The allyl group for protection in carbohydrate chemistry. Part 19. The coupling of allyl 2,3-di-O-methyl-4-O-(3,6-di-O-methyl-β-D-glucopyranosyl)-α-L-rhamnopyranoside to bovine serum albumin. Preparation of a diagnostic reagent for antibodies to the major glycolipid of Mycobacterium leprae(the leprosy bacillus) in human sera

Abstract

Epoxidation of allyl 4-O-(2,4-di-O-benzyl-3,6-di-O-methyl-β-D-glucopyranosyl)-2,3-di-O-methyl-α-L-rhamnopyranoside and subsequent alkaline hydrolysis of the epoxide and hydrogenolysis of the benzyl groups gave 2′,3′-dihydroxypropyl 2,3-di-O-methyl-4-O-(3,6-di-O-methyl-β-D-glucopyranosyl)-α-L-rhamnopyranoside which was cleaved with sodium metaperiodate to give the corresponding formylmethyl glycoside. Two other routes to the latter compound, via allyl 2,3-di-O-methyl-4-O-(3,6-di-O-methyl-β-D-glucopyranosyl)-α-L-rhamnopyranoside, were also developed. The formylmethyl glycoside was coupled to bovine serum albumin using ‘reductive amination’ in the presence of sodium cyanoborohydride to give a glycoconjugate useful for the serodiagnosis of antibodies to the major glycolipid of Mycobacterium leprae in the sera of leprosy patients. 5′,6′-Dihydroxyhexyl and 10′,11′-dihydroxyundecyl 3,6-di-O-methyl-β-D-glucopyranosides were also prepared as intermediates for the synthesis of the 4-formylbutyl and 9-formylnonyl glucosides respectively which are also suitable for coupling to bovine serum albumin by the ‘reductive amination’ technique.