Electron-deficient chiral lactic acid-based hypervalent iodine reagents

Novel electron-deficient chiral hypervalent iodine reagents were prepared in good overall yields. The reactivity and stereoselectivity of these reagents in oxidative rearrangements of alkenes to α-aryl ketones were investigated. The results show that the new reagents have good reactivity and generate products with high enantiomeric excess

Mechanochemical synthesis of N-tert-butanesulfinyl imines under metal-free conditions

A simple and convenient mechanochemical method for the condensation of aldehydes with tert-butanesulfinamide using catalytic amounts of iodine under metal- and solvent-free conditions is described

Hypervalent iodine reagents by anodic oxidation: a powerful green synthesis

The anodic oxidation of aryl iodides is a powerful method for the synthesis of hypervalent iodine reagents, which eliminates the necessity to use expensive or hazardous chemical oxidizing reagents. The hypervalent iodine reagents generated at the anode are successfully used as either in‐cell or ex‐cell mediators for different valuable chemical transformations such as fluorinations and oxidative cyclizations. More recently, recyclable mediators and catalytic protocols have been developed

Investigation of pulse dispersion in a carrier-based UWB system with LO leakage cancellation

Local oscillator (LO) leakage in a carrier-based ultrawideband (UWB) system is a major design concern. In many cases, mixer LO-RF isolation is not sufficient and the LO leakage is well above the useful UWB signal. However, this leakage can be substantially reduced by using a notch filter located before the UWB transmitting antenna as long as it will not lead to unacceptable signal distortion. Therefore, various filter parameters, such as the filter order and 3 dB rejection bandwidth, have been studied to see their effects on providing sufficient band rejection level to reduce the unwanted LO leakage while minimizing the transmitted pulse dispersion. Time domain simulations and measurements have been utilized to evaluate the pulse dispersion using both the relative signal's first pulse amplitude and the pulse time delay spread. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64339/1/20390_ftp.pd

'Dark' singlet oxygen made easy

An operationally simple continuous flow generator of ‘dark’ singlet oxygen has been developed. The singlet oxygen was efficiently reacted with several chemical traps to give the corresponding oxygenated products in high yields. The developed ‘dark’ singlet oxygen generator has been successfully applied in the synthesis of the antimalarial drug artemisinin

Laser and radiofrequency-induced hyperthermia treatment via gold-coated magnetic nanocomposites

Alsayed AM Elsherbini1, Mahmoud Saber2, Mohamed Aggag2, Ahmed El-Shahawy2, Hesham AA Shokier11National Institute of Laser Enhanced Science, 2Children's Cancer Hospital, Cairo, EgyptIntroduction: The current radiofrequency ablation technique requires invasive needle placement. On the other hand, most of the common photothermal therapeutic methods are limited by lack of accuracy of targeting. Gold and magnetic nanoparticles offer the potential to heat tumor tissue selectively at the cellular level by noninvasive interaction with laser and radiofrequency.Methods: Gold nanospheres and gold-coated magnetic nanocomposites were used for inducing hyperthermia to treat subcutaneous Ehrlich carcinoma implanted in female mice.Results: In mice treated with gold nanospheres, tumors continued to grow but at a slow rate. In contrast, more than 50% of the tumors treated with gold-coated magnetic nanocomposites completely disappeared.Conclusion: This simple and noninvasive method shows great promise as a technique for selective magnetic photothermal treatment.Keywords: laser, hyperthermia, gold magnetic nanocomposites, Ehrlich carcinom

C−N axial chiral hypervalent iodine reagents: catalytic stereoselective α‐oxytosylation of ketones

A simple synthesis of a library of novel C−N axially chiral iodoarenes is achieved in a three‐step synthesis from commercially available aniline derivatives. C−N axial chiral iodine reagents are rarely investigated in the hypervalent iodine arena. The potential of the novel chiral iodoarenes as organocatalysts for stereoselective oxidative transformations is assessed using the well explored, but challenging stereoselective α‐oxytosylation of ketones. All investigated reagents catalyse the stereoselective oxidation of propiophenone to the corresponding chiral α‐oxytosylated products with good stereochemical control. Using the optimised reaction conditions a wide range of products was obtained in generally good to excellent yields and with good enantioselectivities

Synthesis, characterisation, and reactivity of novel pseudocyclic hypervalent iodine reagents with heteroaryl carbonyl substituents

Two new hypervalent iodine reagents containing furan and thiophene moieties in addition to a carbonyl group in the vicinity of the iodine atom were synthesised and characterised. The X-ray analysis of both compounds revealed a strong intramolecular contact between the carbonyl oxygen and the hypervalent iodine atom with tosylate as a counter ion. The two reagents showed a broad range of synthetic applications and proved to be versatile oxidizing agents

Continuous electrochemical generator of hypervalent iodine reagents: synthetic applications in flow

An efficient and reliable electrochemical generator of hypervalent iodine reagents has been developed. In the anodic oxidation of iodoarenes under flow conditions to hypervalent iodine reagents the use of electricity replaces hazardous and costly chemical oxidants. Unstable hypervalent iodine reagents can be prepared easily and coupled with different substrates to achieve oxidative transformations in high yields. The unstable electrochemically generated reagents can also easily be transformed into classic bench stable hypervalent iodine reagents via ligand exchange. The combination of electrochemical and flow chemistry advantages largely improves the ecological footprint of the overall process compared to conventional approaches

The New Kumaraswamy Kumaraswamy Family of Generalized Distributions with Application

<p>Finding the best fitted distribution for data set becomes practically an important problem in world of data sets so that it is useful to use new families of distributions to fit more cases or get better fits than before.  In this paper, a new generating family of generalized distributions so called the Kumaraswamy - Kumaraswamy (KW-KW) family is presented. Four important common families of distributions are illustrated as special cases from the KW KW family. Moments, probability weighted moments, moment generating function, quantile function, median, mean deviation, order statistics and moments of order statistics are obtained. Parameters estimation and variance covariance matrix are computed using maximum likelihood method. A real data set is used to illustrate the potentiality of the KW KW weibull distribution (which derived from the kw kw family) compared with other distributions.</p