1,3-Diethyl 2-oxopropanedioate → ethyl 3,4-dihydro-7-[1-(1H-imidazol-1-yl)-2-methylpropyl]3-oxo-2-quinoxalinecarboxylate

Participants

Reaction Steps

A solution of 15 parts of 4-[1-(1H-imidazol-1-yl)-2-methylpropyl]-1,2-benzenediamine and 12.5 parts of diethyl 2-oxo-1,3-propanedioate in 80 parts of ethanol was stirred for 2 hours at reflux temperature. The reaction mixture was evaporated and the residue was purified by column chromatography over silica gel using a mixture of dichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from a mixture of acetonitrile and ethanol. The product was filtered off and dried, yielding 3.1 parts (14.0%) of ethyl 3,4-dihydro-7-[1-(1H-imidazol-1-yl)-2-methylpropyl]-3-oxo-2-quinoxalinecarboxylate; mp. 229.7° C. (comp. 107).

Provenance & Evidence