effective methodologies for efficient preparation of semicarbazones from aldehydes or ketones via milling and the subsequent regeneration of the parent carbonyls by gaseous nitrogen dioxide are described under solid-solid and gas-solid reaction conditions, respectively. these methods are fast, simple and environmentally benign which do not require the use of any auxiliaries such as catalysts or...

BACKGROUND The benzhydryl ether moiety is widely distributed in nature and constitutes a key structural motif in numerous molecules of significant biological potential and of prospective clinical uses. Solvent-free and cost-effective facile synthesis of symmetrical bis(benzhydryl)ethers is, thus, much desirable. RESULTS A simple and efficient method for the facile synthesis of symmetrical bis...

freshly prepared zno nanoparticles were used as an effective heterogeneous base catalyst for the synthesis of aryloximes. the conversion of arylaldehydes and arylketones into the corresponding oximes (up to quantitative yields) was achieved by simply mixing the liquid reactants and hydroxylamine hydrochloride with zno nanoparticles under solvent-free condition. the procedure was carried out und...

as benzimidazole ring is an important pharmacophore in modern drug discovery and benzimidazoles are very important intermediates in organic reactions, the preparation of benzimidazoles has gained considerable attention in recent years. here, a comparative study on the synthesis of benzimidazoles from aromatic, aliphatic and heterocyclic carboxylic acid, benzonitrile and o-phenylenediamine under...

an efficient synthesis of some novel coumarin derivatives via 1, 4- michael addition of indole to coumarin chalcones catalyzed by cellulose sulphonic acid (csa) under solvent free conditions is described. the corresponding michael addition products were obtained in good to excellent yield. the synthesized compounds were screened for their antibacterial activity against e. coli, s. aureus and an...

decatungstodivanadogermanic acid (h6gew10v2o40.22h2o) was used as a green heterogeneous catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1h)-ones from one-pot three-component cyclocondensation reaction of a β-ketoester, an aldehyde and urea/thiourea under solvent-free conditions is reported. this method provides an efficient and much improved modification of the original biginelli reaction...

this paper describes the applicability of 1,3-dichloro-5,5-dimethylhydantoin, as a cheap, stable and commercially available catalyst, in the promotion of the synthesis of 1,8-dioxo-octahydro-xanthenes (doxos) via the one-pot condensation of aldehydes and cyclic 1,3-dicarbonyl compounds. this novel synthetic method has the advantages of high yields, short reaction times, low cost and availabilit...

an efficient synthesis of 1, 8-dioxo-octahydroxanthens and 1, 8-dioxo-decahydroacridines from the reaction of 5,5-dimethyl-1,3-cyclohexanedione (dimedone) with aromatic aldehydes bearing electron-donating or withdrawing substituents either in the presence or absence of primary amines has been described in a single pot using a catalytic amounts of aluminum tris (dodecyl sulfate) trihydrate [al(d...

a simple and green chemical procedure was reported for the synthesis of dihydropyrimidinones from various aldehydes, ethyl acetoacetate and urea or thiourea using  holmium chloride as catalyst. the reactions were performed under solvent free conditions with ultrasound irradiation as the energy source. the advantages of this protocol include the excellent yield, operational simplicity, short tim...

silica-bonded n-propyldiethylenetriamine sulfamic acid (sbpdsa) was found as an efficient solid acid for the synthesis of coumarins. coumarin derivatives were obtained via the pechmann condensation reaction of phenols and β-keto-esters at 80 oc under solvent-free conditions. also, biscoumarins were obtained via the condensation of aldehydes and 4-hydroxycoumarin in water at reflux conditions. t...