A(1,3)-strain mediated epimerization of 2e,3e,5e,6e-tetraarylpiperidin-4-one oximes

A series of tri- and tetraarylpiperidin-4-one oximes were synthesized from 2e,3e,6e-tri- and 2e,3e,5e,6e-tetraarylpiperidin-4-ones, respectively. In the case of the latter compounds, oximation is accompanied by epimerization at C-5 to avoid the A(1,3)-strain between the oxime OH group and the 5e-aryl ring of the initially formed oxime resulting in 2e,3e,5a,6e-tetraarylpiperidin-4-one oximes. 1H, 13C and 2D NMR spectroscopic data were employed to characterize and investigate the stereochemistry of these compounds.     

An economic analysis of microbial reduction of sulfur dioxide with anaerobically digested sewage biosolids as electron donor

Applied Biochemistry and Biotechnology - In summary, it appears that the microbial reduction process is not competitive with conventional SO2-reduction techniques when AD-MSS medium is used as the...     

A three-dimensional chemical phase pharmacophore mapping,QSAR modelling and electronic feature analysis of benzofuran salicylic acid derivatives as LYP inhibitors

Lymphoid tyrosine phosphatase (LYP), encoded by the PTPN22 gene, has a critical negative regulatory role in T-cell antigen receptor (TCR) and emerged as a promising drug target for human autoimmune diseases. A five-point pharmacophore with two hydrogen bond acceptors, one hydrogen bond donor and two aromatic ring features was generated for a series of benzofuran salicylic acid derivatives as LYP inhibitors in order to elucidate their anti-autoimmune activity. The generated pharmacophore yielded a significant 3D-QSAR model with r² of 0.9146 for a training set of 27 compounds. The model also showed excellent predictive power with Q² of 0.7068 for a test set of eight compounds. The investigation of the 3D-QSAR model has revealed the structural insights which could lead to more potent analogues. The most active and inactive compounds were further subjected to electronic structure analysis using density functional theory (DFT) at B3LYP/3?21^?G level to support the 3D-QSAR predictions. The results obtained from this study are expected to be useful in the proficient design and development of benzofuran salicylic acid derivatives as inhibitors of LYP.     

Unidirectional growth,optical, mechanical and dielectric studies on a novel NLO crystal: l-Arginine 4-nitrophenolate 4-nitrophenol dihydrate

The bulk single crystal of l-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP), an efficient organic NLO material of size 74 mm in length, 18 mm in diameter, was grown successfully by Sankaranarayanan–Ramasamy (SR) method. Single crystal X-ray diffraction study reveals that LAPP crystallizes into monoclinic system with the space group P2₁. The unidirectional growth along the plane (1 1 0) was confirmed from the powder XRD pattern with the sharp peak having maximum intensity. Optical absorption spectrum shows that LAPP has highly transparent in the entire visible and IR region with a wide band gap of 3.9 eV for large photon absorption. Vickers micro hardness measurement was performed to know the mechanical strength of the crystal. Dielectric profile of LAPP at room temperature brings forth low value of dielectric loss and dielectric constant at higher frequencies. Photoluminescence study reveals that LAPP exhibit green emission in the wavelength region 538 nm. The SHG efficiency of the crystal is measured by Kurtz's powder test using Nd:YAG Laser.     

Investigations on the Interactions of λPhage-Derived Peptides Against the SrtA Mechanism in Bacillus anthracis

Bacillus anthracis is a well-known bioweapon pathogen, which coordinates the expression of its virulence factors in response to a specific environmental signal by its protein architecture. Absences of sortase signal functioning may fail to assemble the surface linked proteins and so B. anthracis cannot sustain an infection with host cells. Targeting the signaling mechanism of B. anthracis can be achieved by inhibition of SrtA enzyme through λphage-derived plyG. The lysin enzyme plyG is experimentally proven as bacteriolytic agent, specifically kill's B. anthracis by inhibiting the SrtA. Here, we have screened the peptides from λphage lysin, and these peptides are having the ability as LPXTG competitive inhibitors. In comparison to the activator peptide LPXTG binding motif, λphage lysin based inhibitor peptides are having much supremacy towards binding of SrtA. Finally, peptide structures extracted from PlyG are free from toxic, allergic abilities and also have the ability to terminate the signal transduction mechanism in B. anthracis.     

Catalytic activity of TiO2 nanoparticles in the synthesis of some 2,3-disubstituted dihydroquinazolin-4（1H）-ones

Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties （catalytic activity）. Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of eco- friendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles （TiO2 NPs） were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4（l1H）-one synthesis. Synthesized compounds were confirmed using FT-IR.1H NMR, 13C NMR and GC-MS analyses.     

