Facile synthesis,characterisation and anti‐inflammatory activities of ferrocenyl ester derivatives of 4‐arylidene‐5‐imidazolinones

This article describes the synthesis, optoelectronic properties and anti‐inflammatory activities of a series of seven ferrocenyl ester‐linked 4‐arylidene‐5‐imidazolinone conjugates. Three different types of ortho‐, meta‐ and para‐substituted ferrocenyl esters have been prepared. Their UV–Vis spectra and electrochemical studies are described. The structure of one of the conjugates was confirmed by single‐crystal X‐ray diffraction study. These conjugates exhibited moderate anti‐inflammatory activities.     

Sonochemical Effect on Activity and Conformation of Commercial Lipases

The enzyme under lower-intensity ultrasonic irradiation leads to favourable conformational changes, thereby enhancing its activity. The augmentation of activity of ultrasound-treated enzyme is strongly dependent on ultrasound intensity, duty cycle and exposure time, which was investigated for commercial lipases. Thermomyces lanuginosus (TL) lipase showed a 1.3-fold enhanced activity after irradiating at 22 kHz and 11.38 W cm^?2 with 50 % duty cycle for 25-min ultrasonic treatment and 1.5-fold enhanced activity was observed for lipozyme (candida antarctica lipase B (CALB)) lipase, at 22 kHz and 15.48 W cm^?2 with 66.67 % duty cycle for 20-min ultrasonic treatment. After sonication, thermodynamic parameters viz. E _a, ΔH, ΔS and ΔG were evaluated and values were found to be significantly lower for both lipases. In addition, the changes in secondary structure due to sonication were investigated by using Fourier transform infrared (FT-IR), which revealed increase in a certain number of random coiled structure, loss of β-sheets, β-turns and α-helix content in TL lipase and CALB lipase. Also, fluorescence spectroscopy exhibited the increased number of tryptophan on surface of both lipases. Moreover, particle size distribution after sonication also helped to improve surface area and enhanced mass transfer, which contributed to improvement in lipase activity.     

Nanocellulose for biosorption of chlorpyrifos from water: chemometric optimization,kinetics and equilibrium

The study explores the biosorption potential of nanocellulose (NC) to remove an insecticide, chlorpyrifos (CP), from aqueous solutions using the batch method. Biosorption kinetics were very fast and reached equilibrium in 60 min, and the experimental kinetic data had fit well with the pseudo-second-order model. Film diffusion was the rate-limiting step for the biosorption of CP onto crystalline nanocellulose (CNC). The equilibrium sorption was well described by the Sips and Langmuir isotherm models. The values of maximum sorption capacities (7.237–5.017 mg/g for the Sips and 12.325–7.247 mg/g for the Langmuir model) decreased with an increase in temperature from 288 to 308 K, signifying biosorption of CP is an exothermic process. Based on the central composite design (CCD), two-factor interaction (2FI) and quadratic models, the correlation between the effects of variable parameters on the CP biosorption onto NC was evaluated. The chemometric analyses suggested that 1.5 g/l NC required 20 min to biosorb 5 mg/l CP to yield an efficiency of 99.3%. Overall, the results demonstrated that NCs can be a promising biosorbent for the removal of pesticides from aqueous streams.     

Geometry and differentiability requirements in multibody railroad vehicle dynamic formulations

The dynamic equations of multibody railroad vehicle systems can be formulated using different sets of generalized coordinates; examples of these sets of coordinates are the absolute Cartesian and trajectory coordinates. The absolute coordinate based formulations do not require introducing an intermediate track coordinate system since all the absolute coordinates are defined in the global system. On the other hand, when the trajectory coordinates are used, a track coordinate system that follows the motion of a body in the railroad vehicle system is introduced. This track coordinate system is defined by the track geometry and the distance traveled by the body along the track centerline. The configuration of the body with respect to the track coordinate system is defined using five coordinates; two translations and three Euler angles. In this paper, the formulations based on the absolute and trajectory coordinates are compared. It is shown that these two sets of coordinates require different degrees of differentiability and smoothness. When an elastic contact formulation is used to study the wheel/rail dynamic interaction, there are significant differences in the order of the derivatives required in both formulations. In fact, as demonstrated in this study, in the absence of a contact constraint formulation, higher order derivatives with respect to geometric parameters are still required when the equations are formulated using the trajectory coordinates. The formulation of the constraints used in the analysis of the wheel/rail contact is discussed and it is shown that when the absolute coordinates are used, only third order derivatives need to be evaluated. The relationship between the track frame used in railroad vehicle dynamics and the Frenet frame used in the theory of curves to describe the curve geometry is also discussed in this paper. Based on the analysis presented in this paper, the advantages and drawbacks of a hybrid method which employs both the absolute and trajectory coordinates and planar contact conditions in order to reduce the number of contact constraints and relax the differentiability requirements are discussed. In this method, the absolute coordinates are used to formulate the equations of motion of the railroad vehicle system. The absolute coordinate solution can be used to determine the trajectory coordinates and their time derivatives. Using the trajectory coordinates, the motion of the body in the vehicle with respect to the track coordinate system can be predicted and used in the formulation of the planar contact model.     

Sulfated polyborate catalyzed expeditious and efficient three-component synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones

A rapid and highly efficient methodology for the synthesis of 3-methyl-4-(hetero)arylmethylene isoxazole-5(4H)-ones has been developed using sulfated polyborate as a catalyst. The multicomponent reaction of an aromatic/heterocyclic aldehyde, hydroxylamine hydrochloride, and ethyl acetoacetate under a solvent free condition at 80 °C is described. This protocol has promising features for the reaction response such as shorter reaction time, easy work-up, ease of separation of pure product with high yields and simplicity in the experimental procedure. The products have been obtained in high yields (80–90%) and convenient reaction time (15–30 min). The method is operationally simple and eco-friendly.     

Fundamental studies on the feasibility of deep eutectic solvents for the selective partition of glaucarubinone present in the roots of Simarouba glauca

Several deep eutectic solvents prepared by the complexation of choline chloride as the hydrogen bond acceptor and hydrogen bond donors such as urea, thiourea, ethylene glycol, and glycerol were employed to partition glaucarubinone, an antimalarial compound present in roots of the plant, Simarouba glauca. Among all the solvents, the deep eutectic solvent consisting of the mixture of choline chloride and urea the most suitable to partition the antimalarial compound from the extract selectively. Analytical tools such as high‐performance liquid chromatography and electrospray ionization mass spectrometry were used for characterizations, and glaucarubinone extracted from the roots of the plant by conventional solvent extraction method was used as a reference for comparison. The hydrogen and noncovalent bonds formed between glaucarubinone and the deep eutectic solvents could be responsible for the selective partition of the drug molecule.     

Nucleophilic debenzoylation of p‐nitrophenyl benzoate in cationic micellar media

Pseudo‐first‐order rate constants for the nucleophilic debenzoylation reaction of p‐nitrophenyl benzoate with various hydroxamate ions [RC = ONHO^?] were investigated in aqueous cationic micellar media at pH 7.8 and 27°C. The kinetic rate data of the reaction revealed that the nucleophilic reactivity sequence of these hydroxamate ions is generally benzohydroxamic acid > salicylhydroxamic acid > acetohydroxamic acid. The k_obs value increases upon addition of cationic surfactants to the reaction medium involving interfacial ion exchange between bulk aqueous media and micellar pseudophase. The effect of surfactant head and tail group is discussed. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 106–112, 2010