M. Scott Goodman, Ph.D., Professor of Chemistry
Date of Award
Forensic Science, M.S.
M. Scott Goodman, Ph.D., Chair and Professor of Chemistry
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William Durfee, Ph.D., Professor of Chemistry
Jinseok Heo, Ph.D., Associate Professor of Chemistry
The synthesis and characterization of pyrazole-appended tetraazamacrocyclic ligands are reported. Synthesis and separation of t-butoxycarbonyl (Boc) protected 1,4,8,11-tetraazacyclotetradecane (cyclam) allows for the formation of several isomers: triboc cyclam, cis-diboc cyclam, and trans-diboc cyclam. The different isomers were then each functionalized with pyrazole arms by reaction with the corresponding equivalents of either 1-(2-bromoethyl) pyrazole or 1-(2-bromoethyl)-3,5-dimethylpyrazole. Thereafter, the protective Boc groups were removed from the compound by heating in water for an extended time to afford the unprotected macrocycles with one or two pyrazole pendant groups. The resulting ligands can potentially be further functionalized if desired. Synthesis of a structurally similar ligand, 1,8-(2-pyrazoylethyl)-Tet-A or PzTeta, was also carried out. The crystal structure of PzTeta was determined as having a monoclinic unit cell with dimensions: a = 10.2359(6) Å, b = 16.9312(11) Å, c = 15.9755(10) Å, and β = 100.17°. The 1H NMR spectra of all synthesized ligand systems show dispersed and relatively sharp proton resonances. By forming complexes of these ligands with various transition metal ions, it should be possible to prepare novel contrast enhancement agents with applications in magnetic resonance imaging.
Bemisderfer, Kayleigh M., "Synthesis and Characterization of Pyrazole-Substituted Tetraazamacrocyclic Ligands for Potential Applications as Contrast Enhancement Agents in Magnetic Resonance Imaging" (2016). Chemistry Theses. 4.