Cottrell College Science Awards - 2015
Chlorine is widely used in the pharmaceutical industry, notes Tanay Kesharwani, an assistant professor of chemistry at the University of West Florida.
“About 80 percent of pharmaceuticals contain or are manufactured using chlorine,” he said, adding that since 1984 more than 60 drugs have been approved which contain a chlorinated heterocyclic or carbocyclic core structure. “Heterocyclic” refers to a ring-like molecule containing atoms of two or more different elements; “carbocyclic” refers to a ring composed of carbon atoms.
Chlorine is used to create these molecular rings because it can act as electrophile – that is, it seeks after electron-rich areas in other molecules, altering their basic structures, sometimes in useful ways.
Kesharwani has received a Cottrell College Science Award from Research Corporation for Science Advancement to explore substituting harsh and toxic chlorine in this process. He hopes to develop more environmentally friendly compounds such as table salt (sodium chloride, NaCl) in several important “chlorocyclization” reactions -- that is, reactions that use electrophilic chlorine to create useful molecular rings.
“Most of the earlier reported reactions lack generality, require harsh reaction conditions, use toxic reagents and solvents, and give poor to moderate yields,” Kesharwani says. “Therefore, there is a great need to develop greener and more efficient electrophilic chlorocyclization reactions.”
Specifically, Kesharwani will use the funding to study table salt-based electrophilic chlorocyclization in diverse molecular systems involving oxygen, nitrogen and sulfur compounds.
“If successful, our chemistry will enable us to incorporate chlorine in several heterocyclic molecules in the position where it is difficult to attain otherwise,” he said.