Synthesis and biological evaluation of some novel 4H-benzopyran-4-one derivatives as nonsteroidal antiestrogens.

The preparation and characterization of some novel 2- and 3-substituted-7-methoxy-4H-1-benzopyran-4-one are presented. The synthesized compounds were evaluated for their uterotrophic, antiuterotrophic and antiimplantation activities in mature female albino rats. 3-Benzyl-7-methoxy-4H-1-benzopyran-4-one (14) showed the highest uterotrophic activity (87%) based on dry uterine weight gain. The antifertility activity, as assessed by the post-coital antiimplantation activity test, was of weak potency for most compounds (14-29%). Among the products, the 2-(4'-methoxyphenyl)-7-methoxy-4H-1-benzopyran-4-one (19) exhibited the highest antiestrogenic activity of 65%. It also elicited 31% of the uterotrophic activity of estradiol.