The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform
Robert A. Batey - One of the best experts on this subject based on the ideXlab platform.
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enantioselective isoquinuclidine synthesis via sequential diels alder visible light photoredox c c bond cleavage a formal synthesis of the indole alkaloid catharanthine
Organic chemistry frontiers, 2018Co-Authors: Simon J. Kim, Robert A. BateyAbstract:An enantioselective route to substituted chiral isoquinuclidines, present in alkaloids such as catharanthine, Deserpidine, ibogamine and ibogaine, has been developed using a “ketene equivalent” approach. Organocatalyzed Diels–Alder reaction of an N-protected dihydropyridine with acrolein using a valine derived 1,2-aminoalcohol catalyst occurs with high er and dr. Subsequent Ru(Bipy)3Cl2·(H2O)6 catalyzed photoredox cleavage generates an N-protected isoquinuclidinone, providing rapid access to the core structures of a variety of important indole alkaloids. Optimized conditions for the enamine mediated photocleavage employed the use of silica gel, acetic acid (1.5 equiv.) and piperidine (3.0 equiv.), a blue LED light source, and pure oxygen rather than air. The two-step sequence utilizes acrolein as a ketene dienophile equivalent providing a new approach to asymmetric “ketene” Diels–Alder reactions. Further elaboration of the resultant isoquinuclidines permitted an enantioselective route to intermediates previously employed in total syntheses of catharanthine and Deserpidine.
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Enantioselective isoquinuclidine synthesis via sequential Diels–Alder/visible-light photoredox C–C bond cleavage: a formal synthesis of the indole alkaloid catharanthine
Organic Chemistry Frontiers, 2018Co-Authors: Simon J. Kim, Robert A. BateyAbstract:An enantioselective route to substituted chiral isoquinuclidines, present in alkaloids such as catharanthine, Deserpidine, ibogamine and ibogaine, has been developed using a “ketene equivalent” approach. Organocatalyzed Diels–Alder reaction of an N-protected dihydropyridine with acrolein using a valine derived 1,2-aminoalcohol catalyst occurs with high er and dr. Subsequent Ru(Bipy)3Cl2·(H2O)6 catalyzed photoredox cleavage generates an N-protected isoquinuclidinone, providing rapid access to the core structures of a variety of important indole alkaloids. Optimized conditions for the enamine mediated photocleavage employed the use of silica gel, acetic acid (1.5 equiv.) and piperidine (3.0 equiv.), a blue LED light source, and pure oxygen rather than air. The two-step sequence utilizes acrolein as a ketene dienophile equivalent providing a new approach to asymmetric “ketene” Diels–Alder reactions. Further elaboration of the resultant isoquinuclidines permitted an enantioselective route to intermediates previously employed in total syntheses of catharanthine and Deserpidine.
Simon J. Kim - One of the best experts on this subject based on the ideXlab platform.
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enantioselective isoquinuclidine synthesis via sequential diels alder visible light photoredox c c bond cleavage a formal synthesis of the indole alkaloid catharanthine
Organic chemistry frontiers, 2018Co-Authors: Simon J. Kim, Robert A. BateyAbstract:An enantioselective route to substituted chiral isoquinuclidines, present in alkaloids such as catharanthine, Deserpidine, ibogamine and ibogaine, has been developed using a “ketene equivalent” approach. Organocatalyzed Diels–Alder reaction of an N-protected dihydropyridine with acrolein using a valine derived 1,2-aminoalcohol catalyst occurs with high er and dr. Subsequent Ru(Bipy)3Cl2·(H2O)6 catalyzed photoredox cleavage generates an N-protected isoquinuclidinone, providing rapid access to the core structures of a variety of important indole alkaloids. Optimized conditions for the enamine mediated photocleavage employed the use of silica gel, acetic acid (1.5 equiv.) and piperidine (3.0 equiv.), a blue LED light source, and pure oxygen rather than air. The two-step sequence utilizes acrolein as a ketene dienophile equivalent providing a new approach to asymmetric “ketene” Diels–Alder reactions. Further elaboration of the resultant isoquinuclidines permitted an enantioselective route to intermediates previously employed in total syntheses of catharanthine and Deserpidine.
