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The Rosenmund–von Braun synthesis is an organic reaction in which an aryl halide reacts with cuprous cyanide to yield an aryl nitrile. [1] [2] [3]The reaction was named after Karl Wilhelm Rosenmund who together with his Ph.D. student Erich Struck discovered in 1914 that aryl halide reacts with alcohol water solution of potassium cyanide and catalytic amounts of cuprous cyanide at 200 °C.
Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with hydrogen cyanide (HCN) in the presence of excess amounts of sodium cyanide (NaCN) as a catalyst: [1] RR’C=O + HCN → RR’C(OH)CN
The cyanide source can be potassium cyanide (KCN), sodium cyanide (NaCN) or trimethylsilyl cyanide ((CH 3) 3 SiCN). With aromatic aldehydes such as benzaldehyde, the benzoin condensation is a competing reaction. The reaction is used in carbohydrate chemistry as a chain extension method for example that of D-xylose.
Deactivation of Pd(II) with excess cyanide is a common problem. [7] Palladium catalysis conditions for aryl iodides, bromides, and even chlorides have been developed: [ 8 ] Nickel-catalyzed cyanations avoid the use of precious metals, and can take advantage of benzyl cyanide or acetonitrile as a cyanide source, via reductive C-C bond cleavage ...
The commercial production of amino acids, however, usually relies on mutant bacteria that overproduce individual amino acids using glucose as a carbon source. Otherwise amino acids are produced by enzymatic conversions of synthetic intermediates. 2-Aminothiazoline-4-carboxylic acid is an intermediate in one industrial synthesis of L-cysteine.
Cyanuric chloride is employed as a reagent in organic synthesis for the conversion of alcohols into alkyl chlorides, [8] and carboxylic acids into acyl chlorides: [9]. It is also used as a dehydrating agent, e.g. in the conversion of amides to nitriles, [10] and for the activation of carboxylic acids for reduction to alcohols.
In 1857 Hugo Schiff observed that the reaction between benzoyl chloride with potassium cyanide produced the desired benzonitrile. [3] Work done later by British chemist Edmund A. Letts delved much deeper into the synthesis of nitriles. Attempting first to add cyano-groups to acetic acid, he obtained a mixture of acetamide and carbonyl sulfide ...
In general, cyanide is an electronegative substituent. Thus, for example, cyanide-substituted carboxylic acids tend to be stronger than the parents. The cyanide group can also stabilize anions by delocalizing negative charge as revealed by resonance structures.