Synthetic approaches toward total synthesis of 12 beta-methyl- and 12-methylene-19-norpregnanes.

The effect of a substituent in the 12-position of progestagens was studied. To this end, various approaches toward the preparation of 12 beta-alkyl- and 12-alkylidenenorpregnanes were investigated. Eventually, the desired compounds 17 beta-hydroxy-12 beta-methyl-18a-homo-19-nor-17 alpha-pregn-4-en-20-yn-3-one (37) and 17 beta-hydroxy-12-methylene-18a-homo-19-nor-17 alpha-pregn-4-en-20-yn- 3-one (38) were obtained in racemic form by total synthesis; they were shown to lack progestagenic activity.

Strategy in drug research. Synthesis and study of the progestational and ovulation inhibitory activity of a series of 11beta-substituted-17alpha-ethynyl-4-estren-17beta-ols.

Using the strategy based on the Hansch method which analyses effects of substituents on biological activity in terms of their hydrophobic, electronic and steric effects we selectively synthesised a series of 11beta-substituted-17alpha-ethynyl-4-estren-17beta-ols that combine ease of synthesis with good discrimination between these factors aiming at finding the compounds with optimum biological activity in that series. The compounds were tested quantitatively in the Clauberg test (rabbit) and the ovulation inhibition test (rat). The differences in biological activity could reasonably be correlated with two steric effects introduced by the 11beta-substituent. These were a change in the overall shape of the 11beta-substituent and the angular methyl group, and direct steric hindrance of the steroid-receptor protein binding. Some exceptions were found possibly due to metabolic conversion of these compounds to the corresponding 11beta-substituted-17alpha-ethynyl-1,3,5(10)-estra-triene-3,17beta-diols.