Acta Cryst. (2004). E60, o500-o502  [ doi:10.1107/S1600536804004416 ]

The natural diterpenoid kamebacetal A

H. Shi, C. R. Sun and Y. J. Pan

Abstract: Kamebacetal A, or (1S*,2S*,8S*,9R*,11R*,15S*,16S*,18R*)-15,18-dihydroxy-16-methoxy-12,12-dimethyl-6-methylene-17-oxapentacyclo[7.6.2.1^5,8.0^1,11.0^2,8]octadecan-7-one, C₂₁H₃₀O₅, is a natural diterpenoid which has cytotoxic and antibacterial activity. The molecule contains five six-membered rings and one five-membered ring. Ring A adopts a chair conformation, rings B, C, E and F adopt boat conformations, and ring D adopts an envelope conformation. The conjugated -methylenecyclopentanone is the active part of the molecule due to ring strain.

Online 6 March 2004

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