Organocatalyzed oxidative N-annulation for diverse and polyfunctionalized pyridines

Abstract

This paper describes a novel strategy for the synthesis of 2,3,4-trisubstituted pyridines via organocatalyzed three-component reactions. A variety of pyridine derivatives are synthesized from readily available ketones with α,β-unsaturated aldehydes and ammonium acetate under a mild organocatalyst. This protocol leads to rapid N-annulation through C-C and C-N bond formation in a single operation, thereby avoiding the preparation of essential functional groups, such as oximes, imines, or azides. The synthesized compounds are used for the evaluation of antibacterial activities and as fluorescence sensors for Cu(2+) ions.

BF3⋅OEt2‐Promoted Annulation for Substituted 2‐Arylpyridines as Potent UV Filters and Antibacterial Agents

“…Although a number of approaches for the synthesis of 2‐arylpyridines have been developed, a more facile and efficient one‐pot synthetic protocol is still desirable. Recently, we reported an organocatalyzed oxidative N ‐annulation for the synthesis of pyridines from ketones with α,β ‐unsaturated aldehydes and ammonium acetate (method a, Scheme ) . We also described a catalyst‐ and solvent‐free thermal multicomponent cascade of 4‐oxo‐4 H ‐chromene‐3‐ carbaldehydes with cyanoacetates and anilines for the synthesis of 2‐aminopyridines (method b, Scheme ) …”

α,β‐Unsaturated Aldehydes as C‐Building Blocks in the Synthesis of Pyridines, 1,4‐Dihydropyridines and 1,2‐Dihydropyridines

“…For instance, Lee et al. have developed of a facile, versatile and regioselective methodology for the synthesis of 2,3,4‐trisubstituted pyridines 29–31 via organocatalyzed reactions of readily available ketones 26–28 , α,β‐unsaturated aldehydes 25 and ammonium acetate NH 4 OAc (Scheme ) . The L ‐proline 11 displayed the best activity as an organocatalyst.…”

TD-DFT Calculations, NBO, NLO Analysis and Electronic Absorption Spectra of Some Novel Thiazolo[3,2-a]Pyridine Derivatives Bearing Anthracenyl Moiety

“…Table 5. Total static dipol moment (µ), the mean polarizability (˂α˃), the anisotropy of the polarizability (∆α), and the mean first-order hyperpolarizability (˂β˃), for the studied compounds (1)(2)(3)(4)…”

“…The novel structure may be used in designing new potent and less toxic antimicrobial agents. Nitrogen-containing heterocyclic compounds have a diverse range of biological and pharmacological properties [1][2][3][4]. Thiazolo [3,2a]pyridines, containing two fused heterocyclic rings, also; it's found in medicinal chemistry as they have an excellent biological activity with a wide range of applications, including antimicrobial [5], antiviral [6] antihypertensive [7], antihistaminic [8], neurotropic [9], anticonvulsant [10], antidepressant, sedative, analgesic [11,12] and anti-cancer activities.…”