Formaldehyde → 1-Hydroxymethyl-4-chloro-3-(2-nitro-3-chlorophenyl)pyrazole

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Reaction Steps

0.40 ml of 1,8-diazabicyclo[5.4.0]undecen-7-ene is added, at room temperature, to a solution of 7.0 g (0.027 mol) of 4-chloro-3-(2-nitro-3-chlorophenyl)pyrazole and 2.40 g of paraformaldehyde in 100 ml of THF. The reaction mixture is stirred for 4 hours at room temperature, concentrated under reduced pressure and taken up in a mixture of 150 ml of water and 150 ml of methylene chloride. The organic phase is dried over magnesium sulphate and concentrated under vacuum. 7.40 g of 1-hydroxymethyl-4-chloro-3-(2-nitro-3-chlorophenyl)pyrazole melting at 146° C. are obtained (yield: 95.5%).

Provenance & Evidence