An array of C2-symmetric chiral Schiff bases of substituted salicylaldehyde （1R, 2R）-1, 2-cyclohexanediamine and （R）-（＋）-2, 2＇-diamino-1, 1＇-binaphthalene, incorporated with lanthanide complexes, have been ap...An array of C2-symmetric chiral Schiff bases of substituted salicylaldehyde （1R, 2R）-1, 2-cyclohexanediamine and （R）-（＋）-2, 2＇-diamino-1, 1＇-binaphthalene, incorporated with lanthanide complexes, have been applied as catalysts for asymmetric hydrogenation of acetophenone for the first time. Highly enantioselective product with 90% enantiomeric excess （e.e.） was obtained when the catalyst, hybridized by the bulky electron-donating 3, 5-di-tert-butyl substituted Schiff base （2） and SmCl3.4THF, was employed.展开更多
2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 w...2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 were converted to the aryl.ketones(5).The entire process represent a demethylation— alkylation reaction of acetophenones.The mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols(4)was discussed.展开更多
The title compound 2-(4-fluorophenylamino)-2-thiomethyl acetophe-none (C15H14FNOS, M. = 275. 34 ) was synthesized by the reaction of 2-hydroxy-2-thiomethyl acetohenone (abenzoylhemithioacetal ) with 4-fluoroaniline. T...The title compound 2-(4-fluorophenylamino)-2-thiomethyl acetophe-none (C15H14FNOS, M. = 275. 34 ) was synthesized by the reaction of 2-hydroxy-2-thiomethyl acetohenone (abenzoylhemithioacetal ) with 4-fluoroaniline. The crystal ismonoclinic, space group P21/n. with unit cell constants a = 12. 434 (4 ), b = 6. 00l2(6), c=l8. 49l(2) A, β=100. 87(l)° Z = 4, V = 1355. O(5) A, D'= 1. 350g/cm3, μ(MoKa) = 2. 41 cm-l, F(000) = 576, R=0. 029, Rw.= 0. 041 for 14l2 ob-served reflections (I> 3σ(I) ). X-ray analysis reveals that the dihedral angle betweenplane l (C(l)~C(6), F, N ) and plane 2 (C(8)~C(14), O ) is 4. l8° and theC(7) -S bond is longer than normal single C-S bond.展开更多
Eight new brominated 2＇（4＇）-nitro-3-hydroxy diphenyl ethers have been designed and synthesized. The structures of new compounds were confirmed by ^1H NMR, IR and HRMS. The bioactivity tests showed that these compo...Eight new brominated 2＇（4＇）-nitro-3-hydroxy diphenyl ethers have been designed and synthesized. The structures of new compounds were confirmed by ^1H NMR, IR and HRMS. The bioactivity tests showed that these compounds possessed antibacterial activities against the tested bacteria. These new compounds cannot be transformed into dioxins when they were manufactured and used.展开更多
A new method is proposed to determine the amplification factor for 2-hydroxy ethylperoxy radicals （HOC2H4O2·） in chemical amplifier. The radical source comes from the reaction of excess ethene with HO· rad...A new method is proposed to determine the amplification factor for 2-hydroxy ethylperoxy radicals （HOC2H4O2·） in chemical amplifier. The radical source comes from the reaction of excess ethene with HO· radicals generated in the photolysis of water vapor at the wave length of 185 nm in air in a flow tube. This produces a radical source which contains equal amount of HO2·and HOC2H4O2·. The amplification factor is derived from the slopes of the lines between produced NO2 in chemical amplifier and total initial radical concentrations measured for the source of HO2· and that of the same amount of HO2· and HOC2H4O2· respectively. The amplification factor of HOC2H4O2· was similar to that of HO2·, indicating that HOC2H4O2· can be measured with the same sensitivity as HO2· by chemical amplifier.展开更多
We report here a generic,green synthesis of 17 valuable syn-aryl-(2S,3R)-2–chloro-3–hydroxy esters(syn-(2S,3R)-1)in 73%-99%isolated yields along with 6.1:1–83:1 dr and 31%~>99%ee,through dynamic reductive kineti...We report here a generic,green synthesis of 17 valuable syn-aryl-(2S,3R)-2–chloro-3–hydroxy esters(syn-(2S,3R)-1)in 73%-99%isolated yields along with 6.1:1–83:1 dr and 31%~>99%ee,through dynamic reductive kinetic resolution of racemic arylα–chloroβ-keto esters(2)catalyzed by an engineered ketoreductase which was obtained via ep PCR-based directed evolution.The hectogram scale synthesis of syn-(2S,3R)-1b at a substrate concentration of 120 g/L showcased the application potential of the biocatalytic method developed presently.展开更多
Cerebrovascular accident（CVA）or stroke is one of the world＇s leading causes of death and permanent disability.The high social and medical costs associated with this pathology mean there is an urgent need to find ef...Cerebrovascular accident（CVA）or stroke is one of the world＇s leading causes of death and permanent disability.The high social and medical costs associated with this pathology mean there is an urgent need to find effective therapies.Occlusion of the middle cerebral artery（MCAO）,mainly by clots,is the origin of most CVAs in humans.展开更多
The optically active R-4-phenyl-2-hydroxy butyrates were prepared by esterification of the racemic acid or transesterification of the racemic ester catalyzed by lipase from Candida cyclindra (CCL) in organic media.
