Microwave-Assisted Chemoselective Regeneration of Carbonyl Compounds from Oximes by Silica Chromate/WET SiO2 Under Solvent-Free Conditions

The regeneration of carbonyl compounds from oximes were performed by using silica chromate and wet SiO ₂ (w/w 50%) under microwave irradiation and solvent-free conditions with excellent yields.     

SYNTHESIS OF NEW BENZOSULFOXIDE MACROCYCLIC COMPOUNDS

Bis(dibenzosulfoxo)-27,30,35,38-tetramethyl-24-crown-6, bis(dibenzosulfoxo)-21,24,29,32-tetramethyl-18-crown-4, dibenzosulfoxo-15,18-dimethyl-12-crown-3 and dibenzosulfoxo-12,15-dimethyl-9-crown-2 macrocycles are synthesized by the reaction of 2,2′-sulfinyl-bis(4-methyl phenol)and 1,2-dibromoethane and diethyleneglycol di-p-toluenesulfonate.     

Synthesis of New Aza Thia Crowns Bearing 2,2′-Diaminodiphenyl Disulfide

Abstract

New aza thia crowns were prepared from the reaction of 2,2′-diaminodiphenyl disulfide and diacids or diacid chlorides. Diacids are malonic acid, adipic acid, sebacic acid, and 2,2′-thiodiacetic acid and diacid dichlorides are malonyl chloride, adipoyl chloride, sebacoyl chloride, and 2,2′-thiodiacetyl chloride.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures.]     

Efficient Route for the Synthesis of New Dinaphthosulfoxide Aza Crowns Using Ethyleneglycol Under Microwave (MW) Irradiation: Macrocyclization is Preferred to Oligomerization Under MW Irradiation

Abstract

New dinaphthosulfoxide aza crowns were prepared from the corresponding dinaphthosulfoxide diester and diamines under reflux conditions (conventional heating) and microwave (MW) irradiation. These reaction routes were used for the synthesis of a series of aza crowns, such as dinaphthosulfide, dinaphthosulfone, dibenzosulfide, and dibenzosulfoxide. The synthesis of aza crowns under MW irradiation in comparison with conventional heating has several advantages, such as shorter reaction times, simpler reaction conditions, and the use of ecofriendly solvents, higher yields, and regioselectivity. In the MW synthesis, macrocyclization is preferred to oligomerization, and thus, the yields of byproducts are low.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT      

Synthesis of New 1-Naphthol Aza Oxa Thia Crowns

Abstract

New dinaphthosulfide aza oxa thia crowns from 1-naphthol were prepared. At first, 2,2′-thiobis(1-hydroxynaphthalene) (a dinaphthol) was prepared from 1-naphthol. Then diester was prepared from the reaction of dinaphthol and methylchloroacetate. Aza crowns were synthesized from the reaction of diester and diamines (ethylene diamine, 1,3-diaminopropane, 1,4-diaminobutane, and 1,6-diaminohexane) in methanol.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT      

A low-cost optimization framework to solve muscle redundancy problem

Prediction of muscle activations based on optimization procedures mostly leads to a prohibitive computational effort. To overcome this problem, an optimization framework by reformulation of the so-called method of extended inverse dynamics (EID) was developed. A planar, seven-segment model with sixteen muscle groups was used to represent human neuromusculoskeletal dynamics. The muscle activations were estimated based on two methods: EID, which treats the system dynamics (compatibility between muscular and skeletal torques), as an equality constraint, and the proposed method, which employs unconstrained system dynamics of EID (USDEID). The proposed method is based on the idea that the EID equality constraint, which is difficult to satisfy, can be eliminated by reformulation of the governing equations and optimization variables, which not only relaxes the optimization problem and leads to less optimization parameters, but also guarantees the full compatibility of the system dynamics. The comparison of simulation results of optimal muscle activations against experimental data showed a reasonable agreement for both methods during half of a gait cycle. Optimization results showed that USDEID is not only more accurate than EID in terms of the compatibility between the skeletal and muscular system dynamics, but also approximately eight times faster for ten random initial values. USDEID may be used to predict muscle activations, when the computational cost becomes prohibitive.     

Investigation of electronic and optical properties of (CdSe/ZnS/CdSe/ZnS) quantum dot–quantum well heteronanocrystal

In this article, we have investigated the photoluminescence intensity of quantum dot–quantum well heteronanocrystal with non-linear potential profile which has been analyzed by the finite element numerical methods and is compared with traditional potential profile of same heteronanocrystal. We have probed the effect of carrier localization in layers of heteronanocrystal on the photoluminescence intensity. Moreover, the effects of variation of radius layers such as CdSe core, shell, and ZnS barriers radius on the photoluminescence intensity are studied. Besides, for the first time, we demonstrated the shift of quantum dot–quantum well operation wavelength by introducing non-linear potential profile in the core of heteronanocrystal that can be drastically affected on biological application. Furthermore, in biological application, by tuning the emission wavelengths of quantum dot into the far-red and near-infrared ranges, the non-invasive in vivo imaging technique was developed. In this wavelength window, tissue absorption, scattering, and auto-fluorescence intensities have minimum quantities. In our article with new structure, the relation between size and operation wavelength don’t follow traditional relation.     

Three component reactions of N‐nucleophiles and activated acetylenes with NH‐acids: A facile synthesis in water

A straightforward and efficient method for the synthesis of 1,2‐dihydroisoquinolines via a one‐pot, three‐component reaction of isoquinoline, activated acetylenes, and NH‐acids in water at 70°C without using any catalyst is reported. The method offers several advantages including high yields of products and an easy workup procedure. J. Heterocyclic Chem., (2012).     

Optical transmission properties of light propagation through Fibonacci-class ring-resonators

An interesting topology with easy integration capability (from mask designing aspect) for optical filters using Fibonacci-class (FC(J,n)) ring-resonators is introduced. For some special cases, analytical transfer function (Transmission Coefficient H_m⁽ⁿ⁾) is obtained and corresponding simulated result is illustrated. In this work, optical multi-band filter design and analysis using Fibonacci-class ring resonators is considered. With suitable selection of system parameters and FC(J,n), we report multi-band characteristic for this structure. Also, dominant factors effects on multi-band operation are shown. We show that the coupling coefficients, effectively affects (e.g. generation or annihilation of additional band) the multi-band properties obtained in proposed structure. Also, the bandwidth and position of additional band can be controlled using Fibonacci-class basic elements (A, B) parameters such as rings diameters. Also, proposed system is easier than general multistage rings coupled to main waveguide from implementation point of view.