The New Jersey Institute of Technology's
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Title:	Design of stable Di and tetraradical nitroxides as magnetic resonance imaging agents
Author:	Iyer, Radha V.
View Online:	njit-etd1992-049 (ix, 64 pages ~ 1.6 MB pdf)
Department:	Department of Chemical Engineering, Chemistry and Environmental Science
Degree:	Master of Science
Program:	Applied Chemistry
Document Type:	Thesis
Advisory Committee:	Sofer, Samir S. (Committee chair) Perlmutter, Howard David (Committee member) Lei, George Y. (Committee member)
Date:	1992-05
Keywords:	Magnetic resonance imaging -- Materials -- Design Diradical nitroxides Tetraradical nitroxides
Availability:	Unrestricted
Abstract:	Several nitroxides have been prepared in the Biotechnology Laboratory at NJIT to study their image enhancement capability. These nitroxides contain different moieties within one molecule and their paramagnetism is found to be initially increasing proportionally to the number of their radical centers. It is found that the addition of nitroxides at very close distances causes interference and a reduction of intensity due to the interaction of the two paramagnetic centers with each other. Thus MRI contrast agents are not improved by simple addition of nitroxide centers to a given molecule and drug designers must pay special attention to intramolecular spacing. To demonstrate techniques, rigorous controls and more detailed studies are being undertaken. In this research, methods for the synthesis of multiradical nitroxides by structural modification as well as the synthesis of nitroxides with a functional group in close proximity to the radical center have been developed. Specifically, two methods for synthesis of the multiradical nitroxide [bis-(2,2,6,6 tetramethyl-1-oxyl-4-piperidyl) phthalate] have been tested and their overall effect on the yield evaluated. The compounds intended for synthesis were bis (2,2,6,6 tetramethyl-1-oxyl-4-piperidyl) phthalate (by two different routes) and tetrakis (2,2,6,6 tetramethyl-l-oxy1-4-piperidyl) pyromellitate focusing on molecular structure and multi paramagnetic centers.