PHOTOCHEMICAL TRANSFORMATIONS .25. SYNTHESIS OF CYCLOARTENOL

3β-Aoetoxy- and 3β-benzoyloxy-lanost-24-en-11β-ol nitrites, readily available from lanosterol, on photolysis in the presence of iodine give 19-iodo-derivatives. By further transformations cycloartenol has been obtained. The formal total synthesis of this latter compound is, therefore, complete. Photolysis of the above mentioned nitrites in the absence of iodine gives the corresponding 19-oximino- and thence 19-cyano-derivatives. Such derivatives have not, so far, been converted into cycloartenol.