Ethylene Glycol → 4-chloro-3-(4-chloro-5-(1,3-dioxolan-2-yl)-2-fluorophenyl)-1-methyl-5-(trifluoromethyl)-1H-pyrazole

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Reaction Steps

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 mmoles) ethylene glycol and a catalytic amount of p-toluenesulfonic 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 1.5348. Anal. Calc. for C14H10Cl2F4N2O2 : C,43.66; H,262; N,7.27. Found: C,43.67; H,2.59; N,7.24.

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