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A new cucurbitacin D related 16,23-epoxy derivative and its isomerization products
Christoph Seger1, Sonja Sturm, Ernst Haslinger
1Department of Pharmacognosy, Institute of Pharmacy, University of Innsbruck, Innrain 52, A-6020 Innsbruck, Austria. christoph.seger@uibk.ac.at
Abstract:
[reaction: see text] A new (23S,24Z)-16,23-epoxy cucurbitacin derivative was isolated from Ecballium elaterium L. (Cucurbitaceae) fruit juice along with known cucurbitacin derivatives. Structure elucidation of these derivatives was accomplished by NMR spectroscopy and mass spectrometry from HPLC-MS data. Isomerization of the epoxy derivative was monitored by 1D and 2D NMR experiments. The configuration of the reaction products was elucidated as (23R,24E) and (23R,24Z), and a mechanism for the acid-catalyzed rearrangement process is proposed.
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