Diisopropylethylamine → methyl 3-[(2S)-4-[(tert-butoxy)carbonyl]-2-methylpiperazin-1-yl]-2-oxo-1,2-dihydroquinoxaline-6-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 3-chloro-2-oxo-1,2-dihydroquinoxaline-6-carboxylate (1.0 g, crude) in DMSO (10 mL) was added tert-butyl-(3S)-3-methylpiperazine-1-carboxylate (1.0 g, 4.99 mmol) and DIEA (1.0 g, 7.74 mmol). The resulting solution was stirred overnight at 80° C. in an oil bath and then diluted with water (100 mL), extracted with ethyl acetate (4×40 mL) and the organic layers combined and dried over anhydrous magnesium sulfate. The solids were filtered out and filtrate was concentrated in vacuo to give a residue, which was purified by a silica gel column chromatography (2% ethyl acetate in petroleum ether) to afford methyl 3-[(2S)-4-[(tert-butoxy)carbonyl]-2-methylpiperazin-1-yl]-2-oxo-1,2-dihydroquinoxaline-6-carboxylate as a light yellow solid (310 mg).

Provenance & Evidence