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Lin, Wen Xuan

University of British Columbia

This thesis discusses the applications of protected boronic acids in organic synthesis and radioactive tracer design with focus on N-methyliminodiacetyl (MIDA) ester and organotrifluoroborate. Chapter 2 reviews the work on the capability of acylboronate MIDA esters in Suzuki-Miyaura cross coupling. This is the first study on Suzuki coupling with this motif. A comprehensive screening of conditions was carried out to maximize conversion and yield. Substrate scope centres around the coupling between benzoyl boronates with functionalized aryl bromides, accompanied by the exploration of various alkanoyl boronates and modified aroyl MIDA boronates. Chapter 3 presents a salt metathesis reaction between tetrafluoroborate and boronic acid to generate organotrifluoroborate quantitatively. The appreciable inertness of the tetrafluoroborate anion has left its ability to transfer fluoride onto a fluoride acceptor such as boron uninvestigated. A series of conditions were tested for optimization. Despite difficulty in purification, a quality substrate scope was established with isolated yields for numerous organotrifluoroborates. Visualization of real-time reaction progress by nuclear magnetic resonance spectroscopy, along with kinetic and pH studies, provided mechanistic insight to the process. Chapter 4 focuses on ImMBF₃, a novel radioprosthetic that showed comparable capabilities as the well-established AMBF₃ in prostate cancer imaging. The design stemmed from an observed relationship between organotrifluoroborate stability and the acidity of its carboxylic acid analog. Following a similar synthetic route as AMBF₃, ImMBF₃ was conjugated onto an N₃-Gly derivative of a prostate-specific membrane antigen ligand. Standard ¹⁸F-radiolabelling by isotopic exchange yielded promising radiochemical data in conversion, purity, and activity. Despite increased lipophilicity, imaging and biodistribution studies demonstrated satisfactory in vivo behaviour and tumor to background ratio.

Text

2023-07-05

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/85195

Chemistry

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/