Iranian Journal of Catalysis
Volume:3 Issue: 2, Spring 2013

1,3-Dibromo-5,5-dimethylhydantoin (DBH), as a cheap and commercially available reagent, is efficiently able to catalyze the synthesis of polyhydroquinoline derivatives and 12-aryl-8,9,10,12-tetrahydro[a] xanthene-11-ones via one-pot multi-component reactions. This novel synthetic method has the advantages of low cost and availability of the catalyst, short reaction times, high to excellent yields, simple and easy work-up and purification of the products compared to the conventional methods reported in the literature.

Silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. The reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. This method is also simple and inexpensive and leads to high yield of products in short reaction times.

CuO-CeO2 nanocomposite is reported as a green and highly efficient recyclable catalyst for the multicomponent synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones under solvent-free conditions. The catalyst was synthesized by co-precipitation method and characterized by XRD, BET specific surface area, FESEM and EDS analysis.

The reaction kinetics of the isomerization 3,4-dichlorobutene-1 to 1,4-dichlorobutene-2 was investigated by using gas-liquid chromatography method in the presence of Fe2O3/MgO as solid catalyst in the temperature range 25-55°C. Fe2O3/MgO has been prepared by the support saturation method, tested in the isomerization of 3, 4-dichlorobutene-1 into 1, 4-dichlorobutene-2. This catalyst shows a high activity opposite to pure MgO in this reaction. The present investigation focuses on the reactivity of Fe2O3/MgO with the 5 wt % Fe2O3 on the surface of MgO. At the optimizing conditions, the activation parameters have been evaluated using the Arrhenius and Eyring plots. The structure of catalyst was investigated by using Mossbauer spectroscopy.

Organocatalyst trityl chloride (Ph3CCl), by in situ formation of trityl carbocation with inherent instability, efficiently catalyzes the condensation of dimedone (5,5-dimethyl-1,3-cyclohexanedione) (2 equiv.) with arylaldehydes (1 equiv.) under solvent-free conditions to afford 9-aryl-1,8-dioxo-octahydroxanthenes in high to excellent yields and in relatively short reaction times. Formation of the carbocationic system is confirmed by studying IR, 1H NMR and UV spectra according to the literature. Moreover, a plausible mechanism based on the literature and observations is proposed for the reaction.

An efficient and green method for the synthesis of pyrano[3,2-c]chromene or pyrano[4,3-b]pyrone derivatives is described by using a three-component condensation process of malononitrile, aldehyde, and 4-hydroxycoumarine or 4-hydroxypyrone in [BMIm]BF4-LiCl as an ionic liquid.

A new type of magnetically-recoverable catalyst was synthesized by the immobilization of H3PW12O40 on the surface of silica-encapsulated -Fe2O3 nanoparticles. A series of novel 1,3,5-triaryl pyrazoline derivatives has been synthesized by the reaction of chalcone and phenylhydrazine in the presence of the -Fe2O3@SiO2-PW12nanoparticles, in high yields. The structures of compounds obtained were determined by IR and 1H NMR spectra. -Fe2O3@SiO2-PW12was recycled and no appreciable change in activity was noticed after three cycles.

In this research, different alcohols and phenols are subjected to the reaction with HMDS in the presence of ionic liquid and silica-supported catalysts. Silylation was accomplished under mild reaction conditions at room temperature in short reaction times and good to excellent yields.

Vahid Khakyzadeh was born in Hamedan, Iran. He received his B.S. degree (Pure Chemistry) and M.S. degree (Organic Chemistry) from Bu-Ali Sina University, Hamedan, Iran, at 2008, 2010 respectively under supervision of professor Mohammad Ali Zolfigol. He is currently working on his Ph. D. under the supervision of professor Mohammad Ali Zolfigol in organic chemistry. Among his recent awards, Vahid was awarded the outstanding MSc student (2009), the outstanding PhD student (2011) and distinguished PhD student at Bu-Ali Sina University (2012). He has also participated in over 27 research articles and 1 book. His research interests are green chemistry and catalysis, including the application of homogeneous, heterogeneous catalysis in organic synthesis.

Maryam Mashhadinezhad was born in Rasht, Guilan, I. R. Iran. She received her B. Sc in chemistry in 2009 from the University of Guilan and her M.Sc. in organic chemistry in 2011 from the same University. She is studying under the supervision of Dr. Farhad Shirini for her Ph. D. Her research interests include the use of heterogeneous catalysts in organic reactions.