Microwave Synthesis, Characterization, and Antimicrobial Activity of Some Novel Isatin Derivatives

Three series of isatin derivatives [3‐hydrazino, 3‐thiosemicarbazino, and 3‐imino carboxylic acid derivatives] were synthesized employing microwave irradiation. The prepared compounds were characterized by FT‐IR, NMR, elemental analysis, and X‐ray crystallography for derivatives 5b . The synthesized compounds were screened for antimicrobial activity against selected bacteria and fungi. The results revealed that the N ‐alkyl isatin derivatives were biologically active with different spectrums activity. Most of the 3‐hydrazino and 3‐thiosemicarbazino isatin derivatives were biologically inactive and generally the active derivatives showed weak to moderate activity mainly against Gram‐positive bacteria. The imino isatin carboxylic acid derivatives (2‐[4‐(1‐benzyl‐5‐bromo‐2‐oxoindolin‐3‐ylideneamino) phenyl]acetic acid, 5d ) showed promising activity against all tested Gram‐positive bacteria and against fungal pathogens.