Synthesis of bis(indolyl)methanes using molten N-butylpyridinium bromide

Abstract

A simple and rapid protocol has been developed for the synthesis of bis(indolyl)methane compounds in excellent yields using molten N-butyl-pyridinium bromide as a solvent and a working catalyst for the reaction. Synthesis of bis(indolyl)methane compounds were accomplished at moderate experimental conditions of temperature and ambient pressure, also involving an electrophilic substitution reaction of indoles with several aromatic aldehydes. The derivatives were confirmed with mass and other usual spectroscopic techniques. A discussion on plausible mechanism for the reaction is also presented.

Benzophenone Oxime Tosylate as the Photoacid Generator for the Friedel–Crafts Arylation of Aldehydes With Indoles

“…Additional references cited within the Supporting Information . 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 .…”

“…The Friedel–Crafts coupling reaction is a powerful strategy for aromatic functionalization [ 7 , 8 , 9 ], and has proven particularly effective for the construction of diarylmethane derivatives [ 10 ]. Traditional protocols, however, often rely on Lewis or Brønsted acids, requiring high temperatures or toxic reagents—conditions poorly implemented to pharmaceutical applications [ 11 , 12 , 13 , 14 , 15 , 16 ]. To address these challenges, sustainable methodologies have been introduced, including the use of green solvents, solvent‐free conditions, microwave chemistry, sonochemistry [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], organocatalysis [ 25 ], and electrochemistry [ 26 ].…”

“…The Friedel–Crafts coupling reaction is a powerful strategy for aromatic functionalization [7–9], and has proven particularly effective for the construction of diarylmethane derivatives [10]. Traditional protocols, however, often rely on Lewis or Brønsted acids, requiring high temperatures or toxic reagents—conditions poorly implemented to pharmaceutical applications [11–16]. To address these challenges, sustainable methodologies have been introduced, including the use of green solvents, solvent‐free conditions, microwave chemistry, sonochemistry [17–24], organocatalysis [25], and electrochemistry [26].…”

Recent Advancements in Typical Friedel–Crafts Alkylation Reactions Focused on Targeting Arene Nucleophiles

“…[100][101][102][103][104][105][106] An astonishing range of synthetic methods have been utilized to produce bisindolylmethanes (BIMs), which are molecules of interest, the most widely recognized of which is the Friedel-Crafts coupling reaction between aldehydes and indoles. [107][108][109][110][111][112][113] In 2019, Badillo and co-workers reported a highly efficient C-C bond formation strategy using a visible-light-induced thiourea photoacid catalyst (Scheme 19). 114 Photoirradiation of indoles and aldehydes and isatins catalyzed by Schreiner's thiourea [(N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea] (9) resulted in double FC arylation to give triarylmethanes and 3,3′-diarylindolin-2-ones, respectively.…”

Unprecedented exploration of ionic liquids as additives which astonishes the thermal stability of PVC formulations

“…ILs are supposed to be considered as supramolecular materials and provide a broad spectrum of applications, such as green medium for organic reactions, electrolytes for solar and fuel cells, heat transfer fluids in nuclear reactors, in dissolution of cellulose, etc. [6][7][8]. The versatility of these molecules is attributed to their exceptional structural behaviour in vapour and solution phases [9][10][11].…”