Syntheses and characterization of derivatives of 1,4,7-triazacyclononane, methyl cholate, and of ionophores based on EDTA, NTA and IDA

A facile route is described for syntheses of three new types of ligands. 1,4,7-Triazacyclononane was derivatized by using different potentially coordinating groups, e.g. imidazole, pyrazine, tosyl. The complexes using hydrated metal chloride salts [Fe(II), Zn(II), Ni(II) and Co(II)] were prepared and characterized by various techniques including NMR, microanalysis, and single crystal X-ray crystallography. Both symmetric {lcub}1,4,7-tris-[(1-benzylimidazol-2-yl)methyl]-1,4,7-triazacyclononane and 1,4,7-tris-[(pyrazin-2-yl)methyl]-1,4,7-triazacyclononane{rcub} and unsymmetric {lcub}1-(p-tolylsulfonyl)-4,7-bis-[(1-benzyl-2-yl)methyl]-1,4,7-triazacyclononane{rcub} triazacyclononane compounds were synthesized.; A mild one-pot method for the derivatization of every hydroxyl group of cholic acid methyl ester has been achieved. Here we report an efficient method for the conversion of three of the chemically distinguishable functional groups of the cholic acid methyl ester, without the use of base or phase transfer catalyst. The preparation of methyl 3,7,12-tri-O-[(2,3-dibenzyloxy)benzoyl)]cholate (1) has been achieved by a more convenient synthetic route than a method reported by Dr. Norbert. Procedures for the synthesis of methyl 3,7,12-tri-O-[(2-benzyloxy-3-methyl)benzoyl]cholate (7) and the corresponding debenzylated derivatives are also described.; The ionophore based on the 3-oxapentandiamide backbone has been synthesized. Bis (2,6-dimethyl)-3-oxapentanediamide has been prepared and characterized by NMR, IR and X-ray crystallography. A convenient method has been developed for the direct conversion of acid to amide by the use of 1,3-dicyclohexylcarbodiimide (DCC) at room temperature. Here we report a new and very useful method for forming an amide bond. The method is applicable to highly hindered acids, such as EDTA, NTA and IDA.