A naturally occurring chemical that may repel yellow fever mosquitoes can now be made in the laboratory

A naturally occurring chemical that may repel yellow fever mosquitoes can now be made in the laboratory, Indiana University Bloomington scientists report.

"The synthesis requires only seven steps," said organic chemist P. Andrew Evans, who led the research. "It should be quite trivial to scale this up to the production of large quantities."

Gaur acid is a natural skin secretion of the gaur, an Asian wild ox. Preliminary evidence suggests that this chemical discourages the landing and feeding of Aedes aegypti, a common mosquito that carries and transmits the yellow fever virus in some parts of the world.

Evans and his group used a rhodium catalyst to aid the tricky synthesis of gaur acid, also known as bovinic acid. In doing so, the chemists also determined the exact chemical structure of the compound. Their approach is described in Angewandte Chemie, International Edition, a German chemistry journal.

The World Health Organization estimates that yellow fever kills 30,000 people every year, primarily in sub-Saharan Africa, the Caribbean and South America. There is a vaccine against the yellow fever virus, but its widespread administration by WHO, UNICEF and other agencies has not achieved total success.

Organic chemists William J. Andrews, David K. Leahy and Daisuke Uraguchi also contributed to the report. It was funded by the National Institute of General Medical Sciences.

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