Synthesis and characterization of phosphorous containing macromolecular polyether compounds

<p>A radioisotope of rubidium, ⁸²Rb is used in positron emission tomography. Neutral crown ethers and cryptands have been studied as carrier ligands for Rb⁺ but exhibit low ion carrying capacity and high toxicity. The present study involved investigating a lariat ether containing an ionizable phosphoryl moiety and a lipophilic sidearm. This kind of molecule is expected to be ionized at physiological pH. It should be able to form neutral complexes with Rb⁺ and may be able to cross the blood-brain barrier.</p> <p>Molecular modeling of crown ether-alkali metal cation complexes indicates that a macrocycle containing more than 18 but less than 21 atoms can incorporate Rb⁺ ion in its cavity. Molecular modeling of some of the complexes of phospho-lariat ethers with rubidium using the Spartan'02 software package revealed that a lariat ether containing 20 member macrocycle will probably form the most stable complex with Rb⁺ion. Also, it was thought that more flexibility could be imparted to the macrocycle if it contains propyleneoxy units instead of ethyleneoxy units which form most crown ethers. Molecular modeling of two phospho-lariat ethers with 16 and 20 membered rings revealed that 20 membered macrocycle may be a better choice due to the side arm's participation in the complexation with Rb⁺ to a greater extent. Molecular modeling was used to find the bond angles and bond distances in this molecule.</p> <p>The synthesis to obtain ionizable phospho-bipodands was performed using subsequent benzylation, phosphorylation and hydrogenation steps. The characterization of products was done using HPLC, NMR and ESI-MS techniques. The synthetic scheme used was demonstrated to be plausible and could be used to obtain ionizable phoshobipodands. Extraction using solid phase anion exchange columns proved to be a good clean up procedure for obtaining pure bipodand. This bipodand could be used as a precursor for synthesizing an ionizable 20 membered lariat ether.</p>

Name thesis:degree_name

Master of Science (M.S.)

Level thesis:degree_level

Thesis - Pacific Access Restricted

Discipline thesis:degree_discipline

Chemistry

Year dc:date.available

2006

Author dc:creator

• Narayan, Urja Vidya

Contributors dc:contributor

• Larry O. Spreer

• Organophosphorus compounds Synthesis
• Macrocyclic compounds
• Chemistry
• Physical Sciences and Mathematics

Licence

• http://rightsstatements.org/vocab/InC/1.0/

Repository record dc:identifier

https://scholarlycommons.pacific.edu/uop_etds/640

OAI identifier oai:identifier

oai:scholarlycommons.pacific.edu:uop_etds-1639