Ethyl 5,7-diethyl-4-hydroxy-2-oxo-1,2-dihydro-1,6-naphthyridine-3-carboxylate → 5,7-diethyl-4-hydroxy-1,6-naphthyridin-2(1H)-one

Participants

Reaction Steps

Compound B (1 g) was dissolved in a mixture of water (1 ml), 1,4-dioxan (2 ml) and concentrated hydrochloric acid (1 ml) and the mixture was heated at reflux for 3 hours. The reaction mixture was then cooled and the suspended solid was collected by filtration. The solid was washed with ethanol and ether and dried under vacuum to give 5,7-diethyl-4-hydroxy-1,6-naphthyridin-2(1H)-one (C) (0.42 g), m.p. 322°-325° C.; NMR (d6 -DMSO): 1.3(dt, 6H), 2.99(q, 2H), 3.47(q, 2H), 6.0(s, 1H), 7.28(s, 1H), 12.3(s, 1H); mass spectrum (CI, ammonia): 219 (M+H)+ ; microanalysis, found: C, 55.7; H, 5.9; N, 10.5%; C12H14N2O2.HCl.0.25H2O requires: C, 55.6; H, 5.6; N, 10.8%.

Provenance & Evidence