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Enantioselective isoquinuclidine synthesis via sequential Diels–Alder/visible-light photoredox C–C bond cleavage: a formal synthesis of the indole alkaloid catharanthine
Organic Chemistry Frontiers, 2018Co-Authors: Simon J. Kim, Robert A. BateyAbstract:An enantioselective route to substituted chiral isoquinuclidines, present in alkaloids such as catharanthine, Deserpidine, ibogamine and ibogaine, has been developed using a “ketene equivalent” approach. Organocatalyzed Diels–Alder reaction of an N-protected dihydropyridine with acrolein using a valine derived 1,2-aminoalcohol catalyst occurs with high er and dr. Subsequent Ru(Bipy)3Cl2·(H2O)6 catalyzed photoredox cleavage generates an N-protected isoquinuclidinone, providing rapid access to the core structures of a variety of important indole alkaloids. Optimized conditions for the enamine mediated photocleavage employed the use of silica gel, acetic acid (1.5 equiv.) and piperidine (3.0 equiv.), a blue LED light source, and pure oxygen rather than air. The two-step sequence utilizes acrolein as a ketene dienophile equivalent providing a new approach to asymmetric “ketene” Diels–Alder reactions. Further elaboration of the resultant isoquinuclidines permitted an enantioselective route to intermediates previously employed in total syntheses of catharanthine and Deserpidine.
Xiaoyan Chen - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography tandem mass spectrometry method for the quantification of Deserpidine in human plasma application to a pharmacokinetic study
Journal of Chromatography B, 2009Co-Authors: Huaicheng Zhang, Dafang Zhong, Zhenzhong Zhang, Xiaojian Dai, Xiaoyan ChenAbstract:Abstract A sensitive and rapid liquid chromatography/tandem mass spectrometric (LC/MS/MS) method was developed and validated for the determination of Deserpidine in human plasma. The plasma samples were prepared using liquid–liquid extraction (LLE) with ethyl ether–dichloromethane (3:2, v/v). Chromatographic separation was accomplished on an Ultimate XB-C18 column. The mobile phase consisted of methanol–5 mM ammonium acetate–formic acid (72:28:0.036, v/v/v). Detection of Deserpidine and the internal standard tropisetron was achieved by tandem mass spectrometry with an electrospray ionization interface in positive ion mode. The lower limit of quantification was 4.0 pg/ml. The linear range of the method was from 4.0 to 2000 pg/ml. The intra- and inter-day precisions were lower than 14.7% in terms of relative standard deviation (RSD), and the accuracy was within ±8.7% in terms of relative error (RE). This validated method was successfully applied for the evaluation of pharmacokinetics of Deserpidine after a single oral administration dose of 0.25 mg Deserpidine to 22 healthy volunteers.
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Liquid chromatography/tandem mass spectrometry method for the quantification of Deserpidine in human plasma: Application to a pharmacokinetic study
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2009Co-Authors: Huaicheng Zhang, Dafang Zhong, Zhenzhong Zhang, Xiaojian Dai, Xiaoyan ChenAbstract:Abstract A sensitive and rapid liquid chromatography/tandem mass spectrometric (LC/MS/MS) method was developed and validated for the determination of Deserpidine in human plasma. The plasma samples were prepared using liquid–liquid extraction (LLE) with ethyl ether–dichloromethane (3:2, v/v). Chromatographic separation was accomplished on an Ultimate XB-C18 column. The mobile phase consisted of methanol–5 mM ammonium acetate–formic acid (72:28:0.036, v/v/v). Detection of Deserpidine and the internal standard tropisetron was achieved by tandem mass spectrometry with an electrospray ionization interface in positive ion mode. The lower limit of quantification was 4.0 pg/ml. The linear range of the method was from 4.0 to 2000 pg/ml. The intra- and inter-day precisions were lower than 14.7% in terms of relative standard deviation (RSD), and the accuracy was within ±8.7% in terms of relative error (RE). This validated method was successfully applied for the evaluation of pharmacokinetics of Deserpidine after a single oral administration dose of 0.25 mg Deserpidine to 22 healthy volunteers.
Bukar E N Dauda - One of the best experts on this subject based on the ideXlab platform.
