The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Chaoguo Yan - One of the best experts on this subject based on the ideXlab platform.
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diastereoselective synthesis of functionalized spiro cyclopropane 1 3 indolines and spiro indoline 3 1 cyclopropane 2 3 indolines
Tetrahedron, 2016Co-Authors: Ying Han, Chaoguo YanAbstract:In the presence of hexamethylphosphorous triamide, the reaction of Isatin with arylidene pivaloylacetonitriles in dry methylene dichloride afforded functionalized spiro[cyclopropane-1,3′-indolines] in good yields and with high diastereoselectivity. Moreover, the similar reaction of Isatins with isatylidene malononitriles predominately gave spiro[indoline-3,1′-cyclopropane-2′,3″-indolines] in very high yields with two indoline moieties in trans-configuration.
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selective synthesis of functionalized spiro indoline 3 2 pyridines and spiro indoline 3 4 pyridines by lewis acid catalyzed reactions of acetylenedicarboxylate arylamines and Isatins
Journal of Organic Chemistry, 2014Co-Authors: Hong Gao, Jing Sun, Chaoguo YanAbstract:The functionalized spiro[indoline-3,2′-pyridine]-3′,4′,5′,6′-tetracarboxylates were efficiently synthesized by BF3·OEt2-catalyzed reactions of Isatin-3-imines with acetylenedicarboxylates in methylene dichloride. Under similar conditions, the BF3·OEt2-catalyzed three-component reactions of acetylenedicarboxylates, arylamines, and Isatins afforded functionalized spiro[indoline-3,4′-pyridine]-2′,3′,5′,6′-tetracarboxylates in moderate yields.
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Selective Synthesis of Functionalized Spiro[indoline-3,2′-pyridines] and Spiro[indoline-3,4′-pyridines] by Lewis Acid Catalyzed Reactions of Acetylenedicarboxylate, Arylamines, and Isatins
The Journal of organic chemistry, 2014Co-Authors: Hong Gao, Jing Sun, Chaoguo YanAbstract:The functionalized spiro[indoline-3,2′-pyridine]-3′,4′,5′,6′-tetracarboxylates were efficiently synthesized by BF3·OEt2-catalyzed reactions of Isatin-3-imines with acetylenedicarboxylates in methylene dichloride. Under similar conditions, the BF3·OEt2-catalyzed three-component reactions of acetylenedicarboxylates, arylamines, and Isatins afforded functionalized spiro[indoline-3,4′-pyridine]-2′,3′,5′,6′-tetracarboxylates in moderate yields.
Jian Zhou - One of the best experts on this subject based on the ideXlab platform.
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one pot tandem approach to spirocyclic oxindoles featuring adjacent spiro stereocenters
Angewandte Chemie, 2013Co-Authors: Yunlin Liu, Xin Wang, Yulei Zhao, Feng Zhu, Xingping Zeng, Long Chen, Cuihong Wang, Xiaoli Zhao, Jian ZhouAbstract:All in a sequence: An organocatalyzed Morita-Baylis-Hillman (MBH)/bromination/[3+2] annulation sequence for highly stereoselective syntheses of bis(spirooxindole)s featuring adjacent spiro-stereocenters is described. The key step is an unprecedented catalytic asymmetric [3+2] annulation of Isatin-derived MBH adducts, containing a tetrasubstituted alkene moiety, with Isatins.
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A Hg(ClO4)2·3H2O Catalyzed Sakurai–Hosomi Allylation of Isatins and Isatin Ketoimines Using Allyltrimethylsilane
Organic letters, 2011Co-Authors: Zhong-yan Cao, Yan Zhang, Jian ZhouAbstract:It is reported that Hg(ClO4)2·3H2O could efficiently activate the cheap but less reactive allyltrimethylsilane for the allylation of Isatins or Isatin ketoimines, with catalyst loading down to 0.1 mol %. This is the first example of Sakurai–Hosomi allylation of ketoimines using allyltrimethylsilane. A rare example of chiral mercury catalysis is also reported.
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a hg clo4 2 3h2o catalyzed sakurai hosomi allylation of Isatins and Isatin ketoimines using allyltrimethylsilane
Organic Letters, 2011Co-Authors: Zhong-yan Cao, Yan Zhang, Jian ZhouAbstract:It is reported that Hg(ClO4)2·3H2O could efficiently activate the cheap but less reactive allyltrimethylsilane for the allylation of Isatins or Isatin ketoimines, with catalyst loading down to 0.1 mol %. This is the first example of Sakurai–Hosomi allylation of ketoimines using allyltrimethylsilane. A rare example of chiral mercury catalysis is also reported.
Zhong-yan Cao - One of the best experts on this subject based on the ideXlab platform.
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A Hg(ClO4)2·3H2O Catalyzed Sakurai–Hosomi Allylation of Isatins and Isatin Ketoimines Using Allyltrimethylsilane
Organic letters, 2011Co-Authors: Zhong-yan Cao, Yan Zhang, Jian ZhouAbstract:It is reported that Hg(ClO4)2·3H2O could efficiently activate the cheap but less reactive allyltrimethylsilane for the allylation of Isatins or Isatin ketoimines, with catalyst loading down to 0.1 mol %. This is the first example of Sakurai–Hosomi allylation of ketoimines using allyltrimethylsilane. A rare example of chiral mercury catalysis is also reported.
