反应详情

In an apparatus equipped with a Dean-Stark trap for azeotropic removal of water, 2.4 g (7.0 mmoles) 2-chloro-5-[4-chloro-1-methyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-4-fluorobenzaldehyde, 0.4 mL (7.7 moles) ethylene glycol and a catalytic amount of p-toluene-sulfonic acid in 50 mL toluene was heated to reflux for 24 hours. The resultant mixture was concentrated and the residue purified by chromatography to give 1.65 g (61%) of 4-chloro-3-(4-chloro-5-(1,3-dioxolan-2-yl)-2-fluorophenyl)-1-methyl-5-(trifluoromethyl)-1H-pyrazole as a clear colorless oil; nD25 51.5348.

1. temperatureto reflux for 24 hours
2. concentrationThe resultant mixture was concentrated
3. customthe residue purified by chromatography