Dimethylformamide → 1H-Pyrazole-3-carboxamide, 5-(1-methylethyl)-4-nitro-

Participants

Reaction Conditions

Reaction Steps

Oxalyl chloride (6.8 ml, 77.6 mmol) was added dropwise to a suspension of 5-isopropyl-4-nitro-1H-pyrazol-3-carboxylic acid (5.15 g, 25.9 mmol) in dichloromethane (80 ml) containing dimethylformamide (0.1 ml) under nitrogen at 0° C. The reaction was stirred at 0° C. for 1 hours, allowed to warm to room temperature and stirred for a further 2 hours. The solvent was removed under reduced pressure, the residue was dissolved in toluene (100 ml) and ammonia gas was bubbled into the solution for 2 hours. The reaction was stirred under nitrogen at room temperature for 18 hours, concentrated under reduced pressure and the residue was dissolved in hot methanol (300 ml). The resultant precipitate was filtered and the filtrate was concentrated under reduced pressure. The residue was azeotroped with water (300 ml), concentrated to approximately 80 ml under reduced pressure and the precipitate was isolated by filtration. This was washed with water and dried under to give 5-isopropyl-4-nitro-1H-pyrazol-3-carboxylic acid amide (3.1 g) as an orange solid. 1H NMR (400 MHz, DMSO-D6): δ=7.94-7.99 (1H, brs), 7.68-7.72 (1H, brs), 3.45-3.55 (1H, m), 1.24-1.30 (6H, d) ppm. LRMS (electrospray): m/z [M+Na]+ 221, [M−H]+ 197.

Provenance & Evidence