Two new recipes for bird-flu fighter Tamiflu
(15 May 2006: VIDYYA MEDICAL NEWS SERVICE) -- A shortage of star anise is the major bottleneck in production of Tamiflu (oseltamivir), and a key reason for the shortage of Tamiflu that emerged in 2005. Tamiflu is the drug being stockpiled around the world for use in combating a possible epidemic of avian influenza. Star anise has been used for centuries to give a pungent, licorice-like flavor to Chinese foods and western favorites like Pernod and anisette. Grown mainly in China, it now provides the starting material — shikimic acid — for making Tamiflu.
Roche, which markets Tamiflu, uses about 90 percent of the world's star anise harvest. The Roche recipe for Tamiflu not only requires a scarce starting material, but also is complicated.
Two studies, scheduled for publication in the May 24 edition of the Journal of the American Chemical Society, report development of new recipes for making Tamiflu. They are part of an effort to make more Tamiflu available at more affordable prices.
One was developed by Masakatsu Shibasaki and colleagues, at the University of Tokyo. Chemistry Nobel Laureate E. J. Corey headed the Harvard University group that developed the other synthesis. The Corey process uses abundant, inexpensive starting materials, and eliminates a potentially hazardous production step. The Corey synthesis begins with butadiene and acrylic acid (which cost only pennies per pound), has fewer steps than the Roche process, and produces twice as much Tamiflu. The discoveries also are discussed in an article in Chemical & Engineering News.
"A Short Enantioselective Pathway for the Synthesis of the Anti-Influenza Neuramidase Inhibitor Oseltamivir from 1,3-Butadiene and Acrylic Acid."
Journal of the American Chemical Society(May 24, 2006)
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