Synthesis of a thio-linked Lewis A (Le(a)) epitope.
The synthesis of heptyl (alpha-L-fucopyransoyl)-(1-->4)-S-[(beta-D-galactopyranosyl)-(1--> 3)] -1,4-dithio-beta-D-glucopyranoside (2), as thio-linked Lewis A analogue was based on thexyldimethylsilyl 3-O-allyl-2-O-benzoyl-6-O-(4-methoxybenzyl)-4-thio-beta-D-glucopyranosid e (15) which was readily obtained from D-galactose. Reaction of 15 with O-3,4-di-O-acetyl-2-O-(4-methoxybenzyl)-alpha-L-fucopyranosyl trichloroacetimidate (8) as fucosyl donor afforded the alpha-(1-->4)-thio-linked disaccharide. Replacement of the 4-methoxybenzyl groups by acetyl groups and removal of the 3a-O-allyl group afforded as 3a-O-unprotected acceptor thexyldimethylsilyl (2,3,4-tri-O-acetyl-alpha-L-fucopyranosyl)-(1-->4)-S-6-O-acetyl-2-O-benz oyl -4-thio-beta-D-glucopyranoside (19), which gave with 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl trichloroacetimidate as galactosyl donor (20) the trisaccharide. Transformation into a trichloroacetimidate as glycosyl donor, glycosylation of heptylmercaptan, and then removal of the O-acyl protective groups afforded target molecule 2.
Fakultät Chemie, Universität Konstanz, Germany.
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D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D000939:Epitopes / Q000737:chemistry*; D006031:Glycosylation; D007983:Lewis Blood Group Antigens / Q000276:immunology*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D013440:Sulfides / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology; D013455:Sulfur / Q000737:chemistry; D013865:Thioglycosides; D014312:Trisaccharides / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology
D000939:Epitopes; D007983:Lewis Blood Group Antigens; D013440:Sulfides; D013865:Thioglycosides; D014312:Trisaccharides; C114467:heptyl fucopyranosyl-1-4-S-(galactopyranosyl-1-3)-1,4-dithioglucopyranoside; D013455:Sulfur