Author
H. Ott
Bio: H. Ott is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 48 citations.
Papers
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TL;DR: In this article, eine Anzahl neuer, aus dem Formelschema ersichtlicher, optisch aktiver, teils inaktiver Derivate der Pyrrolidoncarbonsaure bzw. der Eegoninsaure hergestellt was found.
Abstract: L-Glutaminsaure konnte konfigurativ mit L-Eegoninsaure verknupft werden. Daraus leitet sich die Konfiguration des naturlichen l-Cocains gemass Formel II ab. Synthetische L-Eegoninsaure war identisch mit der aus naturlichem l-Cocain erhaltenen l-Eegoninsaure. Im Verlauf der Untersuchung wurde eine Anzahl neuer, aus dem Formelschema ersichtlicher, teils optisch aktiver, teils inaktiver Derivate der Pyrrolidoncarbonsaure bzw. der Eegoninsaure hergestellt.
50 citations
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TL;DR: This review provides a comprehensive overview of TAs, highlighting their structural diversity, use in pharmaceutical therapy from both historical and modern perspectives, natural biosynthesis in planta and emerging production possibilities using tissue culture and microbial biosynthesis of these compounds.
Abstract: Tropane alkaloids (TA) are valuable secondary plant metabolites which are mostly found in high concentrations in the Solanaceae and Erythroxylaceae families. The TAs, which are characterized by their unique bicyclic tropane ring system, can be divided into three major groups: hyoscyamine and scopolamine, cocaine and calystegines. Although all TAs have the same basic structure, they differ immensely in their biological, chemical and pharmacological properties. Scopolamine, also known as hyoscine, has the largest legitimate market as a pharmacological agent due to its treatment of nausea, vomiting, motion sickness, as well as smooth muscle spasms while cocaine is the 2nd most frequently consumed illicit drug globally. This review provides a comprehensive overview of TAs, highlighting their structural diversity, use in pharmaceutical therapy from both historical and modern perspectives, natural biosynthesis in planta and emerging production possibilities using tissue culture and microbial biosynthesis of these compounds.
161 citations
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TL;DR: Both cocaine enantiomers were weak inhibitors of acetylcholinesterase (AChE); it is unlikely that the inhibition of BChE is an important factor in the subjective effects of cocaine, but it may have implications for the toxicity of cocaine to the fetus.
100 citations
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TL;DR: In this article, the bicyclic compounds 4a and 4b were synthesized via Li2Cu(CN)Ph2, and the desired compound 23 was obtained from 20.
Abstract: Starting from D-glutamic acid (5), the bicyclic compounds 4a and 4b were synthesized via17 (Schemes 1 and 2). The reaction leading to 4g and 4h with LiCuPh2 was not successful. But treatment of the N-protected model lactams 19, 21, and 22 with Li2Cu(CN)Ph2 gave the amino ketones 24, 26, and 27, respectively (Scheme 3). The desired compound 23 was obtained from 20. Conversion of the unprotected lactams 28, 31, and 32 gave the phenyl derivative 34 in excellent yields. Ester 35 was transformed to the α -amino-γ- oxo-acid derivative 36. This conversion opens a novel access to this type of compounds.
62 citations
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TL;DR: In this paper, ananti-synthesis of the major pungent principle of ginger (Gingerol) and the (-)-(R)-antipode in good yields and optical yields of 33-39% is described.
Abstract: Enantioselektive Synthesen des Hauptgewurzprinzips des Ingwers (+)-(S)-[6]-Gingerol[(s)-1] und des (-)-(R)-Antipoden werden in guten Ausbeuten und mit 33–39% optischer Ausbeute beschrieben. Als Schlusselschritt wird eine Aldolreaktion mit dem″ Anion″ des chiralen Hydrazons 6 und n-Hexanal benutzt. Die chirale Hilfsverbindung ′13 wird in funf Stufen aus (R)-Glutaminsaure hergestellt.
Enantioselective Synthesis of (-)-(R)-and (+)-(S)-[6]-Gingerol-Pungent Principle of Ginger1)
Enantioselective syntheses of the major pungent principle of ginger (+)-(S)-[6]-gingerol [(S)-1] and the (-)-(R)-antipode in good yields and optical yields of 33–39% are described. As a key step, and aldol reaction is used with the “anion” of the chiral hydrazone 6 and n-hexanal. The chiral auxiliary compound 13 is prepared in five steps from (R)-glutamic acid.
61 citations
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TL;DR: No brain uptake was seen, although transport of cocaine into the brain is not expected to be stereoselective, and the explanation for the lack of uptake was determined to be very rapid metabolism of (+)‐cocaine in the blood.
Abstract:
The naturally occurring enantiomer of cocaine, (–)-cocaine, has been previously labeled with 11C on the N-methyl group and used in conjunction with positron emission tomography to show that cocaine is rapidly taken up in the striata of human and baboon brain. In the present study, the behaviorally inactive (+)-cocaine was similarly labeled, with a view to its use for measuring the nonspecific binding of cocaine. No brain uptake was seen, although transport of cocaine into the brain is not expected to be stereoselective. The explanation for the lack of uptake was determined to be very rapid metabolism of (+)-cocaine in the blood. By 30s after administration of labeled (+)-cocaine, it was undetectable in plasma. In vitro studies demonstrated that (+)-cocaine is 50% debenzoylated to (+)-ecgonine methyl ester within 5 s of exposure to baboon plasma but not to washed erythrocytes. The hydrolysis of (–)-cocaine is at least 1,000 times slower. Serum butyrylcholinesterase (EC 3.1.1.8) appears to be responsible for this hydrolysis, as evidenced by its inhibition by physostigmine and catalysis by commercially available pseudocholinesterase from horse and human blood.
59 citations