George 9. Kauffman a n d Steven H. Chooljian California State University, Fresno Fresno. 93740
Wohler's Synthesis of Artificial Urea A modern version of a classic experiment
The year 1978 marks the sesquicentennial of the synthesis of urea by the German chemist Friedrich Wohler (1800-1882), a storv known to everv beeinnine student of oreanic chemistni. In 18% W6hler puhl&hei in ~oggendorffs ~ n n a l e na 4-page article entitled "Ueber kiinstliche Bildune des Harnstoffs" (On the Artificial Production of Urea) (I ). Despite its brevity the paper was soon acknowledged as a chemical classic (236): Beyond all question one of the mast unexpected and therefore most interesting discoveries in the field of animal chemistry is the artificial production of urea (JBns Jacob Berzeliusl (331. The extraordinary and to some extent inexplicable production of urea without the assistance of the vital functions, far which we are indebted to WAhler, must be considered one of the discoveries with which a new era in science has commenced (Justus Liebigl (341.
This synthesis of urea is in the true sense of the word an epochmaking discovery . . . [it] removed at a single hlow the artificial harrier which had been raised between organic and inorganic chemistry (August Wilhelm von Hofmann) (2). The many brilliant syntheses of well-known and valuable organic compounds, which have been made during the past twenty years, are results of this discovery of WBhler (Ira Remsenl (35). Traditionally, the significance of Wohler's discovery has been considered to be threefold: (1) Urea was regarded "as the first organic compound artificially produced" (Liehig) from inorganic substances, and thus "the natural harrier which until then separated the organic from inorganic compounds had fallen, and a classification of chemical compounds into organic and inoreanic in the earlier sense had no natural basis" ( ~ e r m a n Kolbe). i In other words, Wlihler's work demonstrated that a vital force W a n vital or uis uitalis) is not necessary for the production of organic substances, and it therefore encouraged other chemists to attempt the synthesis of comoounds. (2) Wohler's nroduction of urea remeoraanic " seuts the first synthesis of an organic compound in the sense of the term as used by Kolhe (37). (3) The urea synthesis provided another example of the idea that compounds with different o. r o.~ e r t i e can s have the same comoosition, a hen
