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Amide reduction is a reaction in organic synthesis where an amide is reduced to either an amine or an aldehyde functional group. [1] [2] ... Toggle the table of contents.
The Hofmann rearrangement (Hofmann degradation) is the organic reaction of a primary amide to a primary amine with one less carbon atom. [1] [2] [3] The reaction involves oxidation of the nitrogen followed by rearrangement of the carbonyl and nitrogen to give an isocyanate intermediate.
Compared to amines, amides are very weak bases. While the conjugate acid of an amine has a pK a of about 9.5, the conjugate acid of an amide has a pK a around −0.5. Therefore, compared to amines, amides do not have acid–base properties that are as noticeable in water. This relative lack of basicity is explained by the withdrawing of ...
Reactions between aldimines and α-methylene carbonyls are also considered Mannich reactions because these imines form between amines and aldehydes. The reaction is named after Carl Mannich. [2] [3] Scheme 1 – Ammonia or an amine reacts with formaldehyde and an alpha acidic proton of a carbonyl compound to a beta amino carbonyl compound.
These possibilities have been used to account for the fact that, for certain substrates like α-tetralone, the group that migrates can sometimes change, depending on the conditions used, to deliver either of the two possible amides. [8] Two proposed reaction mechanisms for the amide formation from a ketone via Schmidt reaction
The Leuckart reaction is the chemical reaction that converts aldehydes or ketones to amines. The reaction is an example of reductive amination. [1] The reaction, named after Rudolf Leuckart, uses either ammonium formate or formamide as the nitrogen donor and reducing agent. It requires high temperatures, usually between 120 and 130 °C; for the ...
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.
The secondary amide 1 reacts via its enolized form with phosphorus pentachloride to form the oxonium ion 2. This produces a chloride ion which deprotonates the oxonium ion to form and imine 3 and hydrogen chloride. These then react with one another to form an amine, with loss of the phosphorus chloride residue.