Sodium hydride → Ethyl 6-cyanopyrazolo[1,5-a]pyrimidine-3-carboxylate

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Reaction Steps

Sodium hydride (60% dispersion in mineral oil, 0.52 g, 13.0 mmol) was added, at 0° C., to a mixture of 3-amino-1H-pyrazole-4-carboxylic acid ethyl ester (0.9 g, 5.8 mmol) and 3-dimethylamino-2-formyl-acrylonitrile (0.72 g, 5.8 mmol) in anhydrous tetrahydrofuran (30 mL) and the reaction mixture was stirred overnight while warming up to room temperature. Ice-water was added and the resulting mixture was partitioned between water and ethyl acetate; the organic layer was separated and the aqueous layer was extracted 3 times with ethyl acetate. The combined organic extracts were washed with brine, dried over anhydrous sodium sulfate, filtered and evaporated. The yellow crude residue was purified twice on a silica gel plug (EtOAc/hexane) to afford 0.4 g (32% yield) of 6-cyano-pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester.

Provenance & Evidence