Estrogenic activity of B-fluorinated o-carborane-1,2-bisphenol synthesized via SNAr reaction

We previously identified o -carborane bisphenol BE360 ( 4 ) as a selective estrogen receptor modulator (SERM), which ameliorated bone loss without inducing estrogenic action in uterus of OVX and ORX mice. Here, we synthesized a fluorinated derivative, B -fluorinated o -carborane bisphenol BE310 ( 5 ) by means of S N Ar reaction. Compound 5 was a partial ER agonist, like 4 , with little change of ERα and ERβ selectivity as compared with 4 . However, its agonistic activity was 40 times weaker than that of 4 . Thus, 5 is a novel SERM candidate with potential for reduced estrogenic side effects, and in vivo evaluation as an anti-osteoporosis agent seems warranted.