7115-19-7

Upstream product

• 14218-11-2 2,3,4,6-tetra-O-benzoylglucosyl bromide 
• 20750-02-1 methyl 2-O-acetyl-4,6-O-benzylidene-β,D-glucopyranoside 
• 2106-10-7 1-deoxy-1-fluoro-α-D-glucose 
• 709-50-2 methyl beta-D-glucopyranoside 
• 23202-66-6 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl-(1→3)-2,4,6-tri-O-acetyl-α-D-glucopyranosyl bromide 
• 68036-18-0 1,2,4,6-tetra-O-acetyl-3-O-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-α-D-glucopyranose 
• 25577-40-6 methyl 2-O-acetyl-4,6-O-benzylidene-α,D-glucopyranoside 
• 3162-96-7 methyl 4,6-O-benzylidene-α-D-glucopyranoside 
• 572-09-8 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide 
• 229163-04-6 methyl 2,6'-O-(1,3-xylylene)-(2,3,4-tri-O-benzyl-β-D-glucopyranosyl)-(1'->3)-4,6-O-benzylidene-α-D-glucopyranoside 
• 1425503-73-6 ethyl 3-O-benzyl-4,6-O-benzylidene-2-O-propargyl-1-thio-β-D-glucopyranoside 
• 3162-96-7 4,6-O-benzylidene-1-O-methyl-α-D-glucopyranoside 
• 141810-60-8 ethyl 3-O-benzyl-4,6-O-benzylidene-1-thio-β-D-glucopyranoside 
• 1425503-81-6 methyl 2-O-(2-azidobenzyl)-4,6-O-benzylidene-α-D-glucopyranoside 

Downstream Products

• 7322-42-1 methyl O-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-(1->3)-2,4,6-tri-O-acetyl-α-D-galactopyranoside 
• 78797-79-2 methyl 2,4-di-O-acetyl-6-O-p-tolylsulfonyl-3-O-(2,3,4-tri-O-acetyl-6-O-p-tolylsulfonyl-β-D-glucopyranosyl)-β-D-glucopyranoside 
• 78797-77-0 methyl 2,4-di-O-acetyl-3-O-(2,3,4-tri-O-acetyl-6-O-trityl-β-D-glucopyranosyl)-6-O-trityl-β-D-glucopyranoside 

Relevant academic research and scientific papers

Regio- and stereochemical controlled koenigs-knorr-type monoglycosylation of secondary hydroxy groups in carbohydrates utilizing the high site recognition ability of organotin catalysts

The catalytic regio- and stereoselective monoglycosylation of carbohydrates using organotin catalysts is demonstrated. The one-step reaction affords various oligosaccharides linked at the secondary hydroxy group in high chemical yield and good regio- and stereoselectivities. The regioselectivity of the glycosylation is shown to depend on the spatial arrangement of the hydroxy groups in the carbohydrates. Copyright

An exo-β-(1→3)-d-galactanase from Streptomyces sp. provides insights into type II arabinogalactan structure

An exo-β-(1→3)-d-galactanase (SGalase1) that specifically cleaves the β-(1→3)-d-galactan backbone of arabinogalactan-proteins (AGPs) was isolated from culture filtrates of a soil Streptomyces sp. Internal peptide sequence information was used to clone and recombinantly express the gene in E. coli. The molecular mass of the isolated enzyme was ～45 kDa, similar to the 48.2 kDa mass predicted from the amino acid sequence. The pI, pH and temperature optima for the enzyme were ～7.45, 3.8 and 48 °C, respectively. The native and recombinant enzymes specifically hydrolysed β-(1→3)-d- galacto-oligo- or poly-saccharides from the upstream (non-reducing) end, typical of an exo-acting enzyme. A second homologous Streptomyces gene (SGalase2) was also cloned and expressed. SGalase2 was similar in size (47.9 kDa) and enzyme activity to SGalase1 but differed in its pH optimum (pH 5). Both SGalase1 and SGalase2 are predicted to belong to the CAZy glycosyl hydrolase family GH 43 based on activity, sequence homology and phylogenetic analysis. The K m and Vmax of the native exo-β-(1→3)-d- galactanase for de-arabinosylated gum arabic (dGA) were 19 mg/ml and 9.7 μmol d-Gal/min/mg protein, respectively. The activity of these enzymes is well suited for the study of type II galactan structures and provides an important tool for the investigation of the biological role of AGPs in plants. De-arabinosylated gum arabic (dGA) was used as a model to investigate the use of these enzymes in defining type II galactan structure. Exhaustive hydrolysis of dGA resulted in a limited number of oligosaccharide products with a trisaccharide of Gal2GlcA1 predominating.

