Synthesis of 6-Hydroxymethylpterin α- and β-D-Glucosides

The key precursor, N(2)-(N,N-dimethylaminomethylene)-6-hydroxymethyl-3-[2-(4-nitrophenyl)ethyl]pterin (11) was efficiently prepared from 2,5,6-triamino-4-hydroxypyrimidine (8) in 5 steps. The first, unequivocal synthesis of 6-hydroxymethylpterin α-D-glucoside (6a) was achieved by treatment of 11 with 4,6-di-O-acetyl-2,3-di-O-(4-methoxybenzyl)-α-D-glucopyranosyl bromide (16) in the presence of tetraethylammonium bromide and N-ethyldiisopropylamine, followed by removal of the protecting groups, while 6-hydroxymethylpterin β-D-glucoside (6b) was prepared by means of selective glycosylation of 11 with 2,3,4,6-tetra-O-benzoyl-α-D-glucopyranosyl bromide (12) in the presence of silver triflate and tetramethylurea.