[Synthesis and reactions of 2-methylene-canrenone]

Starting from the Mannich salt 1 of the aldosterone antagonist canrenone or from 2-methylene-canrenone (2) the A-ring annulated hetero- and carbocycles 5, 6, 8-13 were prepared. Receptor (estradiol, progesterone, androgen, gluco- and mineralocorticoid) binding studies and competition studies with the serum proteins SHBG and CBG were carried out using the compounds 2, 3, 4b, 5, 6b, 8 and 12. The relative binding affinities with CBG are below 1%, in all other cases lower than 0.01%.