A sample of<unk> .<unk>  is a naturally occurring pregnane steroid and is also known as pregn-4-ene-3,20-dione. It has a double bond (4-ene) between the C4 and C5<unk> sitions and two ketone groups (3,20-dione), one at the C3<unk> sition and the other at the C20<unk> sition. Synthesis<unk>  is commercially produced by semisynthesis. Two main routes are used: one from yam diosgenin first pioneered by Marker in 1940, and one based on soy phytosterols scaled up in the 1970s. Additional (not necessarily economical) semisyntheses of<unk>  have also been reported starting from a variety of steroids. For the example, cortisone can be simultaneously deoxygenated at the C-17 and C-21<unk> sition by treatment with iodotrimethylsilane in chloroform to produce 11-keto-progesterone (ketogestin), which in turn can be reduced at<unk> sition-11 to yield<unk> . Marker semisynthesis An economical semisynthesis of<unk>  from the plant steroid diosgenin isolated from yams was developed by Russell Marker in 1940 for the Parke-Davis pharmaceutical company. This synthesis is known as the Marker degradation. The Marker semisynthesis of<unk>  from diosgenin. The 16-DPA intermediate is important to the synthesis of many other medically-important steroids. A very similar approach can produce 16-DPA from solanine. Soy semisynthesis<unk>  can also be made from the stigmasterol found in soybean oil also. c.f. Percy Julian. Stigmasterol to<unk>  synthesis. Total synthesis The Johnson total synthesis of<unk> . A total synthesis of<unk>  was reported in 1971 by W.S. Johnson. The synthesis begins with reacting the phosphonium salt 7 with phenyl lithium to produce the phosphonium ylide 8. The ylide 8 is reacted with an aldehyde to produce the alkene 9. The ketal protecting groups of 9 are hydrolyzed to produce the diketone 10, which in turn is cyclized to form the cyclopentenone 11. The ketone of 11 is reacted with methyl lithium to yield the tertiary alcohol 12, which in turn is treated with acid to produce the tertiary cation 13. The key step of the synthesis is the π-cation cyclization of 13 in which the B-, C-, and D-rings of the steroid are simultaneously formed to produce 14. This step resembles the cationic cyclization reaction used in the biosynthesis of steroids and hence is referred to as biomimetic. In the next step the enol orthoester is hydrolyzed to produce the ketone 15. The cyclopentene A-ring is then opened by oxidizing with ozone to produce 16. Finally, the diketone 17 undergoes an intramolecular aldol condensation by treating with aqueous<unk> tassium hydroxide to produce<unk> .
Progesterone
Estrogen 
Estrogen
Androgen
Estradiol 
Estradiol
Methyltestosterone
Progestogen