Trifluoroacetic acid → 3-(2-amino-7,8-dihydropyrido[4,3-d]pyrimidin-6(5H)-yl)pyridin-2(1H)-one

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Reaction Steps

A solution of 6-{2-[(4-methoxybenzyl)oxy]pyridin-3-yl}-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-2-amine (1.77 g, 4.87 mmol) in dichloromethane (70 ml) was treated with trifluoroacetic acid (2.68 ml, 36.04 mmol) at room temperature. After stirring for 30 minutes, the solvent and excess acid was removed in vacuo and the residue was treated with ethyl acetate. Washing with sat'd NaHCO3(aq.) gave a yellow, amorphous precipitate. The solid was collected, washed with water, EtOAc, MeOH and dried (774 mg, 65%). The product was suspended in a 2:1 (v/v) mixture of water: MeOH (125 ml) and heated to boiling with vigorous stirring for 1.5 hours. The undissolved solid remaining was collected by filtration while the mixture was still hot and washed with water, MeOH, and dried to give the title compound (478 mg, 40%).

Provenance & Evidence