<unk> , also known as 1,6-didehydro-6-chlororetroprogesterone or as 6-chloro-9β,10α-pregna-1,4,6-triene-3,20-dione, is a synthetic pregnane steroid and a derivative of progesterone and retroprogesterone. Retroprogesterone derivatives like<unk>  are analogues of progesterone in which the hydrogen atom at the 9th carbon has been switched from the α-position (below the plane) to the β-position (above the plane) and the methyl group at the 10th carbon has been switched from the β-position to the α-position. This results in a "bent" configuration in which the plane of rings A and B is orientated at a 60° angle below the rings C and D. Analogues of<unk>  include dydrogesterone (6-dehydroretroprogesterone) and Ro 6-3129 (16α-ethylthio-6-dehydroretroprogesterone).
Trengestone
Trimegestone
Demegestone
Flat wart
Oak wilt
Prayer callus
Cradle cap
Racquet nail