Phenolic analogues of amino carboxylic acid ligands for 99mTc. VN-benzyl-2-(2-hydroxyphenyl)glycines (bhpg) and N-benzyl-2-(4-hydroxyphenyl)glycines (isobhpg)

A series of tridentate ligands, N-benzyl-2-(2-hydroxyphenyl)glycines (bhpg) (4), were prepared by the Mannich reaction of phenol and a number of para-substituted phenols with glyoxylic acid and benzylamine. When the two ortho positions of the phenol were blocked, as in the case of 2,6-dimethyl and 2,6-dichloro phenols, the isomeric compounds N-benzyl-2-(4-hydroxyphenyl)glycines (isobhpg) (5) were formed. When the phenol had one ortho substituent, as in the case of o-cresol and o-chlorophenol, both isomers were isolated. Two examples of the use of the chiral phenylethylamine in place of benzylamine are described. Copyright (2000) CSIRO Australia