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Syntheses of 6,7-dihydro-4H-indolones 6 and 10 by a selective Birch reduction of the benzene ring of the indole system are described. The antiestrogen zindoxifene and the 2-phenylindole 2 as well as 6 and 10 were tested for their relative binding affinities at the androgen receptor as well as for antiandrogenic and estrogenic properties. Both compounds 6 and 10 showed potent indirect antiandrogenic activity which were similar to those of the 2-phenyl-indoles zindoxifene and 2.

Selective Birch-reduction of one of the phenolic rings of meso- or d,l-HES led to compounds 6a and 6b which exert a higher binding affinity to the androgen receptor as the respective parent HES. In vivo testing of 6a and 6b shows that 6a has the same potency in reducing accessory sex organ weights and testosterone levels in the intact mouse as has meso-HES, but strongly decreased estrogenic activity. Syntheses and testing of 7 having no ethyl side chains revealed the necessity of these groups for biological activity.

Among nonsteroidal antiandrogens, mostly compounds of the Flutamide-type are described. For the development of new compounds with affinity to androgen receptors and antiandrogenic activity five new hydroxy-substituted phenyltetralines were prepared and tested. Synthesis was achieved by reaction of the respective 1-tetralones with phenyl magnesium bromides, dehydration of the carbinols, hydrogenation and ether cleavage. In addition to the expected affinity to estrogen receptors, especially the 6-OH, 4'-OH-substituted compound 11 showed an affinity to androgen receptors, too. Whereas none of the tested compounds had a marked estrogenicity, 11 and 15 (6-OH, 3'-OH) exerted antiestrogenic effects. Androgenic properties were not given. In the adult, intact mouse, 11 and 15 exhibited a pronounced inhibition of seminal vesicle weights concomitant with a reduction of the testosterone level. Since in castrated, androgen-substituted animals only relatively weak direct antiandrogenic effects were demonstrable, the antiandrogenic activity of these new phenyltetralines is more due to an inhibition of testosterone biosynthesis than to a direct, receptor-mediated effect.