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A mild and environmentally-benign protocol for the efficient synthesis of polysubstituted pyrroles via a one-pot three-component reaction of amines, α-bromo ketones and dialkyl acetylenedicarboxylate using H 3 PW 12 O 40 as a recyclable heterogeneous catalyst under solvent-free conditions at room temperature is reported. Importantly, the synthesis of symmetrical and unsymmetrical polysubstituted bis-pyrroles has been performed in good yields for the first time, which can be considered as a salient feature of this protocol.

The epoxidation of alkenes with hydrogen peroxide catalyzed by [PZnMo 2 W 9 O 39 ] 5- , ZnPOM, supported on ionic liquid-modified silica, Im-SiO 2 , is reported. The immobilized catalyst, [ZnPOM@Im-SiO 2 ] was characterized by elemental analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR and UV–Vis spectroscopic methods. This new synthesized hybrid catalyst was applied for efficient epoxidation of various olefins with aqueous H 2 O 2 in acetonitrile under reflux conditions. This solid catalyst can be easily recovered by simple filtration and reused several times without significant loss of its catalytic activity.

In the present work, the catalytic activity of high-valent tetraphenylporphyrinatovanadium(IV) trifluoromethanesulfonate, [V IV (TPP)(OTf) 2 ], in the tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) is reported. This new electron-deficient V(IV) compound was used as a highly efficient catalyst for pyranylation of primary (aliphatic and benzylic), sterically-hindered secondary and tertiary alcohols with DHP. Tetrahydropyranylation of phenols with DHP was also performed to afford the desired THP-ethers. The chemoselectivity of this method was also investigated. The results indicated that primary alcohols are more reactive in the presence of secondary and tertiary alcohols and phenols. This catalyst was reused several times without loss of its activity.

An efficient and novel synthesis of 2,3-disubstituted 2,3-dihydroquinazolin-4(1 H )-ones via one-pot, three-component reaction of isatoic anhydride, primary amines and aromatic aldehydes catalyzed by Bi(NO 3 ) 3 ·5H 2 O under solvent-free conditions is described. Oxidation of these 2,3-dihydroquinazolin-4(1 H )-ones to their quinazolin-4(3 H )-ones was also successfully performed in the presence of Bi(NO 3 ) 3 ·5H 2 O. This new method has the advantages of convenient manipulation, short reaction times, excellent yields, very easy work-up, and the use of commercially available, low cost and relatively non-toxic catalyst. The role of Bi(NO 3 ) 3 ·5H 2 O was also investigated in these transformations.

Di[1,6-bis(3-methylimidazolium-1-yl)hexane] decatungstate dihydrate ([C6(MIm)2]2W10O32. 2H2O) as a new family of polyoxometalate-based dicationic ionic liquids (POM-DIL) is synthesized and employed as a novel and powerful heterogeneous catalyst in the synthesis of 4-arylidene-2-phenyl-5(4)-oxazolones (azlactones) under ultrasound-assisted solvent-free condition. On the basis of the results, the products were obtained in excellent yields under mild condition. Utilization of easy work-up and purification make it very interesting from an economic perspective. Moreover, a recycling study confirmed that the catalyst can be reused multiple times without significant loss of its activity.

A simple, green and chemoselective method for methoxymethylation and ethoxymethylation of primary and secondary alcohols using a Lewis acidic room temperature ionic liquid, [C4mim][InCl4], as catalyst and reaction medium under ambient temperature, microwave and ultrasonic irradiations is reported. In this catalytic system, the corresponding MOM-and EOM-ethers are obtained in excellent yields and in short reaction times. Furthermore, this catalytic system was used for mild and efficient transformations of these protected alcohols to their corresponding acetates and trimethylsilyl ethers under thermal conditions and microwave and ultrasonic irradiations.

A novel, clean and efficient tandem process has been established for the synthesis of 2,4,6-triarylpyridines from primary aryl alcohols or 1-arylethanols using 1-methylimidazolium nitrate in 1-butyl-3-methylimidazolium tetrafluoroborate as a binary task-specific ionic liquid under microwave irradiation.