Expedient Synthesis of Indolo[2,3-]quinolines, Chromeno[2,3-]indoles, and 3-Alkenyl-oxindoles from 3,3'-Diindolylmethanes and Evaluation of Their Antibiotic Activity against Methicillin-Resistant .

Easily accessible 3,3'-diindolylmethanes (DIMs) were utilized to generate a focused library of indolo[2,3-]quinolines (), chromeno[2,3-]indoles (), and 3-alkenyl-oxindoles () under 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-mediated oxidative conditions. DIMs with ortho-NHTosyl (NHTs) phenyl group afforded indolo[2,3-]quinolines (), whereas DIMs with ortho-hydroxy phenyl groups yielded chromeno[2,3-]indoles () and 3-alkenyl-oxindoles (). The mild conditions and excellent yields of the products make this method a good choice to access a diverse library of bioactive molecules from a common starting material. Two optimized compounds and displayed excellent activity against clinical isolates of methicillin-resistant (MRSA). Compound showed the minimum inhibitory concentration values in the concentration between 1 and 4 μg/mL, whereas compound revealed the values of 1-2 μg/mL. Furthermore, both the compounds were highly bactericidal and capable to kill the MRSA completely within 360 min. Collectively, the results suggested that both compounds and possess enormous potential to be developed as anti-MRSA agents.