Phenolic Analogues of Amino Carboxylic Acid Ligands for 99m Tc. V. N -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 a-phenylethylamine in place of benzylamine are described.