SYNTHESIS OF 4 GLYCOSIDES OF A DISACCHARIDE FRAGMENT REPRESENTING THETERMINUS OF THE O-POLYSACCHARIDE OF VIBRIO-CHOLERAE O 1, SEROTYPE INABA, BEARING AGLYCONS SUITABLE FOR LINKING TO PROTEINS/

Methyl ido-3-O-benzyl-4,6-dideoxy-alpha-D-mannopyranoside was converte d into the crystalline 2-(trimethylsilyl)ethyl yl-3-O-benzyl-4,6-dideo xy-alpha-D-mannopyranoside. Debenzoylation of the latter, followed by glycosylation of the resulting 2-hydroxy derivative with -acetyl-4-azi do-4,6-dideoxy-alpha-D-mannopyranosyl chloride, gave the 2-(trimethyls ilyl)ethyl glycoside of the corresponding disaccharide (8). Deacetylat ion of 8, followed by reduction of the resulting 4-azido-2-hydroxy der ivative with H2S, gave the corresponding amine 10. The latter was trea ted with 4-O-benzyl-3-deoxy-L-glycero-tetronic acid to give, after deb enzylation and acetylation, the fully protected 2-(trimethylsilyl)ethy l alpha-glycoside of the disaccharide fragment of the O-PS of Vibrio c holerae O:1, serotype Inaba (13). Compound 13 was transformed into the corresponding 1-trichloroacetimidate which was treated, separately, w ith methyl 6-hydroxyhexanoate and 2-(2-methoxycarbonylethylthio)ethano l, to give two analogs of 13 possessing a differing linkage arm, namel y the methyl esters 16 and 17, Each of 16 and 17 was treated with aque ous sodium hydroxide, followed by a cation-exchange resin, to give the two corresponding carboxylic acids (19 and 22). Alternately, treatmen t of 16 and 17 with hydrazine hydrate gave the acid hydrazides 20 and 23. Published by Elsevier Science Ltd.