The title compound 2-oxo-3-phenyl-1-oxaspiro[4.5]dec-3-en-4-yl 4-chlorobenzoate 6 （C22H19ClO4, Mr = 382.82） has been synthesized by the condensation reaction of 4-hydroxy-3-phenyl-1-oxaspiro[4.5]dec-3-en-2-one 5 wit...The title compound 2-oxo-3-phenyl-1-oxaspiro[4.5]dec-3-en-4-yl 4-chlorobenzoate 6 （C22H19ClO4, Mr = 382.82） has been synthesized by the condensation reaction of 4-hydroxy-3-phenyl-1-oxaspiro[4.5]dec-3-en-2-one 5 with 4-chlorobenzoyl chloride, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 10.6749（11）, b = 6.0573（7）, c = 29.680（2） A, β = 94.073（3）°, V= 1914.3（3） A^3, Z = 4, Dc = 1.328 g/cm^3, F（000） = 800, μ = 0.224 mm^-1, S = 1.003, the final R = 0.0605 and wR = 0.1500 for 1828 observed reflections with I〉 2σ（I） and 244 variable parameters. The crystal analysis shows that the molecular structure of the title compound has one planar furan ring, one chair conformation cyclohexane ring and two benzene rings. The furan and cyclohexane rings adopt whorl conformations.展开更多
The title compound mesityl acetic acid 3-mesityl-2-oxo-1-oxaspiro[4,4]non-3-en-4-yl ester （5, C28H32O4, Mr = 432.56）, as a spiromesifen derivative, has been synthesized by the conden- sation reaction of 2,4,6-trimet...The title compound mesityl acetic acid 3-mesityl-2-oxo-1-oxaspiro[4,4]non-3-en-4-yl ester （5, C28H32O4, Mr = 432.56）, as a spiromesifen derivative, has been synthesized by the conden- sation reaction of 2,4,6-trimethylphenylacetic chloride with 4-hydroxyl-3-mesityl-1-oxa-spiro[4,4]- non-3-en-2-one （4）, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.9261（7）, b = 8.2802（8）, c = 18.7604（18） , α = 91.576（3）, β = 93.277（2）, γ = 95.306（12）o, V = 1223.3（2） 3, Z = 2, Dc = 1.174 g/cm3, F（000） = 464, μ = 0.077 mm–1, S = 1.001, the final R = 0.0624 and wR = 0.1415 for 2809 observed reflections with I 2σ（I） and 290 variable parameters. The crystal analysis results show that the five-membered cyclopentyl ring displays an envelope conformation with C（25） atom at the flap position, 0.537（3） out of the mean plane formed by the other four atoms. The dihedral angles between the two benzene and furan rings are 70.0（2） and 80.67（3）o, respectively.展开更多
Hydrophilic polyethersulfone (PES) hollow fiber membranes were prepared via non-solvent induced phase separation (NIPS) by addition of polymeric additives as a membrane modifying agent. The effect of the addition of h...Hydrophilic polyethersulfone (PES) hollow fiber membranes were prepared via non-solvent induced phase separation (NIPS) by addition of polymeric additives as a membrane modifying agent. The effect of the addition of hydrophilic surfactant Pluronic F127, Polyivinylpyrrolidone (PVP), and Tetronic 1307 on the performance of the final PES hollow-fiber membrane was investigated. The morphology of fabricated hollow fiber membrane observed by scanning electron microscopy (SEM) indicated that all of membrane had a skin layer on the surface and finger like macrovoid structure inside the hollow fiber. The addition of 5 wt% polymeric surfactant on the polymer solution results in membrane with improved length and number of macrovoid structure. Sponge formation both near inner surface and near outer surface of hollow fiber membrane was another impact of addition of polymeric additives, which is led to decrease of water permeability of these membrane. Water contact angle measurement was performed to investigate the hydrophilicity property of resulted membrane. It is confirmed that the modified PES hollow fiber membranes had lower water contact angle than that of the original membrane, which indicate that the modified PES membrane with additives has high hydrophilic.展开更多
