Date of Award
Program or Major
Doctor of Philosophy
Kenneth K Andersen
The purpose of this research was to investigate routes towards the synthesis of $\alpha,\alpha\sp\prime$-dehydrodimeric amino acids. This dissertation describes various methods of effecting dehydrodimerization of bioxazoles. Bioxazoles are good candidates to serve as precursors to $\alpha\,\alpha\sp\prime$-dehydrodimeric amino acids, because they are $\alpha,\alpha\sp\prime$-dehydrodimeric amino acid derivatives. This dissertation describes the synthesis and characterization of d,l and meso 4,4$\sp\prime$-bioxazoles as well as, 2,4$\sp\prime$-bioxazoles.
A variety of bioxazoles were synthesized and some were subjected to nucleophilic ring opening. It had been reported that nucleophilic attack at the bioxazole ring caused the dehydrodimeric carbon-carbon bond to be cleaved. Results of this work indicate that cleavage is not a universal pathway in nucleophilic ring opening.
An attempt to complex a bioxazole with nickel bromide led to an investigation which proved that, at elevated temperatures, the bioxazole underwent a thermal isomerization. Though inclusive, investigation of the mechanism by EPR analysis indicated that the mechanism was radical based. A cross-over experiment confirmed that the mechanism of isomerization proceeded through a radical intermediate. Several bioxazoles and one bithiazole were heated in inhibitor free styrene to determine if bioxazoles would serve as a catalyst for radical polymerization. Though the cross-over experiment indicated that the bioxazoles fragmented into radicals at elevated temperatures, none of the bioxazoles heated in the presence of styrene induced polymerization.
Gloster, Daniel Francis, "A study of the synthesis of 2,2',4,4'-(4,4'-bioxazoles)-5,5'(4H,4'H)-diones, their isomers, and the products of nucleophilic ring openings" (1995). Doctoral Dissertations. 1840.