Reductive Cleavage of Acetals/Ketals with ZrCl4/NaBH4

Reductive cleavage of acetals/ketals with zirconium tetrachloride-sodium borohydride leading to the formation of ether alcohols is described.     

Liquid-Phase and Solventless Oxidation of Cyclohexane,Benzene, and Other Hydrocarbons by Cerium(IV) Catalyzed by Iridium(III) in Acidic Medium

Oxidation of some hydrocarbons dissolved in acetic acid by cerium(IV) sulphate at 100 °C in the presence of traces of iridium(III) chloride (catalyst-substrate 1:56818 to 151515) in the solution phase resulted in good to excellent yields of corresponding carbonyl compounds. In the cases of cyclohexane and benzene, 44% and 51.8% yields of corresponding carbonyl compounds were obtained, whereas in other cases, yield ranged from 34.9 to 99.8%. Yield decreased when reactions were performed in a microwave oven by adsorbing reactants (except acetic acid) on alumina. Decrease in the yield was probably due to the high temperature generated during the course of the reaction, resulting in the loss of organics from evaporation. Conditions were optimized for the highest yields under ambient conditions.     

One-Pot Synthesis of 2,4,5-Trisubstituted Imidazoles Using MoO3/SiO2, an Efficient and Recyclable Catalyst

A simple one-pot synthesis has been developed for the synthesis of 2,4,5-trisubstituted imidazoles using an efficient and recyclable MoO₃/SiO₂ solid acid catalyst by condensation of benzil or benzoin, benzaldehyde, and ammonium acetate in acetonitrile as a solvent. Using this solid catalyst, the reactions could be carried out under mild reaction conditions with very good yield of imidazoles, up to 95%. This catalyst could be recycled very easily, which makes this methodology environmentally benign.     

Catalyst free,regioselective one-pot three-component synthesis of thiazol-2-imine derivatives in ionic liquid

A one-pot three-component approach for the synthesis of thiazol-2-imines has been described by the reaction of amine, phenyl isothiocyanate and β-nitroacrylate in [Hbim]BF₄ ionic liquid. The method is applicable for aromatic, benzylic, aliphatic and cyclic amines. Reusable reaction media, regioselectivity, mild reaction condition, catalyst free and high yield of products are the salient features of this protocol.     

Search of truncation of (N−1) electron basis containing full connected triple excitations in computing main and satellite ionization potentials via Fock‐space coupled cluster approach

A valence‐universal multireference coupled cluster (VUMRCC) theory, realized via the eigenvalue independent partitioning (EIP) route, has been implemented with full inclusion of triples excitations for computing and analyzing the entire main and several satellite peaks in the ionization potential spectra of several molecules. The EIP‐VUMRCC method, unlike the traditional VUMRCC theory, allows divergence‐free homing‐in to satellite roots which would otherwise have been plagued by intruders, and is thus numerically more robust to obtain more efficient and dependable computational schemes allowing more extensive use of the approach. The computed ionization potentials (IPs) as a result of truncation of the (N−1) electron basis manifold involving virtual functions such as 2h‐p and 3h‐2p by different energy thresholds varying from 5 to 15 a.u. with 1 a.u. intervals as well as thresholds such as 20, 25, and 30 a.u. have been carefully looked into. Cutoff at around 25 a.u. turns out to be an optimal threshold. Molecules such as C₂H₄ and C₂H₂ (X = D,T), and N₂ and CO (X = D,T,Q) with Dunning's cc‐pVXZ bases have been investigated to determine all main and 2h‐p shake‐up and 3h‐2p double shake‐up satellite IPs. We believe that the present work will pave the way to a wider application of the method by providing main and satellite IPs for some problematic N‐electron closed shell systems. © 2013 Wiley Periodicals, Inc.     

Diverted total synthesis of falcitidin acyl tetrapeptides as new antimalarial leads

We report not only the convergent total synthesis of falcitidin, a natural inhibitor of falcipain-2 from myxobacterium Chitinophaga, but also its diversification into a new antimalarial class of N-acyl tetrapeptides (Acyl-His-Ile-Val-Pro-NH₂). Despite the lack of whole-cell activity of falcitidin itself, our study led to the identification of a trifluoromethyl (CF₃) analogue displaying sub-micromolar IC₅₀ activity against Plasmodium falciparum 3D7 in a standard blood-cell assay, but only when N-tritylated on its histidine (imidazole) residue.     

Investigation of chemical space networks using graph measures and random matrix theory

Journal of Mathematical Chemistry - Large collections of molecules (chemical libraries) are nowadays routinely screened in the process of designing drugs for specific ailments. Chemical and...     

Synthesis,Characterization of Cr Doped TeO2 Nanostructures and its Application as EGFET pH Sensor

In the present work, Cr doped tellurium dioxide nanostructures (CTO NS)(1 wt %, 6 wt %, 8 wt % and 12 wt %) synthesized by co precipitation method and characterized by CV, UV-Visible, SEM, XRD, XPS spectroscopic analysis. Electron beam deposited thin film of CTO NS having 12 wt % of Cr exhibited EGFET-pH sensitivity of 62.03 mV/pH at 250 °C in buffer solutions of pH 6–12, linearity 0.9345, drift rate of 1.12 mV/h and deviation of 0.01145 as compared with 1 wt %, 6 wt % and 8 wt % of CTO NS.