Microwave Assisted Rupture of Furoxans to Nitrile Oxides and Intermolecular Capture by Dipolarophiles

3,4-Diaroylfuroxans 1 react with various dipolarophiles 3 under microwave activation to afford the cycloadduct 4 instead of the expected isoxazole 5 in good yields in the absence of solvent.     

Design,Synthesis, and Biological Activity of New Bis-1,2,3-triazole Derivatives Bearing Thiophene-Chalcone Moiety

Russian Journal of General Chemistry - A series of novel 1,4-substituted bis-aralkyl and aryl 1,2,3-triazoles bearing thiophene chalcones are synthesized via the Claisen condensation of bis...     

Microwave Induced Bismuth Trichloride Catalysed Beckmann Rearrangement of Oximes

A new and efficient method for the rearrangement of oximes 1 has been achieved by a simple reaction of a ketoximes with bismuth trichloride under microwave irradiation in the solid state.     

Temperature-dependent photoelectron spectroscopy of methyl benzoate anions: observation of steric effect in o-methyl benzoate

Temperature-dependent photoelectron spectra of benzoate anion (C6H5CO2(-)) and its three methyl-substituted isomers (o-, m-, p-CH3C6H4CO2(-)) have been obtained using a newly developed low-temperature photoelectron spectroscopy apparatus that features an electrospray source and a cryogenically controlled ion trap. Detachment channels due to removing electrons from the carboxylate group and benzene ring pi electrons were distinctly observed. Well-resolved vibrational structures were obtained in the lower binding energy region due to the OCO bending modes, except for o-CH3C6H4CO2(-), which yielded broad spectra even at the lowest ion trap temperature (18 K). Theoretical calculations revealed a large geometry change in the OCO angles between the anion and neutral ground states, consistent with the broad ground-state bands observed for all species. A strong steric effect was observed between the carboxylate and the methyl group in o-CH3C6H4CO2(-), such that the -CO2(-) group is pushed out of the plane of the benzene ring by approximately 25 degrees and its internal rotational barrier is significantly reduced. The low rotational barrier in o-CH3C6H4CO2(-), which makes it very difficult to be cooled vibrationally, and the strong coupling between the OCO bending and CO2 torsional modes yielded the broad PES spectra for this isomer. It is shown that there is no C-H...O hydrogen bond in o-CH3C6H4CO2(-), and the interaction between the carboxylate and methyl groups in this anion is found to be repulsive in nature.     

Bioactivity and mechanical properties of nickel‐incorporated hydrogenated carbon nanocomposite thin films

In this paper, the influence of nickel incorporation on the mechanical properties and the in vitro bioactivity of hydrogenated carbon thin films were investigated in detail. Amorphous hydrogenated carbon (a‐C:H) and nickel‐incorporated hydrogenated carbon (Ni/a‐C:H) thin films were deposited onto the Si substrates by using reactive biased target ion beam deposition technique. The films' chemical composition, surface roughness, microstructure and mechanical properties were investigated by using XPS, AFM, TEM, nanoindentation and nanoscratch test, respectively. XPS results have shown that the film surface is mainly composed of nickel, nickel oxide and nickel hydroxide, whereas at the core is nickel carbide (Ni₃C) only. The presence of Ni₃C has increased the sp² carbon content and as a result, the mechanical hardness of the film was decreased. However, Ni/a‐C:H films shows very low friction coefficient with higher scratch‐resistance behavior than that of pure a‐C:H film. In addition, in vitro bioactivity study has confirmed that it is possible to grow dense bone‐like apatite layer on Ni/a‐C:H films. Thus, the results have indicated the suitability of the films for bone‐related implant coating applications. Copyright © 2011 John Wiley & Sons, Ltd.     

Studies directed toward the synthesis of rhizopodin: stereoselective synthesis of the C1-C15 fragment

A stereoselective synthesis of the C1-C15 fragment of a G-actin binding natural macrodiolide, rhizopodin was achieved using, as key steps, highly stereoselective acetate aldol reactions to build the C1-C7 fragment, one pot oxazole synthesis and an asymmetric Keck allylation reaction to build the C8-C15 fragment and finally, a Stille reaction to couple both the fragments.     

Electronic structure and properties of isoelectronic magic clusters: Al13X (X=H,Au,Li,Na,K,Rb,Cs)

The equilibrium structure, stability, and electronic properties of the Al(13)X (X=H,Au,Li,Na,K,Rb,Cs) clusters have been studied using a combination of photoelectron spectroscopy experiment and density functional theory. All these clusters constitute 40 electron systems with 39 electrons contributed by the 13 Al atoms and 1 electron contributed by each of the X (X=H,Au,Li,Na,K,Rb,Cs) atom. A systematic study allows us to investigate whether all electrons contributed by the X atoms are alike and whether the structure, stability, and properties of all the magic clusters are similar. Furthermore, quantitative agreement between the calculated and the measured electron affinities and vertical detachment energies enable us to identify the ground state geometries of these clusters both in neutral and anionic configurations.     

An expedient synthesis of ellipticine via Suzuki-Miyaura coupling

A simple and efficient total synthesis of ellipticine was developed via the Suzuki-Miyaura coupling of sterically sensitive 2-hydroxybenzeneboronic acid with a multifunctional aryl halide using Pd(OAc)₂ as a catalyst and Cu(OAc)₂·H₂O as an additive in DMSO/H₂O as a key step followed by double N-arylation and cyclization.     

Cellulose sulphuric acid as a biodegradable and reusable catalyst for the Knoevenagel condensation

A green, mild and efficient method for Knoevenagel condensation of 3-formylchromone/2-chlroquinoline-3-carbaldehyde with active methylene compounds such as Meldrum’s acid/ethyl cyanoacetate using biosupported cellulose sulphuric acid (CSA) in the solid-state by grinding under solvent-free condition has been developed. This method provides several advantages including environmental friendliness, shor t reaction times, high yields and a simple work-up procedure. Moreover, the CSA was successfully reused for four cycles without significant loss of activity.     

Development of novel backwash cleaning technique for reverse osmosis in reclamation of secondary effluent

The objective of the study was to further develop a novel cleaning technique for reverse osmosis in reclamation of municipal secondary effluent. This technique is a new backwash method via direct osmosis (DO) by intermittent injection of the high salinity (HS) solution without stopping of high pressure pump and it is environment and membrane friendly technique. In the study, DO-HS trials were carried out with a UF-RO pilot system which was operated on site with the secondary treated effluent as the raw feed. Different operating conditions for DO-HS treatment in the actual process were investigated. It was found that the operation for implementation of the DO-HS cleaning technique developed was easy. For the first time, the actual profiles of HS concentration, DO backwash flow rate, brine flow rate and permeate pressure during DO-HS treatment have been demonstrated. It was observed that turbidity of the brine stream during DO-HS treatment at 3 NTU was 5 times higher than that before DO-HS treatment. The results from this study have confirmed the previous hypothesis with DO-HS treatment that there would be a strong driving force for DO backwash to lift and sweep the foulants from the membrane surface which would be carried over to the brine. The optimal plant operating conditions in terms of RO feed flow rate, HS concentration and HS injection time are ready for the DO-HS method to be adopted and validated in a long-term continuous plant operation.