Revision of Structure of Anhydronellionol Triacetate

Article abstract of DOI:10.1246/bcsj.56.2981

The structure of anhydronellionol triacetate was revised to 11,12,16-triacetoxy-6-hydroxyabieta-5,8,11,13-tetraen-7-one (18) by the following syntheses.Acetylation of 16-acetoxyabieta-8,11,13-trien-12-ol, followed by oxidation with chromium trioxide, afforded 12,16-diacetoxyabieta-8,11,13-trien-7-one.This was converted into 6,12,16-triacetoxyabieta-5,8,11,13-tetraen-7-one (17) via 12,16-diacetoxyabieta-8,11,13-trien-6-one.Oxidation of 11,12,16-triacetoxyabieta-8,11,13-trien-6-one with Jones reagent gave 18, whose 1H NMR spectrum was in good agreement with that of natural anhydronellionol triacetate. 11,12,16-Triacetoxyabieta-5,8,11,13-tetraen-7-one (28) was also synthesized from 11,12,16-triacetoxyabieta-8,11,13-trien-7-one.The 1H NMR spectra of 17 and 28 were different from that of natural anhydronellionol triacetate.Since the revised structure 18 corresponds to dehydronellionol triacetate, the name of anhydronellionol should now be dropped from the list of natural diterpenes.