α-aminoazoles in synthesis of heterocycles: IV. Regiodirection of 3(5)-amino-5(3)-methylpyrazole reaction with hexafluoroacetylacetone

Abstract

The reaction of 3(5)-amino-5(3)-methylpyrazole with hexafluoroacetylacetone depending on the process conditions led to the formation either of pyrazolo[1,5- a ]pyrimidine or pyrazolo[3,4- b ]-pyridine. By means of 2D NMR spectroscopy the structure was established of a stable intermediate product, 2-methyl-5,7-bis(trifluoromethyl)-4,5,6,7-tetrahydropyrazolo[1,5- a ]-pyrimidine-5,7-diol, whose dehydration yielded the above compounds.