Nanosilica periodic acid (nano-SPIA) is found to be a new, powerful, and reusable heterogeneous catalyst for the rapid synthesis of 2-naphtholazo dyes via diazotization of aromatic amines and followsazo coupling with 2-naphthol under solvent-free conditions at room temperature by grinding. Eco-friendly, heterogeneous reaction conditions, high stability of diazonium salt, simple experimental pro...

Present process of transesterification faces various challenges. The most challenging is to obtain high conversion rate when using high free fatty acid (FFA) feedstock. The aim of this study is to investigate transesterification process of rubber seed oil (RSO) through direct-ultrasonic irradiation (UI) with addition of waste material based heterogeneous catalyst. The waste material based heter...

A simple and mild one-pot three-component reaction for the preparation 1,4-dihydropyridines has been developed from various aldehyde substrates, 1,3-dicarbonyl compounds (dimedone) and ammonium acetate (Hantzsch method) in the presence of a catalytic amount of phospho sulfonic acid (PSA) as an efficient and heterogeneous solid acid in EtOH at room temperature. Preparation of PSA is straightforw...

Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl]ester (SASPSPE) is employed as a recyclable catalyst for the silylation of hydroxyl groups. A good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of SASPSPE at room temperature with short rea...

An efficient and simple procedure for the synthesis of 1,8-dioxo-octahydroxanthenes from the aromatic aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of boric acid [BO3H3 or B(OH)3] as an inexpensive and reusable catalyst is described. The salient features of this methodology are: the elimination of corrosive liquid acids, high yields, simple methodology, short reacti...

melamine trisulfonic acid (mtsa) as an efficient heterogeneous catalyst has been used for the one-pot preparation of triazolo[1,2-a]indazole-1,3,8-trione and 2h-indazolo[2,1-b]phthalazine-1,6,11-trione derivatives by the three-component condensation reaction of urazoles or phthalhydrazide, dimedone or 1,3-cyclohexanedione, and aldehydes under solvent-free conditions in good to excellent yields ...

the reaction of 3-chloropropyl boehmite nanoparticles with caffeine and sulfuric acid afforded bnps-3-propyl-imidazolopyridinium hydrogen sulfate [bnps-caff]hso4 as a new bnps-supported ionic liquid (il) catalyst. [bnps-caff]hso4 proved to be an efficient heterogeneous catalyst for the synthesis of pyrazolopyranopyrimidines via a one-pot four-component reaction of hydrazine hydrate, ethyl aceto...

Sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) with a pore size of 6 nm catalyzed three component coupling of aromatic aldehydes, urea and ethyl acetoacetate to afford the corresponding dihydropyrimidinones under solvent free condition. This new protocol for Biginelli reaction has important advantages such as green synthesis, short reaction time, easy isolation and high yields of ...

β-acetamido ketones were synthesized in excellent yields through one-pot condensation reaction of aldehydes, acetophenones, acetyl chloride, and acetonitrile in the presence of boric acid as a solid heterogeneous catalyst at room temperature. It is the first successful report of boric acid that has been used as solid acid catalyst for the preparation of β-acetamido ketones. The remarkable advan...

An efficient and simple procedure for the synthesis of 1,8-dioxo-octahydroxanthenes from the aromatic aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of boric acid [BO3H3 or B(OH)3] as an inexpensive and reusable catalyst is described. The salient features of this methodology are: the elimination of corrosive liquid acids, high yields, simple methodology, short reacti...