New N-Mannich bases obtained from isatin and piperazine derivatives: the synthesis and evaluation of antimicrobial activity

A Mannich reaction of isatin with monosubstituted piperazines in the presence of aqueous formaldehyde was used to synthesize new, as well as two previously described derivatives of 1-piperazinomethylisatins, which were further converted to isoindigo derivatives. The antimicrobial activity of the obtained heterocycles was evaluated.