The synthesis of pyrido[4,3-d]pyrimidin-4(3H)-ones from 4-amino-nicotinic acid

Abstract

Treatment of either a pyrido[4,3-d][1,3]oxazin-4-one or an ethyl 4-amidonicotinate with amines yields a 4-amidonicotinamide which may be cyclised by longer contact with the amine, or by heat, to give a pyrido[4,3-d]-pyrimidin-4(3H)-one. Some typical infrared and nuclear magnetic resonance spectra are discussed.