Synthesis and Characterization of 1-Substituted Isatin Derivatives by Mannich Reaction

Isatin is an indole 2,3dione derivative. Isatin and substituted isatin derivatives were responsible for broad spectrum of biological activities. Among these, cytotoxic and anti neoplastic were mostly reported. 1-substituted isatin derivatives were prepared by Mannich reaction. A series of 1-substituted isatin derivatives (S1 to S6) were synthesized by reaction of various aldehydes with aromatic secondary amines by stirring method. Their chemical structure were characterized by TLC and confirmed by IR, ¹H NMR, MASS spectral analyses. Biological evaluations such as antioxidant, antineoplastic and anti bacterial activities were also carried out. The anti oxidantactivity was studied by hydrogen peroxide method using ascorbic acid as standard which produces 50% of inhibition. Anti neoplastic activity was studied by MTT assay method in cervical cancer cell line(HeLa). Anti bacterial activity was studied by agar cup plate method and its zone of inhibition was measured using amikacin as standard. Among the series of compound (S1 to S6) tested, S3{1-[(4-methoxyphenyl)piperazinylmethyl]1-Hindole2,3dione}, S4{1-diphenylaminophenyl) ylmethyl] 1-Hindole2,3dione} and S5 {1-[(1H-benzimidazole)ylmethyl]1-H indole2,3 dione} showed favourable activity against Salmonella typhi. Compounds S4{1-[(diphenylaminophenyl)ylmethyl]1-Hindole2,3dione} showed favourable activity against Staph. aureus. Three compounds S2{1-[(4-dimethyl amino)piperazinyl methyl]1-H indole 2,3 dione}, S4{1-[(diphenylaminophenyl)yl methyl]1-H indole 2,3 dione} and S5{1-[(1H-benzimidazole)yl methyl]1-H indole2,3 dione} showed favourable anti oxidant property and S5{1-[(1H-benzimidazole)yl methyl]1-H indole2,3 dione} compound showed favourable anti neoplastic activity when compared with standard.