| Popis: |
The structure of three diterpenoids from Coleus barbatus , Bentham (Labiatae) having a spirocyclopropyl side chain have been determined: they are barbatusin ( 1a ), 3β-hydroxy-3-deoxybarbatusin ( 2 ) and cyclobutatusin ( 3a ). The structures of 1a and 3a were established by X-ray diffraction analysis, and the latter compound has been shown to have an unusual 4-membered ring produced by a bond across C(1) to C(11). Chemical transformations and interconversions are presented, together with spectroscopic studies. |
