Synthesis of 2,6-dimethoxy ) 7U-14C{phenol. )]

Abstract The preparation of 2, 6‐dimethoxy [U‐ 14 C]phenol was carried out in five steps from [U‐ 14 C]phenol. [U‐ 14 C]Phenol was converted to 2‐[U‐ 14 C]phenoxy‐5‐nitrobenzophenone which was sequentially hydroxylated with hydrogen peroxide‐acetic acid to give the di‐ ortho hydroxylated phenolic intermediate, 2‐(2′',6″‐dihydroxy [U‐ 14 C]phenoxy)‐5‐nitrobenzophenone. Methylation of this intermediate and subsequent scission of the aryl ether link with piperidine gave the required di‐ ortho substituted phenol. An alternative sequence was investigated for the conversion of 2‐(2″‐hydroxy‐phenoxy)‐5‐nitrobenzophenone to 2‐(2″,6″‐dimethoxyphenoxy)‐5‐nitrobenzophenone but it gave a poorer overall yield with an unstable intermediate. Characterization data are included.