Synthesis of 3,3′- Di-indolylmethanes under mild conditions by Microwave Irradiation Mediated Reactions of Indoles with C, N-Diaryl nitrones

Abstract

3,3′-Di-indolylmethane derivatives are important biologically active compounds possessing anti-cancer properties. Hence, development of synthetic routes to these are of great interest to organic chemists. In the present communication we report a high-yield method using mild reaction conditions and short reaction times for the synthesis of 3,3′-di-indolylmethane derivatives. The method involved reactions of indole and substituted indoles with C,N-disubstituted nitrones in the presence of acid catalysts, with the utilisation of microwave irradiation techniques. Reactions of indole, 2-methyl indole and 2-phenyl indole were performed with ten different C,N-diaryl- and C-aryl-N-methyl- nitrones in dichloromethane solution in the absence and presence of acid catalysts, viz. ytterbium triflate, p-toluene sulphonic acid and Montmorillonite clay K-10. Reaction times varied between 2 to 18 minutes. In general, yields of the catalysed reactions were above 75%. The products were characterised spectroscopically, including two-dimensional NMR studies. The microwave irradiation technique enhanced reaction rates by a significant amount. Ytterbium triflate proved to be the best catalyst, giving clean reactions, without formation of by-products, in high yields. The structure and conformation of 3,3′-di-indolyl-phenylmethane were computed. GRAPHICAL ABSTRACT: We report a high-yield method using mild reaction conditions and short reaction times for the synthesis of 3,3′-di-indolylmethane derivatives, involving reactions of indole and substituted indoles with C, N-disubstituted nitrones in the presence of acid catalysts using microwave irradiation.

To Synthesis and Characterization of Novel 1,3,4-Oxadiazinoindole Derivatives for the Purpose of Antidepressant Activity

“…• IR (KBr)ν(cm - ( [1,3,4]Oxadiazino [6,5-b]indol-3-yl)methanamine(5a) (b, DMSO impurity), 1.9 (m, 1H, CH of methine), 1.14-1.23 (m, 2H, C-CH 2 -C of methylene), 1.08 (d, 3H, CH of β 1 -methyl), and 0.89 (q, 3H, CH of β 2 -methyl). • MS (ESI) m/z (rel.…”

“…Indole, an electronrich nitrogen heterocycles, have allured chemists because of their fascinating chemistry and diversity in their reactions. 4 Both biologically active moieties (indole ring and Oxadiazole) are combined for novel 1,3,4-oxadiazinoindole derivatives, which could be more potent and safer drugs for central nervous system (CNS) disorders 5 such as depression, convulsion, etc. On the basis of the above paragraph.…”

“…NMR (δ ppm, DMSO-d6): 10.2-10.87 (b, 2H, -NH), 7.37-6.8 (m, 4H, ArH), 3.787 (t, 2H, -CH2-), 2.492 and 3.33 (b, DMSO impurity).• MS (ESI) m/z (rel. abundance): 200.07 (100.0%), 201.07 (10.8%)1-([1,3,4]Oxadiazino[6,5-b] indol-3-yl) -2-(1H-imidazol-4yl)ethanamine(5b) • IR (KBr)ν(cm -1 ): 3626 (N-H amine str), 3294 (N-H ar str), 3074 (C-H ar str), 2852 (aliphatic C-H str), 1620(C=N str), 1479(C= C ar str), 1394 (C-N str), 1197 (C-O-C str). • UV (DMSO) l max : 266nm • NMR (δ ppm, DMSO-d 6 ): 13.993 (b, 1H, secondary amine), 10.89-10.234 (b, 2H, -NH 2 ), 9.001(s, 1H, C-CH-N of imidazole), 8.649 (b, 1H, N-CH-N), 7.50-6.959 (m, 4H, ArH), 4.16 (s, 1H a , of methylene), 4.066 (s, 1H b , of methylene), 2.5 and 3.33 (b, DMSO impurity) and 1.149 (m, 1H, C-CH-C of methane).…”

Novel Synthesis, Physicochemical Characterization of 1,3,4-Oxadiazinoindole Derivatives for the Purpose of Antidepressant Activity

“…Indoles, which are electron-rich nitrogen heterocyclic, have allured chemists because of their fascinating chemistry and diversity in their reactions. 6 Indole ring and oxadiazole nucleus (both biologically active moieties) are combined to synthesize novel 1,3,4-oxadiazinoindole moiety-containing compounds showing more potent and safer effects for CNS disorders such as depression and convulsion etc. On the basis of the above principle, a series of 1,3,4-oxadizinoindole moiety-containing compounds has been synthesized, characterized, and evaluated for its antidepressant activity.…”