4-Methylpregna-1, 3, 5 (10)-trien-20-one and 4-methylpregna-1, 3, 5 (10), 16-tetraen-20-one have been obtained by a dienol: benzene type of rearrangement of 5α, 6α-epoxypregnanes possessing a further double bond equivalent on ring A. The crystal structure of 4-methyl-19- norpregna-1, 3, 5 (10)-trien-20-one is reported.
