TESTUDINARIOL-A AND TESTUDINARIOL-B, 2 UNUSUAL TRITERPENOIDS FROM THESKIN AND THE MUCUS OF THE MARINE MOLLUSK PLEUROBRANCUS TESTUDINARIUS

The skin of the Notaspidea mollusc Pleurobranchus testudinarius contai ns a very unusual triterpenoid, testudinariol-A (1), which is also the main liposoluble component of the defensive mucous secretion. The str ucture, and the absolute stereochemistry, of I has been assigned on th e basis of extensive spectral and chemical studies. The structural wor k on a minor co-occurring metabolite, testudinariol-B (2), led to the epimer of 1 at C-10. (C) 1997 Elsevier Science Ltd.