Goswami A, Macdonald T L, Hubbard C, Duffel M W, Rosazza J P
Division of Medicinal Chemistry and Natural Products, College of Pharmacy, University of Iowa, Iowa City 52242.
Chem Res Toxicol. 1988 Jul-Aug;1(4):238-42. doi: 10.1021/tx00004a009.
The dimeric Vinca alkaloid leurosine undergoes an unusual fission of the piperidine ring of the Iboga substructure when reacted with horseradish peroxidase and hydrogen peroxide. A preparative-scale oxidation of leurosine provided 15'-hydroxycatharinine, which was identified by infrared and proton and carbon-13 NMR spectroscopies and high-resolution mass spectrometry. A proposed pathway for the formation of 15'-hydroxycatharinine involves radical and iminium intermediates and cleavages of a putative diol. The enzymatic transformation product is 3 orders of magnitude less active than leurosine or vinblastine in vitro, in inhibiting the polymerization of tubulin.