Dissipative sampled‐data control of uncertain nonlinear systems with time‐varying delays

This article investigates the delay‐dependent robust dissipative sampled‐data control problem for a class of uncertain nonlinear systems with both differentiable and non‐differentiable time‐varying delays. The main purpose of this article is to design a retarded robust control law such that the resulting closed‐loop system is strictly (Q, S, R)‐dissipative. By introducing a suitable Lyapunov–Krasovskii functional and using free weighting matrix approach, some sufficient conditions for the solvability of the addressed problem are derived in terms of linear matrix inequalities. From the obtained dissipative result, we deduce four cases namely, H_∞ performance, passivity performance, mixed H_∞, and passivity performance and sector bounded performance of the considered system. From the obtained result, it is concluded that based on the passivity performance it is possible to obtain the controller with less control effort, and also the minimum H_∞ performance and the maximum allowable delay for achieving stabilization conditions can be obtained via the mixed H_∞ and passivity control law. Finally, simulation studies based on aircraft control system are performed to verify the effectiveness of the proposed strategy. © 2015 Wiley Periodicals, Inc. Complexity 21: 142–154, 2016     

Dissipative analysis for discrete‐time systems via fault‐tolerant control against actuator failures

This article investigates the problem of robust dissipative fault‐tolerant control for discrete‐time systems with actuator failures. Based on the Lyapunov technique and linear matrix inequality (LMI) approach, a set of delay‐dependent sufficient conditions is developed for achieving the required result. A design scheme for the state‐feedback reliable dissipative controller is established in terms LMIs which can guarantee the asymptotic stability and dissipativity of the resulting closed‐loop system with actuator failures. In addition, the proposed controller not only stabilize the fault‐free system but also to guarantee an acceptable performance of the faulty system. Also as special cases, robust H_∞ control, passivity control, and mixed H_∞ and passivity control with the prescribed performances under given constraints can be obtained for the considered systems. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed fault‐tolerant control technique. © 2016 Wiley Periodicals, Inc. Complexity 21: 579–592, 2016     

Selective synthesis of vitamin K3 over mesoporous NbSBA-15 catalysts synthesized by an efficient hydrothermal method

Well hexagonally ordered NbSBA-15 catalysts synthesized by an efficient hydrothermal method were used, for the first time, for the selective synthesis of vitamin K(3) by liquid-phase oxidation of 2-methyl-1-naphthol (2MN1-OH) under various reaction conditions. The recyclable NbSBA-15 catalysts were also reused to find their catalytic activities. To investigate the leaching of non-framework niobium species on the surface of silica networks, the results of original and recyclable NbSBA-15 catalysts were correlated and compared. To find an optimum condition for the selective synthesis of vitamin K(3), the washed NbSBA-15(2.2pH) was extensively used in this reaction with various reaction parameters such as temperature, time and ratios of reactant (2M1N-OH to H(2)O(2)), and the obtained results were also demonstrated. Additionally, the liquid-phase oxidation of 2M1N-OH was carried out with different solvents to find the best solvent with a good catalytic activity. Based on the all catalytic studies, the vitamin K(3) selectivity (97.3%) is higher in NbSBA-15(2.2pH) than that of other NbSBA-15 catalysts, and the NbSBA-15(2.2pH) is found to be a highly active and eco-friendly heterogeneous catalyst for the selective synthesis of vitamin K(3).     

Optimization of Elicitation Conditions with Methyl Jasmonate and Salicylic Acid to Improve the Productivity of Withanolides in the Adventitious Root Culture of Withania somnifera (L.) Dunal

Adventitious root cultures derived from leaf derived callus of Withania somnifera (L.) Dunal were treated with methyl jasmonate and salicylic acid independently. Biomass accumulation, culture age, elicitation period, and culture duration were optimized for higher withanolides production in the two best-responding varieties collected from Kolli hills (Eastern Ghats) and Cumbum (Western Ghats) of Tamil Nadu, India. Between the two elicitors, salicylic acid (SA) improved the production of major withanolides (withanolide A, withanolide B, withaferin A, and withanone) as well as minor constituents (12-deoxy withastramonolide, withanoside V, and withanoside IV) in the Kolli hills variety. Treatment of root biomass (11.70?g FW) on 30-day-old adventitious root cultures with 150???M SA for 4?h elicitor exposure period resulted in the production of 64.65?mg?g^?l dry weight (DW) withanolide A (48-fold), 33.74?mg?g^?l DW withanolide B (29-fold), 17.47?mg?g^?l DW withaferin A (20-fold), 42.88?mg?g^?l DW withanone (37-fold), 5.34?mg?g^?l DW 12-deoxy withastramonolide (nine fold), 7.23?mg?g^?l DW withanoside V (seven fold), and 9.45?mg?g^?l DW withanoside IV (nine fold) after 10?days of elicitation (40th day of culture) when compared to untreated cultures. This is the first report on the use of elicitation strategy on the significant improvement in withanolides production in the adventitious root cultures of W. somnifera.