A Tabu Search Based Approach for Solving a Class of Bilevel Programming Problems in Chemical Engineering

In this paper an approach based on the tabu search paradigm to tackle the bilevel programming problems is presented. The algorithm has been tested for a number of benchmark problems and the results obtained show superiority of the approach over the conventional methods in solving such problems.     

Band bending at the Si(1 0 0)-Si3N4 interface studied by photoreflectance spectroscopy

Photoreflectance spectroscopy has been used to measure the band bending at the p-Si(1 0 0)-Si₃N₄ interface subjected to annealing and ion implantation. Upon annealing, unimplanted interfaces exhibit a constant band bending of about 0.77 eV, even though the spectral amplitude changes due to variations in the way minority carriers are annihilated at the interface. Implantation reduces the band banding, although subsequent annealing in stages up to 900 °C progressively restores the bending to its original value through pathways exhibiting a wide range of activation barriers.     

A simple,economical, and environmentally benign protocol for the synthesis of 2-amino-3,5-dicarbonitrile-6-sulfanylpyridines at ambient temperature

A simple, economical, and environmentally benign protocol has been described for one-pot synthesis of medicinally privileged 2-amino-3,5-dicarbonitrile-6-sulfanylpyridines by three-component condensation between aldehyde, malononitrile, and thiol using diethylamine as a catalyst. Ambient temperature and avoidance of conventional work-up as well as purification procedure qualify this cost-effective protocol for “green synthesis.”     

Visible-Light-Mediated Controlled Radical Branching Polymerization in Water

Hyperbranched polymethacrylates were synthesized by green-light-induced atom transfer radical polymerization (ATRP) under biologically relevant conditions in the open air. Sodium 2-bromoacrylate (SBA) was prepared in situ from commercially available 2-bromoacrylic acid and used as a water-soluble inibramer to induce branching during the copolymerization of methacrylate monomers. As a result, well-defined branched polymethacrylates were obtained in less than 30 min with predetermined molecular weights (36 000<M_n<170 000), tunable degree of branching, and low dispersity values (1.14≤Đ≤1.33). Moreover, the use of SBA inibramer enabled the synthesis of bioconjugates with a well-controlled branched architecture.     

Hypervalent iodine (III)-mediated oxidation of aryl sulfonylhydrazones: A facile synthesis of N-aroyl-N′-acyl arylsulfonylhydrazides

We have developed a novel and efficient method for the oxidation of aryl sulfonylhydrazones to N-aroyl-N′-acyl arylsulfonylhydrazides, using hypervalent iodine (III) reagent in good yields at room temperature.     

Iridium complexes bearing a PNP ligand, favoring facile C(sp3)-H bond cleavage

Hydrogen iodide is lost upon reaction of PNP with IrI(3), where PNP = 2,6-bis-(di-t-butylphosphinomethyl)pyridine to give crystallographically characterized Ir(PNP)*(I)(2), which reacts with H(2) to give Ir(PNP)(H)(I)(2). Ir(PNP)(Cl)(3) is relatively inert towards the intramolecular C-H activation of the tert-butyl's of the PNP ligand.     

Design,synthesis, evaluation,and molecular dynamic simulation of triclosan mimic diphenyl ether derivatives as antitubercular and antibacterial agents

In the present work, we have explored triclosan mimic diphenyl ether derivatives as inhibitors of Mycobacterium tuberculosis enoyl acyl carrier protein reductase (InhA) using a structure-based drug design approach. The virtual library of diphenyl ethers was designed and compounds with acceptable absorption, distribution, metabolism, excretion, and toxicity properties were docked. The compounds with higher dock score (5a-g) than triclosan were synthesized, characterized, and evaluated for in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv. Among the synthesized compounds, compounds 5f and 5c appeared to be the most promising with minimum inhibitory concentration of 18 μM and 36 μM respectively. The molecular dynamics simulation study of the most active compound 5f and triclosan was performed, which correlates with its activity in comparison with triclosan. All the compounds were further evaluated for cytotoxicity studies against Vero, and HepG2 were found to be safe. Furthermore, compound 5f was evaluated for in vitro cytotoxicity against mouse macrophage cell lines (RAW 264.7), and the study indicated its safety in eukaryotes at 50-μM concentration. In addition, compounds 5a-g were also screened for their in vitro antibacterial activity against two gram-positive and two gram-negative bacteria by resazurin-based microtiter dilution assay method. Among the synthesized compounds, 5f and 5b appeared to be promising, against various gram-positive and gram-negative microorganisms, indicating its broad-spectrum potential.