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a hg clo4 2 3h2o catalyzed sakurai hosomi allylation of Isatins and Isatin ketoimines using allyltrimethylsilane
Organic Letters, 2011Co-Authors: Zhong-yan Cao, Yan Zhang, Jian ZhouAbstract:It is reported that Hg(ClO4)2·3H2O could efficiently activate the cheap but less reactive allyltrimethylsilane for the allylation of Isatins or Isatin ketoimines, with catalyst loading down to 0.1 mol %. This is the first example of Sakurai–Hosomi allylation of ketoimines using allyltrimethylsilane. A rare example of chiral mercury catalysis is also reported.
Hweeling Koh - One of the best experts on this subject based on the ideXlab platform.
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determination of indican Isatin indirubin and indigotin in isatis indigotica by liquid chromatography electrospray ionization tandem mass spectrometry
Rapid Communications in Mass Spectrometry, 2007Co-Authors: Peng Zou, Hweeling KohAbstract:The roots and leaves of Isatis indigotica, named 'Ban-Lan-Gen' and 'Da-Qing-Ye', respectively, are widely used for the treatment of influenza, viral pneumonia, mumps, pharyngitis, and hepatitis. The indoxyl derivatives detected in the roots and leaves of I. indigotica have been reported to be biologically active. In the present study, a liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method was developed to determine indican, Isatin, indirubin and indigotin in the roots and leaves of I. indigotica. The method has been validated for linearity, precision and accuracy. Using multiple reaction monitoring (MRM), the limits of detection (LODs) were determined as 0.004 ng for indican, 0.01 ng for Isatin, 0.01 ng for indrubin and 0.03 ng for indigotin, while the limits of quantitation (LOQs) were 0.015 ng for indican, 0.04 ng for Isatin, 0.04 ng for indirubin and 0.1 ng for indigotin. Compared with previously reported methods, the current method is more rapid, selective and sensitive. This is the first report of the LC/MS/MS determination of indican, Isatin, indirubin and indigotin.
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Determination of indican, Isatin, indirubin and indigotin in Isatis indigotica by liquid chromatography/electrospray ionization tandem mass spectrometry
Rapid communications in mass spectrometry : RCM, 2007Co-Authors: Peng Zou, Hweeling KohAbstract:The roots and leaves of Isatis indigotica, named 'Ban-Lan-Gen' and 'Da-Qing-Ye', respectively, are widely used for the treatment of influenza, viral pneumonia, mumps, pharyngitis, and hepatitis. The indoxyl derivatives detected in the roots and leaves of I. indigotica have been reported to be biologically active. In the present study, a liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method was developed to determine indican, Isatin, indirubin and indigotin in the roots and leaves of I. indigotica. The method has been validated for linearity, precision and accuracy. Using multiple reaction monitoring (MRM), the limits of detection (LODs) were determined as 0.004 ng for indican, 0.01 ng for Isatin, 0.01 ng for indrubin and 0.03 ng for indigotin, while the limits of quantitation (LOQs) were 0.015 ng for indican, 0.04 ng for Isatin, 0.04 ng for indirubin and 0.1 ng for indigotin. Compared with previously reported methods, the current method is more rapid, selective and sensitive. This is the first report of the LC/MS/MS determination of indican, Isatin, indirubin and indigotin.
Hong Gao - One of the best experts on this subject based on the ideXlab platform.
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selective synthesis of functionalized spiro indoline 3 2 pyridines and spiro indoline 3 4 pyridines by lewis acid catalyzed reactions of acetylenedicarboxylate arylamines and Isatins
Journal of Organic Chemistry, 2014Co-Authors: Hong Gao, Jing Sun, Chaoguo YanAbstract:The functionalized spiro[indoline-3,2′-pyridine]-3′,4′,5′,6′-tetracarboxylates were efficiently synthesized by BF3·OEt2-catalyzed reactions of Isatin-3-imines with acetylenedicarboxylates in methylene dichloride. Under similar conditions, the BF3·OEt2-catalyzed three-component reactions of acetylenedicarboxylates, arylamines, and Isatins afforded functionalized spiro[indoline-3,4′-pyridine]-2′,3′,5′,6′-tetracarboxylates in moderate yields.
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Selective Synthesis of Functionalized Spiro[indoline-3,2′-pyridines] and Spiro[indoline-3,4′-pyridines] by Lewis Acid Catalyzed Reactions of Acetylenedicarboxylate, Arylamines, and Isatins
The Journal of organic chemistry, 2014Co-Authors: Hong Gao, Jing Sun, Chaoguo YanAbstract:The functionalized spiro[indoline-3,2′-pyridine]-3′,4′,5′,6′-tetracarboxylates were efficiently synthesized by BF3·OEt2-catalyzed reactions of Isatin-3-imines with acetylenedicarboxylates in methylene dichloride. Under similar conditions, the BF3·OEt2-catalyzed three-component reactions of acetylenedicarboxylates, arylamines, and Isatins afforded functionalized spiro[indoline-3,4′-pyridine]-2′,3′,5′,6′-tetracarboxylates in moderate yields.
