Thiourea → 79382-71-1

Participants

Reaction Conditions

Reaction Steps

Using the method of Rosenmund, 88 g of the above 3-methyl-1-(4-chloroformylphenyl)pyrazole are hydrogenated with hydrogen at 140° C. in 900 ml of xylene with the addition of 0.23 g of thiourea and 9 g of Pd/BaSO4 (5%). After cooling to 80° C. and removing the catalyst by filtration, the xylene solution is evaporated to dryness and the precipitated product is recrystallised from a mixture of hexane and toluene, affording 68.3 g of 3-methyl-1-(4-formylphenyl)pyrazole in the form of pale yellow crystals with a melting point of 96°-98° C.

Provenance & Evidence