Prepn. of N-(phenyl)alkyl-pyrazole or deriv., useful as intermediate

摘要

The prepn. of an N-substd. pyrazole deriv. of formula (I) comprises reacting pyrazole deriv. of formula (II) with an alcohol of formula R1OH (III) at 50-400 deg C in the presence of a catalyst. The mole ratio (II): (III) is 0.001-1:1 and reaction is carried out in the liq. phase at a pressure of below atmos. to 250 bar. The catalyst is an acid and/or its alkyl ester or anhydride. The mole ratio catalyst:(II) is 0.0001-0.5:1. R1 = 1-12C alkyl or 7-20C phenylalkyl; R2-R4 = H, 1-12C alkyl, 7-20C phenylalkyl or opt. substd. aryl.