Knowles, William Standish (1917-2012), an American chemist, won a share of the 2001 Nobel Prize in chemistry for his creation of molecules that are widely used in the manufacture of drugs and other products. He shared the prize with the Japanese chemist Ryoji Noyori and the American chemist K. Barry Sharpless. Noyori and Sharpless created molecules that function in much the same way as those developed by Knowles. The three scientists worked separately.
The molecules created by the prizewinners share three characteristics: (1) they are catalysts, (2) they are synthetic, and (3) they are chiral.
A catalyst is a substance that increases the speed of a chemical reaction without being consumed by the reaction. A chemical reaction converts one or more substances into one or more different substances. The starting substances are known as reactants, and the final substances are the products. Catalysts enable drug manufacturers to make large amounts of certain products quickly.
Synthetic molecules are created in a laboratory or a manufacturing facility. Many drugs are synthetic. They are duplicates or improved versions of drugs obtained from natural sources, such as plants, molds, bacteria, animals, or minerals.
Chiral molecules occur in pairs. Both molecules of a pair consist of the same kinds of atoms and the same number of each kind. However, the atoms are arranged in forms that mirror each other. As a result, the molecules differ from each other as your left hand differs from your right hand. Most drugs consist of chiral molecules. In some cases, only the left-handed form can provide the desired medical benefit. The right-handed form may provide no benefit, or it may even cause harm.
Before Knowles’s work, no one knew how to synthesize chiral drugs without producing equal amounts of both forms. As a result, manufacturers made both forms, then separated them and discarded the right-handed molecules—half the product.
Knowles worked on a kind of reaction, known as hydrogenation, that adds hydrogen atoms to a molecule. In 1968, Knowles created a catalyst that accomplished a “first” for a hydrogenation reaction. The catalyst helped convert a nonchiral reactant into a chiral product containing more of one chiral form than the other. Knowles’s work led quickly to an industrial process for the production of the drug L-dopa, which is used to treat Parkinson disease.
In the 1980’s, Noyori became a leader in the further development of catalysts for hydrogenation reactions. Sharpless pioneered in the creation of catalysts for another kind of reaction, called oxidation.
William Standish Knowles was born in Taunton, Massachusetts, on June 1, 1917. In 1942, he received a Ph.D. degree in organic chemistry at Columbia University in New York City. He then joined the Monsanto Company, a leading maker of chemicals, in Dayton, Ohio. In 1944, he moved to the company’s headquarters in St. Louis, Missouri. He retired from Monsanto in 1986. Knowles died on June 13, 2012.
