Trifluoroacetic acid → 5-(3-chloro-benzylamino)-2-methyl-2H-pyrazole-3-carboxylic acid methyl ester

Participants

Reaction Steps

5-Amino-2-methyl-2H-pyrazole-3-carboxylic acid methyl ester (644, 1.3 g, 8.0 mmol) was combined with 3-chlorobenzaldehyde (645, 0.95 mL, 8.4 mmol) and acetonitrile (40 mL). Trifluoroacetic acid (3.2 mL, 42.0 mmol) was added followed by triethylsilane (6.7 mL, 42.0 mmol). The reaction was heated to reflux overnight and then concentrated. Ethyl acetate was added and the solution was washed with 1N potassium carbonate. The organic portion was dried over anhydrous sodium sulfate, filtered and concentrated. The compound (646, 0.944 g, 42%) was crystallized from a mixture of ethyl acetate:hexane.

Provenance & Evidence