Reaktionen an Indolderivaten, XXX Die stereoselektive und stereospezifische Totalsynthese der Geissoschizin‐Isomeren

Abstract

Uber eine stereoselektive und stereospezifische Claisen-Umlagerung kann die exocyclische, Z-konfigurierte Doppelbindung des 19,20-lsogeissoschizins (4a) eingefuhrt werden. Die Konfiguration der Produkte lieD sich durch Korrelation mit Naturstoffen beweisen. Reactions with Indole Derivatives, XXX") The Stereoselective and Stereospecific Total Synthesis of Geissoschizine Isornerslb'The exocyclic, Z-configurated double bond of 19,20-isogeissoschizine (4a) can be introduced via a stereoselective and stereospecific Claisen rearrangement. The configuration of the products is proven by correlation to natural products.Im Zuge der Erarbeitung stereoselektiver Techniken zum gezielten Aufbau trisubstituierter exocyclischer Doppelbindungen -eine notwendige Voraussetzung fur eine stereoselektive Totalsynthese des Geissoschizins (5) ' ) -untersuchten wir auch den sterischen Verlauf von Claisen-Umlagerungen an Vinylathern des Typs 3. '' l a ' XXIX. 3172 (1968).

Chemistry and Pharmacology of Analgesic Indole Alkaloids from the Rubiaceous Plant, Mitragyna speciosa

“…Mitragynine (1) (1 nM-3 mM) inhibited ileum contraction elicited by electrical stimulation, and its pD 2 value was 6.59Ϯ0.13 (nϭ5); the inhibitory effect was reversed by the addition of naloxone. Its potency is onefourth of that of morphine (37). Mitragynine did not show any effect on smooth muscle contraction induced by acetylcholine or histamine.…”

“…Then, in order to attach an acetic acid residue to the C15 position, each allylic alcohol (43, 44) was subjected to Claisen rearrangement. [36][37][38][39] By heating with trimethyl orthoacetate in the presence of a catalytic amount of benzoic acid in o-xylene, 43 and 44 produced acetates 45 and 46, respectively, as the sole product. The absolute configurations at C3 in 45 and 46 were clearly determined from the CD spectra.…”

“…7-Hydroxymitragynine (5), a minor constituent of M. speciosa, was found to exhibit high potency to opioid receptors: approximately 13-and 46-fold higher than morphine (37) and mitragynine (1), respectively (Fig. 16).…”

“…The EC 50 value estimated for mitragynine (1) was 60.22 nmol/mouse (95% confidence limit, 39.10-92.75 nmol/mouse). The antinociceptive activities of mitragynine (1), mitragynine pseudoindoxyl (57) and morphine (37) were completely inhibited by naloxone at 2 mg/kg, s.c. Therefore, these compounds induce analgesic activity via opioid receptors.…”

2,7-Dihydroxyapogeissoschizine from root bark of Strychnos gossweileri

“…Such a seven-membered ring has, to our knowledge, only been observed in apogeissoschizine, obtained after treatment of geissospermine with concentrated hydrochloric acid Cl33 or by treatment of geissoschizine with trifluoroacetic acid [14]. In mavacurine-and pleiocarpamine-type alkaloids, the additional ring has one carbon less.…”