One-pot synthesis of 4,5-disubstituted 1,2,3-(NH)-triazoles by silica supported-zinc bromide in the aerobic condition

An efficient one-pot cross-coupling/1,3-dipolar cycloaddition sequence was developed for a convenient synthesis of 4,5-disubstituted-1,2,3-(NH)-triazoles, starting from various acid chlorides, terminal alkynes and sodium azide in the presence of silica supported-zinc bromide under aerobic conditions.     

Regioselective Syntheses of 1-Aryl-substituted-5H-[1,3]thiazolo[3,2-a]quinazoline-5-ones During Sonogashira Coupling

Abstract

Reaction of 2-mercaptopropargylquinazoline-4-one with various aryliodides catalyzed by Pd–Cu leads to the regioselective formation of 1-arylsubstituted-5H-[1,3]thiazolo-[3,2-a]quinazoline-5-ones.

GRAPHICAL ABSTRACT      

Pd-Cu–Mediated Synthesis of 2-Substituted Imidazo[1,2-α]pyridines in Water

The reaction of 2-amino-1-(2-propynyl)pyridinium bromide with various iodobenzenes, catalyzed by Pd-Cu, in the presence of sodium lauryl sulfate as the surfactant and cesium carbonate as the base, in water, leads to the formation of 2-substituted imidazo[1,2-α]pyridines.     

Synthesis of 1-aryl-substituted-4-chloroimidazo[1,2-a]quinoxalines catalyzed by PdCl2 in water

The reaction of 2-chloro-3-propargylaminoquinoxaline with various aryl iodides and bromides catalyzed by Pd–Cu in the presence of potassium carbonate as the base in water leads to the one-pot formation of 1-aryl-substituted-4-chloroimidazo[1,2-a]quinoxalines in moderate-to-high yields.     

Rapid,green, and catalyst-free one-pot three-component syntheses of 5-substituted 1<Emphasis Type="Italic">H</Emphasis>-tetrazoles in magnetized water

The catalyst-free multi-component reactions of aldehydes, malononitrile, and sodium azide at a relatively low temperature in magnetized water provided 5-substituted 1H-tetrazoles in high-to-excellent yields. This method offers the advantages of short reaction times, low costs, quantitative reaction yields, simple work-up, green, and no need for any organic solvent.     

A catalyst-free and green method for synthesis of 9-substituted-9H-diuracilopyrans in magnetized water: experimental aspects and molecular dynamics simulation

Research on Chemical Intermediates - The reactions of aldehydes and barbituric acid at low temperatures in magnetized water, as a green-promoting medium, provides 9-substituted-9H-diuracilopyrans...     

Sodium 4-amino-5-hydroxy-7-sulfonaphthalene-2-sulfonate an efficient ligand for click reaction in water: Synthesis of 1,2,3-triazole pharmacophore linked-quinazolinone scaffold

Water soluble sodium 4-amino-5-hydroxy-7-sulfonaphthalene-2-sulfonate ligand was used successfully for the preparation of 1,2,3-triazoles pharmacophore linked-quinazolinone scaffold. The reaction of ethyl 4-oxo-3,4-dihydroquinazoline-2-carboxylate and related amide compounds with propargyl bromide afforded ethyl 4-oxo-3-(prop-2-yn-1-yl)-3,4-dihydroquinazoline-2-carboxylate and its amide derivatives. The reaction of propargylated compounds with azides catalyzed by copper (II) salt, in the presence of Sodium 4-amino-5-hydroxy-7-sulfonaphthalene-2-sulfonate as a ligand in water produced novel 1,2,3-triazole pharmacophore linked-quinazolinone-4-one scaffold with high-to-excellent yields. The ligand assisted in the click reaction and reduced loading of copper salt to 2 mol%. Simplicity, short reaction times, use of water as green solvent, and low catalyst loading are the main advantages of this procedure.     

Practical and efficient synthesis of tetrahydrobenzo[<Emphasis Type="Italic">b</Emphasis>]pyran using caffeine supported on silica as an ionic liquid solid acid catalyst

The new catalyst silica-caffeine hydrogen sulfate [SiO₂-caff.]HSO₄ was conveniently prepared from commercially available 3-chloropropyltriethoxysilane via immobilization on silica followed by reaction with caffeine. The catalyst prepared was then characterized by the FT-IR spectroscopy, TGA, EDX, and SEM techniques. It was found that this heterogeneous catalyst was a highly efficient one for the synthesis of tetrahydrobenzo[b]pyrans in good-to-high yields, and could be recovered by a simple filtration of the reaction solution and reused for five consecutive runs. The attractive features of this method are simple procedure, clean reaction, easy work-up, use of a reusable catalyst, and performing a multi-component reaction.