Ethanol → Ethyl 5-nitro-1H-pyrazole-3-carboxylate

Participants

Reaction Steps

To a solution of 5-nitropyrazol-3-carboxylic acid (19.9 g) in ethanol (200 mL) was added dropwise thionyl chloride (9.7 mL) over a period of 5 minutes and the mixture was refluxed for 4 hours. After cooling to room temperature, the reaction mixture was diluted with water (25 mL) and ethanol (50 mL) and to the mixture was neutralized with sodium hydrogencarbonate (54 g). The mixture was filtered and the residue was washed with ethanol. The filtrate and the washings were combined and concentrated in vacuo. The residue was azeotropically distilled with ethanol and the residue was dissolved in ethyl acetate, dried over magnesium sulfate and filtered. The filtrate was concentrated in vacuo and to the residue was added isopropylether. The precipitates were collected by filtration and washed with ethyl acetate/diisopropylether (1/2) to give ethyl 5-nitropyrazol-3-carboxylate (20 g, yield: 85%) as a colorless solid.

Provenance & Evidence