| Abstract: | We prepared the organometallic complex 17α‐(ferrocenylethynyl)estradiol (=(3,17β‐dihydroxyestra‐1,3,5(10)‐trien‐17α‐yl)ethynyl]ferrocene; FcEE; 1 ) by a novel synthetic method. This metallocene possesses sufficient stability in aqueous media to permit the study of its biological properties. Thus, we were able to show that, despite the addition of a bulky substituent at the 17α position of the steroid, the metallocene is still well‐ recognized by an antibody specific to estradiol (CR=40%) and by both subtypes (ERα, ERβ) of the estrogen receptor (at 0°, RBA=28 and 37%, resp.). A DCI‐MS study of the stability of the carbocation FcEE?OH]+ showed moderate stabilization of the carbocation, in agreement with the pK value of ?0.72 found for the metallocene by means of Deno's method. The presence of the ferrocene allows the electrochemical detection of FcEE ( 1 ) by HPLC‐ED, with a detection limit of ca. 1 nM , suitable for quantitative pharmacological analysis. |