The interaction of N-(2-methyl thiophenyl)-2-hydroxy-1-naphthaldimine (NMTHN) with tin dioxide nanoparticles (SnO2 NPs) has been investigated by spectroscopic tools such as absorption and fluorescence spectroscopy. Ab...The interaction of N-(2-methyl thiophenyl)-2-hydroxy-1-naphthaldimine (NMTHN) with tin dioxide nanoparticles (SnO2 NPs) has been investigated by spectroscopic tools such as absorption and fluorescence spectroscopy. Absorption spectroscopy reveals the formation of ground state complex. Fluorescence spectroscopy has been used to study the signatures of fluorescence quenching. SnO2 NPs are found to quench the intrinsic fluorescence of NMTHN via static and dynamic quenching. The deviation from linearity in the Stern-Volmer plot has been observed.展开更多
基金This work is financially supported by the National Natural Science Foundation of China （No. 20271018 ＆ 20572018） Heilongjiang Province （ZJG0504, 1055HZ001 ＆ GB04A416）Heilongjiang University.
文摘An array of C2-symmetric chiral Schiff bases of substituted salicylaldehyde （1R, 2R）-1, 2-cyclohexanediamine and （R）-（＋）-2, 2＇-diamino-1, 1＇-binaphthalene, incorporated with lanthanide complexes, have been applied as catalysts for asymmetric hydrogenation of acetophenone for the first time. Highly enantioselective product with 90% enantiomeric excess （e.e.） was obtained when the catalyst, hybridized by the bulky electron-donating 3, 5-di-tert-butyl substituted Schiff base （2） and SmCl3.4THF, was employed.
文摘2-(1,3-dithian-2-ylidene)-1-arylethenones 3 Via chemoselective 1,2-addition with methyl,ethyl, phenyl,allyl,and benzyl Grignard reagents afforded the corresponding alcohols(4).Catalyzing by silica gel,the alcohols 4 were converted to the aryl.ketones(5).The entire process represent a demethylation— alkylation reaction of acetophenones.The mechanism of reaction are proposed and the structure requirement for the conversion of the alcohols(4)was discussed.
文摘The title compound 2-(4-fluorophenylamino)-2-thiomethyl acetophe-none (C15H14FNOS, M. = 275. 34 ) was synthesized by the reaction of 2-hydroxy-2-thiomethyl acetohenone (abenzoylhemithioacetal ) with 4-fluoroaniline. The crystal ismonoclinic, space group P21/n. with unit cell constants a = 12. 434 (4 ), b = 6. 00l2(6), c=l8. 49l(2) A, β=100. 87(l)° Z = 4, V = 1355. O(5) A, D'= 1. 350g/cm3, μ(MoKa) = 2. 41 cm-l, F(000) = 576, R=0. 029, Rw.= 0. 041 for 14l2 ob-served reflections (I> 3σ(I) ). X-ray analysis reveals that the dihedral angle betweenplane l (C(l)~C(6), F, N ) and plane 2 (C(8)~C(14), O ) is 4. l8° and theC(7) -S bond is longer than normal single C-S bond.
文摘Eight new brominated 2＇（4＇）-nitro-3-hydroxy diphenyl ethers have been designed and synthesized. The structures of new compounds were confirmed by ^1H NMR, IR and HRMS. The bioactivity tests showed that these compounds possessed antibacterial activities against the tested bacteria. These new compounds cannot be transformed into dioxins when they were manufactured and used.
文摘A new method is proposed to determine the amplification factor for 2-hydroxy ethylperoxy radicals （HOC2H4O2·） in chemical amplifier. The radical source comes from the reaction of excess ethene with HO· radicals generated in the photolysis of water vapor at the wave length of 185 nm in air in a flow tube. This produces a radical source which contains equal amount of HO2·and HOC2H4O2·. The amplification factor is derived from the slopes of the lines between produced NO2 in chemical amplifier and total initial radical concentrations measured for the source of HO2· and that of the same amount of HO2· and HOC2H4O2· respectively. The amplification factor of HOC2H4O2· was similar to that of HO2·, indicating that HOC2H4O2· can be measured with the same sensitivity as HO2· by chemical amplifier.
基金The National Key Research and Development Program of China(Nos.2021YFA0911400 and 2021YFF0600704)the National Natural Science Foundation of China(Nos.22071033 and 21801047)are acknowledged for the financial supports。
文摘We report here a generic,green synthesis of 17 valuable syn-aryl-(2S,3R)-2–chloro-3–hydroxy esters(syn-(2S,3R)-1)in 73%-99%isolated yields along with 6.1:1–83:1 dr and 31%~>99%ee,through dynamic reductive kinetic resolution of racemic arylα–chloroβ-keto esters(2)catalyzed by an engineered ketoreductase which was obtained via ep PCR-based directed evolution.The hectogram scale synthesis of syn-(2S,3R)-1b at a substrate concentration of 120 g/L showcased the application potential of the biocatalytic method developed presently.
文摘Cerebrovascular accident（CVA）or stroke is one of the world＇s leading causes of death and permanent disability.The high social and medical costs associated with this pathology mean there is an urgent need to find effective therapies.Occlusion of the middle cerebral artery（MCAO）,mainly by clots,is the origin of most CVAs in humans.
文摘The optically active R-4-phenyl-2-hydroxy butyrates were prepared by esterification of the racemic acid or transesterification of the racemic ester catalyzed by lipase from Candida cyclindra (CCL) in organic media.
文摘The interaction of N-(2-methyl thiophenyl)-2-hydroxy-1-naphthaldimine (NMTHN) with tin dioxide nanoparticles (SnO2 NPs) has been investigated by spectroscopic tools such as absorption and fluorescence spectroscopy. Absorption spectroscopy reveals the formation of ground state complex. Fluorescence spectroscopy has been used to study the signatures of fluorescence quenching. SnO2 NPs are found to quench the intrinsic fluorescence of NMTHN via static and dynamic quenching. The deviation from linearity in the Stern-Volmer plot has been observed.