Multifrequency,multitechnique pulse EPR spectroscopy was employed to unravel the spin Hamiltonian parameters of^(17)O in the[Fe^(Ⅴ)=O]moiety with two different tetraamido macrocyclic ligands(TAMLs),[Fe^(Ⅴ)(O)(TAML-1...Multifrequency,multitechnique pulse EPR spectroscopy was employed to unravel the spin Hamiltonian parameters of^(17)O in the[Fe^(Ⅴ)=O]moiety with two different tetraamido macrocyclic ligands(TAMLs),[Fe^(Ⅴ)(O)(TAML-1)]^(−)(1,H_(4)(TAML-1)=3,4,8,9-tetrahydro-3,3,6,6,9-hexamethyl-1H-1,4,8,11-benzotetraazocyclotridecane-2,5,7,10-(6H,11H)-tetrone)and[Fe^(Ⅴ)(O)(TAML-2)]^(−)(2,H_(4)(TAML-2)=H_(4)[(Me_(2)CNCOCMe_(2)NCO)_(2)CMe_(2)]),to investigate the electronic structure of Fe^(Ⅴ)-oxo species.Although rigorous computational studies on highvalent iron-oxo species have been reported recently,experimental evidence to explicate the electronic structure of Fe^(Ⅴ)-oxo species is sparse.In particular,a complete hyperfine tensor of^(17)O can hardly be detected.Herein,we successfully probed the hyperfine tensor of^(17)O of the Fe^(Ⅴ)-oxo moiety using ENDOR spectroscopy.Hence,the EPR spectroscopic results reported here provide a conclusive experimental basis for elucidating the electronic structure of the Fe^(Ⅴ)-oxo complex.Moreover,the reactivity of the two different complexes is very distinct,and our results may provide insight into how their electronic structure contributes to their reactivity.展开更多
Tetronate antibiotics, a growing family of natural products featuring a characteristic tetronic acid moiety, are of importance and of particular interest for their typical structures, especially the spirotetronate str...Tetronate antibiotics, a growing family of natural products featuring a characteristic tetronic acid moiety, are of importance and of particular interest for their typical structures, especially the spirotetronate structure, and corresponding versatile biolog- ical activities. Considerable efforts have persistently performed since the first tetronate was isolated, to elucidate the biosyn- thesis of natural tetronate products, by isotope-labeled feeding experiments, genetical characterization of biosynthetic gene clusters, and biochemical reconstitution of key enzymatic catalyzed reactions. Accordingly, the biosynthesis of spirotetronates has been gradually determined, including biosynthesis of a polyketide-derived backbone for spirotetronate aglycone, incorpo- ration of a glycerol-derived three-carbon unit into tetronic acid moiety, formation of mature aglycone via Diels-AIder-like re- action, and decorations of aglycone with various deoxysugar moieties. In this paper, the biosynthetic investigations of natural tetronates are well documented and a common biosynthetic route for this group of natural products is summarized accordingly.展开更多
基金Supported by the National Natural Science Foundation of China (Nos. 31101470 and 30700532)
文摘The title compound 2-oxo-3-phenyl-1-oxaspiro[4.5]dec-3-en-4-yl 4-chlorobenzoate 6 （C22H19ClO4, Mr = 382.82） has been synthesized by the condensation reaction of 4-hydroxy-3-phenyl-1-oxaspiro[4.5]dec-3-en-2-one 5 with 4-chlorobenzoyl chloride, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 10.6749（11）, b = 6.0573（7）, c = 29.680（2） A, β = 94.073（3）°, V= 1914.3（3） A^3, Z = 4, Dc = 1.328 g/cm^3, F（000） = 800, μ = 0.224 mm^-1, S = 1.003, the final R = 0.0605 and wR = 0.1500 for 1828 observed reflections with I〉 2σ（I） and 244 variable parameters. The crystal analysis shows that the molecular structure of the title compound has one planar furan ring, one chair conformation cyclohexane ring and two benzene rings. The furan and cyclohexane rings adopt whorl conformations.
基金Supported by the Natural Science Foundation of Zhejiang Province (2008C21029)
文摘The title compound mesityl acetic acid 3-mesityl-2-oxo-1-oxaspiro[4,4]non-3-en-4-yl ester （5, C28H32O4, Mr = 432.56）, as a spiromesifen derivative, has been synthesized by the conden- sation reaction of 2,4,6-trimethylphenylacetic chloride with 4-hydroxyl-3-mesityl-1-oxa-spiro[4,4]- non-3-en-2-one （4）, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.9261（7）, b = 8.2802（8）, c = 18.7604（18） , α = 91.576（3）, β = 93.277（2）, γ = 95.306（12）o, V = 1223.3（2） 3, Z = 2, Dc = 1.174 g/cm3, F（000） = 464, μ = 0.077 mm–1, S = 1.001, the final R = 0.0624 and wR = 0.1415 for 2809 observed reflections with I 2σ（I） and 290 variable parameters. The crystal analysis results show that the five-membered cyclopentyl ring displays an envelope conformation with C（25） atom at the flap position, 0.537（3） out of the mean plane formed by the other four atoms. The dihedral angles between the two benzene and furan rings are 70.0（2） and 80.67（3）o, respectively.
