Syntheses and antimicrobial activities of five-membered ring heterocycles coupled to indole moieties.

Indole-substituted oxazolidinones, oxazolones, pyrrolidinone, imidazolidinone and imidazolones were synthesized. Their inhibitory potencies towards protein kinase C and protein kinase A were determined and their in vitro activities against Streptomyces chartreusis, Streptomyces griseus, Bacillus cereus, Candida albicans and Escherichia coli were examined. The inhibition of Streptomyces sporulation observed for some of them could not be linked to in vitro protein kinase C inhibition. All proved inactive against C. albicans but three of them exhibited a marked activity towards E. coli. This effect extends to other Gram-negative bacteria.