3′,6′-anhydro-6- O-corynomycoloyl trehalose: Synthesis and identification as the impurity in synthetic cord factor preparations

Abstract

Acylation of 2,3,4,2′,3′,4′-hexa- O-benzyl-6,6′-di- O-methanesulphonyl-α-α-trehalose (1) with a reduced amount of potassium corynomycolate yielded a mixture which consisted mainly of 2,3,4,2′,3′,4′-hexa- O-benzyl-6- O-corynomycoloyl-6′- O-methanesulphonyl-α,α-trehalose (2). Catalytic hydrogenolysis of 2 gave the mono-mesylate 4 which was converted into 3′,6′-anhydro-6- O-corynomycoloyl-α,α-trehalose (5) but treatment with sodium hydride. The structure of 5 was studied by mass-spectroscopy. Compound 5 was found to be identical with the byproduct obtained in the acylation of 6,6′-di- O- p-toluenesulphonyl-α,α-trehalose with potassium corynomycolate.