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

Abstract

Easily accessible 3,3′-diindolylmethanes (DIMs) were utilized to generate a focused library of indolo[2,3-b]quinolines (2), chromeno[2,3-b]indoles (3), and 3-alkenyl-oxindoles (4) 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-b]quinolines (2), whereas DIMs with ortho-hydroxy phenyl groups yielded chromeno[2,3-b]indoles (3) and 3-alkenyl-oxindoles (4). 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 2a and 2n displayed excellent activity against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). Compound 2a showed the minimum inhibitory concentration values in the concentration between 1 and 4 μg/mL, whereas compound 2n 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 2a and 2n possess enormous potential to be developed as anti-MRSA agents.

A review on quinoline derivatives as anti-methicillin resistant Staphylococcus aureus (MRSA) agents

“…The synthesized compounds were tested in vitro for their antibacterial activity against a panel of Gram positive and negative bacterial strains including MRSA. The results indicated that compound 9 was found to be most potent anti-MRSA agent having MIC value 2 µg/mL against MRSA strain MRSA-ATCC33591 and 1 µg/mL against MRSA-R3545, MRSA-R3889 and MRSA-R3890 (Table 6) [25].…”

Synthesis of π‐Functional Molecules through Oxidation of Aromatic Amines

“…reported the synthesis of indolo[2,3-b]quinolines (7), chromeno[2, 3-b]indoles,a nd 3-alkenyl-oxindoles from3 ,3'-diindolylmethanes (6;S cheme 5). [21] Quinoline derivatives were afforded also from ortho-substituted anilines by double CÀHo xidative amination.A labugine tal.…”

Crystal structure and Hirshfeld analysis of 2-[bis(1-methyl-1H-indol-3-yl)methyl]benzoic acid

“…Bisindolyl methane and its derivatives are relatively easy to synthesize and show a broad spectrum of potential biological activities: for example, bis(indolyl)imidazole shows antiplasmodial activity towards plasmodium falciparum (Alvarado et al, 2013). Furthermore, they also have good potential as antibacterial (Imran et al, 2014;Challa et al, 2017), antileishmanial (Bharate et al, 2013), antitumor (Carbone et al, 2013), antiplatelet (Grumel et al, 2002) and anticancer (Guo et al, 2010;Jamsheena et al, 2016) agents. Oxidized bis(indolyl)methanes containing an acidic hydrogenbond-donor group and a basic hydrogen-bond-acceptor group can act as selective colorimetric sensors for either F À or HSO 4 À in an aprotic solvent (He et al, 2006).…”