Potential antimicrobial agents--I: Structural modifications and antimicrobial activity of some isatin derivatives

New isatin-3-isonicotinylhydrazones, isatinazine and its Mannich bases and spiro (indoline-3, 2'-thiadiazoline)-2-one have been synthesized. These compounds have been screened for their antibacterial activity against the Gram-positive and Gram-negative bacteria.