Efficient Synthesis of (1R)‐[3,5‐Bis(trifluoromethyl)phenyl] Ethanol,a Key Intermediate for Aprepitant,an NK‐1 Receptor Antagonist

Enzyme‐catalyzed efficient synthesis of (1R)‐[3,5‐bis (trifluoromethyl) phenyl] ethanol (R)‐(3), a key intermediate for aprepitant, via enantioselective transesterification of racemic 1‐[3,5‐bis (trifluoromethyl) phenyl] ethanol (RS)‐3 using vinyl acetate as the acyl donor in the presence of Candida antarctica lipase‐B (CAL‐B) in an overall yield of 84% with >99% ee is described.     

Synthesis of new heterometallic complexes by tin-sulfur bond cleavage of pySSnPh3 (pySH = pyridine-2-thiol) at triruthenium and triosmium centres

The ruthenium-tin complex, [Ru₂(CO)₄(SnPh₃)₂(μ-pyS)₂] (1), the main product of the oxidative-addition of pySSnPh₃ to Ru₃(CO)₁₂ in refluxing benzene, is [Ru(CO)₂(pyS)(SnPh₃)] synthon. It reacts with PPh₃ to give [Ru(CO)₂(SnPh₃)(PPh₃)(κ²-pyS)] (2) and further with Ru₃(CO)₁₂ or [Os₃(CO)₁₀(NCMe)₂] to afford the butterfly clusters [MRu₃(CO)₁₂(SnPh₃)(μ₃-pyS)] (3, M=Ru; 4, M=Os). Direct addition of pySSnPh₃ to [Os₃(CO)₁₀(NCMe)₂] at 70 °C gives [Os₃(CO)₉(SnPh₃)(μ₃-pyS)] (5) as the only bimetallic compound, while with unsaturated [Os₃(CO)₈{μ₃-PPh₂CH₂P(Ph)C₆H₄}(μ-H)] the previously reported [Os₃(CO)₈(μ-pyS)(μ-H)(μ-dppm)] (6) and the new bimetallic cluster [Os₃(CO)₇(SnPh₃){μ-Ph₂PCH₂P(Ph)C₆H₄}(μ-pyS)[(μ-H)] (7) are formed at 110 °C. Compounds 1, 2, 4, 5 and 7 have been characterized by X-ray diffraction studies.     

Impact of Altitudes and Habitats on Valerenic Acid,Total Phenolics,Flavonoids, Tannins,and Antioxidant Activity of <Emphasis Type="Italic">Valeriana jatamansi</Emphasis>

The changes in total phenolics, flavonoids, tannins, valerenic acid, and antioxidant activity were assessed in 25 populations of Valeriana jatamansi sampled from 1200 to 2775 m asl and four habitat types of Uttarakhand, West Himalaya. Significant (p?<?0.05) variations in total phenolics, flavonoids, valerenic acid, and antioxidant activity in aerial and root portions and across the populations were observed. Antioxidant activity measured by three in vitro antioxidant assays, i.e., 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic) (ABTS) radical scavenging, 2,2′-diphenyl-1-picryylhydrazyl (DPPH) free radical scavenging, and ferric-reducing antioxidant power (FRAP) assays, showed significant (p?<?0.05) differences across the populations. However, no clear pattern was found in phytochemicals across the altitudinal range. Among habitat types, (pine, oak, mixed forest, and grassy land), variation in phytochemical content and antioxidant activity were observed. Equal class ranking, neighbor-joining cluster analysis, and principal component analysis (PCA) identified Talwari, Jaberkhet, Manjkhali, and Khirshu populations as promising sources with higher phytochemicals and antioxidant activity. The results recommended that the identified populations with higher value of phytochemicals and antioxidants can be utilized for mass multiplication and breeding program to meet the domestic as well as commercial demand.     

Parametric Amplification in Four-Layered QPM Leaky Waveguides

Parametric amplification of signal wave in a four-layered leaky waveguide configuration in Z-cut LiNbO 3 , where the pump and signal waves are guided modes and the idler is radiated into the substrate has been studied using coupled mode approach. It is shown that in this configuration, the signal gain can be greatly enhanced as compared to the case of a three-layered QPM Cerenkov-idler configuration. The studies show that by appropriately choosing the waveguide parameters, one can have a trade-off between signal gain bandwidth and the peak signal gain achieved. These studies should find application in designing optical parametric amplifiers and oscillators.     

Neurosteroids: Structure-Uptake Relationships and Computational Modeling of Organic Anion Transporting Polypeptides (OATP)1A2

In this study, we investigated the delivery of synthetic neurosteroids into MCF-7 human breast adenocarcinoma cells via Organic Anionic Transporting Polypeptides (OATPs) (pH 7.4 and 5.5) to identify the structural components required for OATP-mediated cellular uptake and to get insight into brain drug delivery. Then, we identified structure-uptake relationships using in-house developed OATP1A2 homology model to predict binding sites and modes for the ligands. These binding modes were studied by molecular dynamics simulations to rationalize the experimental results. Our results show that carboxylic acid needs to be at least at 3 carbon-carbon bonds distance from amide bond at the C-3 position of the androstane skeleton and have an amino group to avoid efflux transport. Replacement of hydroxyl group at C-3 with any of the 3, 4, and 5-carbon chained terminal carboxylic groups improved the affinity. We attribute this to polar interactions between carboxylic acid and side-chains of Lys33 and Arg556. The additional amine group showed interactions with Glu172 and Glu200. Based on transporter capacities and efficacies, it could be speculated that the functionalization of acetyl group at the C-17 position of the steroidal skeleton might be explored further to enable OAT1A2-mediated delivery of neurosteroids into the cells and also across the blood-brain barrier.     

