Pyrazole Pendant Tetraazamacrocyclic Ligands for Possible Medicinal Applications

Publication Year:
2016
Usage 111
Abstract Views 62
Downloads 49
Repository URL:
https://digitalcommons.buffalostate.edu/forensic_science_theses/11
Author(s):
Bhandari, Anjuli
Tags:
Cyclam; cyclen; pyrazole; paraCEST; tetraazamacrocycle; Inorganic Chemistry; Organic Chemistry
artifact description
Gadolinium is the element typically used for MRI contrast agents, which are sometimes injected prior to performing an MRI. The element accumulates in inflamed areas, which indicates where there may be an infection or a tumor. However, gadolinium is more toxic to the body than preferred and the potential long-term effects have been studied in individuals who experience health issues.Complexes containing metal ions that are naturally occurring have been proposed to replace gadolinium use. Complexing a metal ion (i.e. copper(II) or iron(II)) to a macrocyclic ligand that has a high water exchange rate would potentially be able to replicate gadolinium–based dye conditions while also having a higher excretion rate and lower toxicity. A research project was proposed based on the findings of Morrow and co-workers that an iron-containing complex could function as a PARACEST MRI contrast agent.Tetraazamacrocyclic ligands such as cyclam and cyclen are useful macrocyclic ligands for new research in drug therapy and imaging techniques. The addition of pyrazole pendant arms has been proposed as a possible option to improve their ligating properties. Appending these groups to the tetraazamacrocyclic ligands cyclam and cyclen was the initial focus of the research. These ligands were subsequently used to attempt to form stable complexes using a variety of metal ions and solvents. All new compounds were characterized using a combination of NMR, mass spectrometry, and X-ray crystallography. Compounds of the type synthesized show promise in one day being a strong contender for use in MRI contrast and possibly therapy for cancerous tumors.