Diisopropylamine → N-(2-Hydroxy-2-methylpropyl)-1-methyl-4-nitro-1H-pyrazole-3-carboxamide

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1-methyl-4-nitro-1H-pyrazole-3-carboxylic acid (0.9 g, 5.26 mmol) and 1-amino-2-methylpropan-2-ol (469 mg, 5.26 mmol) in THF (20 mL) cooled to 0-5° C. were added N,N-diisopropylamine (3.67 mL, 21.0 mmol) and 1-propanephosphonic acid cyclic anhydride (8.37 mL, 13.1 mmol, 50% solution in ethyl acetate). The mixture was stirred at 70° C. for 16 hours, cooled to ambient temperature, poured into ethyl acetate (50 mL) and extracted with HCl (1 M, 20 mL). The organic phase was washed with water and brine. The aqueous layers were back-extracted separately with ethyl acetate and dichloromethane. The combined organic layers were dried and concentrated in vacuo to give 1.4 g crude product. The crude material was purified by silica gel chromatography using a methanol/ethyl acetate gradient to give the title compound as colorless foam (391 mg, 31% yield).

Provenance & Evidence