Brønsted Acidic Ionic Liquid Catalyzed Three-Component Friedel–Crafts Reaction for the Synthesis of Unsymmetrical Triarylmethanes

Abstract

convenient and practical methodology for the synthesis of unsymmetrical triarylmethanes was demonstrated through a one-pot three-component double Friedel-Craft reaction between various aliphatic aromatic and heteroaromatic aldehydes, N,N-dialkylanilines and indoles using Bronsted acidic ionic liquid as catalyst. This method was successfully performed under metal- and solvent-free conditions at 80oC, affording the corresponding unsymmetrical triarylmethane products in moderate to high yields with a broad range of substrates. In addition, the mechanistic proposal of this methodology was studied by using quantitative NMR analysis (qNMR).

B(OH)3‐Catalyzed Dual Friedel‐Crafts Type Reaction of Anilines and Aldehydes to Access Di‐ or Triarylmethanes (TRAMs)

“…In recent times, Afonso and co‐workers have described the synthesis of TRAMs by using Yb(OTf) 3 ‐catalyzed reaction conditions at high pressure (Scheme 1a) [3a] . In 2021, Sirion group reported a BAILs (Brønsted Acidic Ionic Liquids)‐catalyzed approach towards the synthesis of aniline and phenol‐based triarylmethanes (Scheme 1b) [14a–b] . Moreover, Pan and co‐workers have designed an AgOTf‐catalyzed Friedel‐Crafts reaction of anilines and glyoxylates to access diarylmethanes (Scheme 1c) [14c] …”

Furanyl bis(indolyl)methane as a palladium ion-selective chromogenic agent

“…A decrease in the reaction temperature to −40 °C slightly improved the yield of 5 to 71% (entry 3). During the nucleophilic addition of the two indoles to the formyl group of 1 , H 2 O was generated via the formation of iminium intermediate B 20 (Fig. 2A).…”

Chiral spirocyclic phosphoric acid-catalyzed enantioselective synthesis of heterotriarylmethanes bearing an amino acid moiety

“…Triarylmethanes are incredibly interesting, with incredible potential for various applications in fields including medicinal chemistry, materials science and organic synthesis. 1 Among these applications, several triarylmethanes have emerged with promising importance in organic functional materials, 2 dyes 3 and biologically active compounds with different pharmacological activities such as anti-tuberculosis, 4 antibacterial, 5 anti-viral, anti-cancer 6 and cytotoxic activities against MCF-7 cells ( Fig. 1 ).…”