17α-methylprogesterone 17α-methylprogesterone 17α-methylprogesterone (17α-mp), or 17α-methylpregn-4-ene-3,20-dione, is a steroidal progestin related to progesterone that was synthesized and characterized in 1949 but was never marketed. along with ethisterone (1938) and 19-norprogesterone (1951), 17α-mp was one of the earliest derivatives of progesterone to be identified as possessing progestogenic activity. similarly to progesterone and derivatives like 17α-hydroxyprogesterone and 19-norprogesterone, 17α-mp was found to possess poor (though not negligible) oral bioavailability, but showed improved progestogenic activity relative to progesterone when administered via other routes (e.g., subcutaneous or vaginal). in addition to its activity as a progestogen, 17α-mp has also been found to possess some antiglucocorticoid activity. 17α-methylprogesteroneclinical dataother names17α-mp; 17α-methylpregn-4-ene-3,20-dionedrug classprogestin; progestogenidentifiers iupac name (8r,9s,10r,13s,14s,17s)-17-acetyl-10,13,17-trimethyl-2,6,7,8,9,11,12,14,15,16-decahydro-1h-cyclopentaphenanthren-3-one cas number1046-28-2 ypubchem cid101951chemspider92105uniityw2g0d7nccomptox dashboard (epa)dtxsid30909052 chemical and physical dataformulac22h32o2molar mass328.496 g·mol−13d model (jsmol)interactive image smiles cc(=o)c1(ccc2c1(ccc3c2ccc4=cc(=o)ccc34c)c)c inchi inchi=1s/c22h32o2/c1-14(23)21(3)11-9-19-17-6-5-15-13-16(24)7-10-20(15,2)18(17)8-12-22(19,21)4/h13,17-19h,5-12h2,1-4h3/t17-,18+,19+,20+,21-,22+/m1/s1key:ufiqezhbgzcwrs-qzkgnrecsa-n the observation of two-fold improved potency of 17α-mp relative to progesterone led to renewed interest in 17α-substituted derivatives of progesterone. subsequently, hydroxyprogesterone acetate and hydroxyprogesterone caproate were synthesized in 1953 and introduced in 1956 and 1957, respectively, and medroxyprogesterone acetate was discovered in 1957 and introduced in 1959. in addition, though 17α-mp itself was never introduced for medical use, progestogen derivatives of the compound, including medrogestone (1966) and the 19-norprogesterone derivatives demegestone (1974), promegestone (1983), and trimegestone (2001), have been marketed. chemistry