Synthesis and Antifungal Evaluation of Barbiturate Saponins And Progress Towards Cysteinyl Metal Peptides

• Main Author: Madhav, Monika
• Format: Others
• Published: ScholarWorks@UNO 2013
• Subjects: antifungal; barbiturates; antioxidants; steroids; saccharide; aminoacids; Medicinal-Pharmaceutical Chemistry; Organic Chemistry
• Online Access: http://scholarworks.uno.edu/td/1649; http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=2580&context=td

Invasive fungal infections are a major threat to immune-compromised patients. There is a critical need to develop new antifungal agents because of increasing resistance to the common antifungal drugs. In the first part of this dissertation, methods for preparation of novel barbiturate saponin as antifungals and their biological activities would be described. Barbiturates and steroidal saponins have shown remarkable antifungal activity in the biological assays. Therefore, attempts were directed to combine the barbiturate with the steroid to give novel antifungal agents. The need for extensive SAR studies and to better understand these compounds efforts were directed to synthesize novel saponin barbiturates. Glycosylation of barbiturates was achieved under basic conditions to synthesize mono and disaccharide barbiturates. Saccharide molecules were directly introduced into the barbiturate without requiring protection and deprotection of saccharides. Efficient methods were developed for synthesis of 3β derivatized steroid derivatives containing ether, carbonate, ester and carbamate linker. Synthesized mono and disaccharide barbiturates were incorporated into the steroidal skeleton to give the novel antifungal agents. Several reaction conditions were explored to give the best yield under the most efficient reaction conditions. However, a better understanding and extensive SAR study needs to be done in order to develop more promising and potent antifungal compounds. The second part of this dissertation describes the progress towards monocysteine metal complex synthesis and their biological activities. In this attempt, several protection deprotection strategies were explored and some novel protective groups were designed for peptide synthesis.