Five-membered 2,3-dioxo heterocycles: LXXX. Recyclization of 1H-pyrrole-2,3-diones into pyrazolo[1,5-a]pyrimidines by the action of pyrazolamine. Crystalline and molecular structure of substituted pyrazolo[1,5-a]pyrimidine

Methyl 1-aryl-3-aroyl-4,5-dioxo-4,5-dihydro-1H-pyrrole-2-carboxylates reacted with 3-methyl-4-phenyl-1H-pyrazol-5-amine to give methyl 7-arylcarbamoyl-6-aroyl-2-methyl-3-phenylpyrazolo1,5-a]-pyrimidine-5-carboxylates. The molecular and crystalline structures of methyl 6-benzoyl-7-(4-chlorophenylcarbamoyl)-2-methyl-3-phenylpyrazolo1,5-a]pyrimidine-5-carboxylate were studied by X-ray analysis.