Progesterone derivatives that bind to the digitalis receptor: synthesis of 14 beta-hydroxyprogesterone. A novel steroid with positive inotropic activity.

The synthesis of 14-hydroxy-14 beta-pregn-4-ene-3,20-dione (14 beta-hydroxyprogesterone) is described. This novel steroid is about 10 times more potent than progesterone and one-tenth as potent as ouabagenin in an [3H]ouabain radioligand binding assay and is the first in a series of progesterone congeners that interact at the cardiac glycoside receptor both to possess the C/D cis ring junction and to enhance contractility of isolated cardiac tissue.