Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DISACCHARIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 775 records · Page 43Linked to original sources
PubMed1990

Purification of alpha-L-fucosidase by C-glycosylic affinity chromatography, and the enzymic synthesis of alpha-L-fucosyl disaccharides.

An alpha-L-fucosidase from porcine liver was purified using the new C-glycosylic affinity adsorbent, Sepharose-epsilon-aminocaproyl-3-(alpha-L-fucopyranosyl)propylamine. The C-fucosylic linkage was synthesized by a radical reaction of 2,3,4-tri-O-acetyl-alpha-L-fucopyranosyl bromide with acrylonitrile. In transglycosylation reactions with p-nitrophenyl alpha-L-fucopyranoside or alpha-L-fucopyranosyl fluoride as donor and methyl beta-D-galactopyranoside as acceptor, the enzyme mediated the formation of (1----2)- and (1----6)-linked alpha-L-fucosyl derivatives (6.5 and 10.0%, respectively).

Animals↗
PubMed1991

Syntheses of disaccharides with (1----4)-beta glycosidic linkages related to the 4- and 6-sulfates and the 4,6-disulfates of chondroitin.

The solution salts of the 6'-sulfate 12, the 4'-sulfate 15 and the 4',6'-disulfate 17 of benzyl 4-O-(beta-D-galactopyranosyl)-beta-D-glucopyranosiduronate 10 have been synthesized. Methyl [benzyl 2,3-di-O-benzoyl-4-O-(2,3-di-O-benzoyl-beta-D-galactopyranosyl)-beta-D-+ ++glucopyranosid]uronate (9) has been prepared as a key intermediate from benzyl 4',6'-O-benzylidene-beta-D-lactopyranoside (2). Protection of 2 at C-6 with the tert-butyldimethylsilyl group, followed by O-perbenzoylation and disilylation, gave benzyl 2,3-di-O-benzoyl-4-O-(2,3-di-O-benzoyl-4,6-O-benzylidene-beta-D-galac top yranosyl)-beta-D-glucopyranoside (7). Oxidation of the 6-position of 7 proved to be difficult. However, 7 could be converted into the tert-butyl glucuronate 8 using chromium trioxide-pyridine and tert-butanol. Simultaneous hydrolysis of the benzylidene acetal and the tert-butyl ester groups, followed by esterification of the resulting free acid with diazomethane, yielded 9. Compound was directly sulfated with sulfur trioxide-trimethylamine within 12 h to give the 6'-sulfate 11. The 4',6-disulfate 16 was accessible by running the reaction under the same conditions for 14 days. The 4'-sulfate 14 was obtained after protecting the 6'-OH group of 9 with benzoyl cyanide to give the 6'-benzoate 13 followed by sulfation under more vigorous reaction conditions. Deesterification of 9, 11, 14, and 16 was achieved by treatment with aqueous sodium hydroxide in tetrahydrofuran to give 10, 12, 15, and 17, respectively.

Carbohydrate Conformation↗
PubMed1993

Synthesis and evaluation of diastereoisomeric alkylating pseudo-disaccharides as potential affinity reagents for trehalase.

Reaction of (+/-)-(3/4,5,6)-4-bromo-5,6-epoxy-3-hydroxycyclohexene with 2,3,4,6-tetra-O-acetyl-1-thio-alpha-D-glucopyranose, followed by treatment of the resulting isolated diastereoisomeric 4-bromo-3,5-dihydroxycyclohexene 1-thioglycoside derivatives with base under phase-transfer conditions, gave (R)- and (S)-(3,4,6/5)-3,4-epoxy-6-S-(1-thio-alpha-D-glucopyranosyl)-5- hydroxycyclohexene. None of them was substrate or inhibitor for cockchafer trehalase.

Alkylation↗
PubMed1995

Synthesis of disaccharide glycosyl donors suitable for introduction of the beta-D-Gal p-(1-->3)-alpha-and-beta-D-Gal pNAc groups.

2-(Trimethylsilyl)ethyl 2-azido-4,6-O-benzylidene-2-deoxy-beta-D- galactopyranoside (4) was glycosylated with phenyl 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-galactopyranoside to give 2-(trimethylsilyl)ethyl 2-azido-4,6-O-benzylidene-2-deoxy-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D-galactopyranoside (6) in 99% yield. Removal of the benzylidene group and acetylation gave the key intermediate 2-(trimethylsilyl)ethyl 4,6-di-O-acetyl-2-azido-2-deoxy-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D-galactopyranoside (7), which was transformed into methyl 4,6-di-O-acetyl-2-deoxy-2-phthalimido-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-1-thio-beta-D-galactopyranosid e (9) in two steps in an overall yield of 69%. Similarly, 7 was transformed in two steps into 4,6-di-O-acetyl-2-azido-2-deoxy-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-alpha-D-galactopyranosyl bromide (11) in an over-all yield of 86%. Compounds 9 and 11 are suitable glycosyl donors for introduction of the beta-D-Gal p-(1-->3)-beta- and -alpha-D-Gal pNAc groups.

Acetylgalactosamine↗
PubMed1995

Enzymic glycosylation of (+/-)-(3,5/4,6)-3,6-diazido-4,5- dihydroxycyclohexene. A way to prepare stereochemically pure and enzyme resistant, basic pseudo-disaccharides as competitive enzyme inhibitors.

By beta-D-galactosylation of (+/-)-(3,5/4,6)-3,6-diazido-4,5-dihydroxycyclohexene, pure (+)-3,5/4,6)-3,6-diazido-4-O-(beta-D-galactopyranosyl)-5-hydrox ycyclohexene (3) was obtained. The diamine (+)-(1,3/2,6)-3,6-diamino-1-O-(beta-D-galactopyranosyl)-2-hydroxycycl ohexane, derived from compound 3 by catalytic hydrogenation, is stable against enzymic cleavage and competitively inhibits beta-D-galactosidase from Escherichia coli with a Ki-value of 5.5 mM. Sigmatropic rearrangement of 3 in methanolic solution partially led to an unseparable mixture of the regioisomers (3,5/4,6)-3,4-diazido-5-O-(beta-D-galactopyranosyl)-6-hydroxycy clohexene and (3,5/4,6)-3,4-diazido-6-O-(beta-D-galactopyranosyl)-5-hydroxycy clohexene. Catalytic hydrogenation thereof yielded an equally unseparable mixture of the diamines (1,3/2,4)-1,2-diamino-4-O-(beta-D-galactopyranosyl)-4-hydroxycyclohex ane and (1,3/2,4)-1,2-diamino-4-O-(beta-D-galactopyranosyl)-3-hydroxycyclohex ane, inhibiting beta-D-galactosidase competitively with K(i) 0.9 mM.

Azides↗