Retracted Article: An efficient one pot three-component synthesis of 2,4,6-triarylpyridines using triflimide as a metal-free catalyst under solvent-free conditions

Abstract

A simple and efficient protocol developed for one pot three-component synthesis of 2,4,6-triarylpyridines from aromatic aldehydes, substituted acetophenones and ammonium acetate using the versatile super Brønsted acid triflimide (HNTf 2 ) as an effective catalyst is described. The reactions proceed well in the presence of 1 mol% of HNTf 2 at 80 C under solvent-free conditions and provide the corresponding triarylpyridines in good to excellent yields. The method reported has several advantages such as a metalfree and commercially available catalyst, mild reaction conditions and lower loading of catalyst.

Transition‐Metal‐Free Synthesis of N‐Heterocyclic Compounds via Multi‐Component Reactions

“…Initially, the reaction between 4-hydroxycoumarin ). [107] The reaction was performed by reacting aromatic aldehydes 1, substituted acetophenones 18 and ammonium acetate in presence of a Brønsted acid (HNTf 2 ) at 80 °C under solvent-free conditions. Initially, the aldol condensation reaction between aromatic aldehyde 1 and substituted acetophenone 18 in presence of HNTf 2 formed 1,3-diaryl-2-propen-1-one 472 which further undergoes Michael addition with substituted acetophenone formed intermediate 473.…”

“…reported a triflimide (HNTf 2 ) catalyzed one‐pot three‐component reaction for the synthesis of pyridine derivatives 471 (Scheme 87). [107] The reaction was performed by reacting aromatic aldehydes 1 , substituted acetophenones 18 and ammonium acetate in presence of a Brønsted acid (HNTf 2 ) at 80 °C under solvent‐free conditions.…”

[3 + 2 + 1] Pyridine Skeleton Synthesis Using Acetonitrile as C4N1 Units and Solvent

“…Yield: 61% (M = 385.05, 23.5 mg, EA/PE = 1:8). 43 1 H NMR (600 MHz, CDCl 3 ) δ 8.22−8.18 (m, 4H), 7.88 (t, J = 1.7 Hz, 1H), 7.83 (s, 2H), 7.66 (d, J = 7.7 Hz, 1H), 7.60 (dd, J = 8.0, 0.9 Hz, 1H), 7.52 (t, J = 7.5 Hz, 4H), 7.45 (t, J = 7.3 Hz, 2H), 7.39 (t, J = 7.8 Hz, 1H); 13 4-(2,6-Diphenylpyridin-4-yl)benzonitrile 3ia. Yield: 54% (M = 332.13,17.8 mg, EA/PE = 1:5).…”

TMSOTf-mediated Kröhnke pyridine synthesis using HMDS as the nitrogen source under microwave irradiation

“…Most Chichibabin-type TAP synthetic approaches start from acetophenones with benzaldehydes in the presence of ammonium acetate and are catalyzed by a variety of catalysts. 15,16,19 Among these, the synthetic routes for the synthesis of symmetrical TAPs not only involve the Chichibabin reaction but also methods with fixed nitrogen on starting materials such as benzylamines 20 or oxime acetates. 21 For the preparation of symmetrical TAPs, chalcones are usually applied as the starting material or paired with condensable synthons from various ammonia sources.…”