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IUPAC name
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ChemSpider 199224
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PubChem 228864
Molar mass 300.435 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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19-Norprogesterone, also known as 19-norpregn-4-ene-3,20-dione, is a close analogue of the steroid progesterone, lacking only the C-19 methyl group of that molecule. The 1953 discovery that a preparation of 19-norprogesterone gave results equivalent to progesterone in assays detecting inhibitors of ovulation led to the birth of an ultimately successful industrial-academic program of medicinal chemistry-driven research into contraception; when arduous preparation of synthetic 19-norprogesterone was streamlined and crystalline material was obtained, the norsteroid proved 4-8 more active than the natural steroid.[1] Chemistry used in 1938 to increase the bioavailability of ethisterone was cross-applied by Carl Djerassi and coworkers at Syntex in Mexico City in 1951 to prepare norethisterone, a synthetic norsteroid that was the first orally bioavailable progestin highly active in preventing ovulation. First human trials regarding contraceptive safety and efficacy were conducted using the related noretynodrel from G.D. Searle & Co.[2]

From the perspective of modern pharmaceutical design, 19-norprogesterone possesses mineralocorticoid activities and remains a potent progestogen; however, it is no longer considered a clinically useful agent.[citation needed] Nevertheless, it is the parent of a series of progestins that remain in use as drugs, including nomegestrol acetate, promegestone, trimegestone, gestonorone, and nestorone.[3][non-primary source needed]

See also[edit]


  1. ^ Here and following see: Enrique Ravina, 2011, "The Evolution of Drug Discovery," Weinheim, Germany: Wiley-VCH, p. 185-188; ISBN 978-3-527-32669-3. See [1], accessed 28 May 2014.
  2. ^ See Combined oral contraceptive pill#Studies of progestins to prevent ovulation, and references therein.
  3. ^ Paris J, Botella J, Fournau P, Bonnet P, Thevenot R (October 1987). "Extinction of mineralocorticoid effects in 19-norprogesterone derivatives: structure-activity relationships". J. Pharmacol. Exp. Ther. 243 (1): 288–91. PMID 2822901.