Wohler synthesis of urea

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 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) ... 

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 . 

Wohler s synthesis of urea by which a product of the living cell was first prepared artificially more than a century ago is the prototype of many addition reactions which take place with the reactive molecules of cyanic acid and its esters, as well as with the series of analogous thio-compounds. In these reactions NH3 is added to the C = N double bond ... 

After Dalton, the word synthesis was not usually used yet in chemical parlance. Berzelius (1779-1848), Dumas (1800-1884) and even Wohler (1800-1882) refer to the classical synthesis of urea -achieved in 1828 by Wohler himself-as an artificial production or formation of an organic compound. Only after the publications by Kolbe (1818-1884), Frankland (1825-1899) and Bertholet (1827-1907) was the word synthesis normally used and became familiar to chemists. 

The idea of describing the chemical reactions that are germane to the origin of life has a long history - particularly if one starts from Wohler s experiments in 1828 on the synthesis of urea, as recently proposed by Bada and Lazcano (2003). Wohler s reaction was a fortunate accident, in the sense that the German chemist did not have in mind any ambitious Faustian dream. In what follows some basic notions... 

The material in this chapter traced the history of organic chemistry from Wohler s synthesis of urea through Kekule s structure of benzene. The millions of organic chemicals known to exist can be classified into a relatively small number of families, each defined by a common functional group. During the last century, chemists have discovered how to mimic nature to synthesize organic chemicals. A multitude of familiar products are natural or synthesized organic chemicals. 

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

For more than 150 years, since the synthesis of urea by Friedrich Wohler in 1828 [1.2], molecular chemistry has developed a vast array of highly sophisticated and powerful methods for the construction of ever more complex molecular structures by the making or breaking of covalent bonds between atoms in a controlled and precise fashion. 

N-Arylureas are obtained when salts of primary aromatic amines react with solutions of alkali metal cyanates. The process involves the rearrangement of an amine cyanate, and is analogous to Wohlers classical synthesis of urea from ammonium cyanate. 

The marrying of the fields of coordination chemistry, chemotherapy and enzymology was finally spurred on by the advent of modern instrumental and synthetic techniques, and not least by the dramatic developments in organic synthesis, which was born as a discipline in itself in 1828 with Friedrich Wohler s synthesis of urea from ammonium cyanate. In the course of the development of supramolecular chemistry, enormous progress has been made on quantifying the details of receptors with an affinity for guests which fit inside them. The lock and key image especially has suffered... 

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... 

Historically, the first chemical synthesis of urea by Wohler, from ammonium cyanate in 1828, was a milestone that established a bridge between inorganic and organic chemistry. Urease was the first enzyme ever to be crystallized (6), and it was the first protein shown to contain nickel ions in the active site (7). The first X-ray crystal structure of urease became known in 1995 (8). Significant progress was made since then toward an understanding of its catalytic mechanism, as well as toward the structural and functional emulation of its active site by synthetic model complexes (5, 9). 

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