4-Thiopyranoside and 4-thiofuranoside derivatives of d-galactosamine

Methyl 2-benzamido-2-deoxy-4-thio-α-d-galactopyranoside (7) was prepared in different ways starting from methyl 2-benzamido-3,6-di-O-benzoyl-2-deoxy-α-d-glucopyranoside (1). A 4,6-epidithiogalactopyranoside was obtained from the 4-O-mesyl derivative of 1. The transformations of 7 into 2-benzamido-2-deoxy-4-thio-d-galactofuranose and into the corresponding methyl α- and β-4-thio-d-galactofuranosides are reported. The 2T3 conformation is proposed for the α anomers of the prepared furanoid compounds.