Chloroform → 1-(4-Hydroxymethylphenyl)-3-methyl-2-pyrazolin-5-one

Participants

Reaction Steps

Into 250 ml of anhydrous chloroform were added 5.0 g of 4-(3-methyl-5-oxo-2-pyrazolin-1-yl)benzoic acid and 25 ml of triethylamine and, further under ice-cooling, 12.5 ml of ethyl chlorocarbonate was added dropwise into the mixture. After evaporation of the solvent, the residue was dissolved in 200 ml of THF, the insolubles were filtered off, and then a solution of 2.08 g of NaBH4 dissolved in 60 ml of water was added dropwise into the filtrate, followed by stirring at room temperature for 2 hours. After evaporation of the solvent, water was added to the residue, and the mixture was adjusted with dil. hydrochloric acid to pH 4-5 and then extracted with chloroform. The organic layer was dried, concentrated and purified on silica gel column chromatograph with the use of chloroform-ethanl (100:1) as eluant, followed by recrystallization from chloroformethyl ether to give 1.16 g of 1-(4-hydroxymethylphenyl)-3-methyl-2-pyrazolin-5-one as colorless crystals.

Provenance & Evidence