Medroxyprogesterone acetate

Medroxyprogesterone acetate (74) is stmcturaHy related to and has been prepared from hydroxyprogesterone (39) (Fig. 10). Formation of the bis-ketal accomplishes the protection of the ketones and the required migration of the double bond. Epoxidation with peracetic acid produces a mixture of epoxides (75), with a predominating. Treatment of the a-epoxide with methyl magnesium bromide results in diaxial opening of the epoxide. Deprotection of the ketones provides (76), which is dehydrated to (77) by treatment with dilute sodium hydroxide in pyridine. Upon treatment with gaseous hydrochloric... 

Fig. 10. Preparation of medroxyprogesterone acetate (74) and medroxyprogesterone (78) from hydroxyprogesterone (39).

Megestrol acetate (79) is stmcturaHy related to progesterone (1). It has been prepared from medroxyprogesterone acetate (74) by chloranil-mediated dehydrogenation. It also has been prepared from hydroxyprogesterone acetate (42) via 6-methylenation and double-bond migration (109,110). 

The pregnanes include megestrol, medroxyprogesterone acetate [71-58-9] C24H34O4 (6), chlormadinone acetate [302-22-7] C23H2QCIO4, and cyproterone acetate [427-51-0], C24H2gC104 (7). 

Medroxyprogesterone Acetate Megestrol Acetate Melengestrol Acetate Norethindrone Pregnenolone Acetate Progesterone... 

Progestin-only contraceptives (Fig. 4) contain low-doses of progestins (e.g. 350 pg norethindrone or 75 pg norgestrel) that have to be administered daily without interruption. The lowest expected failure rate during the first year of use is 0.5%, while the typical failure rate amounts to 3%. Subdermal implants of norgestrel (216 mg) for sustained release provides for long-term (for up to 5 years) contraceptive effects characterized by failure rates of only 0.05%. Reliable contraception for 3 months can be achieved by an intramuscular injection of a crystalline suspension of 150 mg medroxyprogesterone acetate (Fig. 3) (failure rate 0.3%). 

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