Stereoselective synthesis of (+)-5-thiosucrose and (+)-5-thioisosucrose

+)-5-Thiosucrose 1, a novel isosteric sulfur analog of sucrose, was synthesized stereoselectively for the first time via indirect β-d-fructofuranosidation involving selective β-d-psicofuranosidation, followed by stereo-inversion of the secondary hydroxy group at the C-3 position on the furanose ring. Glycosidation of protected 5-Thio-d-glucose with a d-psicofuranosyl donor provided β-d-psicofuranosyl 5-Thio-α-d-glucopyranoside and that with d-fructofuranosyl donor gave α-d-fructofuranosyl 5-Thio-α-d-glucopyranoside. Two anomeric stereocenters of the glycosyl donor and acceptor were controlled correctly to provide a single disaccharide among four possible anomeric isomers in the glycosylation. Conversion of the resulting disaccharides afforded (+)-5-Thiosucrose 1 and (+)-5-Thioisosucrose 2 in excellent yields, respectively. Inhibitory activities of 1 and 2 against α-glucosidase in vitro were also examined

Microstructure and Mechanical Behavior of AlCoCrFeNi HEA Particles Reinforced 6063Al Alloy Matrix Composites

Lightweight composites consisting of 6063 aluminum alloy matrix reinforced with AlCoCrFeNi high-entropy alloy (HEA) particles were fabricated by the powder metallurgy through hot pressing and hot extrusion under vacuum. A detailed microstructural characterization was carried out along with the analysis of mechanical properties. The results revealed that the observed uniform distribution of HEA powders and a good bonding strength resulted in an effective strengthening and increased plastic strain of the reinforced composite. The tensile properties of composites were effectively improved by the addition of 10 and 30 vol % of reinforcing HEA particles

Stereoselective synthesis of (+)-5-thiosucrose and (+)-5-thioisosucrose

+)-5-Thiosucrose 1, a novel isosteric sulfur analog of sucrose, was synthesized stereoselectively for the first time via indirect β-d-fructofuranosidation involving selective β-d-psicofuranosidation, followed by stereo-inversion of the secondary hydroxy group at the C-3 position on the furanose ring. Glycosidation of protected 5-Thio-d-glucose with a d-psicofuranosyl donor provided β-d-psicofuranosyl 5-Thio-α-d-glucopyranoside and that with d-fructofuranosyl donor gave α-d-fructofuranosyl 5-Thio-α-d-glucopyranoside. Two anomeric stereocenters of the glycosyl donor and acceptor were controlled correctly to provide a single disaccharide among four possible anomeric isomers in the glycosylation. Conversion of the resulting disaccharides afforded (+)-5-Thiosucrose 1 and (+)-5-Thioisosucrose 2 in excellent yields, respectively. Inhibitory activities of 1 and 2 against α-glucosidase in vitro were also examined

Materials selection considerations for high entropy alloys

Increased interest in high entropy alloys (HEA)s has led to significant activity in the development of new equimolar multicomponent metal systems. The present viewpoint article suggests applying a lens of practicality related to alloy economics and resource usage issues. A framework for HEA materials selection is presented to assist the metallurgical community as it searches for HEAs with feasible implementation possibilities, by identifying unsuitable alloying elements based on price or metrics of supply availability. For some metrics, such as price volatility, the elemental diversification in HEAs could prove beneficial, while for others, such as recyclability, elemental breadth introduces significant challenges. Keywords: High-entropy alloys; Multicomponent; Modeling; Analytical methodsNational Science Foundation (Grant CBET-1605050