simplified. Considerably lower alkylthiol/halide ratio were necessary to reach the complete reaction in comparison with thiourea or azide reactions. While the presented mechanochemical syntheses were carried out on the millimolar scale, they are easily scalable.

SUBMITTER: Jicsinszky L

PROVIDER: S-EPMC5238617 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins.

Jicsinszky Laszlo L Caporaso Marina M Martina Katia K Calcio Gaudino Emanuela E Cravotto Giancarlo G

Beilstein journal of organic chemistry 20161110

A number of per-6-substituted cyclodextrin derivative syntheses have been effectively carried out in a planetary ball mill under solvent-free conditions. The preparation of Bridion<sup>®</sup> and important per-6-amino/thiocyclodextrin intermediates without polar aprotic solvents, a source of byproducts and persistent impurities, could be performed. Isolation and purification processes could also be simplified. Considerably lower alkylthiol/halide ratio were necessary to reach the complete react ...[more]

PMID: 28144304

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Project description:?-N-Acetylhexosaminidases have attracted interest particularly for oligosaccharide synthesis, but their use remains limited by the rarity of enzyme sources , low efficiency, and relaxed regioselectivity of transglycosylation. In this work, genes of 13 ?-N-acetylhexosaminidases, including 5 from Bacteroides fragilis ATCC 25285, 5 from Clostridium perfringens ATCC 13124, and 3 from Bifidobacterium bifidum JCM 1254, were cloned and heterogeneously expressed in Escherichia coli The resulting recombinant enzymes were purified and screened for transglycosylation activity. A ?-N-acetylhexosaminidase named BbhI, which belongs to glycoside hydrolase family 20 and was obtained from B. bifidum JCM 1254, possesses the bifunctional property of efficiently transferring both GalNAc and GlcNAc residues through ?1-3 linkage to the Gal residue of lactose. The effects of initial substrate concentration, pH, temperature, and reaction time on transglycosylation activities of BbhI were studied in detail. With the use of 10 mM pNP-?-GalNAc or 20 mM pNP-?-GlcNAc as the donor and 400 mM lactose as the acceptor in phosphate buffer (pH 5.8), BbhI synthesized GalNAc?1-3Gal?1-4Glc and GlcNAc?1-3Gal?1-4Glc at maximal yields of 55.4% at 45°C and 4 h and 44.9% at 55°C and 1.5 h, respectively. The model docking of BbhI with lactose showed the possible molecular basis of strict regioselectivity of ?1-3 linkage in ?-N-acetylhexosaminyl lactose synthesis.Oligosaccharides play a crucial role in many biological events and therefore are promising potential therapeutic agents. However, their use is limited because large-scale production of oligosaccharides is difficult. The chemical synthesis requires multiple protecting group manipulations to control the regio- and stereoselectivity of glycosidic bonds. In comparison, enzymatic synthesis can produce oligosaccharides in one step by using glycosyltransferases and glycosidases. Given the lower price of their glycosyl donor and their broader acceptor specificity, glycosidases are more advantageous than glycosyltransferases for large-scale synthesis. ?-N-Acetylhexosaminidases have attracted interest particularly for ?-N-acetylhexosaminyl oligosaccharide synthesis, but their application is affected by having few enzyme sources, low efficiency, and relaxed regioselectivity of transglycosylation. In this work, we describe a microbial ?-N-acetylhexosaminidase that exhibited strong transglycosylation activity and strict regioselectivity for ?-N-acetylhexosaminyl lactose synthesis and thus provides a powerful synthetic tool to obtain biologically important GalNAc?1-3Lac and GlcNAc?1-3Lac.

Dataset Information

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins.

Publications

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins.

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