This short communication is an overview and revision of previous published papers about the relative and absolute stereochemistry of hyperforin and discovery of a new isomer of hyperforin that has been named perforatrin.
A system of structure depiction, as an extension of the wedge and hashed wedge bonds (Natta projection), and text notation is herein suggested that embodies more explicit information—or reduced over-statement as circ...A system of structure depiction, as an extension of the wedge and hashed wedge bonds (Natta projection), and text notation is herein suggested that embodies more explicit information—or reduced over-statement as circumstances warrant—on the stereochemical nature of the system at hand, in particular, for those cases where only the relative stereochemistry of a compound is known.展开更多
In the presence of tetrazole,2'-substituted nucleosidesreacted ster■os■ifi■ally with n-BuOPIN■_2H_5■_2I_2 to nucleoside 3',5'-■lopnosphites with avial n-Buo group.The stereochemistry of oxidation of...In the presence of tetrazole,2'-substituted nucleosidesreacted ster■os■ifi■ally with n-BuOPIN■_2H_5■_2I_2 to nucleoside 3',5'-■lopnosphites with avial n-Buo group.The stereochemistry of oxidation of■y■lophosphite was investigated.展开更多
A solid-phase synthesis of 1α-hydroxylation of 5,6-trans-vitamin D3 8 is described.The solid phase resin acts as a special protecting group, which gives a higher stereoselectivity in oxidation step than classical pro...A solid-phase synthesis of 1α-hydroxylation of 5,6-trans-vitamin D3 8 is described.The solid phase resin acts as a special protecting group, which gives a higher stereoselectivity in oxidation step than classical protecting groups. The stereochemistry control is favored by using high crosslinkage polymer support in a poor solvent. This work may be of benefit to the synthesis of vitamin D system.展开更多
The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α,5-cyclo-5α-cholestane-6-one,was established on the basis of NMR techniques and the mechanism of the formation of 2 was discus...The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α,5-cyclo-5α-cholestane-6-one,was established on the basis of NMR techniques and the mechanism of the formation of 2 was discussed.展开更多
Diacholest-13(17)-ene ozonide(1a andlb) and 4, 4-dimethyldiacholest-13 (17)-eneozonides(2a and 2b) underwent pyrolysis to afford the coressponding 17-oxo-13,14;13,17- dis14-lactones (3a and 3b)and 4.4-dimethyl-17-ox...Diacholest-13(17)-ene ozonide(1a andlb) and 4, 4-dimethyldiacholest-13 (17)-eneozonides(2a and 2b) underwent pyrolysis to afford the coressponding 17-oxo-13,14;13,17- dis14-lactones (3a and 3b)and 4.4-dimethyl-17-oxo-13,14; 13,17-disecodiacholestano-13,14-lactones(4 and 4b), respectively. The stereochemi-stry of the migratingpoups was Proven to be conserved by comparison with the Baeyer-Villiger oxidation of the corresponding 13,17-secodiacholesta-13,17-diones (5) and 4,4-dimethyl-13, 17-secodiacholesta13, 17-diones(6).展开更多
Tricyclic compound 6 was synthesized form compound 1 through sis steps, thus preblem of the stereochemistry of C2α-H being solved. The stereochemistry for introducing hydroxy groups at C3β and C4α positions in com...Tricyclic compound 6 was synthesized form compound 1 through sis steps, thus preblem of the stereochemistry of C2α-H being solved. The stereochemistry for introducing hydroxy groups at C3β and C4α positions in compound 1 was also described.展开更多
Relative and absolute stereochemistry for hyperforin has been proposed by Brondz et al. was supported and new isomer of hyperforin-perforatrin has been discovered. Relative and absolute stereochemistry for perforatrin...Relative and absolute stereochemistry for hyperforin has been proposed by Brondz et al. was supported and new isomer of hyperforin-perforatrin has been discovered. Relative and absolute stereochemistry for perforatrin was proposed and elucidated by using gas-chromatography mass-spectrometry with supersonic molecular beams (SMB). The possibility of the existence of ambiguities in chirality as a hypothesis for the existence, and a new understanding, of chiral substances with shifting chirality is presented.展开更多
Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination...Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic performance.Here,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium groups.The pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the film.Furthermore,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type modification.Ultimately,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.展开更多
文摘This short communication is an overview and revision of previous published papers about the relative and absolute stereochemistry of hyperforin and discovery of a new isomer of hyperforin that has been named perforatrin.
