title: Methodology for the synthesis and specific activity determination of 16 alpha-[77Br]-bromoestradiol-17 beta and 16 alpha-[77Br]-11 beta-methoxyestradiol-17 beta, two estrogen receptor-binding radiopharmaceuticals.
abstract: 16 alpha-[77 Br]-Bromoestradiol-17 beta (3a) has been synthesized from estrone enol diacetate (1) by bromination with Na77Br and hydrogen peroxide-acetic acid, followed by reduction with lithium aluminum hydride to give a mixture of 16 alpha-[77 Br]-bromoestradiol-17 beta (3a) and 16 alpha-[77Br]-bromoestradiol-17 alpha (3b) from which the desired epimer (3a) can be obtained in 50% overall radiochemical yield (from Na77Br) by HPLC. Analogous procedures can be used in the preparation of 16 alpha-[77Br]-bromo-11 beta-methoxyestradiol-17 beta. (4a) The effective specific activities of these radiopharmaceuticals, determined by binding to the uterine estrogen receptor, are 900-1500 Ci/mmol. Both have affinity and good binding selectivity for the estrogen receptor and are useful as imaging agents for mammary tumors.
mesh_terms: D000818:Animals; D001966:Bromine; D004958:Estradiol / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D005260:Female; D007553:Isotope Labeling; D009376:Neoplasms, Hormone-Dependent / Q000000981:diagnostic imaging; D011485:Protein Binding; D011868:Radioisotopes; D011877:Radionuclide Imaging; D011960:Receptors, Estrogen / Q000378:metabolism*; D012756:Sheep; D014599:Uterus / Q000378:metabolism
chemical_list: D011868:Radioisotopes; D011960:Receptors, Estrogen; D004958:Estradiol; C034554:16 alpha-bromo-17 beta-estradiol; C034553:16 alpha-bromo-11 beta-methoxy-17 beta-estradiol; D001966:Bromine