Dimethylformamide → Ethyl 7-Chloropyrimido[4,5-b]quinolin-4(3H)-one-2-carboxylate

Participants

Reaction Steps

A mixture of 6-chloro-2-aminoquinoline-3-carboxamide (2.2 g., 0.01 mole), sodium hydride (0.52 g. 0.012 mole as 56% dispersion in oil) and N,N-dimethylformamide (20 ml.) is added to a solution of diethyl oxalate (5 ml.) and N,N-dimethylformamide (5 ml.). The reaction mixture is stirred for fifteen minutes, a second portion of sodium hydride (0.52 g., 0.012 mole) added and stirred continued for an additional 15 minutes. Acetic acid (25.0 ml.) is cautiously added to the mixture followed by water (50 ml.). The tan precipitate is removed by filtration and dried (2.0 g. of crude ester). It is purified by chromatography on silica gel using chloroform:2B ethanol (99:1) as eluant. The product, recovered by concentration of the eluate, is recrystallized from acetic acid. Yield = 1.3 g. (37.3%). M.P. 260.5° C. (dec.). Mass spectra gave m/e = 303.

Provenance & Evidence