Infrared-assisted eco-friendly selective synthesis of diindolylmethanes

Indion Ina 225H resin as a novel, selective, recyclable, eco-benign heterogeneous catalyst for the synthesis of bis(indolyl)methanes

“…Vibrindole A (3w) is a metabolite of the marine bacterium Vibrio parahaemolyticus which exhibit antibacterial activity (5). In recent studies on cancer therapeutics, 4-(di(1H-indol-3-yl)methyl)benzene-1,2-diol (3x) served as a HIV-1 integrase inhibitor (77). The products mentioned in Table 3 were isolated without any column purification.…”

“…Literature enumerates various methods for synthesis of bis(indoloyl)methane using protic acids (9Á15), Lewis acids (16Á20), and inorganic compounds. However, most of the methods suffer from drawbacks like long reaction times of 4Á5 days (21), high catalyst loading and use of expensive catalysts (22Á27) or less easily available reagents (28,29), low selectivity (30), use of toxic solvents (31,32), tedious manipulations in the isolation of the pure products (33), unsatisfactory yields, or limited applicability only for aryl aldehydes (34). Furthermore, some of these methods require strictly anhydrous conditions (35Á38).…”

Synthesis of novel benzimidazole-diindolylmethane hybrid compounds within the green chemistry context

“…Its 13 C-NMR spectra showed 18 signals which corresponds to all magnetically inequivalent carbons. According to all of above, we think that our methodology to form compounds 3a-l has important green advantages over some previous mentioned synthetic methodologies for DIM derivatives, such as not use of solvent on reactions, compared with the use of dichloromethane 11,23,29,30,33,35 , chloroform 13,32 , acetonitrile 12,38 , ionic liquids 27,28,29 , not use of Broensted-Lowry and Lewis acid catalyst 11,12,13,23,25,26,30,32,33,34,37,39 , resins 31,35,36,38 , inert atmosphere 26 , and does not require long reaction times (7-10 h , with the use of microwave energy for the activation of reactions. In addition, to obtain benzimidazole compounds 4a-l we do not require any redox reagents, such as nitrobenzene 16 , sodium metabisulfite 17 , neither catalyst 16,18,22 or solvent.…”

“…In some cases, many byproducts were formed when the reactions were carried out in aqueous medium and under controlled conditions at pH values of 1.0, 1.5, 2.5 and 7.2, respectively. 24 In recent years, diindolylmethane synthesis has taken a greener direction, such as: using infrared energy in solvent-less conditions and in presence of a bentonitic clay, 25 with ultrasound energy and aminosulfonic acid as catalyst, 26 under microwave solvent-free irradiation with Lewis acid-catalysis, 27 in ionic liquids, [28][29][30] with SBA-15-supported poly [4-styrenesulfonyl(perfluorobutylsulfonyl)imide] as heterogeneous Broensted-Lowry acid catalyst, 31 using Montmorillonite K-10 clay, 32,33 with nickel nanoparticles as a reusable catalyst under solvent-free conditions, 34 employing ion exchange resins, 35,36 with eutectic salts, 37 synthesis mediated by Zeokarb-225, 38 and with zeolites, 14,39 amongst others.…”

Infrared Radiation Assisted Stokes’ Law Based Synthesis and Optical Characterization of ZnS Nanoparticles

“…Infrared-assisted ecofriendly green chemistry based methods have been employed in organic chemistry [26][27][28][29] but the infrared-assisted synthesis of inorganic nanoparticles has not been unveiled. Inspired from this, recently, we have synthesized IR assisted CdS nanoparticles by means of a kinetic approach using the well-known Stokes law without using any surfactant, capping agent, or stirring [3].…”