Paul Karrer, a Swiss organic chemist famous for his work with vitamins and natural dyes, was born on this day in 1889.
Karrer studied the chemistry of plant pigments, including anthocyanins, xanthophylls, and carotenoids. He showed that carotene--the yellow, orange, or red color in fruits and vegetables--came in two forms and that one of them, beta-carotene, was a precursor to vitamin A.
By 1930, Karrer had worked out the chemical structures of carotene and vitamin A, which he finally succeeded in synthesizing in 1950. Karrer also solved the structures of vitamin B-2 (riboflavin), vitamin E (alpha-tocopherol), and vitamin B-12. For these achievements he shared the 1937 Nobel Prize in chemistry. Karrer's organic chemistry textbook, Lehrbuch der Organischen Chemie, published in 1930 and translated into five languages, became a standard reference book for several generations of chemists.