Ethanol → Ethyl 5,7-diethyl-4-hydroxy-2-oxo-1,2-dihydro-1,6-naphthyridine-3-carboxylate

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Reaction Steps

4-amino-2,6-diethylpyridine-3-carbaldehyde (1.78 g), diethylmalonate (1.92 g), ethanol (15 ml) and piperidine (4 drops) were heated at reflux for 16 hours. Volatile material was removed by evaporation and the residue was recrystallised from ethyl acetate/petroleum ether to give ethyl 5,7-diethyl-2-oxo-1,2-dihydro-1,6-naphthyridine-3-carboxylate (B) (1.4 g), m.p. 159°-160° C.; NMR (CDCl3): 1.34(t, 3H), 1.38(t, 3H), 1.47(t, 3H), 2.87(q, 2H), 3.14(q, 2H), 4.47(q, 2H), 7.03(s, 1H), 8.78(s, 1H), 12.2(s, 1H); mass spectrum (CI, ammonia): 275 (M+H)+ ; microanalysis, found: C, 65.8; H, 6.8; N, 10.4%; C15H18N2O3 requires: C, 65.7; H, 6.6; N, 10.2%.

Provenance & Evidence