Design and synthesis of oxaprozin-1,3,4-oxadiazole hybrids as potential anticancer and antibacterial agents

In the present study, we report design, synthesis and screening of new novel 5-substituted-2-mercapto-1,3,4-oxadiazole analogues appended to oxaprozin for their in vitro anticancer and antibacterial activity. The synthesised compounds were characterized using various spectroscopic techniques. Furthermore, the structure of 5b (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-(ethylthio)-1,3,4-oxadiazole) was unequivocally confirmed by X-ray analysis. Among the series 5c (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-(propylthio)-1,3,4-oxadiazole) showed most promising anticancer activity against A549 cancer cell line and all the reported analogues manifested satisfactory safety profiles against human normal cell line HEK293T. The products exhibited good antibacterial activity and among the tested 5j (2-(2-[4,5-diphenyloxazol-2-yl]ethyl)-5-([4-fluorobenzyl]thio)-1,3,4-oxadiazole) exhibited most potent.     

A combined resonance-Doppler technique for studying bubble evolution in liquids

Gas bubbles in liquids have been studied for decades with a variety of optical and acoustic techniques. The evolution of a bubble consists of several stages, including formation and growth at a nozzle, detachment and resonance, and rise towards terminal velocity. Most existing techniques can monitor only a single aspect of the bubble behaviour. This work describes an acoustic technique to monitor all stages of an air bubble's evolution. The technique uses a combination of passive acoustic listening and active ultrasonic Doppler observation to study millimetre-sized air bubbles in liquid. A hollow cylindrical piezoelectric transducer, located around the nozzle used to produce the bubbles, detects the resonance of the bubble following its detachment. An ultrasonic Doppler system, positioned several centimetres above the nozzle, monitors both the growth and the rise of the bubble, including shape oscillations and the terminal velocity through the use of joint time-frequency analysis. Because all aspects of the bubble evolution are affected by the properties of the liquid, by monitoring the bubble evolution with this technique the rising bubble can potentially be used as a tool to characterize the liquid.     

Palladium-catalyzed C-CN activation for intramolecular cyanoesterification of alkynes

Conditions for the C-CN activation and intramolecular cyanoesterification of alkynes to provide butenolides in good to excellent yields are presented. Pd catalysts, high temperatures/short reaction times (microwave irradiation), and Lewis basic solvents minimized competitive decarbonylation. Less sterically encumbered, electron-rich alkynes underwent cyanoesterification with greater ease compared to sterically encumbered, electron-deficient alkynes. The results led to the hypothesis that migratory insertion of the alkyne, rather than C-CN activation, might be the product-determining step.     

Neural network-based nonlinear tracking control of kinematically redundant robot manipulators

In this paper, neural network-based nonlinear dynamical control of kinematically redundant robot manipulators is considered. The neural network-based controller achieves end-effector trajectory tracking as well as subtask tracking effectively. A feedforward neural network is employed to learn the parametric uncertainties, existing in the dynamical model of the robot manipulator. The whole system is shown to be stable in the sense of Lyapunov. Numerical simulation studies are carried out for a 3R planar robot manipulator to show the effectiveness of the control scheme.     

Thermodynamic properties of a magnetically modulated graphene monolayer

The effect of magnetic modulation on thermodynamic properties of a graphene monolayer in the presence of a constant perpendicular magnetic field is reported here. One-dimensional spatial electric or magnetic modulation lifts the degeneracy of the Landau levels and converts into bands and their bandwidth oscillates with magnetic field, leading to Weiss-type oscillations in the thermodynamic properties. The effect of magnetic modulation on the thermodynamic properties of a graphene sheet is studied and then compared with electrically modulated graphene and magnetically modulated conventional two-dimensional electron gas (2DEG). We observe Weiss-type and de Haas-van Alphen oscillations at low and high magnetic fields, respectively. There is a definite phase difference in Weiss-type oscillations in thermodynamic quantities of magnetically modulated graphene compared to electrically modulated graphene. On the other hand, the phase remains the same and the amplitude of the oscillation is large when compared with the magnetically modulated two-dimensional electron gas (2DEG). Explicit asymptotic expressions of the density of states and the Helmholtz free energy are provided to understand the phase and amplitude of the Weiss-type oscillations qualitatively. We also study thermodynamic properties when both electric and magnetic modulations are present. The Weiss-type oscillations still exist when the modulations are out-of-phase.     

