Syntheses and characterisation of N,N'-biscarbazolyl azine and N,N'-carbazolyl hydrazine derivatives and their antimicrobial studies

Reaction of 1-oxo-1,2,3,4-tetrahydrocarbazoles 1a-e with hydrazine hydrate in absolute ethanol afforded N,N'-bis-carbazolylazine derivatives 2a-e. Treatment of compounds 1a-e with hydroxylamine hydrochloride in ethanol with a catalytic amount of pyridine resulted in the formation of 1-hydroxyimino-1,2,3,4-tetrahydrocarbazoles 3a-e. Reduction of 3 with hydrazine hydrate in the presence of palladized carbon afforded N,N'-carbazolyl hydrazine derivatives 4a-e. The newly formed compounds were characterized by IR, 1H NMR, mass spectra and by elemental analysis. All compounds proved to have great potentialities as antibacterial and antifungal agents due to the presence of the azine or the hydrazine group. Particularly, the chloro substituted derivatives 2e and 4e showed excellent antibacterial and antifungal activity.