Synonyms: Ergosta-1,4-dien-3-one,7-(acetyloxy)-16,17-epoxy-22,24,25-[ethylidynetris(oxy)]-, [7a,16b,17a,22R(S)]-; 16,17-Epoxy-3H-cyclopenta[a]phenanthrene,ergosta-1,4-dien-3-one deriv.; 2,7,8-Trioxabicyclo[3.2.1]octane,ergosta-1,4-dien-3-one deriv.; (+)-Petuniasterone K; Petuniasterone K