As a part of our interest in biologically active germacranolides from the genus Carpesium （Compositae）, we have investigated the constituents of Carpesium cernuum. This paper reports the isolation and structural elu...As a part of our interest in biologically active germacranolides from the genus Carpesium （Compositae）, we have investigated the constituents of Carpesium cernuum. This paper reports the isolation and structural elucidation of a new germacranolide, cernolide A （Compound 1）, from the herb. The structure of Compound 1 was determined as 2α,3β-dihydroxy-9-angeloxygermacra-4-en-6,12-olide on the basis of spectral evidence. The skeleton of Compound 1 was elucidation by IR, MS, ^1H and ^13C NMR, COSY, HMQC and HMBC experiments. The stereochemistry of Compound 1 was deduced by ROESY spectral data. Finally, the procedures of extraction and isolation were described in detail.展开更多
Glufosinate-ammonium is a highly efficient, non-selective herbicide. The former synthesis schemes of glufosinate-ammonium were introduced and analyzed, the main of which are Arbuzov synthesis method, method under cata...Glufosinate-ammonium is a highly efficient, non-selective herbicide. The former synthesis schemes of glufosinate-ammonium were introduced and analyzed, the main of which are Arbuzov synthesis method, method under catalyzer and high pressure, targeted method under low temperature, Gabriel synthesis method, Zelinsky-Strecher synthetic method, synthetic method with chiral-synthon, and several special methods such as with enzyme or stereochemistry. Based on the structure and synthesis characteristic of glufosinate-ammonium as well as Arbuzov reaction and Michael reaction, a novel and reasonable scheme, which was named Arbuzov-Michael method, was put forward as the more economical one with simpler raw reagents and less waste.展开更多
A series of Schiff base aluminum(III) complexes bearing morpholinomethyl substituents were synthesized. Comprehensive investigations on their stereoselective and kinetic features in the ring opening polymerization of ...A series of Schiff base aluminum(III) complexes bearing morpholinomethyl substituents were synthesized. Comprehensive investigations on their stereoselective and kinetic features in the ring opening polymerization of lactide were carried out. The ring opening polymerization proved to be first-order in the catalyst and the monomer. Linear relationships between the numberaverage molecular weight of the polylactide and the monomer conversion were consistent with a well-controlled polymerization. The propagation rate was strongly affected by morpholinomethyl substituents on the salicylaldehyde moiety.展开更多
Two-dimensional(2D)superconductors have intriguing physical properties and abundant potential applications.Recently,2D superconductingα-Mo2C and facecentered cubic Mo2C have been controllably prepared and they bring ...Two-dimensional(2D)superconductors have intriguing physical properties and abundant potential applications.Recently,2D superconductingα-Mo2C and facecentered cubic Mo2C have been controllably prepared and they bring new viewpoints to carbon-based superconductivity.Although molybdenum carbides(Mo-Cs)have multiple crystalline stacking orders,there are still few structures reported for the lack of higher energy supply during growth.In this study,we report a two-step vapor deposition method to grow superconducting η-Mo3C2 films with different thicknesses,with the assistance of controllable plasma power.The grownη-Mo3C2 films show polycrystalline characteristics,but they still present superior superconductivity.The 3.0-nm-thick film has the superconducting transition temperature of 5.38 K,and its electrical performances follow truly 2D superconducting transitions.This study will not only exhibit a robust superconductingη-Mo3C2 ultrathin film,but also provides a convenient growth way to realize more carbide-based heterostructures for future device applications.展开更多
文摘As a part of our interest in biologically active germacranolides from the genus Carpesium （Compositae）, we have investigated the constituents of Carpesium cernuum. This paper reports the isolation and structural elucidation of a new germacranolide, cernolide A （Compound 1）, from the herb. The structure of Compound 1 was determined as 2α,3β-dihydroxy-9-angeloxygermacra-4-en-6,12-olide on the basis of spectral evidence. The skeleton of Compound 1 was elucidation by IR, MS, ^1H and ^13C NMR, COSY, HMQC and HMBC experiments. The stereochemistry of Compound 1 was deduced by ROESY spectral data. Finally, the procedures of extraction and isolation were described in detail.
文摘Glufosinate-ammonium is a highly efficient, non-selective herbicide. The former synthesis schemes of glufosinate-ammonium were introduced and analyzed, the main of which are Arbuzov synthesis method, method under catalyzer and high pressure, targeted method under low temperature, Gabriel synthesis method, Zelinsky-Strecher synthetic method, synthetic method with chiral-synthon, and several special methods such as with enzyme or stereochemistry. Based on the structure and synthesis characteristic of glufosinate-ammonium as well as Arbuzov reaction and Michael reaction, a novel and reasonable scheme, which was named Arbuzov-Michael method, was put forward as the more economical one with simpler raw reagents and less waste.
基金supported by the National Natural Science Foundation of China(51173183,51233004,51390484,51321062,51473029)
文摘A series of Schiff base aluminum(III) complexes bearing morpholinomethyl substituents were synthesized. Comprehensive investigations on their stereoselective and kinetic features in the ring opening polymerization of lactide were carried out. The ring opening polymerization proved to be first-order in the catalyst and the monomer. Linear relationships between the numberaverage molecular weight of the polylactide and the monomer conversion were consistent with a well-controlled polymerization. The propagation rate was strongly affected by morpholinomethyl substituents on the salicylaldehyde moiety.
基金the National Key R&D Program of China(2018YFA0305800)the Fundamental Research Funds for the Central Universities(020414380145 and 020414380153)+2 种基金the National Natural Science Foundation of China(11674154,11761131010,51972163,11904163,61974021 and 11525415)the Natural Science Foundation of Jiangsu Province(BK20190010)the Fok Ying-Tong Education Foundation of China(171038)。
文摘Two-dimensional(2D)superconductors have intriguing physical properties and abundant potential applications.Recently,2D superconductingα-Mo2C and facecentered cubic Mo2C have been controllably prepared and they bring new viewpoints to carbon-based superconductivity.Although molybdenum carbides(Mo-Cs)have multiple crystalline stacking orders,there are still few structures reported for the lack of higher energy supply during growth.In this study,we report a two-step vapor deposition method to grow superconducting η-Mo3C2 films with different thicknesses,with the assistance of controllable plasma power.The grownη-Mo3C2 films show polycrystalline characteristics,but they still present superior superconductivity.The 3.0-nm-thick film has the superconducting transition temperature of 5.38 K,and its electrical performances follow truly 2D superconducting transitions.This study will not only exhibit a robust superconductingη-Mo3C2 ultrathin film,but also provides a convenient growth way to realize more carbide-based heterostructures for future device applications.
