A new synthesis of cord factors and analogs

Treatment of 6,6′-di-O-trityl-trehalose (1) 2] with benzyl chloride in dioxane followed by acid hydrolysis and chromatography gave the chromatographically pure 2,3,4,2′,3′,4′-hexa-O-benzyl trehalose (2). Compound 2 was converted into the corresponding 6,6′-di-O-methane-sulphonyl derivative 3 in quantitative yield. Treatment of the latter compound with the potassium salts of 4-p-(hexadecyloxy)-phenyl]butyric acid, corynomycolic acid and mycolic acid from Mycobacterium bovis afforded the corresponding benzylated-6,6′-di-O-acyl esters 4, 5 and 6 respectively. Catalytic hydrogenolysis of 4, 5, and 6 yielded 6,6′-di-O-4-p-(hexadecyloxy)-phenyl] butyryl-trehalose 7; 6,6′-di-O-corynomycolyl-trehalose 8; and 6,6′-di-O-bovi-mycolyl-trehalose 9 respectively.