Electrochemical synthesis of quinones and other derivatives in biphasic medium

Electrochemical synthesis of quinones has been attempted from phenols, 1,4-dihydroxybenzenes, 1,4-dihydroxynaphthalenes and related compounds using biphasic media. Excellent yields of quinones (98%) or brominated diols have been achieved with good current efficiency. Reuse of the electrolyte without any modification and quantitative conversion of substrate with theoretical amount of current are the advantages of this method.     

Facile redbrick clay as splendid catalyst for selective dehydration of alcohols

Research on Chemical Intermediates - Excellent catalytic activity of activated redbrick clay (ARB) for dehydration and highly selective conversion of cyclohexanol to cyclohexene and 1-phenylethanol...     

Determination of gemifloxacin on dried blood spots by hydrophilic interaction liquid chromatography with fluorescence detector: application to pharmacokinetics in rats

A highly selective, sensitive and rapid hydrophilic liquid interaction chromatographic method was developed and validated for determination of gemifloxacin on dried blood spots. The chromatographic separation was achieved on a reversed‐phase zwitterionic hydrophilic interaction liquid chromatographic ZIC®HILIC‐C₁₈ (4.6 × 100 mm; 5 µm) column using acetonitrile–10 mM ammonium acetate (pH 3.5; 80:20, v/v) as a mobile phase in an isocratic elution mode at a flow rate 0.6 mL/min at 27 °C. An on‐line fluorescence detector set at excitation and emission wavelengths of 269 and 393 nm, respectively was used for monitoring column eluents. Ciprofloxacin was used as an internal standard. The method was validated for accuracy, precision, linearity and selectivity by design of experiments following ICH guidelines. The assay exhibited a linear range of 25–5000 ng/mL for gemifloxacin on dried blood spots. The lower limit of detection was found to be 10 ng/mL. The intra‐ and inter‐assay coefficients of variation did not exceed 7.4% deviation of the nominal concentration. The recovery of GFX from dried blood spots was >95.0% and its stability was excellent with no evidence of degradation during sample processing for at least 3 months storage in a freezer at ?20 °C. Copyright © 2012 John Wiley & Sons, Ltd.     

Stereoselective total synthesis of the cytotoxic lactone (−)-spicigerolide

A highly stereoselective synthesis of the naturally occurring lactone (−)-spicigerolide has been achieved utilizing OsO₄-catalyzed dihydroxylation, CBS, Lindlar’s reductions, Still-Gennari, and Grignard reactions as the key reaction steps.     

DNA fastening and scission actions of Cu(II), Co(II), Ni(II) and Zn(II) complexes: synthesis,spectral characterization and cytotoxic study

A heterocyclic compound, 2‐(aminomethyl)benzimidazole dihydrohydrochloride, was treated with nitrobenzaldehyde to form a Schiff base that was made to react with divalent metals. A co‐ligand, either 1,10‐phenanthroline or 2,2′‐bipyridine, was added to this mixture to obtain metal chelators of type [ML(co‐L)₂]Cl₂. They were in 1:1:2 stoichiometry ratio, which was characterized by various spectroscopic techniques that suggested an octahedral geometry around the central metal ions. These complexes were investigated for their binding affinities with calf thymus (CT) DNA, using various techniques, such as UV–Vis, viscosity, cyclic voltammetry (CV), etc. The binding interaction studies revealed intercalation as the possible binding mode of the complexes with the CT DNA. In addition, these complexes were screened for their antimicrobial potential and DNA denaturing tendencies using gel electrophoretic assay. The antimicrobial screening investigation showed that the complexes behaved as better antimicrobial agents than the ligand, especially, complex 5 shows exceptional activity even in the electrophoretic assay along with the antimicrobial efficacy. Moreover, complex 5 was able to denature the plasmid DNA better than the other compounds. All the compounds were screened for cytotoxic efficacy, and the IC₅₀ values suggest that the compounds possess cytotoxic activity to some extent that is almost the same as the activity of cisplatin.