Synthesis and antinociceptive activity of some substituted-{5-[2-(1,2,3,4-tetrahydrocarbazol-9-yl)ethyl]tetrazol-1-yl}alkanones

Twelve different derivatives of substituted-{5-[2-(1,2,3,4-tetrahydrocarbazol-9-yl)ethyl]tetrazol-1-yl}alkanones (3-14) were synthesized by reacting 9-[2-(1H-tetrazol-5-yl)-ethyl]-2,3,4,9-tetrahydro-1H-carbazole (2) and the appropriate acid chlorides. 9-[2-(1H-tetrazol-5-yl) ethyl]-2,3,4,9-tetrahydro-1H-carbazole (2) was synthesized by reacting 3-(1,2,3,4-tetrahydrocarbazol-9-yl) propionitrile (1) with sodium azide and ammonium chloride. The chemical structures were confirmed by means of IR, 1H-NMR, mass spectra and elemental analysis. The compounds were screened for antinociceptive activity by acetic acid induced writhing method and hot plate method. 1-Phenyl-2-{5-[2-(1,2,3,4-tetrahydrocarbazol-9-yl)ethyl]tetrazol-1-yl}ethanone (13) was found to be the most active compound of the series.