文摘Hydrophilic polyethersulfone (PES) hollow fiber membranes were prepared via non-solvent induced phase separation (NIPS) by addition of polymeric additives as a membrane modifying agent. The effect of the addition of hydrophilic surfactant Pluronic F127, Polyivinylpyrrolidone (PVP), and Tetronic 1307 on the performance of the final PES hollow-fiber membrane was investigated. The morphology of fabricated hollow fiber membrane observed by scanning electron microscopy (SEM) indicated that all of membrane had a skin layer on the surface and finger like macrovoid structure inside the hollow fiber. The addition of 5 wt% polymeric surfactant on the polymer solution results in membrane with improved length and number of macrovoid structure. Sponge formation both near inner surface and near outer surface of hollow fiber membrane was another impact of addition of polymeric additives, which is led to decrease of water permeability of these membrane. Water contact angle measurement was performed to investigate the hydrophilicity property of resulted membrane. It is confirmed that the modified PES hollow fiber membranes had lower water contact angle than that of the original membrane, which indicate that the modified PES membrane with additives has high hydrophilic.
基金supported by the National Research Foundation of Korea(NRF-2017M3D1A1039380 and NRF-2020R1F1A1069151)KBSI grant C1300000 to S.H.K+1 种基金supported by the NRF of Korea through CRI(NRF-2012R1A3A2048842 to W.N.)the Basic Science Research Program(NRF-2020R1I1A1A01074630 to Y.-M.L.).
文摘Multifrequency,multitechnique pulse EPR spectroscopy was employed to unravel the spin Hamiltonian parameters of^(17)O in the[Fe^(Ⅴ)=O]moiety with two different tetraamido macrocyclic ligands(TAMLs),[Fe^(Ⅴ)(O)(TAML-1)]^(−)(1,H_(4)(TAML-1)=3,4,8,9-tetrahydro-3,3,6,6,9-hexamethyl-1H-1,4,8,11-benzotetraazocyclotridecane-2,5,7,10-(6H,11H)-tetrone)and[Fe^(Ⅴ)(O)(TAML-2)]^(−)(2,H_(4)(TAML-2)=H_(4)[(Me_(2)CNCOCMe_(2)NCO)_(2)CMe_(2)]),to investigate the electronic structure of Fe^(Ⅴ)-oxo species.Although rigorous computational studies on highvalent iron-oxo species have been reported recently,experimental evidence to explicate the electronic structure of Fe^(Ⅴ)-oxo species is sparse.In particular,a complete hyperfine tensor of^(17)O can hardly be detected.Herein,we successfully probed the hyperfine tensor of^(17)O of the Fe^(Ⅴ)-oxo moiety using ENDOR spectroscopy.Hence,the EPR spectroscopic results reported here provide a conclusive experimental basis for elucidating the electronic structure of the Fe^(Ⅴ)-oxo complex.Moreover,the reactivity of the two different complexes is very distinct,and our results may provide insight into how their electronic structure contributes to their reactivity.
基金supported by the Research Fund for the Doctoral Program of Higher Education of Chinathe Research and Development Program of Hubei Province,and the China Postdoctoral Science Foundation(2012M521461)
文摘Tetronate antibiotics, a growing family of natural products featuring a characteristic tetronic acid moiety, are of importance and of particular interest for their typical structures, especially the spirotetronate structure, and corresponding versatile biolog- ical activities. Considerable efforts have persistently performed since the first tetronate was isolated, to elucidate the biosyn- thesis of natural tetronate products, by isotope-labeled feeding experiments, genetical characterization of biosynthetic gene clusters, and biochemical reconstitution of key enzymatic catalyzed reactions. Accordingly, the biosynthesis of spirotetronates has been gradually determined, including biosynthesis of a polyketide-derived backbone for spirotetronate aglycone, incorpo- ration of a glycerol-derived three-carbon unit into tetronic acid moiety, formation of mature aglycone via Diels-AIder-like re- action, and decorations of aglycone with various deoxysugar moieties. In this paper, the biosynthetic investigations of natural tetronates are well documented and a common biosynthetic route for this group of natural products is summarized accordingly.
