4-Bromophenylhydrazine → Ethyl 5-amino-1-(4-bromophenyl)-1H-pyrazole-4-carboxylate

Participants

Reaction Steps

A solution of 4-bromophenylhydrazine (2.76 g, 14.7 mmol) and ethyl (ethoxymethylene)cyanoacetate (2.50 g, 14.8 mmol) in ethanol (15 mL) was heated at reflux for 2 hours. Upon cooling, a tan precipitate formed. The suspension was diluted with diethyl ether and suction filtered to remove solid. The filtercake was rinsed with diethyl ether and vacuum oven dried to afford 3.20 g (70%) of product as a tan solid: 1H NMR (CDCl3) d 7.79 (s, 1H), 7.64 (d, J=8.7 Hz, 2H), 7.45 (d, J=8.7 Hz, 2H), 5.30 (s, 2H), 4.31 (q, J=7.2 Hz, 2H), 1.37 (t, J=7.2 Hz, 3H) ppm.

Provenance & Evidence