A 3D schematic representation of the chemical structures of progesterone (top) and<unk>  (bottom), showing the retrosteroid spatial configuration of<unk> .<unk> , also known as 6-dehydro-9β,10α-progesterone or as 9β,10α-pregna-4,6-diene-3,20-dione, is a synthetic pregnane steroid and a derivative of progesterone and retroprogesterone (9β,10α-progesterone). 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 reversed configuration in<unk>  results in a "bent" spatial geometry in which the plane of rings A and B is orientated at a 60° angle below the rings C and D.<unk>  also has an additional double bond between the C6 and C7 positions (4,6-dien-3-one configuration). While its chemical structure is close to that of progesterone, these changes result in<unk>  having improved oral activity and metabolic stability, among other differences, in comparison to progesterone. Analogues Other retroprogesterone derivatives, and analogues of<unk> , include trengestone (1,6-didehydro-6-chlororetroprogesterone) and Ro 6-3129 (16α-ethylthio-6-dehydroretroprogesterone). Synthesis<unk>  is synthesized and manufactured by treatment of progesterone with ultraviolet light exposure. Chemical syntheses of<unk>  have been published.
Dydrogesterone
Haloprogesterone
Hydroxyprogesterone acetate
Gestodene
Vinyltestosterone
Retroprogesterone
Ethinylestradiol
Algestone