Recycling of 4-(2,2,2-trichloroacetyl)furan-2,3-diones under the action of (hetero)arylhydrazides

Abstract

The interaction of 4-(2,2,2-trichloroacetyl)furan-2,3-diones with aryl- or thienoyl hydrazides in anhydrous chloroform with stirring for several hours leads to the formation of a mixture of diasteriomers A and B (ratio approximately 70:30) of 1-substituted 3-aryl-4,5-dihydro-5-hydroxy-4-(2,2,2-trichloroacetyl)-1 H -pyrazole-5-carboxylic acids.