Synthesis of 8-(hydroxyalkyl)adenines

Treatment of methyl 4,6-O-benzylidene-2-O-p-tolylsulfonyl-α-D-ribo-hexopyranosid-3-ulose (1) with triethylamine-methanol at reflux temperature yields methyl 2,3-anhydro-4,6-O-benzylidene-3-methoxy-α-D-allopyranoside (2), a derivative (3) of 3-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one, and methyl 4,6-O-benzylidene-α-D-ribo-hexopyranosid-3-ulose dimethyl acetal (4). The reaction of methyl 4,6-O benzylidene-3-O-p-tolylsulfonyl-α-D-arabino-hexopyranosid-2-ulose (12) with triethylamine-methanol afforded methyl 4,6-O-benzylidene-α-D-ribo-hexopyranosid-2-ulose dimethyl acetal (19) and methyl 2,3-anhydro-4,6-O-benzylidene-2-methoxy-α-D-allopyranoside (20); from the reaction of the β-D anomer (13) of 12, methyl 4,6-O-benzylidene-β-D-ribo-hexopyranosid-2-ulose dimethyl acetal (21) was isolated. Syntheses of the α-keto toluene-p-sulfonates 12 and 13 are described. Mechanisms for the formation of the compounds isolated from the reactions with triethylamine-methanol are proposed.