文摘A system of structure depiction, as an extension of the wedge and hashed wedge bonds (Natta projection), and text notation is herein suggested that embodies more explicit information—or reduced over-statement as circumstances warrant—on the stereochemical nature of the system at hand, in particular, for those cases where only the relative stereochemistry of a compound is known.
文摘In the presence of tetrazole,2'-substituted nucleosidesreacted ster■os■ifi■ally with n-BuOPIN■_2H_5■_2I_2 to nucleoside 3',5'-■lopnosphites with avial n-Buo group.The stereochemistry of oxidation of■y■lophosphite was investigated.
基金supported by the Major State Basic Research Development Program(Grant No.F2000078100)the National Natural Science Foundation of China(No.20172059)the Found of Chinese Academy of Sciences.
文摘A solid-phase synthesis of 1α-hydroxylation of 5,6-trans-vitamin D3 8 is described.The solid phase resin acts as a special protecting group, which gives a higher stereoselectivity in oxidation step than classical protecting groups. The stereochemistry control is favored by using high crosslinkage polymer support in a poor solvent. This work may be of benefit to the synthesis of vitamin D system.
文摘The configuration of the hydroxy acid 2, a product from base-catalyzed autoxidation of 3α,5-cyclo-5α-cholestane-6-one,was established on the basis of NMR techniques and the mechanism of the formation of 2 was discussed.
文摘Diacholest-13(17)-ene ozonide(1a andlb) and 4, 4-dimethyldiacholest-13 (17)-eneozonides(2a and 2b) underwent pyrolysis to afford the coressponding 17-oxo-13,14;13,17- dis14-lactones (3a and 3b)and 4.4-dimethyl-17-oxo-13,14; 13,17-disecodiacholestano-13,14-lactones(4 and 4b), respectively. The stereochemi-stry of the migratingpoups was Proven to be conserved by comparison with the Baeyer-Villiger oxidation of the corresponding 13,17-secodiacholesta-13,17-diones (5) and 4,4-dimethyl-13, 17-secodiacholesta13, 17-diones(6).
文摘Tricyclic compound 6 was synthesized form compound 1 through sis steps, thus preblem of the stereochemistry of C2α-H being solved. The stereochemistry for introducing hydroxy groups at C3β and C4α positions in compound 1 was also described.
文摘Relative and absolute stereochemistry for hyperforin has been proposed by Brondz et al. was supported and new isomer of hyperforin-perforatrin has been discovered. Relative and absolute stereochemistry for perforatrin was proposed and elucidated by using gas-chromatography mass-spectrometry with supersonic molecular beams (SMB). The possibility of the existence of ambiguities in chirality as a hypothesis for the existence, and a new understanding, of chiral substances with shifting chirality is presented.
基金financially supported by the National Ten Thousand Talent Program for Young Top-notch Talent,China,the National Natural Science Fund for Excellent Young Scholars,China(52022030)the National Natural Science Foundation of China,China(51972111,52203330)+7 种基金the Shanghai Pilot Program for Basic Research,China(22TQ1400100-5)the “Dawn”Program of Shanghai Education Commission,China(22SG28)the Shanghai Municipal Natural Science Foundation,China(22ZR1418000)the Science and Technology Innovation Plan of Shanghai Science and Technology Commission,China(22YF1410000)the Postdoctoral Research Foundation of China,China(2021M701190)the Fundamental Research Funds for the Central Universities,China(JKD01231632,JKVD1231041)the Major Science and Technology Projects of Inner Mongolia Autonomous Region,China(2021ZD0042)the Shanghai Engineering Research Center of Hierarchical Nanomaterials,China(18DZ2252400)。
文摘Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic performance.Here,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium groups.The pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the film.Furthermore,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type modification.Ultimately,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.