Intramolecular glycosidation by click reaction mediated spacer generation followed by spacer cleavage

2-O-Propargyl-substituted glycosyl donors and O-(2-azidobenzyl)-substituted acceptors having a vicinal hydroxy group readily underwent the click reaction. Intramolecular glycosidation with N-iodosuccinimide/trifluoromethansulfonic acid as the activating system afforded β-(1-3)- and α-(1-2)-linked disaccharides as part of 14-membered macrocycles. Descriptors for these reactions are proposed that consider the donor and acceptor attachment sites and the stereochemistry of the functional groups. Investigation of the influence of 2-O-linked 1-aryl-1,2,3-triazol-4-ylmethyl groups, as contained in the spacer, on the anomeric selectivity exhibited no anchimeric assistance. In addition, it was shown that the spacer group can be readily cleaved under Birch reduction conditions. The 1,2,3-triazole-forming click reaction was employed to generate glycosyl donor-spacer-acceptor constructs. Upon glycosidation, 14-membered macrocycles were obtained with high anomeric selectivity. Spacer cleavage was performed under Birch reduction conditions. Copyright

Characterization of a bacterial laminaribiose phosphorylase

Bacterial laminaribiose phosphorylase (LBPbac) was first identified and purified from cell-free extract of Paenibacillus sp. YM-1. It phosphorolyzed laminaribiose into α-glucose 1-phosphate and glucose, but did not phosphorolyze other glucobioses. It slightly phosphorolyzed laminaritriose and higher laminarioligosaccharides. The specificity of the degree of polymerization of the substrate was clearly different from that of the enzyme of Euglena gracilis (LBPEug): LBPbac was more specific to laminaribiose than LBPEug. It showed acceptor specificity in reverse phosphorolysis similar to LBPEug. Cloning of the gene encoding LBPbac (lbpA) has revealed that LBPbac is a member of the glucoside hydrolase family 94, which includes cellobiose phosphorylase, cellodextrin phosphorylase, and N,N0-diacetylchitobiose phosphorylase. The genes that encode the components of an ATP-binding cassette sugar transporter specific to laminarioligosaccharides were identified upstream of lbpA, suggesting that the role of LBPbac is to utilize laminaribiose generated outside the cell. This role is different from that of LBPEug, which participates in the utilization of paramylon, the intracellular storage 1,3-β-glucan.

Thermus thermophilus glycosynthases for the efficient synthesis of galactosyl and glucosyl β-(1→3)-glycosides

Inverting mutant glycosynthases were designed according to the Withers strategy, starting from wild-type Thermus thermophilus retaining Tt-β-Gly glycosidase. Directed mutagenesis of catalytic nucleophile glutamate 338 by alanine, serine, and glycine afforded the E338A, E338S, and E338G mutant enzymes, respectively. As was to be expected, the mutants were unable to catalyze the hydrolysis of the transglycosidation products. In agreement with previous results, the E338S and E338G catalysts were much more efficient than E338A. Moreover, our results showed that these enzymes were inactive in the hydrolysis of the α-D-glycopyranosyl fluorides used as donors, and so suitable experimental conditions, under which the rate of spontaneous hydrolysis of the donor was considerably lower than that of enzymatic transglycosidation, provided galactosyl and glucosyl β-(1→3)-glycosides in yields of up to 90%. The structure of native Tt-β-Gly available in the Protein Data Bank offers a good basis for interpretation of our results by means of molecular modeling. Thus, in the case of the E338S mutant, a lower energy of the system was obtained when the donor and the acceptor were in the right position to form the β-(1→3)-glycosidic bond. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.

