Ethyl 2-methylacetoacetate → 2-(2-Cyano-3-methylamino-4-nitrophenyl)-2-methyl-3-oxobutyric acid ethyl ester

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Reaction Steps

To a stirred solution of potassium t-butoxide (24.3 g, 206 mmol) in DMSO (500 mL) was added ethyl 2-methylacetoacetate (34.3 g, 233 mmol), dropwise over 5 min. The temperature rose to 30° C. 6-Chloro-2-methylamino-3-nitrobenzonitrile (43.6 g, 190 mmol) was added in portions over 15 min. The temperature rose to 40° C. The solution was stirred for 1 h with no external heating or cooling. The mixture was poured into 10% NH4Cl (500 mL), and extracted with EtOAc (2×500 mL). The combined extracts were washed with water (2×250 mL) and brine, and evaporated. MeOH (200 mL) was added to the residue and stirred for 1.5 h. The yellow solid was filtered, washed with cold MeOH (25 mL) and dried to give 2-(2-cyano-3-methylamino-4-nitrophenyl)-2-methyl-3-oxobutyric acid ethyl ester (36.2 g, 60%), mp 87-91° C.

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