REACTIONS OF 2-HYDRAZINO-1-AZAAZULENES WITH DIPHENYLCYCLOPROPENONE

The reaction of ethyl 2-hydrazino-1-azaazulene-3-carboxylate with diph enylcyclopropenone (DPP) gave ethyl ylpropenoyl)hydrazino]-1-azaazulen e-3-carboxylate, ethyl 2,9b-triazaindeno[1,7,6-bcd]azulene-3-carboxyla te, ethyl )-1,2,3a-triazacyclopent[a]-azulene-9-carboxylate, and ethyl 2-amino-1-azaazulene-3-carboxylate (8a), together with the products o f 8a with DPP. However, the reaction of 2-hydrazino-1-azaazulene with DPP gave 4H-2,3-diphenyl-1,4a-diazabenz-[a]azulen-4-one, [(1-azaazulen -2-yl)amino]-2,3-diphenylpropenamide, henyl-3,4-dihydro-2H-1,4a-diazab enz[a]azulen-2-one and 2-amino-1-azaazulene. The structures of the obt ained products were determined by inspections of their physical and sp ectral data, as well as single-crystal X-ray structure analyses of som e of these compounds. The reaction mechanisms are discussed.