Enzymatic syntheses and selective hydrolysis of O-β-d- galactopyranosides using a marine mollusc β-galactosidase

The use of crude extract of the hepatopancreas of Aplysia fasciata, a large mollusc belonging to the order Anaspidea containing a β-galactosidase activity, was reported for the synthesis of different galactosides. Good yields with polar acceptors and the

1-O-Acetyl-β-D-galactopyranose: A novel substrate for the transglycosylation reaction catalyzed by the β-galactosidase from Penicillium sp.

1-O-Acetyl-β-D-galactopyranose (AcGal), a new substrate for β-galactosidase, was synthesized in a stereoselective manner by the trichloroacetimidate procedure. Kinetic parameters (KM and kcat) for the hydrolysis of 1-O-acetyl-β-D-galactopyranose catalyzed by the β-D-galactosidase from Penicillium sp. were compared with similar characteristics for a number of natural and synthetic substrates. The value for kcat in the hydrolysis of AcGal was three orders of magnitude greater than for other known substrates. The β-galactosidase hydrolyzes AcGal with retention of anomeric configuration. The transglycosylation activity of the β-D-galactosidase in the reaction of AcGal and methyl β-D-galactopyranoside (1) as substrates was investigated by 1H NMR spectroscopy and HPLC techniques. The transglycosylation product using AcGal as a substrate was β-D-galactopyranosyl-(1→6)-1-O-acetyl-β-D-galactopyranose (with a yield of ～70%). In the case of 1 as a substrate, the main transglycosylation product was methyl β-D-galactopyranosyl-(1→6)-β-D-galactopyranoside. Methyl β-D-galactopyranosyl-(1→3)-β-D-galactopyranoside was found to be minor product in the latter reaction.

Transferase activity of a β-glycosidase from Thermus thermophilus: Specificities and limits - Application to the synthesis of β-[1 → 3]- disaccharides

The aim of this paper is to test the ability of a β-glycosidase from Thermus thermophilus to catalyse transglycosylation reactions in the presence of nitrophenyl glycosides as donors and other monosaccharides as acceptors. Our results show that this enzym

Efficient Intramolecular Glycosylation Supported by a Rigid Spacer

The m-xylylene moiety was employed as rigid spacer in intramolecular glycoside bond formation. Fifteen-membered macrocycle formation starting from 6-O-linked donor and 6- and 4-O-linked acceptor (5a,b, 6b) led exclusively to β(1-4)- and β(1-6)-linked compounds 7β and 8β, respectively, which gave cellobioside and gentiobioside derivatives. The glycosylation yields could be improved by 14-membered macrocycle formation. In the four cases studied, the donor was 6-O-linked to the spacer. For the acceptor linkage to the spacer and the accepting hydroxy group, relative D-/L-threo- and D-/L-erythro-arrangements were chosen. Standard glycosylation conditions led in three cases (13, 14, 23) only to β-linkage in high yield (16β, 17β, 25β). For the transformation of 24, having a D-erythro-arrangement in the acceptor moiety, the α-anomer 26α was preferentially obtained. Limitation of the conformational space of the donor and the acceptor as in 31, which is stereochemically identical with 24, led to the corresponding α-glycoside 32α in 87% yield. Synthesis of a pseudo mirror image of 23 [having 6-(D)/3-(D-threo)-arrangement], namely 35, having 3(L)/6-(L-threo)-arrangement of the donor and acceptor moieties, expectedly gave only α-glycoside 36α in very high yield. Thus, the efficiency and versatility of this conceptual approach to intramolecular glycoside bond formation is exhibited.

Transglycosylation activity of Bacillus 1,3-1,4-β-D-glucan 4-glucanohydrolases. Enzymic synthesis of alternate 1,3,-1,4-β-D-glucooligosaccharides

The title enzyme from Bacillus licheniformis has been shown to catalyse the effective autocondensation of β-laminaribiosyl fluoride, and lead to alternate 1,3-1,4-β-D-glucotetraose and -glucohexaose products. The transglycosylation using the same donor an