Synthesis of some new tetrahydrocarbazole derivatives as possible antibacterial agents

Tetrahydrocarbazoleacetylhydrazide (2) and its thiosemicarbazide (3) have been synthesized by condensing N-(carbethoxymethyl)-tetrahydrocarbazole with hydrazine hydrate and phenylisothiocyanate respectively. Cyclization of thiosemicarbazide (3) with conc. H2SO4, NaOH, I-2/KI afforded 1,3,4-thiadiazole (4), 1,2,4-triazole (6) and 1,3,4-oxadiazole (6) derivatives. Condensation of 3 with chloroacetic acid and malonic acid yielded 7 and 8 respectively. All these compounds have been tested for their antibacterial activity. Structural assignments of these compounds have been made on the basis of elemental analyses, IR and PMR spectral data.