Synonyms: Cyclobuta[2,3]cyclopenta[1,2-a]phenanthrene,13,21-cyclo-18-norpregnane deriv.; Cyclobuta[2,3]cyclopenta[1,2-a]phenanthrene,octadecahydro-10a-methyl-, [2aR-(2aa,4aa,4bb,10ab,10ba,12aR*)]-; [2aR-(2aa,4aa,4bb,10ab,10ba,12aR*)]-Octadecahydro-10a-methylcyclobuta[2,3]cyclopenta[1,2-a]phenanthrene