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Novel Cassane and Cleistanthane Diterpenes from Myrospermum f rutescens : Absolute Stereochemistry of the Cassane Diterpene Series

2004; American Chemical Society; Volume: 67; Issue: 10 Linguagem: Inglês

10.1021/np049890c

1520-6025

Daniel Torres‐Mendoza, Luis David Ureña González, Eduardo Ortega-Barrı́a, Phyllis D. Coley, Thomas A. Kursar, Todd L. Capson, Kerry L. McPhail, Luis Cubilla‐Rios,

Plant biochemistry and biosynthesis

Four new diterpenes (1−4) were isolated from the leaves of Myrospermum frutescens as minor constituents. Chagresnol (1), 6β,18-diacetoxycassan-13,15-diene (2), and chagreslactone (3) possess cassane skeletons, while chagresnone (4) exhibits a cleistanthane skeleton. Molecular structures and their relative stereochemistries were elucidated using NMR spectroscopy in combination with UV, IR, and MS spectral data. Although compound 2 was previously reported as a synthetic product, we report its first isolation as a natural product. Derivative products (10−13) were obtained to test their activities against Chagas's disease. In addition, the absolute stereochemistry of the previously isolated cassane diterpene 5 from M. frutescens is presented.