Diethyl Ether → 4-chloro-1-(difluoromethyl)-1H-pyrazole-3-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A solution of 4-chloro-1-difluoromethyl-1H-pyrazole-3-carboxylic acid methoxy-methyl-amide (930 mg, 3.9 mmol) in tetrahydrofuran (30 ml) was cooled to 0° C. and treated dropwise with a solution of lithium aluminium hydride in tetrahydrofuran (1M, 2 ml). Stirring was continued at 0° C. for 45 minutes. In order to complete the reaction, another 2 ml of the solution of lithium aluminium hydride in tetrahydrofuran (1M) was added. After 45 minutes the reaction mixtures was cooled to −15° C. and a saturated solution of potassium hydrogensulphate (25 ml) was added dropwise. Stirring was continued at −15° C. for 10 minutes, then ether (30 ml) was added and again stirred for 30 minutes. Thereafter, the reaction mixture was left to warm to room temperature, the organic layer separated, washed with water, finally dried over sodium sulphate and evaporated. The crude material was purified by chromatography on silica gel using a 4:1-mixture of cyclohexane and ethyl acetate as the eluent. The 4-chloro-1-difluoromethyl-1H-pyrazole-3-carbaldehyde was obtained as a colourless oil (582 mg, 83%).

Provenance & Evidence