The revised generalized Tikhonov method for the backward time-fractional diffusion equation

In this paper, we solve the backward problem for a time-fractional diffusion equation with variable coefficients in a bounded domain by using the revised generalized Tikhonov regularization method. Convergence estimates under an a-priori and a-posteriori regularization parameter choice rules are given. Numerical example shows that the proposed method is effective and stable.     

Inclusion of temperature dependent shell corrections in Landau theory for hot rotating nuclei

Landau theory used for studying hot rotating nuclei usually uses zero temperature Strutinsky smoothed total energy for the temperature dependent shell corrections. This is replaced in this work by the temperature dependent Strutinsky smoothed free energy. Our results show that this replacement has only marginal effect for temperatures greater than 1 MeV but plays significant role at lower temperatures.     

Binuclear Ru(III) Schiff base complexes: synthesis,spectral characterization,oxidation, C?C coupling reactions and antibacterial activities

New hexa‐coordinated binuclear Ru(III) Schiff base complexes of the type {[(B)₂X₂Ru]₂L} (where B = PPh₃ or AsPh₃; X = Cl or Br; L = binucleating N₂O₂ Schiff bases) were synthesized and characterized by elemental analysis, magnetic susceptibility measurement, FT‐IR, UV–vis, ¹³C{¹H}‐NMR, ESR at 300 and 77 K, cyclic voltammetric technique, powder X‐ray diffraction pattern and SEM. The new complexes were used as catalysts in phenyl–phenyl coupling reaction and the oxidation of alcohols to their corresponding carbonyl compounds using molecular oxygen atmosphere at room temperature. Further, the new Schiff base ligands and their Ru(III) complexes were also screened for their antibacterial activity against K. pneumoniae, Shigella sp., M. luteus, E. coli and S. typhi. From this study, it was found that the activity of the ruthenium(III) Schiff base complexes almost reaches the effectiveness of the conventional bacteriocide standards. Copyright © 2009 John Wiley & Sons, Ltd.     

Hydrophosphination of boron–boron multiple bonds

Five compounds containing boron–boron multiple bonds are shown to undergo hydrophosphination reactions with diphenylphosphine in the absence of a catalyst. With diborenes, the products obtained are highly dependent on the substitution pattern at the boron atoms, with both 1,1- and 1,2-hydrophosphinations observed. With a symmetrical diboryne, 1,2-hydrophosphination yields a hydro(phosphino)diborene. The different mechanistic pathways for the hydrophosphination of diborenes are rationalised with the aid of density functional theory calculations.

Compounds containing boron–boron double and triple bonds are shown to undergo uncatalysed hydrophosphination reactions with diphenylphosphine.     

Chemical diversity and anti-proliferative activity of marine algae

The chemical diversity of three macroalgae (Ulva reticulata, Sargassum wightii, Gracilaria sp) were determined using the GC-MS method with principal component analysis (PCA) and their potential efficacy against human pathogens and cervical carcinoma cells evaluated using MTT bioassay method. Our results showed that >30 metabolites were detected in three seaweeds, among these, steroids and fatty acids are the most dominant chemical group that highly contributes to discriminate this species. The PCA of GC-MS mass spectral variables showed a clear discrimination between three different species based on the phytochemical diversity of seaweeds. The extracts of U. reticulata exhibited anti-microbial activity with Pseudomonas aeruginosa (6.00?mm) and showed potential anti-proliferative activity against the HeLa cells (IC₅₀ 37?µmol/L) at concentration 1–50?µM treatment. Results of this study concluded that PCA analysis of mass spectral variables could be utilized as a reliable tool for species discrimination and chemotaxonomic classification of seaweeds.     

A concise enantioselective synthesis of 1-[(S)-3-(dimethylamino)-3,4-dihydro-6,7-dimethoxyquinolin-1(2H)-yl]propan-1-one, (S)-903

A concise enantioselective synthesis of (S)-903, an inotropic agent, is described in nine linear steps and 95% ee based on asymmetric dihydroxylation of cinnamate ester and Co-catalyzed multifunctional reduction of several functional groups leading to the construction of core tetrahydroquinolin-3-ol, as the key steps.     

A concise enantioselective synthesis of (+)-febrifugine

A short enantioselective synthesis of (+)-febrifugine, a potent antimalarial alkaloid, has been described based on the regioselective asymmetric dihydroxylation of a 1,4-dienic ester as the key step. The strategy also involves chemoselective [3,3]-sigmatropic rearrangement of 1,5-hexadiene-3-ol and intramolecular lactamization of azidolactone for the construction of piperidine core.     

A new synthesis of 2-(hetero)aryl-substituted pyrazines

2-Chloropyrazine showed remarkable reactivity towards AlCl₃-mediated heteroarylation of arenes and heteroarenes providing direct access to a variety of 2-aryl and heteroaryl-substituted pyrazines, respectively, in good to excellent yields under mild reaction conditions.     

Construction of conjugated molecular structures on gold nanoparticles via the Sonogashira coupling reactions

Functional, conjugated molecular structures have been fabricated on Au nanoparticles via the Sonogashira coupling reactions.     

Convenient route to super-expanded calixpyrroles: synthesis of Calix

meso-Alkylporphyrinogen-like cyclic oligomers containing furans and pyrroles have been synthesized by "3 + 2" and "4 + 2" approaches. Condensation of 5,5,10,10,15,15-hexaethyl-21, 22-dioxatetrapyrromethane with 2,5-bis[(alpha-hydroxy-alpha, alpha-dimethyl)furan] resulted in the formation of cyclic hexamer and cyclic dodcamer. Effects of catalysts, temperature, inorganic additives, solvent, and reaction concentration were examined.