Pure 3Z (syn) and 3E (anti) stereoisomers of testosterone 3-[O-(2-carboxyethyl)]oxime were synthesized, separated by HPLC or TLC, and used for preparation of tyrosine methyl ester (TME) conjugates by using mixed anhydride or carbodiimide-N-hydroxysuccinimide methods. While the latter method provided more than 96% of product with retained configuration, the mixed anhydride method yielded a mixture containing 26-40% of the opposite stereoisomer. The stereoisomers were used as model compounds, to which the other steroid TMEs and the corresponding radioiodinated products could be aligned according to their chromatographic properties. The TME conjugates of 3-(O-carboxymethyl)oximes of seven 4-en-3-oxo steroids were further prepared by carbodiimide-N-hydroxysuccinimide method. With exception of cortisol, the stereoisomeric (Z and E) radioiodinated TME conjugates could be separated by TLC. In addition, the conjugates with TME and consequently radioiodinated tracers were synthesized from hemisuccinates of cortisol and its 11α-isomer, via 11β- and 11α-hydroxy group. The radioiodinated conjugates were tested as radioligands with rabbit polyclonal antisera raised by using position-homologous conjugates of the respective steroid carboxy derivatives with bovine serum albumin as immunogens. With the exception of 11-deoxycorticosterone, the stereoisomeric Z and E radioiodinated TMEs did not differ in their binding properties. In the case of isomeric cortisol tracers conjugated through position 11 the antisera recognized only the sterically homologous radioligands, but the specificity of the system was poor.
纯的3
Z(
syn)和3
E(
anti)
睾酮3-[
O-(2-羧乙基)]
肟的立体异构体被合成,并通过HPLC或TLC分离,然后使用混合酸酐或碳二
亚胺-
N-羟基琥珀
酰亚胺方法制备
酪氨酸甲酯(TME)共轭物。后一种方法提供了96%以上保留构型的产物,而混合酸酐方法产生了一个含有26-40%相反立体异构体的混合物。这些立体异构体被用作模型化合物,其他类
固醇TME和相应的放射性
碘化产物可以根据它们的色谱特性对齐。通过碳二
亚胺-
N-羟基琥珀
酰亚胺法进一步制备了七种4-烯-3-
酮类固醇的3-(
O-羧甲基)
肟TME共轭物。除
皮质醇外,立体异构的(
Z和
E)放射性
碘化TME共轭物可以通过TLC分离。此外,从
皮质醇及其11α异构体的半
琥珀酸盐出发,通过11β-和11α-羟基合成了TME共轭物以及相应的放射性
碘标记示踪剂。使用通过将相应类
固醇羧基衍
生物与
牛血清白蛋白作为免疫原制备的兔多克隆抗血清,测试了放射性标记的共轭物作为放射性
配体的性质。除去氢化-
皮质酮外,立体异构的
Z和
E放射性
碘化TME在结合性质上没有区别。在通过位置11共轭的异构
皮质醇示踪剂的情况下,抗血清仅识别立体异构的放射性
配体,但是该系统的特异性较差。