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synthesis of 18r hydroxy epiallo yohimbines from 3 iso 19 20 dehydro β yohimbine an enantiospecific route to Deserpidine and reserpine analogues from secologanin
Tetrahedron Letters, 2000Co-Authors: Falmai Binns, Richard T Brown, Bukar E N DaudaAbstract:Abstract (−)-3-Iso-19,20-dehydro-β-yohimbine has been converted into epiallo -yohimbines and, via a novel regio- and stereoselective hydration, into the 18 R -hydroxy derivative, an analogue of Deserpidine. Its 11-methoxy derivative, also prepared from secologanin, is a potential precursor for a reserpine analogue.
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Synthesis of 18R-hydroxy-epiallo-yohimbines from (−)-3-iso-19,20-dehydro-β-yohimbine: an enantiospecific route to Deserpidine and reserpine analogues from secologanin
Tetrahedron Letters, 2000Co-Authors: Falmai Binns, Richard T Brown, Bukar E N DaudaAbstract:Abstract (−)-3-Iso-19,20-dehydro-β-yohimbine has been converted into epiallo -yohimbines and, via a novel regio- and stereoselective hydration, into the 18 R -hydroxy derivative, an analogue of Deserpidine. Its 11-methoxy derivative, also prepared from secologanin, is a potential precursor for a reserpine analogue.
Huaicheng Zhang - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography tandem mass spectrometry method for the quantification of Deserpidine in human plasma application to a pharmacokinetic study
Journal of Chromatography B, 2009Co-Authors: Huaicheng Zhang, Dafang Zhong, Zhenzhong Zhang, Xiaojian Dai, Xiaoyan ChenAbstract:Abstract A sensitive and rapid liquid chromatography/tandem mass spectrometric (LC/MS/MS) method was developed and validated for the determination of Deserpidine in human plasma. The plasma samples were prepared using liquid–liquid extraction (LLE) with ethyl ether–dichloromethane (3:2, v/v). Chromatographic separation was accomplished on an Ultimate XB-C18 column. The mobile phase consisted of methanol–5 mM ammonium acetate–formic acid (72:28:0.036, v/v/v). Detection of Deserpidine and the internal standard tropisetron was achieved by tandem mass spectrometry with an electrospray ionization interface in positive ion mode. The lower limit of quantification was 4.0 pg/ml. The linear range of the method was from 4.0 to 2000 pg/ml. The intra- and inter-day precisions were lower than 14.7% in terms of relative standard deviation (RSD), and the accuracy was within ±8.7% in terms of relative error (RE). This validated method was successfully applied for the evaluation of pharmacokinetics of Deserpidine after a single oral administration dose of 0.25 mg Deserpidine to 22 healthy volunteers.
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Liquid chromatography/tandem mass spectrometry method for the quantification of Deserpidine in human plasma: Application to a pharmacokinetic study
Journal of chromatography. B Analytical technologies in the biomedical and life sciences, 2009Co-Authors: Huaicheng Zhang, Dafang Zhong, Zhenzhong Zhang, Xiaojian Dai, Xiaoyan ChenAbstract:Abstract A sensitive and rapid liquid chromatography/tandem mass spectrometric (LC/MS/MS) method was developed and validated for the determination of Deserpidine in human plasma. The plasma samples were prepared using liquid–liquid extraction (LLE) with ethyl ether–dichloromethane (3:2, v/v). Chromatographic separation was accomplished on an Ultimate XB-C18 column. The mobile phase consisted of methanol–5 mM ammonium acetate–formic acid (72:28:0.036, v/v/v). Detection of Deserpidine and the internal standard tropisetron was achieved by tandem mass spectrometry with an electrospray ionization interface in positive ion mode. The lower limit of quantification was 4.0 pg/ml. The linear range of the method was from 4.0 to 2000 pg/ml. The intra- and inter-day precisions were lower than 14.7% in terms of relative standard deviation (RSD), and the accuracy was within ±8.7% in terms of relative error (RE). This validated method was successfully applied for the evaluation of pharmacokinetics of Deserpidine after a single oral administration dose of 0.25 mg Deserpidine to 22 healthy volunteers.