A Novel Regioselective Desulfation Method Specific to Carbohydrate 6-Sulfate Using Silylating Reagents

Abstract

Sulfated primary alcohols and methyl α-D-galactopyranoside 6-sulfate were converted into desulfated and trimethylsilylated alcohols and galactoside, respectively, by treating their pyridinium salts with N,O-bis(trimethylsilyl)acetamide (BTSA) or N,O-bis(trimethylsilyl)triftuoroacetamide (BTSTFA) in pyridine. Sulfated secondary alcohols and methyl galactoside 2-, 3-, and 4-sulfates did not have their sulfates eliminated under similar conditions, indicating that the reaction was specific to the primary hydroxyl groups. Methyl α-galactoside 2-sulfate was preparatively obtained by the BTSA treatment of methyl α-galactoside 2,6-disulfate, indicating that the method is applicable to regioselective desulfation on a preparative scale.