Synthesis and pharmacological studies of some phthalimidoxy substituted spiro-thiazolidinone derivatives of isatin

Abstract

Novel spiro-isatin-thiazolidino-pyrazoline compounds containing alkoxyphthalimide moiety have been synthesized through a four step pathway starting from chalcone <b style="">1a-e</b>. Cyclization of these with hydrazine hydrate in absolute ethanol have yielded 1-acetyl-3-(4-aminophenyl)-5-(4-substituted phenyl)-2-pyrazoline <b style="">2a-e</b>. Acid catalyzed condensation of <b style="">2a-e</b> with isatin <b style="">3</b> has yielded 3-[4-{1-acetyl-5-(4-substituted phenyl)-2-pyrazoline-3-yl}phenylimino]indole-2-one<b style=""> 4a-e</b>. These Schiff bases on reaction with mercaptoacetic acid in presence of anhydrous ZnCl₂ gave their corresponding spiro-thiazolidinone derivatives <b style="">5a-e</b>. Subsequent treatment with bromoethoxyphthalimide yielded titled compounds 3'-{4-(1-acetyl-5-(4-substituted phenyl)-2-pyrazoline-3-yl)phenyl}-1-<i style="">N</i>-ethoxyphthalimido-4'<i style="">H</i>-spiro[indole-3,2'-[1,3]thiazolidene]-2,4'-1<i style="">H</i>-dione <b style="">6a-e</b>.