Iranian Journal of Catalysis
Volume:3 Issue: 3, Summer 2013

A practical and green method for the synthesis of 5H-dibenzo[b,i]xanthene-tetraones and spiro[dibenzo[b,i]xanthene-13,3''-indoline]-pentaones by the condensation of 2-hydroxynaphthalene-1,4-dione with aldehydes or isatins, respectively, in the presence of a catalytic amount of cellulose sulfuric acid (CSA) under solvent-free conditions at 100 °C is described. The significant features of this procedure are high yields of the products, simple work-up, solvent-free conditions, operational simplicity and non-toxicity of the catalyst. Moreover, cellulose sulfuric acid is successfully reused for four cycles without significant loss of activity.

Surface of mesostructured silica, KIT-6, was modified by grafting 3-aminopropyl-triethoxysilane (APTES) to have the positive charge, and thus, to provide sites for the immobilization of H3PW12O40 (PW12). This modified-nanosized mesoporous silica (PW12-APTES@ KIT-6) was characterized by FTIR, XRD, BET and TEM. The oxidation of sulfides occurs effectively and selectively with H2O2 as the oxidant. PW12-APTES@KIT-6 was used as the catalyst. The catalyst can be reused for several times but it will be less active.

Two possible isomers of some 1,3-diaryl-H-benzo[f]chromene have been studied using density functional theory. Structures of E1 and E2 isomers were optimized at the B3LYP and MP2 levels with different basis sets. The total electronic energies show that E2 isomer is about 3-5 kcal/mol more stable than E1 isomer and this energy difference is attributed to the planarity of heterocyclic ring and more establishment resonance in E2 isomer, that is confirmed by second order interaction energies E(2) of NBO results. The calculated geometry for both chromene isomers were also compared with the experimental data. The X-ray data indicate the E1 isomer as the stable structure for 1,3-diaryl-1H-benzo[f]chromene, while the E2 isomer is fixed for 3-phenyl-1-p-tolyl-1H-benzo[f]chromene. The compared dihedral angles of both isomers show that phenyl (I) group in E2 isomer has more contribution in resonance with the heterocyclic and naphthalene rings than that in E1, while in E1 isomer phenyl (II) group is more engaged in resonance than that in E2.

The direct and indirect methods in solvent media and grinding method in a solvent-free media were used to prepare the MCM-41/ZnO and MCM-48/ZnO photocatalysts. The X-ray diffraction (XRD) patterns showed that zinc oxide nanoparticles were put into MCM-41 and MCM-48 substrates and there were ZnO crystallites as secondary phase in the extra framework of mesoporous materials. The decrease of surface areas, pore volume and average pore size of mesoporous materials with incorporation of ZnO nanoparticles were confirmed by N2 adsorption and desorption isotherms. The FT-IR spectra showed an absorption peak at 490 cm-1 that was related to formation of ZnO in the substrate of MCMs. The photocatalytic activity of MCM-41/ZnO and MCM-48/ZnO were studied in photodegradation reaction of Congo red as a dye pollutant. The photocatalysts of MCM-41/ZnO and MCM-48/ZnO which were prepared by grinding method showed the highest photocataltyic activity with pseudo first-order kinetic rate constants of 34.6 and 27.810-3 min-1, respectively. The obtained results indicated complete incorporation of zinc ions in mesoporous material of MCMs in a solvent-free media. The elimination of solvent and facility of proposed method were the advantages of grinding method in preparation of MCM/ZnO photocatalyst.

A highly efficient procedure for the preparation of N,N''-alkylidenebisamides in the presence of BF3.SiO2 as a catalyst is described. N,N''-alkylidenebisamides have been prepared via one-pot three-component condensation reaction of various aldehydes and amides. All of the reactions proceeded in high yields and in moderately short reaction times.

Sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}ester (SASPSPE) is employed as a recyclable catalyst for the synthesis of α-amino nitriles. These syntheses were performed via a one-pot three-component condensation of aldehydes, amines, and trimethylsilyl cyanide under mild reaction conditions at room temperature. The catalyst could be recycled and reused several times without any loss of efficiency.

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 anti-fungal activity against C. albicans. All the synthesized compounds show moderate to good antimicrobial activity.

Some 2-iminothiazolidin-4-ones have been synthesized by the reaction of dialkyl acetylenedicarboxylates with thiosemicarbazones. The reaction was performed in the presence of 10 mol% of triphenylphosphine and tetrabutylammonium bromide as a phase transfer catalyst in water as a green solvent. All the synthesized compounds were characterized by their physical and spectral data.

Toktam Faal Rastegar was born in Quchan (Iran). She completed her B.Sc. in Chemistry in 2005 from Ferdowsi University, Mashhad. She was graduated from M.Sc. degree in Organic Chemistry from Bu-Ali Sina University (2008), Hamadan, Iran. She is currently Organic Chemistry Ph.D student under the supervision of Prof. A. Khazaei and Prof. M.A. Zolfigol in Department of Chemistry at Bu-Ali Sina University, Hamedan, Iran. Her research interest is organic methodology especially the application of solid acids in organic synthesis.

Mohaddeseh Safarpoor Nikoo Langroodi was born in Langrood, Guilan, I.R. Iran. She received B.S. in chemistry from Shahid Beheshti University (2006) and his M.S. in organic chemistry from University of Guilan (2010) under the direction of Professor Farhad Shirini. After two years, she began her Ph.D. studies at University of Guilan under supervision of Professor Farhad Shirini. Her current researches focuses on the development of new synthetic methodologies.