Two new labdane aldehydes from the skin of the notaspidean Pleurobranchaea meckelii

The paper reports the first chemical study of a shell-less notaspidean mollusc. Two isomeric aldehydes (1, 2) have been isolated from the skin of the Mediterranean Pleurobranchaea meckelii. The structure has been established mainly by spectral methods whereas the absolute stereochemistry was clarified by converting 2 to labd-13E-en-8 alpha,15-diol.