An efficient synthesis of New chiral oxazolines

Several new chiral oxazolines were prepared conveniently in good to high yields using a two-step synthesis involving formation of an optically active amide, in situ conversion of the amide into tosylate (OTs) and finally ring closing reaction under MW irradiation (800 W) in solvent free condition. A comparison of these results with those obtained from the ring closing reaction under classical conditions was also made.     

Microwave-assisted simple, one-pot, four-component synthesis of 2,4,6-triarylpyrimidines under solvent-free conditions

2,4,6-Triarylpyrimidines are synthesized via a simple, one-pot, four-component reaction between aryl methyl ketones, benzaldehydes, aromatic nitriles, and hydroxylamine under microwave irradiation and solvent-free conditions in good to excellent yields.     

Correlation between biological activity and energies of electronic transitions in benzodiazepines. Negative ion mass spectrometry and ultraviolet absorption spectroscopy study of some derivatives

A correlation between the energies of electronic singlet transitions in benzodiazepines and their biological activity, which was revealed earlier by means of negative ion mass spectrometry with resonance electron capture, has been verified with a UV absorption spectroscopy investigation. Also, it has been noted that the energies of electronic singlet transitions in benzodiazepines are close in value to the ionization energies of atoms Cs, Rb, K, Na, Li and Tl, the cations of which are known to play an important role in nerve cell excitation processes. Copyright 1999 John Wiley & Sons, Ltd.     

Numerical experiments on a hybrid WENO5 filter for shock‐capturing

In the present paper, a hybrid filter is introduced for high accurate numerical simulation of shock‐containing flows. The fourth‐order compact finite difference scheme is used for the spatial discretization and the third‐order Runge–Kutta scheme is used for the time integration. After each time‐step, the hybrid filter is applied on the results. The filter is composed of a linear sixth‐order filter and the dissipative part of a fifth‐order weighted essentially nonoscillatory scheme (WENO5). The classic WENO5 scheme and the WENO5 scheme with adaptive order (WENO5‐AO) are used to form the hybrid filter. Using a shock‐detecting sensor, the hybrid filter reduces to the linear sixth‐order filter in smooth regions for damping high frequency waves and reduces to the WENO5 filter at shocks in order to eliminate unwanted oscillations produced by the nondissipative spatial discretization method. The filter performance and accuracy of the results are examined through several test cases including the advection, Euler and Navier–Stokes equations. The results are compared with that of a hybrid second‐order filter and also that of the WENO5 and WENO5‐AO schemes.     

Synthesis of Competitive Inhibitors of Phospholipase A 2 (PLA 2 )

The synthetic routes for preparation of several phospholipid analogues such as lithium alkyl-3-alkoxy allylvinyl-sn-glycerol 5 and 6 and lithium trans-2-amidomethyl phosphate 7 and lithium cholesterol ester phosphate 8 containing ether, amide, and phosphate ester moieties are described.     

A sustainable approach to the Ugi reaction in deep eutectic solvent

The Ugi reaction goes fast with high yields in a recyclable and biodegradable low-melting mixture of choline chloride and urea (DES) as a novel and efficient reaction medium. The DES is applicable to a wide range of aldehydes, amines, isocyanides, and acids in good to excellent isolated yields (60–92%) and short reaction times (2–5 h) and can be reused four times without any loss of activity.     

Design,in silico,one-pot synthesis,and biological evaluations of novel bis-urea analogs

Research on Chemical Intermediates - The structure of urea has received special attention due to its biological activity. A new and efficient one-pot three-component reaction for the synthesis of...     

Chemo- and diastereoselective synthesis of new oxa[3.3.3]propellane via a domino cascade four-component reaction based on diketene

A highly convergent, eco-friendly and straightforward synthesis of new O-fused heterocycles, functionalized indeno[1,2-b]furan derivatives was successfully accomplished through a one-pot four-component cascade reaction involving, ninhydrin, malononitrile, diketene and various primary amines in the presence of a catalytic quantity of triethylamine in ethanol at ambient temperature, in one pot fashion. This new efficient cascade reaction generates two rings by the simultaneous construction of C-N (one), C-O (two) and C-C (two) multiple bonds, presumably through a sequence of Knoevenagel reaction/Michael addition/intramolecular O-cyclization and imine-enamine/keto-enol tautomerization. The merits of this protocol are highlighted as utilization of inexpensive commercially accessible starting materials, operational simplicity, atom economy, clean reaction profile, simple work-up procedure being conducted at ambient temperature in relatively short reaction times, preventing chromatographic purification, giving excellent yields, and tolerance to a wide variety of functional groups.     

In Vitro Assessment of Poly (Vinyl Alcohol) Film Incorporating Aloe Vera for Potential Application as a Wound Dressing

Since skin tissue acts as a vital protective barrier between the body and the external atmosphere, the repair or regeneration of skin injuries serves as a great challenge in regenerative medicine. Herein, hydrogel films composed of poly vinyl alcohol (PVA) and aloe vera (AV) extracted gel were prepared and characterized for wound dressing application. The physical and morphological properties, water absorption capacity, biodegradation behavior, and water transmission rate were characterized for several variations in the AV content (0–50%). The cytocompatibility of the films, as well as cell morphology in response to different films, was assessed using MTT assay and SEM, respectively. According to the results, AV incorporation improved the surface morphology, water absorption capacity, in vitro degradation rate, and water vapor permeability of the PVA films. However, these properties were affected by the AV content. The mechanical properties of the films were enhanced by introducing AV up to 30%, and then decreased significantly with further AV increase. Evaluation of fibroblast proliferation showed that AV can positively improve the bioactivity of the films without any cytotoxicity. In conclusion, the results demonstrated that PVA/AV optimized hydrogel film can be suggested as promising wound dressings for improving wound treatment.