Reactions of 2-arylhydrazones of 1,2,3-triketones with 1,2-diaminoethane. I. Synthesis and spectral characterization of 6-arylazo-2,3-dihydro-1H-1,4-diazepines and 3,10-diarylazo-4,9-dimethyl-5,8-diaza-3,9-dodecadiene-2,11-diones

Reactions of 3-arylhydrazones of 2,3,4-pentanetrione ( 1a–1e ) and 2-arylhydrazones of 1,3-diphenyl-1,2,3-propanetrione ( 1f–1l ) with 1,2-diaminoethane have been studied. It was found, that 3-arylhydrazones of 2,3,4-pentanetrione react with 1,2-diaminoethane with formation of 6-arylazo-2,3-dihydro-1,4-diazepines ( 2a–2e ) or the diarylazo derivatives of 4,9-dimethyl-5,8-diaza-3,9-dodecadiene-2,11-dione ( 3a–3e ). Analogous reactions of 2-arylhydrazones of 1,3-diphenyl-1,2,3-propanetrione yielded exclusively the derivatives of dihydrodiazepine. The structure of obtained products has been elucidated on the basis of i.r., m.s. and ¹H-n.m.r. spectra.