On the mechanism of the addition of dithianylidene anions to cyclic α,β-unsaturated ketones

The high diasteroselectivity in the 1,4-addition of dithianylidene anions to α,β-unsaturated ketones is demonstrated to proceed through an alkoxy-Cope rearrangement.     

Superunified model with naturally ultralight dirac neutrinos

The recently proposed mechanism to naturally generate one ultralight Dirac neutrino per fermion family is implemented by construction of a globally supersymmetric SO(10) GUT superpotential featuring geometric hierarchy. A step forward is thus taken towards providing a firm theoretical basis for the relation $\text{m}{}_{\mathrm{\nu }}\text{=}\text{O}\text{(m}\text{3}\text{2}\text{)M}{}_{\mathrm{<mtext>SUSY</mtext>}}\text{/M}{}_{\mathrm{<mtext>GUT</mtext>}}$.     

A highly efficient heterogeneous montmorillonite K‐10‐supported palladium catalyst for Suzuki–Miyaura cross‐coupling reaction in aqueous medium

A heterogeneous montmorillonite K‐10‐supported palladium triphenylphosphine catalyst is reported for the Suzuki–Miyaura cross‐coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross‐coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles. Copyright © 2014 John Wiley & Sons, Ltd.     

Bacterial production of the fungus‐derived cholesterol‐lowering agent mevinolin

Forty‐five strains from two different species (Salinispora arenicola and Salinispora pacifica) were isolated from three different marine sponge species in the Great Barrier Reef region of Australia. We found that two of the strains of Salinispora arenicola (MV0335 and MV0029) produced mevinolin, a fungus‐derived cholesterol‐lowering agent. Compound structure was determined using an integrated approach: (a) high performance liquid chromatography‐quadrupole time‐of‐flight‐mass spectrometric analysis with multimode ionization (electrospray ionization and atmospheric pressure chemical ionization) and fast polarity switching; and (b) database searching and matching of monoisotopic masses, retention times and mass spectra of the precursor and product ions of the compounds of interest and the authentic reference standards thereof. Copyright © 2014 John Wiley & Sons, Ltd.     

Part 1. modular approach to obtaining diverse tetrahydroquinoline-derived polycyclic skeletons for use in high-throughput generation of natural-product-like chemical probes

A practical synthesis of a tetrahydroaminoquinoline scaffold (12) was developed that used a stereocontrolled aza Michael as the key reaction. Three tetrahydroquinoline alkaloid-like, tricyclic derivatives 16, 18, and 19 with different medium to macrocyclic ring skeletons were obtained, using this scaffold as the starting material, in a modular manner. The macrocyclic compounds with an isolated olefin and an electron-deficient olefin were obtained by ring-closing metathesis approaches. Compounds 16 and 18 are unique and contain bridged 10- and 12-membered functionalized rings. The NMR studies of these compounds revealed interesting information on the conformation of the bicyclic scaffolds that was dependent on the nature and the size of the macrocyclic rings. Finally, this modular methodology, using compound 21 anchored onto the solid support, successfully led to the generation of different macrocyclic derivatives, 23, 25, and 27 in solid-phase synthesis. The solid-phase synthesis approach outlined in this article has the potential to generate tetrahydroquinoline-based tricyclic compounds containing different medium to macrocyclic architectures.     

Rapid and Sensitive LC Method for the Analysis of Gemifloxacin in Human Plasma

A simple liquid chromatographic method for the determination of gemifloxacin (CAS number 175463-14-6) in human plasma has been developed. An aliquot quantity of 1 mL plasma sample was taken and 0.1 mL internal standard was added and mixed. 1 mL methanol was added to it. The mixture was then sonicated for 10 min followed by 20 min centrifugation at 5000 rpm (g = 3600). The supernatant layer was separated and filtered through simple filtration unit (membrane filter, 0.45 μm) and injected into the LC system consisting of Hypersil BDS, C18 (250 × 4.6 mm, 5 μm particle size) column, using 1% formic acid : methanol = 65:35 (v/v) as mobile phase with ultra violet detection at 328 nm. Lower limit of detection was 20 ng mL^?1 and lower limit of quantitation was 50 ng mL^?1. Maximum between-run precision was 14.614%. Mean extraction recovery was found to be 87.32 to 89.32%. Stability study showed that after three freeze-thaw cycles the loss of three quality control samples were less than 10%. Samples were stable at room temperature for 12 h and at ?20 °C for 3 months. Before injecting into LC system, the processed samples were stable for at least 8 h. The method was used to perform bioequivalence study in human volunteers.     

Synthesis,characterization, and application of novel biodegradable self-assembled 2-(N-phthalimido) ethyl-palmitate nanoparticles for cancer therapy

We report the synthesis of novel biodegradable nanoparticles (NPs) which can kill the cancer cells without any additional drug loading. The NP was a self-assembled form of a phthalimide based conjugate, in which the phthalimide moiety was responsible for the anticancer activity. We describe the synthesis of a novel 2-(N-phthalimido) ethyl palmitate (PHEP-Pal) conjugate and subsequent preparation of NPs by a simple self assembly process. The successful synthesis of conjugate was confirmed by various characterization studies including nuclear magnetic resonance spectroscope, Fourier transform infrared spectroscope, TOF-liquid chromatography mass spectroscope, differential scanning calorimetry, and X-ray diffraction unit. The synthesis, shape, size, and size distribution of PHEP-Pal NPs were determined by transmission electron microscope, atomic force microscope, and dynamic light scattering technique. Finally, cell culture studies using A549 and HeLa cells were done to evaluate the anticancer effect of PHEP-Pal NPs, which demonstrated the potency of these NPs for use in cancer chemotherapy.     

Leptogenesis with linear,inverse or double seesaw

The left-right symmetric model with doublet and bi-doublet Higgs scalars can accommodate linear, inverse or double seesaw for generating small neutrino masses in the presence of three singlet fermions. If the singlet fermions have small Majorana masses, they can form three pairs of quasi-degenerate Majorana fermions with three right-handed neutrinos. The decays of the quasi-degenerate Majorana fermions can realize the resonant leptogenesis. Alternatively, the right-handed neutrinos can obtain seesaw suppressed Majorana masses if the singlet fermions are very heavy. In this case leptogenesis, with or without resonant effect, is allowed in the decays of the right-handed neutrinos.     

Higher Dimensional Dark Energy Investigation with?Variable Λ and G

Two phenomenological models of Λ, viz. L ~ ([(a)\dot]/a)²\Lambda \sim (\dot{a}/a)^{2} and L ~ [(a)\ddot]/a\Lambda \sim \ddot{a}/a are studied under the assumption that G is a time-variable parameter. Both models show that G is inversely proportional to time as suggested earlier by others including Dirac. The models considered here can be matched with observational results by properly tuning the parameters of the models. Our analysis shows that L ~ [(a)\ddot]/a\Lambda \sim \ddot{a}/a model corresponds to a repulsive situation and hence correlates with the present status of the accelerating Universe. The other model L ~ ([(a)\dot]/a)²\Lambda \sim (\dot{a}/a)^{2} is, in general, attractive in nature. Moreover, it is seen that due to the combined effect of time-variable Λ and G the Universe evolved with acceleration as well as deceleration. This later one indicates a Big Crunch.