Synthesis and biological activity of substituted 3-fluoro/3-trifluoromethyl 10H-phenothiazines, its ribofuranosides and sulfones

The present article describes the synthesis of new fluorinated 10H-phenothiazines by Smiles rearrangement. The reaction of these synthesized phenothiazines with sugar (beta-d-ribofuranose 1-acetate-2,3,5-tribenzoate) afforded the new ribofuranosides and the oxidation of these synthesized phenothiazines with 30% hydrogen peroxide in glacial acetic acid resulted in the formation of 10H-phenothiazine sulfones. These compounds were evaluated for their antioxidant and antimicrobial activities (using broth microdilution method). The structural assignments of the synthesized compounds were made on the basis of elemental analysis and spectroscopic data.     

Sequential coupling/desilylation-coupling/cyclization in a single pot under Pd/C-Cu catalysis: synthesis of 2-(hetero)aryl indoles

A new one-pot synthesis of 2-(hetero)aryl indoles via sequential C-C coupling followed by C-Si bond cleavage and a subsequent tandem C-C/C-N bond forming reaction is described. A variety of functionalized indole derivatives were prepared by conducting this four step reaction under Pd/C-Cu catalysis. The methodology involved coupling of (trimethylsilyl)acetylene with iodoarenes in the presence of 10% Pd/C-CuI-PPh(3) and triethylamine in MeOH, followed by treating the reaction mixture with K(2)CO(3) in aqueous MeOH, and finally coupling with o-iodoanilides. The single crystal X-ray data of a synthesized indole derivative is presented. Application of the methodology, in vitro pharmacological properties of the synthesized compound, along with a docking study is described.     

Effect of Microwave Irradiation on Xylanase Production from Wheat Bran and Biobleaching of Eucalyptus Kraft Pulp

Microwave irradiation (MWI) was used as pretreatment of wheat bran and eucalyptus kraft pulp to examine its effect on xylanase production by Bacillus halodurans FNP 135 using solid state fermentation and biobleaching with xylanase, respectively. Irradiation of wheat bran under optimized conditions (600?W, 6?min, and 20?% consistency) resulted in 56.8, and 31.7?% increase in xylanase yield and water absorbance of wheat bran and 17.3?% reduction in reducing sugars content. Optimized MWI of kraft pulp at 850?W, 2?min, and 20?% consistency led to 0.9?% increase in brightness, 10?% decrease in kappa number, 7.7?% increase in water absorbance, 4.6?% decrease in tear factor, 0.9?% increase in burst factor, and 7.5?% increase in viscosity. Also, MWI enhanced xylanase-mediated biobleaching by increasing brightness (1.1?%) and decreasing kappa number (14.3?%) and leading to a total of about 20?% reduction in chlorine consumption. MWI is an economical, efficient, and environment-friendly pretreatment of wheat bran and pulp for enhanced enzyme yield and rapid heating, respectively.     

Crystal and Molecular Structure Studies of 1′-Benzyl-8-(4-fluorobenzyl)-8-azaspiro[bicyclo-[3.2.1]octane-3,4′-imidazolodine]-2′,5′-dione

Abstract  

The title compound, C₂₃H₂₃FN₃O₂ has been synthesized and the structure was investigated by X-ray diffraction studies. The compound crystallizes in the triclinic crystal class in the space group P[`1]P\overline{1} with cell parameters a = 9.345(2) ?, b = 10.940(3) ?, c = 11.986(4) ?, α = 72.349(6)°, β = 68.106(18)°, γ = 66.867(5)°, Z = 2 and V = 1027.8(5) ?³. The hydantoin ring adopts a planar conformation and is affected by the π conjugation. The pyrrolidine and piperidine rings in the bicyclo octane moiety adopt envelope and chair conformations respectively. The structure exhibits both inter and intramolecular hydrogen bonds of the type N–H···O, C–H···O and C–H···N. One of the oxygen atoms attached to the hydantoin ring simultaneously accepts two hydrogen bonds to form a three centered hydrogen bonding pattern.