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Benzonitrile is a useful solvent and a versatile precursor to many derivatives. It reacts with amines to afford N-substituted benzamides after hydrolysis. [3] It is a precursor to diphenylmethanimine via reaction with phenylmagnesium bromide followed by methanolysis.
Benzyl cyanide undergoes many reactions characteristic of nitriles. It can be hydrolyzed to give phenylacetic acid [7] or it can be used in the Pinner reaction to yield phenylacetic acid esters. [8] Hydrogenation gives β-phenethylamine. [9] The compound contains an "active methylene unit". Bromination occurs gives PhCHBrCN. [10]
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.
Hydrolysis (/ h aɪ ˈ d r ɒ l ɪ s ɪ s /; from Ancient Greek hydro- 'water' and lysis 'to unbind') is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution , elimination , and solvation reactions in which water is the nucleophile .
The reaction is catalyzed by nucleophiles such as a cyanide or an N-heterocyclic carbene (usually thiazolium salts). The reaction mechanism was proposed in 1903 by A. J. Lapworth . [ 7 ] In the first step in this reaction, the cyanide anion (as sodium cyanide ) reacts with the aldehyde in a nucleophilic addition .
The intermediate M(H)(CN)L n (alkene) then undergoes migratory insertion to give an alkylmetal cyanide. The cycle completes with reductive elimination of the nitrile, which is rate-limiting . Lewis acids , such as triphenylboron ( B(C 6 H 5 ) 3 ), speed elimination, increasing the overall reaction rate.
Cyanide is unstable in water, but the reaction is slow until about 170 °C. It undergoes hydrolysis to give ammonia and formate, which are far less toxic than cyanide: [14] CN − + 2 H 2 O → HCO − 2 + NH 3. Cyanide hydrolase is an enzyme that catalyzes this reaction.
The Beckmann rearrangement, named after the German chemist Ernst Otto Beckmann (1853–1923), is a rearrangement of an oxime functional group to substituted amides. [1] [2] The rearrangement has also been successfully performed on haloimines and nitrones.