Premium
Radiolabeling of the B‐ and C‐ring of estradiol using no‐carrier‐added bromine‐77
Author(s) -
Hylarides Mark D.,
Leon Alberto A.,
Mettler Fred A.,
Wilbur D. Scott
Publication year - 1985
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580220505
Subject(s) - chemistry , bromine , phenol , yield (engineering) , ring (chemistry) , adduct , medicinal chemistry , base (topology) , methanol , molecule , nuclear chemistry , organic chemistry , mathematical analysis , materials science , mathematics , metallurgy
Two estradiol derivatives, Δ 6 ‐ and Δ 9 ‐estradiol 3‐acetate (1) and (2) were prepared and allowed to react with Na 77 Br and N‐chlorosuccinimide (NCS) in methanol. The rapid addition of 77 Br‐OCH 3 to the B‐ring (Δ 6,7 ) and C‐ring (Δ 9,11 ) double bonds produced brominated adducts 3a and 4b, respectively, in excellent radiochemical yields. Product 3a showed excellent radiochemical stability over a 3‐day period; however, attempts to prepare the free phenol 5 by removal of the 3‐acetyl group with base, result in loss of all activity from the molecule. Contrary to this, the 3‐acetyl group of 4b was readily removed with base without loss of radioactivity and the resultant phenol 6 could be isolated in 73% radiochemical yield. Unfortunately 6 was moderately unstable since 80% of the activity was dissociated from the compound within 48 hours.