Mecigestone
Mecigestone, also known as pentarane B, as well as 6α-methyl-16α,17α-cyclohexanoprogesterone, 6α-methylcyclohexanopregn-4-ene-3,20-dione, or 17α-acetyl-6α-methyl-16β,24-cyclo-21-norchol-4-en-3-one, is a steroidal progestin that was developed by the Zelinskii Institute of Organic Chemistry of the Russian Academy of Sciences and has been proposed for clinical use as a progestogen but has not been marketed. It is the 6α-methylated analogue of pentarane A, which is also known as D'6-pentarane or pregna-D'6-pentarane.
Synthesis
The synthesis has been reported: Patent: Precursor: Micronization technology:- The Diels-Alder reaction of 16-DPA with butadiene gives PC99565806. It is important to recognize that for mecigestone the stereochemistry about the E-ring is cis and not trans. The trans isomer is PC99565808.
- Ex 1: Epoxidation of the olefin with ethereal Monoperphthalic acid occurs to give. A search of the pubchem registry only gave the trans configuration about the E-ring, and not the expected cis stereochemistry.
- The reaction with methyl magnesium iodide occurs with a regioselectivity to the 6 position from the beta face. Saponification of the acetate ester also occurs during the work-up to give.
- The Jones oxidation leads to the enone of the finished product. Epimerization of the beta-methyl group also occurred during this step. Thus, completing the synthesis of mecigestone.