Hydrogenation of substituted nitroarenes by a polymer-bound palladium(II) Schiff base catalyst

The catalytic activity of a polymer-bound palladium Schiff base catalyst was investigated toward the reduction of aryl nitro compounds under ambient temperature and pressure. The dependence of the rate of hydrogenation of o-nitroaniline and o-nitrotoluene on substrate concentration, catalyst concentration and temperature has been determined. Based on the results obtained a plausible mechanism for the hydrogenation reaction is proposed and a rate expression is deduced. The energy and entropy of activation have been evaluated from the kinetic data. The polymer-bound catalyst was found to be better than its homogeneous analog PdCl₂(NSBA) [NSBA = N-salicylidene benzylamine] for both stability and reusability. Recycling studies revealed that the catalyst could be used six times without metal leaching or significant loss in activity.     

Novel N-Alkyl-4-(6-fluoro-1H-indol-3-yl)benzamide Derivatives as Anticancer Agents: Design,Synthesis, Biological Evaluation,and Molecular Docking Study

Russian Journal of Organic Chemistry - A number of novel N-alkyl-4-(6-fluoro-1H-indol-3-yl)benzamide derivatives were synthesized and characterized with modern spectroscopic techniques (NMR, IR,...     

Microwave assisted synthesis of 4-methyl-3-arylpyrano[2,3-f]chromen-2(8H)-one derivatives,evaluation of antiproliferative,and antimicrobial activities

A series of new 4-methyl-3-arylpyrano[2,3-f]chromen-2(8H)-one derivatives were designed and synthesized through an efficient, an eco-friendly manner under microwave irradiation and conventional heating methods. Structures of final compounds established based on IR, NMR and mass spectral analysis. The final target compounds were screened for their in vitro antiproliferative activity by taking cisplatin as a reference, Further, antibacterial activity by taking strains such as Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia and Escherichia coli. Furthermore, antifungal activity screened with Aspergillus niger, Aspergillus flavus and Fusarium oxysporum strains. Many compounds results good activity.     

Simple and Highly Efficient Method for the Deprotection of Allyl Ethers Using Dimethylsulfoxide–Sodium Iodide

A simple and highly efficient method for deprotection of allyl ethers has been developed using dimethylsulfoxide–sodium iodide (catalytic amount). This method is inexpensive, has simple reaction conditions, has an easy workup procedure, proceduces excellent yields (60–99%), and is effective for several structurally varied allyl ethers.     

Deformylation of indole and azaindole-3-carboxaldehydes using anthranilamide and solid acid heterogeneous catalyst via quinazolinone intermediate

The deformylation of indole and azaindole-3-carboxaldehydes was achieved in the presence of anthranilamide and a solid acid heterogeneous catalyst under reflux conditions in 25–90% yield. The reaction proceeds via quinazolinone intermediate, which undergoes acid catalyzed cleavage to form deformylated product.     

Easy access to α-hydroxyimino-β-oxodithioesters and application towards the synthesis of diverse 1,4-thiazine-3-ones via reduction/annulation cascade

An operationally simple and facile synthesis of α-hydroxyimino-β-oxodithioesters has been achieved by nitrosation of α-enolicdithioesters. They were further treated with internal alkynes to afford diverse 1,4-thiazin-3-ones via domino reduction/annulation strategy under mild reaction conditions. Importantly, this is the first straightforward entry to highly functionalized 1,4-thiazin-3-one derivatives from simple starting materials.     

Comparative study on formamide–water complex

The hydrogen bonding of 1:1 complexes formed between formamide and water molecule have been investigated systematically using Hartree–Fock (HF), hybrid density functional theory (B3LYP), and post‐Hartree–Fock (MP2 and CCSD(T)) methods with range of basis sets 6‐31G(d), cc‐pVXZ (X = D, T, Q) and aug‐cc‐pVYZ (Y = D, T). Three stable structures are considered on the potential energy surface of formamide and water system. The optimized geometric parameters and interaction energies for various isomers at different levels are estimated. The IR frequencies, intensities, and frequency shifts are reported. This study shows that B3LYP/aug‐cc‐pVDZ method gives better performance for formamide‐water complexes. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010.     

Electrochemical actuation of growing copper dendrimers in water

We report the observation of electrochemical actuation in growing dendritic fibers made of self-assembled copper nanostructures (of 100 nm or less in diameter), on the metallic cathode of an ordinary aqueous electrochemical cell. This could be achieved when a copper anode and another metal cathode is placed in aqueous solution of either dilute HCl or CuSO(4), or CuCl(2), or H(2)O, and upon application of a DC voltage in the range of 1.5-12.0 V. The actuation could be observed with an on-off cycle of the applied voltage in the above range. The phenomenon was also observed with the growth of bimetallic structures using a number of electrolytes such as Ag(NO(3)), Pb(NO(3))(2), CoCl(2), NiCl(2), CdCl(2), ZnCl(2), and HAuCl(4). The fibrous structures remained stretched as they grew longer with time in the presence of an applied voltage. The extent of actuation was dependent on the applied voltage, the concentration of Cu(2+) ions in the solution, and also on ions such as Na(+), which did not get deposited at the cathode. The observed phenomena under different conditions have been explained on the basis of electrocapillarity.     

Development and validation of a reversed-phase HPLC method for monitoring of synthetic reactions during the manufacture of a key intermediate of an anti-hypertensive drug

A reversed-phase high-performance liquid-chromatographic method for monitoring of reactions involved in process development of a key intermediate of antihypertensive drugs, e.g, doxazosin mesylate, prazosin, alfuzosin, terazosin, etc., has been developed and validated. The HPLC profiles of impurities of 4-amino-2-chloro-6,7-dimethoxyquinazoline were used as fingerprints to follow the synthetic procedures in the manufacturing unit. The separation was accomplished on an Inertsil ODS-3 column with isocratic elution using acetonitrile-ammonium acetate (10 mM; pH 4.0; 50:50 v/v) as mobile phase and a photodiode array detector set at 240 nm at ambient temperature. The method was validated with respect to accuracy, precision, linearity, and limits of detection and quantification. The method could detect the impurities at a level of 0.01 to 0.20 microg/mL and it was found to be suitable not only for monitoring of reactions but also for quality assurance of 4-amino-2-chloro-6,7-dimethoxyquinazoline.     

Parabolic pulse generation in a dispersion-decreasing solid-core photonic bandgap Bragg fiber

We analyze the interplay of nonlinearity and dispersion in a dispersion-decreasing photonic bandgap Bragg fiber as a new platform for generating parabolic pulses. A suitably designed linearly tapered, low-index-contrast, solid-core Bragg fiber - amenable to fabrication by conventional modified chemical vapor deposition technology - is shown to yield stable parabolic pulses. The fiber design was optimized through a simple and accurate transfer-matrix formalism and pulse evolution was studied by the well-known split-step Fourier method. Our study revealed feasibility of generating parabolic pulses in such a dispersion-decreasing Bragg fiber of length as short as 1 m. We have also studied the effect of third order dispersion on generated parabolic pulse, which is an important deteriorating factor in such applications. The effective single-mode operation of the proposed device is achieved through appropriate tailoring of the outer cladding layers.