Decoherence control mechanisms of a charged magneto-oscillator in contact with different environments

In this work, we consider two different techniques based on reservoir engineering process and quantum Zeno control method to analyze the decoherence control mechanism of a charged magneto-oscillator in contact with different type of environment. Our analysis reveals that both the control mechanisms are very much sensitive on the details of different environmental spectrum (J?(ω)), and also on different system and reservoir parameters, e.g., external magnetic field (r _c ), confinement length (r ₀), temperature (T), cut-off frequency of reservoir spectrum (ω _cut ), and measurement interval (τ). We also demonstrate the manipulation scheme of the continuous passage from decay suppression to decay acceleration by tuning the above mentioned system or reservoir parameters, e.g., r _c , r ₀, T and τ.     

Micropropagation of Rare Scutellaria havanensis Jacq. and Preliminary Studies on Antioxidant Capacity and Anti-Cancer Potential

We report the development of in vitro propagation protocols through an adventitious shoot induction pathway for a rare and medicinal Scutellaria havanensis. In vitro propagation studies using nodal explants showed MS medium supplemented with 10 µM 6-Benzylaminopurine induced the highest number of adventitious shoots in a time-dependent manner. A ten-day incubation was optimum for shoot bud induction as longer exposures resulted in hyperhydricity of the explants and shoots induced. We also report preliminary evidence of Agrobacterium tumefaciens EHA105-mediated gene transfer transiently expressing the green fluorescent protein in this species. Transformation studies exhibited amenability of various explant tissues, internode being the most receptive. As the plant has medicinal value, research was carried out to evaluate its potential antioxidant capacity and the efficacy of methanolic leaf extracts in curbing the viability of human colorectal cancer cell line HCT116. Comparative total polyphenol and flavonoid content measurement of fresh and air-dried leaf extract revealed that the fresh leaf extracts contain higher total polyphenol and flavonoid content. The HCT 116 cell viability was assessed by colorimetric assay using a 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide, showed a steady growth inhibition after 24 h of incubation. Scanning electron microscopy of leaf surface revealed a high density of glandular and non-glandular trichomes. This research provides a basis for the conservation of this rare plant and future phytochemical screening and clinical research.     

Structural,Magnetic, and Magneto-Caloric Properties of Cu-Substituted Nd0.67Ba0.33MnO3 Manganites

Physics of the Solid State - The crystal structure and magnetic properties of polycrystalline Nd0.67Ba0.33Mn1&nbsp;–&nbsp;xCuxO3 (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.10) manganites...     

Polymeric Multiporous Materials from Fibrillar Networks

Summary: Poly(vinylidene fluoride) (PVF₂) forms thermoreversible gels with liquid alkyl diesters as well as with camphor which is solid at room temperature. The diesters are replaced by another low boiling solvent cyclohexane by solvent exchange technique while camphor is dried just by exposing the material in vacuum to yield highly porous materials. Nano pores are generated as a result of solvent removal from polymer-solvent intercalates whereas macropores are contributed by percolation of polymer fibrils. The porosity thus created covers a wide range from 3 nm to 400 µm producing multiporous materials. Pores greater than 6 nm are measured by mercury intrusion porosimetry (MIP) and pores of diameter less than 6 nm is observed by N₂ adsorption porosimetry. The dried samples show two melting regions, low temperature hump for porous portion and high temperature peak for bulk portion. The porous materials have the ability to absorb water-soluble herbicides from around 10-ppm aqueous solution as indicated in UV spectrophotometric experiment.     

A strong discontinuity based adaptive refinement approach for the modeling of crack branching

In the current work, the physical phenomena of dynamic fracture of brittle materials involving crack growth, acceleration and consequent branching is simulated. The numerical modeling is based on the approach where the failure in the form of cracks or shear bands is modeled by a jump in the displacement field, the so called ‘strong discontinuity’. The finite element method is employed with this strong discontinuity approach where each finite element is capable of developing a strong discontinuity locally embedded into it. The focus in this work is on branching phenomena which is modeled by an adaptive refinement method by solving a new sub-boundary value problem represented by a finite element at the growing crack tip. The sub-boundary value problem is subjected to a certain kinematic constraint on the boundary in the form of a linear deformation constraint. An accurate resolution of the state of material at the branching crack tip is achieved which results in realistic dynamic fracture simulations. A comparison of resulting numerical simulations is provided with the experiment of dynamic fracture from the literature. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)