CUHK PhD Graduate Finds Novel Way to Solve Tamiflu Supply Problem
A PhD graduate in chemistry of The Chinese University of Hong Kong, Dr Yeung Ying-yeung, under the guidance of Professor Elias James Corey, successfully found a new organic synthesis that would substantially reduce the cost of production and improving the supply of Tamiflu. Dr Yeung is currently working as a post-doctoral fellow at the laboratory of Professor Elias James Corey, 1990 Nobel Prize Winner in Chemistry who is renowned for his achievements in theory and methodology of the organic synthesis of natural products, in Harvard University.
At present Tamiflu is made in a costly 14-stage manufacturing process first by obtaining the starting material shikimic acid via extraction from Chinese star anise fruit. Chinese star anise, an ancient cooking spice, is the star-shaped seeds of Illicium verum, which is a small native evergreen tree of southwest China. This complex starting material is expensive and in limited supply. Another reason for the slow production of Tamiflu is that the drug can be made only in small quantities at a time because the manufacturing process involves a highly explosive chemical. With a breakthrough in the synthesis process, Dr Yeung and his research co-workers avoided the use of shikimic acid and depended on an asymmetric catalytic step early in the synthesis to create a key building block.
"Our synthetic pathway has several advantages over the current production method," said Dr Yeung. "It is substantially efficient, about 30% in eleven steps, with the use of inexpensive and readily available starting materials called 1,3-butadiene and 2,2,2-trifluoroethyl acrylate. In addition, we have avoided using a highly explosive chemicals called azides in the synthesis, in which that risky step is also one reason that slows down the Tamiflu synthesis process in industry.¡¨
Dr Yeung earned his Bachelor of Science degree in chemistry at CUHK. He showed great interest in doing research work which was demonstrated by having a paper published in Journal of Organic Chemistry (2001, 66, 1910) when he was an undergraduate research assistant, working under Professor Chow Hak-Fun. With keen interest in synthetic organic chemistry research, he joined Professor Tony Kung Ming Shing¡¦s group as a Ph.D. student in the same department, dealing with anti-cancer natural molecule synthesis. His passion in research and his unflagging attitude to be an outstanding organic chemist, as perceived by his supervisor, rewarded him excellence in his research work. Part of his Ph.D. thesis describes the total synthesis of a complex quassinoid, Samaderine Y, an antitumor agent, was published in a top chemistry journal (T. K. M. Shing and Y. Y. Yeung, Angew. Chem. Int. Ed. 2005, 44, 7981-7984). He was offered a postdoctoral fellowship by Professor Corey 18 months before his Ph.D. graduation. He graduated in 2005 and then joined the Department of Chemistry and Chemical Biology at Harvard University. Dr Yeung¡¦s successful career in organic chemistry presents an exemplar to high school students that by choosing a pure science subject of own interest and working hard with a passion for research work, one can earn a rewarding career with bright future.
The new synthesis process developed was reported on the high-impact Journal of American Chemical Society. The process was put into the public domain with the hope to stimulate others to work on different ways of synthesizing Tamiflu. ¡§Althrough the current supply of Tamiflu has grown, it is still expensive. We wish to reduce the price, increase the supply of the drug and save human lives, especially in poor countries,¡¨ explained Dr Yeung.