Sulfuryl chloride → 4-Chloro-3-methyl-5-nitro-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

Nitropyrazole 9 (10.0 g, 78.68 mmol) was dissolved in a mixture of chloroform (500 mL) with 1 drop DMF. To this was added sulfuryl chloride (9.60 mL, 14.33 g, 118.0 mmol) and the mixture heated to reflux for 20 hour at 115° C. external temperature. After additional 48 hours stirring at ambient temperature the mixture was evaporated to dryness in vacuo, dichloromethane (250 mL) added and the solution again evaporated in vacuo. Crude 15 was purified by column chromatography (1 kg SiO2, 0-10% methanol in DCM) yielding pure 15 (11.7 g, 72.42 mmol, 92%).

Provenance & Evidence