Date of Award
Program or Major
Master of Science
Roy P Planalp
Cis, cis-1,3,5-triaminocyclohexane (tach) has been synthesized according to various routes, and the methods were evaluated on the basis of product yield, number of steps, and expense of reagents. The conversion of cis, cis-1,3,5-cyclohexanetricarboxylic acid to the desired product by the Curtius rearrangement, as previously described in the literature, was found to be the most suitable procedure based on yield and number of steps. From the standpoint of cost, the reagents of the Curtius rearrangement were derived from inexpensive, commercially available starting materials. The yields of the synthesis are variable, and preliminary studies of yield optimization are described.
Three ligands based on the tach framework, tachenPh (N,N',N" -tris(2-amino-2-phenylethyl)-cis, cis-1,3,5-triaminocyclohexane), tacheniPr (N,N',N"-tris(2-amino-2-isopropylethyl)- cis, cis-1,3,5-triaminocyclohexane), and tachenNMe (N,N',N" -tris[2-(methylamino)ethyl)-cis, cis-1,3,5-triaminocyclohexane) were complexed with divalent nickel and copper in solution. The relative ligand field strength of the chelators was assigned for each metal. For most of the cases, an octahedral geometry of the metal-ligand complexes can be inferred based on UV-Vis data, though there is some suggestion of a five-coordinate species for the copper complex of tachenPh.
The synthesis of another tach-based ligand, tachENSH (N,N',N" -tris(2-mercaptoethyl)-cis, cis-1,3,5-triaminocylcohexane), containing an N3S3 donor set was evaluated. The thiol arms were derived from a prepared active ester and were combined by peptide linkage with three amine frameworks. The frameworks utilized are triaminocyclohexane (tach), ethylenediamine (en) and trans-1,2-diaminocyclohexane (dach). Borane in THF appeared to reduce the prepared amides, however isolation of a borane-free product has not yet proved feasible. Initial in silico evaluation of the proposed novel dachENSH ligand shows it to be a promising divalent copper or zinc chelator.
Lindell, Allison Lisa, "Synthetic approaches to cis,cis-1,3,5-triaminocyclohexane (tach) and tach-based ligands" (2006). Master's Theses and Capstones. 235.