An effective green and ecofriendly catalyst for synthesis of bis(indolyl)methanes as promising antimicrobial agents

Abstract

An effective and suitable meglumine‐catalyzed high‐yielding process was considered and engaged for the synthesis of new bis(indolyl)methanes at ambient temperature under aqueous conditions. The catalytic reaction proceeds very smoothly. Clean reaction, ease of product isolation/purification, easily available reactant and ecofriendly reaction conditions are the notable advantages of the present methodology. All the title compounds were characterized by IR, 1H, 13C NMR, and mass spectra. All the synthesized compounds were tested for antimicrobial activity, and the results indicated that most of the synthesized compounds exhibited excellent activity against the tested microorganisms. In this new series, compound 3l, having nitro substituent on the aromatic ring, showed exceptional potent inhibitory activity against Pseudomonas aeruginosa and Penicillium chrysogenum.

A Simple Environmentally Friendly Method for the Synthesis of Hydroxyisoxazolidine Derivatives

“…Today it is necessary to take into account the ecological aspect of reaction, especially in the synthesis of heterocyclic rings. [10][11][12][13][14][15][16] For the hydroxyisoxazolidine derivatives the "green approach" is often skipped. The most common reagents are alkali hydroxides, metal complexes and toxic organic solvents, such as toluene.…”

Humic acid: A Biodegradable Organocatalyst for Solvent‐free Synthesis of Bis(indolyl)methanes, Bis(pyrazolyl)methanes, Bis‐coumarins and Bis‐lawsones

“… [20] The widely used protocol to design this important molecule is very straightforward and it can easily obtained by the reaction between aldehydes and indole following the Friedel‐Craft alkylation type pathway. A few protocols are reported in literature using various catalyst and solvent such as enzymes, [21] meglumine, [22] thiamine hydrochloride, [23] graphene oxide, [24] ethyl lactate, [25] sulphated polyborate, [26] Lewis acids, [27–32] Brønsted acids, [33] heteropoly acids, [34–36] solid acids, [37–42] ionic liquids, [43] metal complexes, [44–46] 4‐sulfophthalic acid [47] and Iodine/tert‐Butyl Hydroperoxide [48] . Recently, a number of methodologies have been developed in this field [49–68] .…”

“…[48] Recently, a number of methodologies have been developed in this field. [49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] A generalize scheme for the different processes so far reported in literature are drawn in Scheme 1. But some of these protocols have many drawbacks like use of toxic metal salts or catalytic systems with expensive reagents, photosensitive catalysts, high catalyst loadings, high temperatures, chromatographic purifications, costly catalyst as well as solvent, time consuming during preparation of catalyst, harsh reaction conditions and hazardous solvent.…”

A simple and efficient preparation of bis(indolyl)methanes catalyzed by HCl/silica gel under solvent-free conditions

“…[1][2][3][4][5] Among the various indoles, bis(indolyl)methanes (BIMs) are valuable and ubiquitous in numerous natural resources and synthetic compounds. BIMs exhibit a variety of biological properties such as anti-bacterial, [6][7][8][9] anti-oxidative, 10 cytotoxic, 11 anti-tumor, 12 and anti-cancer. [13][14][15][16][17] Some selected biologically active bis(indolyl)methanes (BIMs) are shown in Figure 1.…”