Isolation of two new C30 sterols, (24E)-24-N-propylidenecholesterol and 24 epsilon-N-propylcholesterol, from a cultured marine Chrysophyte.

Two new sterols, (24E)-24-n-propylidenecholesterol and 24 epsilon-n-propylcholesterol, were isolated from a cultured marine Chrysophyte. Since most of the steroids found in marine invertebrates are unchanged or modified sterols of algal or symbiotic origin, the discovery of these two unusual sterols in a unicellular alga grown under well-defined conditions contributes to our knowledge of sterols in marine food chains and offers a potential substrate for biosynthetic labeling experiments.