Date of Graduation
7-2021
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Chemistry (PhD)
Degree Level
Graduate
Department
Chemistry & Biochemistry
Advisor/Mentor
Matthias C. McIntosh
Committee Member
Stefan M. Kilyanek
Second Committee Member
Jingyi Chen
Third Committee Member
Nan Zheng
Keywords
Breslow, Organic, Radicals, Thiazole rings
Abstract
Electron rich enamines are capable of C-N bond homolysis and subsequent recombination and/or disproportionation. It is unclear what causes these radicals to undergo recombination or disproportionation. Density Functional Theory (DFT) calculations do not provide a transition state for the recombination and disproportionation processes and therefore they cannot be used to predict the favorable reaction. Breslow intermediates formed by deprotonation of thiazolium salts and reaction with aromatic aldehydes are examples of electron rich enamines. These breslow intermediates can undergo C-N bond homolysis to form a radical pair the either recombine or disproportionate. Upon investigation of the factors influencing recombination and disproportionation, it was determined that when fluorene is employed as the nitrogen substituent on thiazole, the reaction favors disproportionation at low and high temperatures.
The biological compound “vitachrome” was synthesized by reacting thiamine HCl with triethylamine in DMF. We hypothesize vitachrome forms through a radical mechanism which is supported by the observation of pyrimidine monomer and dimer in the reaction mixture. An asymmetric dimer can also be formed using this method when diphenylmethylthiazolium bromide salt and diphenylmethylbenzothiazolium bromide salt are used as starting materials.
Citation
Burnett, T. (2021). Investigation of Factors Influencing Recombination Versus Disproportionation of Complex Radicals Formed by C-N Homolysis of Breslow Type Intermediates and Related Compounds. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/4181