Synthesis, characterization and antimicrobial activity of some new N-substituted-oxindole derivatives

The aim of this research is the synthesis of new heterocyclic derivatives containing 4-oxo-thiazolidines, tetrazol or oxoazetidin ring from oxindole. To obtain these derivatives, oxindole [1] was chosen as the starting material to synthesize -chloro-N-oxindole acetamide [2] which was prepared by two methods. The first method by direct condensation of oxindole with chloroacetylchloride in presence of triethylamine and absolute ethanol as solvent. The second method by reaction of chloroacetylchloride with sodium salt of oxindole. Treatment of -chloro-N-oxindole acetamide [2] with hydrazine hydrate gave -hydrazino-N-(oxindole)acetamide [3] which is the desired chiron. Compound [3] was reacted with different aromatic aldehydes which gave the corresponding Schiff base derivatives [4a-d]. 4-Oxothiazolidines [5a-d], tetrazole [6a-d] and 2-oxoazetidine [7a-d], were obtained from cyclization of Schiff base derivatives [4a-d] using mercaptoacetic acid, sodium azide and chloroacetylchloride respectively. The synthesized compounds were characterized by spectral methods FTIR, 1H-NMR,and 13C-NMR . Biological activities of prepared compounds were tested against three types of bacteria, which showed promising antibacterial activity of 4-oxothiazolidines [5a, b] and tetrazole [6b].