Synthesis of p-nitrobenzyl and p-nitrophenyl 1-trioglycopyranosides

Reaction of 2,3,4-tri-O-acetyl-α-L-fucopyranosyl bromide (1),with thiourea (2), followed by reductive cleavage of the product, gave 2,3,4-tri-O-acetyl-1-thio-β-L-fucopyranose (4). Reaction of 4 with p-nitrobenzyl bromide followed by O-deacylation yielded p-nitrobenzyl 1-thio-β-L-fucopyranoside (6). Similar reaction conditions were used for the synthesis of p-nitrobenzyl 1-thio-β-D-fucopyranoside (11) and 1-thio-α-D-mannopyranoside (16). A facile preparation of O-acylated p-nitro-phenyl 1-thioglycopyranosides was achieved by condensing the appropriate glycosyl halide with sodium p-nitrobenzenethioxide in N,N-dimethylformamide.