Reactions of 2-acyl-1,3-indandiones with monosubstituted hydrazines and hydrazides

Methyl- and phenylhydrazines react with 2-(diphenylacetyl)-1,3-indandione (1) to yield respectively the 1-(methylhydrazone) and the 1-(phenylhydrazone) of 2-(diphenylacetyl)-1,3-indandione (2a and 2b). In comparison, acetic and benzoic acid hydrazides react with 1 to give respectively the α-(acetylhydrazone) and the α-(benzoylhydrazone) of 2-(diphenylacetyl)-1,3-indandione (3a and 3b). Cyclization of 2a and 2b gives 2,3-disubstituted indeno[1,2-c]pyrazol-4(2H)-ones (7a and 7b). Cyclization of 3a and 3b, followed by methylation, gives 1-methyl- and 2-methyl-3-(diphenylmethyl)indeno[1,2-c]pyrazol-4(1 and 2H)-ones (9a and 9b). 2-Isovaleryl-1,3-indandione reacts with phenylhydrazine to give directly 3-isobutyl-1-phenylindeno[1,2-c]-pyrazol-4(1H)-one (10).