Formamidine acetate → 5,6,7,8-Tetrahydro-7-(phenylmethyl)pyrido(3,4-d)pyrimidin-4(3H)-one

Participants

Reaction Steps

Sodium metal (10.1 g, 0.44 mol) was added to ethanol (520 mL) and stirred at room temperature under nitrogen gas until a clear solution had formed. Ethyl-3-oxo-N-benzylpiperidine-4-carboxylate hydrochloride (56.5 g, 0.19 mol) and formamidine acetate (22.9 g, 0.22 mol) were then added and the reaction mixture heated under reflux for 40 hours. The reaction mixture was concentrated under reduced pressure, and the residue partitioned between water (400 mL) and dichloromethane (400 mL). The aqueous phase was re-extracted with dichloromethane (2×100 mL). The combined organic extracts were dried (MgSO4) and concentrated under reduced pressure. The resulting solid was triturated with diethyl ether (100 mL) and the product collected by filtration to give the title compound as a light brown solid (32.0 g, 70%).

Provenance & Evidence