Efficient green synthesis of 3,3-di(indolyl)indolin-2-ones using sulfonic acid functionalized nanoporous SBA-Pr-SO3H and study of their antimicrobial properties

SBA-Pr-SO3H with pore sizes of 6 nm was determined to be a green and effective solid acid catalyst in the reaction of isatins with indoles under mild reaction conditions for the production of a novel class of symmetrical 3,3-di(indolyl)indolin-2-ones with excellent yields. The antimicrobial activities of the synthesized compounds were tested. Antimicrobial tests demonstrated that the MIC value of compound 3e against B. subtilis was equal to that of Chloramphenicol.