Syntheses and Configuration Inversion of Substituted Oxazolines

The present paper covers the simply and highly stereoselective syntheses of (α-S, 4S)-2-dichloromethyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol (4a), (α-S, 4S)-2-methyl-4, 5-dihydro-α-(4-nitrophenyl)-4-oxazolemethanol (4b), and (α-R, 4R)-2-dichloromethyl-4, 5-dihydro-α-[(4-methylsulfonyl)phenyl]-4-oxazolemethanol(4c) with good yields(80%—90%). A configuration inversion product, (1R, 2S)-2-dichloroacetamido-1-(4-nitrophenyl)-1, 3-propanediol (8), was obtained during our attempting to convert compound 4a into (4S, 5R)-2-(dichloromethyl)-4, 5-dihydro-5-(4-nitrophenyl)-4-oxazolemethanol(7).

Toroidicity and shape dependence of peeling mode growth rates in axisymmetric toroidal plasmas

The growth rate of the peeling mode instability with large toroidal mode number is calculated for general axisymmetric toroidal plasmas, including tokamaks and the spherical toms （ST） equilibia by using formalism presented by Connor et al. Analytic equilibia with non-zero edge current density and quasi-uniform current profiles are assumed. It is found that in sharp D-shape tokamak plasma, the derivative of the safety factor with respect to the poloidal flux becomes very large, making the perturbed poloidal motion very large, in turn making a significant reduction of the growth rate of the peeling mode, similar to the X-point effect in diverted plasma. The large aspect ratio effect is also studied, which reduces the growth rate further.

Metal-free C(sp^(2))-H perfluoroalkylsulfonylation and configuration inversion:Stereoselective synthesis ofα-perfluoroalkylsulfonyl E-enaminones

The perfluoroalkylsulfonylation(CF_(3)SO_(2),C_(2)F_(5)SO_(2)and CHF_(2)SO_(2))in the enaminone C-H bonds has been developed simply via the promotion of molecular iodine by using stable and cheap sodium perfluoroalkyl sulfinates as coupling partners.The stereoselective synthesis of E-configuratedα-perfluoroalkylsulfonyl enaminones has been realized via unprecedented C-H bond elaboration and C=C double bond configuration inversion by free radical process.

An easy route to exotic 9-epimers of 9-amino-(9-deoxy) cinchona alkaloids with(8S,9R) and(8R,9S)-configurations through two inversions of configuration

Four exotic chiral organocatalysts, 9-amino-（9-deoxy） cinchona alkaloids with （8S, 9R） and （8R, 9S）- configurations, were conveniently synthesized for the first time in 27-72% total yields through two conversions of configuration at the 9-stereogenic centers of commercially available cinchona alkaloids.

Simultaneous inversion of configurations of C_(22),C_(23) in 24S-ethyl-3,5-cyclo-cholestane-22S,23S-diol-6-one

In this paper,obtainment of 3 by simultaneous inversion of configurations of C_(22),C_(23) in 2 via its ditosylate or dimesylate was unsuccessful,leading to elimination products instead.However, monotosylate of 2 can be readily obtained with exclusive regioselectivity,which in turn gave a single epoxide 7b Hydrolysis of 7b gave 3 and 2 is a ratio of 2:1,with a combined yield of 80%.The recovered 2 can of course be recycled again.

Aerodynamic Design Methodology for Blended Wing Body Transport

This paper puts forward a design idea for blended wing body（BWB）.The idea is described as that cruise point,maximum lift to drag point and pitch trim point are in the same flight attitude.According to this design idea,design objectives and constraints are defined.By applying low and high fidelity aerodynamic analysis tools,BWB aerodynamic design methodology is established by the combination of optimization design and inverse design methods.High lift to drag ratio,pitch trim and acceptable buffet margin can be achieved by this design methodology.For 300-passenger BWB configuration based on static stability design,as compared with initial configuration,the maximum lift to drag ratio and pitch trim are achieved at cruise condition,zero lift pitching moment is positive,and buffet characteristics is well.Fuel burn of 300-passenger BWB configuration is also significantly reduced as compared with conventional civil transports.Because aerodynamic design is carried out under the constraints of BWB design requirements,the design configuration fulfills the demands for interior layout and provides a solid foundation for continuous work.