Reaktionen an Indolderivaten, XVI. Die autoxydative Indol‐Chinolon‐Umwandlung eines Camptothecin‐Modells

Abstract

Die pentacyclische Modellverbindung 10 wurde durch autoxydative Indol-Chinolon-Umlagerung in 12 umgewandelt und dieses iiber einige einfache Reaktionsschritte (4 14-+15) in den aromatischen Grundkbrper 11 des Camptothecins (1) iibergefiihrt. Reactions with Indole Derivatives, XVIThe Autoxidative Indole-quinolone Rearrangement of a Camptothecin Model CompoundThe pentacyclic model compound 10 is transformed into 12 by autoxidative indole-quinolone rearrangement. 12 yields in some simple reaction steps (+ 14 + 15) the aromatic camptothecin analogue 11.Das pentacyclische Alkaloid Camptothecin (l), das von Wall2) aus der Rinde und dem Holz des in Zentralchina heimischen Baumes Camptotheca acuminata (Nyssacee) isoliert worden war, erwies sich als eine der aktivsten natiirlich vorkommenden antiTumor-wirksamen Substanzen3). In Tierversuchen wurde hohe Aktivitat gegen Leu-

A Domino N-Amidoacylation/Aldol-Type Condensation Approach to the Synthesis of the Topo-I Inhibitor Rosettacin and Derivatives

“…Compound 10g (342 mg, 1 mmol) in 7 mL of 48% HBr was then heated under stirring at 135 °C for 12 h. After cooling, the solution was alkalinized and extracted twice with DCM (10 mL). A classical workup provided pure rosettacin ( 2g ) as a light-yellow solid in 61% yield (171 mg): R f 0.19 (cyclohexane/AcOEt 1:1); mp 288 °C (lit . mp 289−291 °C; lit .…”

The Witkop-Winterfeldt-Oxidation of Indoles

“…In model studies preceeding the total synthesis of camptothecin Winterfeldt investigated the direct conversion of indoles to quinolones for a variety of substrates. (Scheme 22 and 23) [7,43,50]. In particular, the oxidation of the natural product ajmalicine (104) occurred in an excellent yield of 92%.…”

Camptothecin

“…In a recent development, the camptothecin analog CLXXX was obtained through the indole-quinolone conversion from the indole compound CLXXIX (56).…”