Studies on the biosynthesis of the oogoniols.

In feeding experiments withAchlya heterosexualis, [3-(3)H] fucosterol was efficiently incorporated into oogoniols possessing an unsaturated side chain as well as those with a saturated side chain (clionasterol skeleton). [23,25-(3)H]-29-Hydroxyfucosterol was also efficiently incorporated into the oogoniols and its role as an intermediate in the biosynthesis was confirmed by a trapping experiment. This indicated the presence of a small pool of endogenous 29-hydroxyfucosterol in the mycelium. [23, 25-(3)H]-29-Oxofucosterol was also well incorporated into the oogoniols and it is probably an intermediate in the biosynthesis. It was found to be converted to 29-hydroxyfucosterol in a trapping experiment. Reduction of the C-24(28) double bond make take place after all the functional groups have been introduced, at C7, C-11 and C-15, in the tetracyclic structure.