Int. J. Chem. Sci.: 7(2), 2009, 1185-1194 SYNTHESIS AND BIOLOGICAL EVALUATION OF SOME ETHOXYPHTHALIMIDE DERIVATIVES OF BENZO (g) INDAZOLES BHAWANA THADHANEY, DEVENDRA SAIN, AJIT JOSHI and G. L. TALESARA * Synthetic Organic Chemistry Laboratory, Department of Chemistry, M. L. Sukhadia University, UDAIPUR – 313001 (Raj.) INDIA ABSTRACT 1-Tetralone was reacted with various araldehydes (1a-d) to give their related arylidene derivatives (2a-d). [3-(4-Substituted phenyl)-3,3a,4,5-tetrahydro-2H-benzo[g]indazoles (3a-d) were obtained as the result of cyclocondensation reaction between (2a-d) and hydrazine hydrate. Subsequently compounds (3a-d) were converted to corresponding 2-N-ethoxyphtalimido-3,3a,4,5- tetrahydro-[3-(4-substituted phenyl)]- 2H-benzo[g]indazoles (5a-d) by the treatment with phthalimidoxyethyl bromide (4). Structures of synthesized compounds were confirmed by means of IR, 1 H NMR and mass spectral data. Final compounds were screened for antibacterial and antifungal activities. Key words : 1-Tetralone, Cyclocondensation, Phthalimidoxyethyl bromide, Indazoles, Antibacterial studies. INTRODUCTION α, β-Unsaturated ketones are versatile and convenient intermediates for the synthesis of a wide variety of heterocyclic compounds. The α,β-enone moiety of a molecule is a favourable unit for dipolar cycloaddition with numerous reagents providing heterocyclic compounds of different ring sizes with one or several heteroatoms. Their reactions with dinucleophiles usually result in the formation of polycyclic ring systems which may be the skeleton of important heterocyclic compounds. Among the α,β- unsaturated ketones, chalcones and their analogues are especially important starting materials or intermediates for the synthesis of naturally occurring flavonoids 1 and various nitrogen-containing heterocyclic compounds. For this reason, their syntheses have been * Author for correspondence; E-mail : gtalesara@yahoo.com