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Nitrilase was first discovered in the early 1960s for its ability to catalyze the hydration of a nitrile to a carboxylic acid. [2] Although it was known at the time that nitrilase could operate with wide substrate specificity in producing the corresponding acid, later studies reported the first NHase (nitrile hydratase) activity exhibited by nitrilase.
The resulting nitrilium ion is hydrolyzed to the desired amide. Primary, [7] secondary, [4] tertiary, [8] and benzylic [9] alcohols, [1] as well as tert-butyl acetate, [10] also successfully react with nitriles in the presence of strong acids to form amides via the Ritter reaction. A wide range of nitriles can be used.
Nitrile hydratase and amidase are two hydrating and hydrolytic enzymes responsible for the sequential metabolism of nitriles in bacteria that are capable of utilising nitriles as their sole source of nitrogen and carbon, and in concert act as an alternative to nitrilase activity, which performs nitrile hydrolysis without formation of an intermediate primary amide.
The Beckmann rearrangement scheme for acetophenone oxime under oxonium–acetic acid complex and hydronium–water complex. With the cyclohexanone-oxime, the relief of ring strain results in a third reaction mechanism, leading directly to the protonated caprolactam in a single concerted step without the intermediate formation of a π-complex or ...
The classical procedure to convert a nitrile to the corresponding primary amide calls for adding the nitrile to cold concentrated sulfuric acid. [29] The further conversion to the carboxylic acid is disfavored by the low temperature and low concentration of water. RC≡N + H 2 O → RC(O)NH 2. Two families of enzymes catalyze the hydrolysis of ...
Mechanism for acid-catalyzed hydrolysis of an amide. Upon hydrolysis, an amide converts into a carboxylic acid and an amine or ammonia (which in the presence of acid are immediately converted to ammonium salts). One of the two oxygen groups on the carboxylic acid are derived from a water molecule and the amine (or ammonia) gains the hydrogen ion.
Reaction mechanism for the amine formation from a carboxylic acid via Schmidt reaction. In the reaction mechanism for the Schmidt reaction of ketones, the carbonyl group is activated by protonation for nucleophilic addition by the azide, forming azidohydrin 3, which loses water in an elimination reaction to diazoiminium 5.
The German chemist Adolph Strecker discovered the series of chemical reactions that produce an amino acid from an aldehyde or ketone. [9] [10] Using ammonia or ammonium salts in this reaction gives unsubstituted amino acids. In the original Strecker reaction acetaldehyde, ammonia, and hydrogen cyanide combined to form after hydrolysis alanine ...