An improved synthesis of cis,cis-1,3,5-triaminocyclohexane. Synthesis of novel hexadentate ligand derivatives for the preparation of gallium radiopharmaceuticals

An improved synthesis of cis,cis-1,3,5-triaminocyclohexane in 82% yield involves reaction of the commercially available cis,cis-1,3,5-cyclohexanetricarboxylic acid with DPPA to afford the tri(benzylcarbamate) as the Curtius rearrangement product. Deprotection yields the triamine which serves as a platform from which a variety of chelating structures may be assembled. Novel tris(2-methylenepyridyl)triamine and tris(2-methylenethienyl)triamine ligands are prepared to investigate their suitability for use as gallium radiopharmaceuticals.