Wohler synthesis

Stanley Miller at the University of Chicago more than 50 years ago. This experiment (in fact, of course, many were carried out prior to the successful one) is probably as well known as the Wohler synthesis of urea Miller s doctoral supervisor, Harold Urey (winner of the Nobel Prize in 1934), had suggested to Miller that he simulate a reducing primeval Earth atmosphere (as required by the Oparin-Haldane hypothesis) to electrical discharges and see what happens . Urey apparently expected that such an experiment would lead to a huge variety of organic compounds. 

Wohler. Synthesis of urea from ammonium cyanate. Microscopic examination of plant and animal cells by Dutrochet, Schlieden, and Schwann led to acceptance of the cellular origin of all tissues. ... 

Tsipis, C. A. Karipidis, P. A. Mechanism of a Chemical Classic Quantum Chemical Investigation of the Autocatalyzed Reaction of the Serendipitous Wohler Synthesis of Urea. J. Am. Chem. Soc. 2003, 125, 2307-2318. 

Wohler was actually attempting to synthesize ammonium cyanate when he discovered crystals of urea in his samples. He first prepared urea in 1824, but he did not identify this product and report his findings until 1828. In a note written to Berzelius he proclaimed I must tell you that I can make urea without the use of kidneys, either man or dog. Ammonium cyanate is urea. Although Wohlers synthesis of urea signaled the birth of organic chemistry, it... 

WOHLER SYNTHESIS. Classical synthesis of urea by heating an aqueous solution of ammonium cyanate extended to preparation of urea derivatives. 

The development of biochemistry as a subject may be traced to Lavoisier s work on the chemistry of life258 and to Prout and Berzelius.259 The age-old question about the nature of life has left organic chemistry with a legacy of thinking about vitalism which, despite claims to the contrary, is still associated in the popular mind with the synthesis of urea by Wohler in 1828, by which it is alleged vital forces were banished for ever from organic chemistry.260 Yet another article on the Wohler synthesis... 

Alkyl Ureas.—By substituting alkyl amines for ammonia in the reaction for the synthesis of urea from carbonyl chloride, or by using alkyl derivatives of ammonium cyanate (cyanic acid salts of alkyl amines), in the Wohler synthesis, alkyl ureas may be obtained. They are of different t es as illustrated by the following formulas showing their relationship to urea. 

Mono-substituted and unsymmetrical di-substituted ureas may be prepared by a modification of Wohler s urea synthesis, salts of primary or secondary amines being used instead of the ammonium salt for interaction with potassium cyanate. Thus when an aqueous solution containing both aniline hydrochloride and potassium cyanate is heated, aniline cyanate is first formed, and then C,HjNH,HCl -h KCNO = C,H6NHj,HCNO -h KCl C,HsNH HCNO = C.H NHCONH, by the usual molecular rearrangement is converted into monophenyburea. 

Wohler s classical synthesis of urea from ammonium cyanate may be carried out by evaporating solutions of sodium cyanate and ammonium sulphate ... 

The hydroxyl derivative of X-CN is cyanic acid HO-CN it cannot be prepared pure due to rapid decomposition but it is probably present to the extent of about 3% when its tautomer, isocyanic acid (HNCO) is prepared from sodium cyanate and HCI. HNCO rapidly trimerizes to cyanuric acid (Fig. 8.25) from which it can be regenerated by pyrolysis. It is a fairly strong acid (Ka 1.2 x 10 at 0°) freezing at —86.8° and boiling at 23.5°C. Thermolysis of urea is an alternative route to HNCO and (HNCO)3 the reverse reaction, involving the isomerization of ammonium cyanate, is the clas.sic synthesis of urea by F. Wohler (1828) ... 

The naturally occurring compound urea, CO(NH,), was first synthesized by Friedrich Wohler in Germany in 1828 by heating ammonium cyanate. This synthesis was a significant event because it was the first time that an organic compound had been produced from an inorganic substance. Urea may also be made by the reaction of carbon dioxide and ammonia ... 

Ammonia and primary and secondary amines can be added to isocyanates to give substituted ureas. Isothiocyanates give thioureas. This is an excellent method for the preparation of ureas and thioureas, and these compounds are often used as derivatives for primary and secondary amines. Isocyanic acid (HNCO) also gives the reaction usually its salts (e.g., NaNCO) are used. Wohler s famous synthesis of urea involved the addition of ammonia to a salt of this acid. "... 

The term organic chemistry was first used by the Swedish chemist Berzelius in 1807 (Larsson, 1981). He coined the name to describe the chemistry of substances derived from living matter. Berzelius was a staunch believer in the vis vitalis theory, which held that such substances were endowed with a mystical vital force that precluded their synthesis in the laboratory from materials of mineral origin. Ironically, it was a student of Berzelius, Wohler, who heralded the demise of vitalism with his synthesis of urea from ammonium cyanate (Wohler, 1928). In a letter to Berzelius in 1828, Wohler wrote I must tell you that I can make urea without requiring kidneys, or even an animal, whether a human being or a dog . 

---