Targeting the estrogen receptor with metal-carbonyl derivatives of estradiol.

As part of our program to develop new probes for the estrogen receptor binding domain, we prepared and evaluated a novel 17α-(rhenium tricarbonyl bipyridyl) vinyl estradiol complex. Preparation of the final compound was achieved using the Stille coupling between the preformed brominated rhenium tricarbonyl bipyridine complex and the tributylstannyl vinyl estradiol. Competitive receptor binding assays and stimulatory assays demonstrated that the final complex retained affinity and efficacy comparable to the corresponding pyridyl vinyl estradiol analog, but lower than that of the phenyl vinyl estradiol analog.