The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Karl-heinz Engel - One of the best experts on this subject based on the ideXlab platform.
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Reinvestigation of the Absolute Configurations of Chiral β-Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis.
Journal of agricultural and food chemistry, 2016Co-Authors: Christiane Kiske, Svenja Nörenberg, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses o...
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Reinvestigation of the Absolute Configurations of Chiral β‑Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis
2016Co-Authors: Christiane Kiske, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Svenja Nörenberg, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses of HTA- and MPA-thioesters were in agreement. However, they were opposite to those deduced for (S)-MαNP thioesters via the sector rule. Consequently, the formerly assigned configurations of β-mercaptoalkanones deduced via investigation of (S)-MαNP-derivatives have to be revised
D Y Wang - One of the best experts on this subject based on the ideXlab platform.
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the stereoselectivity of chrono pharmacokinetic parameters of Hydratropic Acid in rats
Acta pharmaceutica Sinica, 1993Co-Authors: D Y WangAbstract:The stereoselective chrono-pharmacokinetic parameters of Hydratropic Acid in rats were studied. The results showed that under standard light-dark cycle pharmacokinetic parameters of T1/2 alpha and CL are stereoselective and under reverse light-dark cycle, parameters T1/2 beta, AUC, CL, Vc and MRT were shown to be stereoselective. To compare the corresponding parameters of the two different light-dark cycles using t-test, no differences were found in most of them.
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stereoselective chronopharmacokinetics of Hydratropic Acid in rats
Acta pharmaceutica Sinica, 1993Co-Authors: D Y WangAbstract:The circadian rhythms of Hydratropic Acid (HTA) pharmacokinetic parameters were studied by using consinor method. Under standard light-dark cycle, the T1/2 beta and CL of S(+)-HTA, T1/2 beta of R(-)-HTA and CL, MRT of RS (+/-)-HTA were found to have circadian rhythm. Circadian rhythms were also found in the T1/2 beta and AUC of S (+)-HTA, CLS of R(-)-HTA and RS(+/-)-HTA under reverse light--dark cycle. Stereoselective circadian rhythms were found in CL of S(+)-HTA under standard light-dark cycle and in T1/2 beta and AUC of S(+)-HTA and CL of R(-)-HTA under reverse light-dark cycle. After ip administration of RS(+/-)-HTA to rat under two different light-dark cycles, the peak phases of circadian rhythms in the biotransformation of R(-)-HTA to S(+)-HTA in rat were both at the end of the dark phase. This suggests that administration of the drug at early morning is a recommendable scheme for chronotherapy with HTA.
Christiane Kiske - One of the best experts on this subject based on the ideXlab platform.
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Reinvestigation of the Absolute Configurations of Chiral β-Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis.
Journal of agricultural and food chemistry, 2016Co-Authors: Christiane Kiske, Svenja Nörenberg, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses o...
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Reinvestigation of the Absolute Configurations of Chiral β‑Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis
2016Co-Authors: Christiane Kiske, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Svenja Nörenberg, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses of HTA- and MPA-thioesters were in agreement. However, they were opposite to those deduced for (S)-MαNP thioesters via the sector rule. Consequently, the formerly assigned configurations of β-mercaptoalkanones deduced via investigation of (S)-MαNP-derivatives have to be revised
Wolfgang Eisenreich - One of the best experts on this subject based on the ideXlab platform.
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Reinvestigation of the Absolute Configurations of Chiral β-Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis.
Journal of agricultural and food chemistry, 2016Co-Authors: Christiane Kiske, Svenja Nörenberg, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses o...
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Reinvestigation of the Absolute Configurations of Chiral β‑Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis
2016Co-Authors: Christiane Kiske, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Svenja Nörenberg, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses of HTA- and MPA-thioesters were in agreement. However, they were opposite to those deduced for (S)-MαNP thioesters via the sector rule. Consequently, the formerly assigned configurations of β-mercaptoalkanones deduced via investigation of (S)-MαNP-derivatives have to be revised
Kenji Monde - One of the best experts on this subject based on the ideXlab platform.
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Reinvestigation of the Absolute Configurations of Chiral β-Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis.
Journal of agricultural and food chemistry, 2016Co-Authors: Christiane Kiske, Svenja Nörenberg, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses o...
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Reinvestigation of the Absolute Configurations of Chiral β‑Mercaptoalkanones Using Vibrational Circular Dichroism and 1H NMR Analysis
2016Co-Authors: Christiane Kiske, Miriam Ecker, Tohru Taniguchi, Kenji Monde, Wolfgang Eisenreich, Svenja Nörenberg, Karl-heinz EngelAbstract:The absolute configurations of chiral β-mercaptoalkanones were previously assigned on the basis of the 1H NMR anisotropy method using (S)-2-methoxy-2-(1-naphthyl)propionic Acid ((S)-MαNP) as the chiral auxiliary. This study presents a reinvestigation of the configurations of 4-mercapto-2-pentanone 1, 4-mercapto-2-heptanone 2, and 2-mercapto-4-heptanone 3. Enantiomers of 1, 2, and 3 were obtained by lipase-catalyzed hydrolyses of the respective acetylthioalkanones. Upon derivatization with (S)-MαNP, the configurations of the reaction products were deduced based on the order of the HPLC elution of the diastereoisomeric thioesters, assuming that the sector rule previously developed for secondary alcohols is also valid for thiols. In addition, the configurations were experimentally determined by vibrational circular dichroism (VCD) and 1H NMR analyses after esterification with (R)-Hydratropic Acid (HTA) and 2-methoxy-2-phenylacetic Acid (MPA). The assignments of the configurations using VCD and NMR analyses of HTA- and MPA-thioesters were in agreement. However, they were opposite to those deduced for (S)-MαNP thioesters via the sector rule. Consequently, the formerly assigned configurations of β-mercaptoalkanones deduced via investigation of (S)-MαNP-derivatives have to be revised
