Synthesis and application of chitosan supported vanadium oxo in the synthesis of 1,4-dihydropyridines and 2,4,6-triarylpyridines via anomeric based oxidation

Abstract

1,4-Dihydropyridines and 2,4,6-triarylpyridines were synthesized via anomeric based oxidation using chitosan supported vanadium oxo.

One‐Pot and Solvent‐Free Hantzsch Condensation Reaction Catalyzed by Mononuclear Dy(III) Complex

“…The first step is the activation of ethyl acetoacetate by catalyst 1 , which leads to the formation of Knoevenagel product ( I ). Simultaneously, the activated ethyl acetoacetate reacts with ammonia (generated from ammonium acetate) and forms an ester enamine intermediate ( II ) . Then the two key intermediates I and II undergo an intermolecular Michael addition to produce III .…”

Four-Component Fusion Protocol with NiO/ZrO2 as a Robust Recyclable Catalyst for Novel 1,4-Dihydropyridines

“…Due to the vast biological and synthetic importance of 1,4-DHP derivatives, several protocols have been reported via a one-pot strategy and employing different catalysts like nano-tungsten trioxide-supported sulfonic acid (n-WSA), 24 sulfated boric acid nanoparticles, 25 chitosan-supported copper(II) sulfate, 26 Fe 3 O 4 @SiO 2 @Si-(CH 2 ) 3 @melamine-picolineimine@SO 3 H, 27 sulfated polyborate, 28 Fe 3 O 4 /KCC-1/BPAT, 29 chitosan-supported vanadium oxo, 30 magnetic guanidinylated chitosan, 31 nano-ZrO 2 -SO 3 H (n-ZrSA), 32 Gd(OTf) 3 , 33 nicotinic acid, 34 γ-Fe 2 O 3 /Cu@cellulose, 35 SBA-15@AMPD-Co, 36 sulfamic acid, 19 Fe 3 O 4 @D-NH-(CH 2 ) 4 -SO 3 H, 37 Cu-adenine@boehmite, 38 hydromagnesite, 39 Cu(OTf) 2 , 40 ascorbic acid, 41 NS-C 4 (DABCO-SO 3 H) 2 ·4Cl, 42 CBr 4 , 43 and aminated CNTs. 14 Many of these methods either suffer from usage of reflux conditions, lower yields, or long reaction times.…”

Sulfonated Caspian Sea Sand: A Promising Heterogeneous Solid Acid Catalyst in Comparison with –SO3H Functionalized NiFe2O4@SiO2@KIT‐6

“…Although the classical Hantszch method is a straightforward route for preparation of 1,4‐dihydropyridines from β‐ketoesters, an aldehyde and ammonia, there are several modifications for this method to facilitate the synthesis of other substituted 1,4‐dihydropyridines. These include the use of enamines in presence of either aldehydes or ketones, reduction of pyridine and pyridinium salts in presence of metal‐hydrides, condensation of α,β‐unsaturated carbonyl compounds with active‐methylene compounds and amines, and multi component condensation of 1,3‐dicarbonyl compounds with aldehydes and NH 4 OAc, in presence of a wide range of homogeneous and heterogeneous catalysts . Also, 3,4‐dihydropyrimidin‐2( 1H )‐ones as analogs of 1,4‐dihydropyridines, play significant biological roles such as antibacterial, antioxidant, anti HIV and anticancer.…”