Abstract
9-Fluorenone azine 2a or benzophenone azine 2b have been synthesized, respectively, by treatment of 9-fluorenone hydrazone la or benzophenone hydrazone 1b with FeCl3 Lewis acid catalyst in CHCl3. Treatment of la and 1b with FeCl3 affords the asymmetrical azine 1-(diphenylmethylene)-2-(9H-fluoren-9-ylidene)hydrazine 2c. 1,3-Dipheny1-2-propenone 3 reacts with hydrazine to produce 1-((E)-1,3-diphenylallylidene)hydrazine 3a. Under prolonged heating, 3a undergoes a cyclization to yield 3,5-diphenyl-1H-pyrazole 4. Chalcone 3 reacts with la or 1b to produce a mixture of 4 and 2a or 4 and 2b, respectively. The reaction of cyclohexanone 5 with hydrazine leads to the formation of 1,2-dicyclohexylidene hydrazine 6. Ketone 5 reacts with la or 1b to give the asymmetrical azine product 6a or 6b, respectively. The progress of the reactions has been monitored by electrospray ionization mass spectrometry (ESI-MS), and the compounds have been characterized by elemental analyses, IR, H-1, C-13 and DEPT-135 NMR spectroscopy and also by high resolution ESI+-MS.