New novel derivatives of 3-chloro-6-(2,5-difluorobenzoyl)-8-(2-(4-substituted phenyl)-4-oxothiazolidin-3-yl)-1-((4- (trifluoromethyl)phenyl)amino)-1,6,7-triazaspiro[3.4]oct-7-ene-2,5-dione (10 a-f) were synthesized when 3-chloro-6-(2,5- difluorobenzoyl)-8-((4-substituted benzylidene) amino)-1-((4-(trifluoromethyl) phenyl)amino)-1,6,7-triazaspiro[3.4]oct-7-ene- 2,5-dione (9 a-f) and marcapto acetic acid were refluxed in dioxane in presence of anhydrous Zinc Chloride. The synthesis of 3- chloro-6-(2,5-difluorobenzoyl)-8-(5-(4-substituted phenyl)-1H-tetrazol-1-yl)-1-((4-(trifluoromethyl) phenyl) amino)-1,6,7- triazaspiro[3.4]oct-7-ene-2,5-dione(11 a-f) were synthesized by refluxing a mixture of 3-chloro-6-(2,5-difluorobenzoyl)-8-((4- substituted benzylidene)amino)-1-((4-(trifluoromethyl)phenyl)amino)-1,6,7-triazaspiro[3.4]oct-7-ene-2,5-dione (9 a-f), sodium azide and PCl5. The novel 3-chloro-8-(3-chloro-2-(4-substituted phenyl)-4-oxoazetidin-1-yl)-6-(2,5-difluoro benzoyl)- 1((4(trifluoromethyl)phenyl)amino)-1,6,7-triazaspiro[3.4]oct-7-ene-2,5-dione( 12a-f) were synthesized by refluxing a mixture of 3-chloro-6-(2,5-difluorobenzoyl)-8-((4-substituted benzylidene) amino)-1-((4-(trifluoromethyl) phenyl)amino)-1,6,7-triazaspiro [3.4]oct-7-ene-2,5-dione (9 a-f) and mono chloro acetyl chloride in di chloro methane. The newly synthesized compounds were characterized by IR, 1H-NMR, 13C-NMR, mass spectra & Elemental analysis. The newly synthesized compounds were screened for their Biological activity.