Synthesis of di- and tri-saccharides corresponding to receptor structures recognised by pyelonephritogenic E. coli...

Syntheses are described of di- and tri-saccharides required for studies of the inhibition of adhesion by means of fimbriae of pyelonephritogenic E. coli bacteria to epithelium cells in the urinary tract containing suitable receptor sites. The disaccharides are the rho-nitrophenyl and methyl glycosides of 4-omicron-alpha-D-galactopyranosyl-beta-D-galactopyranose, and the trisaccharides are the rho-nitrophenyl and methyl glycosides of 4-omicron-(4-omicron-alpha-D-galactopyranosyl-beta-D-galactopyranosyl)-beta- D-glucopyranose. The key aglycons were the 1,2,3,6-tetrabenzoate of alpha-D-galactose and the 1,2,3,6,-2',3',6'-heptabenzoate of alpha-lactose. Glycosidations were performed with 2,3,4,6-tetra-omicron-benzyl-alpha-D-galactopyranosyl chloride as glycosylating agent and silver triflate as promoter.