Synthesis, characterization and antitubercular activities of heterocyclic selenosemicarbazones.

Reaction of cyclohexanoneselenosemicarbazone with aldehydes and ketones containing heterocyclic rings (2-oxindole, 6-cholro-2-oxindole, 3-methyl-2-oxindole, isatin, 1-methyl isatin, furfural, pyrrole-2-carboxldehyde) in ethanol yielded, respective, selenosemicarbazones {2-oxindoleselenosemicarbazone (2-HOxsesc,H1L), 6-chloro-2-oxindole selenosemicarbazone (6-ClHOxsesc, H2L), 3-methyl-2-oxindole selenosemicarbazone (3-MeHOxses, H3L), isatinselenosemicarbazone (HIstsesc, H4L), 1-methyl isatinselenosemicarbazone (1-MeHIstsesc, H5L), 2-thiopheneselenosemicarbazone (2-Hthiosesc, H6L), 2-furfuralselenosemicarbazone (2-Hfursesc, H7L) and 2-pyrrole selenosemicarbazone (2-Hpysesc, H8L)}. However the similar reaction with aldehyde containing single aromatic ring (3-chlorobenzaldehyde and 4-chlorobenzaldehyde) formed 1, 2-bis(3-chlorobenzylidiene) hydrazine (A) and 1, 2-bis(4-chlorobenzylidiene) hydrazine (B) rather than selenosemicarbazone. All the synthesized compounds were characterized using IR and NMR (1H, 13C) spectroscopy. Structure of A and B were confirmed by single crystal X-ray crystallography. The synthesized selenosemicarbazones were tested for their anti-tubercular activities and H1L, H3L, H5L and H6L are found to exhibit excellent anti-TB activity. The experimental data will give an opportunity to examine their anti-tubercular activities and identify the lead molecule.