title: (Z)-17(20)-dehydrocholesterol. A new sterol with C-21 and C-22 spatially fixed.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D008968:Molecular Conformation; D009904:Optical Rotation; D011284:Pregnenolone
chemical_list: D011284:Pregnenolone; D002784:Cholesterol