1,8-Diazabicyclo(5.4.0)undec-7-ene → Ethyl 3-(2-chloro-5-nitropyridin-4-yl)-2-oxopropanoate

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Reaction Steps

1 g (5.79 mmol) of 2-chloro-4-methyl-5-nitropyridine and 4.23 g (28.94 mmol) of ethyl oxalate are placed, under a stream of nitrogen, in a 100 ml three-necked flask equipped with a magnetic stirrer. 0.96 ml (6.4 mmol) of 1,8-diazabicyclo[5.4.0]undec-7-ene is then added to the reaction medium stirred at room temperature. The reaction mixture is then stirred at room temperature for 1 hour, and then diluted with a mixture of ethyl acetate (40 ml), water (30 ml) and acetic acid (1 ml). The mixture is extracted twice with ethyl acetate. The combined organic phases are washed with 100 ml of water, with 100 ml of saturated aqueous sodium chloride solution, dried over sodium sulfate and then concentrated under reduced pressure. The residue is purified by chromatography on a column of silica gel, eluting with a mixture of heptane and ethyl acetate. 1.33 g (4.87 mmol) of the expected product are thus isolated in the form of a pink powder.

Provenance & Evidence