Synthesis and biological activity of 17-esters of 6-dehydro-16-methylene-17 -hydroxyprogesterones

Efficient Synthesis of 16α-Methyl Cyproterone Acetate

An effective method for synthesis of 16α-methyl cyproterone acetate was accomplished starting from commercially available 16-dehydropregnenolone acetate in eight steps, 11.5% overall yield.

Bromination of steroidal 3-keto-4,6-diene

The bromination reaction on 3-keto-4,6-diene steroids, via an epoxide intermediate, with hydrobromic acid in acetic acid medium gives the corresponding 6-bromo derivative. On the other hand, bromination with molecular bromine and subsequent dehydrobromination in an aprotic solvent and basic media afforded the unexpected 4-bromo derivative. In this work we suggest an alternative mechanism for explaining the bromine transposition from C6 to C4.

New progesterone esters as 5alpha-reductase inhibitors

The pharmacological activity of four new progesterone derivatives: 4-bromo-17alpha-(p-fluorobenzoyloxy)-4-pregnene-3,20-dione (7), 4-bromo-17alpha-(p-bromobenzoyloxy)-4-pregnene-3,20-dione (8), 4-bromo-17alpha-(p-chlorobenzoyloxy)-pregnene-3,20-dione (9) and 4-bromo-17alpha-(p-toluoyloxy)-4-pregnene-3,20-dione (10) was determined. These compounds were evaluated as 5alpha-reductase inhibitors on gonadectomized hamster seminal vesicles and flank organs. The pharmacological data of this study indicate that compounds 7 and 9 having at C-17 p-fluorobenzoyloxy and p-chlorobenzoyloxy ester functions respectively showed the highest antiandrogenic effect as measured by the reduction of the weight of the seminal vesicles. In the flank organ model, the same compounds 7 and 9 exhibited a smaller diameter, 1.8 and 1.0 mm, respectively, than the commercially available finasteride 3 (2.3 mm), thus indicating a higher inhibitory effect on 5alpha-reductase enzyme. Steroid 7 showed a higher inhibitory activity on the conversion of T to DHT (Fig. 3) than the presently used finasteride, thus indicating a higher antiandrogenic effect. The nonsubstituted benzoyloxy ester (compound 15) showed a lower antiandrogenic activity as measured in the seminal vesicles model than the p-substituted benzoyloxy compounds.

Synthesis and biological activity of a new progestogen, 16-methylene-17alpha-hydroxy-18-methyl-19-norpregn-4-ene-3, 20-dione acetate

The progestational activity of second- and third-generation progestins in oral contraceptives were markedly increased by addition of an 18-methyl group. A new progestin, the 18-methyl analog of Nestorone, 16-methylene-17alpha-hydroxy-18-methyl-19-norpregn-4-ene-3,2 0-dione acetate (10), was synthesized. The relative binding affinity and biologic activity of 10 was compared with Nestorone, levonorgestrel, and progesterone using a binding assay for rat progesterone receptors, the Clauberg assay in the rabbit, and by assessing pregnancy maintenance in the rat. These studies, as summarized in Table 4, show that 10 is three to ten times more potent than Nestorone. The addition of the 18-methyl group to Nestorone markedly increased its potency as noted above, but is unlikely to change its rate of delivery from sustained release systems. 10 should be ideally suited for administration by implants or small skin patches.

Androgenic and anti-androgenic effects of progesterone derivatives with different halogens as substituents at the C-6 position

The pharmacological activities of four pregnane derivatives: 17alpha-hydroxy-16beta-methylpregna-4,6-diene-3,20-dio ne (7), 17alpha-acetoxy-16beta-methylpregna-4,6-diene-3,20-dio ne (8), 17alpha-acetoxy-6-bromo-16beta-methylpregna-4,6-diene- 3,20-dione (10), and 17alpha-acetoxy-6-chloro-16beta-methylpregna-4,6-diene -3,20-dione (11), were determined. The derivatives were evaluated on gonadectomized male hamster flank organs and seminal vesicles. The results indicate that topical applications of testosterone (T) on the flank organs increased the diameter of the pigmented spot. Similarly, the same phenomenon occurred on the glands treated with compound 11, whereas compound 10 decreased the size of the spot significantly. In this study, we determined the effects of several new steroids on the conversion of T to DHT in flank organs and seminal vesicles. The results show that compound 10 inhibited T conversion to DHT, but compound 11, at a dose of 200 microg, stimulated T conversion in both flank organs and seminal vesicles. However, when 2 mg of compound 11 was applied, it inhibited the conversion of T to DHT, suggesting that this compound also represses gonadotropin release. The difference between compounds 10 and 11 involves the electronegativity of the halogen at the C-6 position of the progesterone skeleton. These data clearly indicate that by decreasing the electronegativity of the halogen at C-6 (compound 10), 5alpha-reductase is inhibited in both tissues and at different pHs. On the other hand, when the electronegativity of the halogen atom was increased (11), there was a much lower inhibitory effect on the conversion of T to DHT.

Synthesis and progestational activity of 16-methylene-17 alpha-hydroxy-19-norpregn-4-ene-3,20-dione and its derivatives

16-Methylene-17 alpha-hydroxy-19-norpregn-4-ene-3,20-dione 1 and its 17 alpha-acylated derivatives were synthesized. The length of the 17 alpha-side-chain ranges from C2-C6. As anticipated, compound 1 did not show any progestational activity or receptor binding activity; whereas, the acylated compounds, especially the butyrate, showed remarkable ability to bind to progesterone receptors. These compounds also showed progestational activity in an in vitro T47D cell culture assay in which progestins increase alkaline phosphatase activity and in an in vivo ovulation inhibition assay. All of the compounds synthesized were without estrogenic activities. The results showed that acylation of 16-methylene-17 alpha-hydroxy-19-norprogesterone can increase progestational activity. The progestational activities of these compounds varied with the 17 alpha-side chain.