Acid-catalyzed tandem reaction for the synthesis of pyridine derivatives via CC/C(sp³)–N bond cleavage of enones and primary amines

Abstract

2,4,6-Trisubstituted pyridines can be generated from an acid-catalyzed tandem reaction via CC/C(sp3)–N bond cleavage of enones and primary amines.

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

“…Yield: 54% (M = 332.13,17.8 mg, EA/PE = 1:5). 44 1 H NMR (600 MHz, CDCl 3 ) δ 8.19 (d, J = 7.3 Hz, 2H), 7.87−7.78 (m, 6H), 7.53 (t, J = 7.5 Hz, 4H), 7.47 (t, J = 7.3 Hz, 2H); 13 C{ 1 H} NMR (151 MHz, CDCl 3 ) δ 158.0, 148.3, 143.6, 139.1, 132.9, 129.4, 128.8, 128.0, 127.2, 118.5, 116.9, 112.8.…”

Two C═C Bond Participation in Annulation to Pyridines Based on DMF as the Nonadjacent N and C Atom Donors

“…Notably, DMF provided an isolated N atom, instead of −CN and −NMe n ( n = 1, 2) groups, which were usually provided by DMF in other reactions. To the best of our knowledge, while some groups have developed the synthesis of pyridines by using one CC bond with other units, participation of two simple CC bonds in the synthesis of pyridines has not been reported. In addition, this is the first report that DMF devoted nonadjacent N and C atoms to the ring in an organic annulation reaction.…”

Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3‐Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses

“…In particular, cinnamic aldehyde derivatives find widespread application in food,[3a] cosmetic and perfume, agrochemical and pharmaceutical industry. As Michael systems α,β‐unsaturated ketones and aldehydes are valuable three‐carbon building blocks in syntheses of five‐, six‐ and seven‐membered nitrogen heterocycles, such as pyrazoles, quinolines, or pyridines . In addition, they have recently received considerable attention as substrates in organocatalysis …”