Chemistry Masters Candidate Thesis Defense Presentation
Precious Nnamdi, Candidate
Dr. Wei Shi (Advisor)
"Progress on the Sustainable Total Synthesis of an Active Analog of OSW-1"
Thursday, June 12th, 1pm, Foundational Science Building - FB-253
Abstract: OSW-1 is a plant-derived glycosylated steroid (saponin) recognized for its potential medicinal benefits, particularly in cancer treatment. Despite advances in understanding its chemistry and biology over the past thirty years, the molecular targets for its anticancer activities remain unclear. Recent studies have led to the development of efficiently synthesized analogs of OSW-1 that maintain similar biological activity. In this presentation, we will discuss the synthesis of a simplified analog called OSW-1'. Our approach focuses on the convergent assembly of the disaccharide core. We synthesized the steroid aglycone of OSW-1' in two steps from an inexpensive commercial material, beginning with the coupling of the aglycone to a peracetylated L-arabinose trichloroacetimidate donor. This product is transformed into an L-arabinose acceptor over five steps. Next, this acceptor is coupled with a D-xylose trichloroacetimidate donor, synthesized in parallel over seven steps. The final step involves removing all protecting groups to yield OSW-1'. This efficient approach may enhance future chemical biology research on OSW-1.