We report an efficient Mukaiyama-aldol reaction of tryptanthrin with fluorinated enol silyl ethers, which is carried out in methanol without the use of any catalyst. This method is applied to the total synthesis of the difluoro analogues of the natural product Phaitanthrin B.

nano-sbcl5.sio2 and sbcl5.sio2 are bench-top catalysts which are reusable, readily available, versatile andefficient for promotion of many acid catalyzed organic reactions. these catalysts do not need specialprecautions for preparation, handling or storage, and they can be stored at an ambient temperature for monthswithout losing their catalytic activity. 4-dihydropyrimidin-2(1h)-ones(thiones) ...

Highly efficient protocols for the alkynylation of H-phosphi(na)tes and secondary phosphine oxides with silyl, aryl and alkyl ethynyl-benziodoxolone (EBX) reagents are reported. Alkynyl phosphorus compounds were obtained in 69-93% yield without the need for a transition metal catalyst at room temperature under open flask conditions.

A highly enantioselective method for the catalytic Mukaiyama aldol reaction of silyl enol ethers with aldehydes in aqueous conditions was developed. The desired aldol products were obtained in excellent yields, diastereo- and enantioselectivities. Structural evidence of the pre-catalyst revealed an unprecedented heptadentate Fe(II) complex with the chiral bipyridine ligand.

We report the synthesis of a new Au nanocatalyst with increased thermal stability. This catalyst system consisted of gold nanoparticles attached to functionalized TiO2/SiO2 core-shell nanocomposites, together with the encapsulation of mesoporous silica. The synthesis process mainly involved four steps, which included the synthesis of the TiO2/SiO2 core-shell composites, synthesis of the Au/TiO2...

Hexavalent chromium (Cr(VI)) is a serious environmental pollutant and human toxicant. Mammalian cells are very sensitive to chromate as they lack efficient chromate detoxifying strategy, e.g., chromate-reducing genes that are widely present in prokaryotes. To test whether introduction of prokaryotic chromate-reducing gene into mammalian cells could render higher chromate resistance, an Escheric...

A facile and eminent method has been reported for the preparation of amido alkyl naphthols. Amido naphthol derivatives were synthesized by condensation pyrazole aldehydes, β-naphthol acetamide in presence a heterogeneous SiO2 supported sodium hydrogen sulphate catalyst using acetic acid as solvent. This protocol is advantageous its shorter reaction hours, simplest workup technique, excellent yi...

Hydrogen production through methane dry reforming holds the promise of lowering greenhouse gases, that is CO2 and CH4, concentrations. Herein, Ca-, Cr-, Ga- Gd-promoted lanthana-zirconia–supported Ni catalysts are investigated characterized by X-ray diffraction, Raman, infrared UV-vis spectroscopy, CH4-temperature programmed surface reaction cyclic reduction-desorption experiment. All promoted ...

The emission control of NOx in exhaust gases is one of the greatest engineering challenges to extend the practical and commercial application of diesel and lean burn engines. One solution is selective NOx reduction using hydrocarbons in an oxidizing atmosphere. We mainly focused on catalytic reactions under temperature excursion because of the resemblance to conditions prevailing in real automo...

Well-defined model catalyst samples, prepared under ultra-high-vacuum (UHV) conditions, hold the potential of bridging the gap between traditional surface science and technical catalysis studies. However, work remains to understand and characterize reaction kinetics of such samples under more realistic pressure conditions, specifically, how reaction kinetics of a well-studied reaction (such as ...