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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] Catalytic hydrogenation
Nahm and Weinreb also reported the synthesis of aldehydes by reduction of the amide with an excess of lithium aluminum hydride (see amide reduction). The Weinreb–Nahm ketone synthesis. The major advantage of this method over addition of organometallic reagents to more typical acyl compounds is that it avoids the common problem of over-addition.
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.
These hydrides facilitate the reduction of imines or iminium ions—key intermediates in reductive amination—into secondary or tertiary amines. This reaction typically occurs under mild conditions with excellent selectivity, which often makes H 2 /Pd the first choice for synthesizing amines in pharmaceuticals and fine chemicals.
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 ...
Amide reduction: Amines, aldehydes Reagent: lithium aluminium hydride followed by hydrolysis Vilsmeier–Haack reaction: Aldehyde (via imine) POCl 3, aromatic substrate, formamide Bischler–Napieralski reaction: Cyclic aryl imine: POCl 3, SOCl 2, etc. Tautomeric chlorination: Imidoyl chloride: Oxophilic halogenating agents, e.g. COCl 2 or SOCl 2
In the third step, an isomerization step protonates the nitrogen atom leading to the amide. The Beckmann rearrangement mechanism. The same computation with a hydroxonium ion and 6 molecules of water has the same result, but when the migrating substituent is a phenyl group, the mechanism favors the formation of an intermediate three-membered π ...
Attack by water converts 6 to protonated imidic acid 7, which undergoes loss of proton to arrive at the imidic acid tautomer of the final amide. In an alternative mechanism, the migration occurs at 9, directly after protonation of intermediate 3, in a manner similar to the Baeyer–Villiger oxidation to give protonated amide 10. Loss of a ...