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In a similar fashion, the intermediate isocyanate can be trapped by tert-butyl alcohol, yielding the tert-butoxycarbonyl (Boc)-protected amine. The Hofmann Rearrangement also can be used to yield carbamates from α,β-unsaturated or α-hydroxy amides [2] [8] or nitriles from α,β-acetylenic amides [2] [9] in good yields (≈70%).
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
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 vast majority of these procedures utilize the commercially available salt N,O-dimethylhydroxylamine hydrochloride [MeO(Me)NH•HCl], which is typically easier to handle than the free amine. [6] Treatment of an ester or lactone with AlMe 3 or AlMe 2 Cl affords the corresponding Weinreb amide in good yields. Alternatively, non-nucleophilic ...
A few methodologies allow for the rearrangement of aldoximes to primary amides, but fragmentation commonly competes in these systems. Nitrone rearrangement also occurs without stereospecificity; the regioisomer formed has the amide nitrogen substituted with the group possessing the greatest migratory aptitude. The Beckmann Rearrangement
In organic chemistry, the Mannich reaction is a three-component organic reaction that involves the amino alkylation of an acidic proton next to a carbonyl (C=O) functional group by formaldehyde (H−CHO) and a primary or secondary amine (−NH 2) or ammonia (NH 3). [1] The final product is a β-amino-carbonyl compound also known as a Mannich base.
The substituent R next the amine methylene bridge is an electron-withdrawing group. The original 1928 publication by Thomas S. Stevens [ 2 ] concerned the reaction of 1-phenyl-2-(N,N-dimethylamino)ethanone with benzyl bromide to the ammonium salt followed by the rearrangement reaction with sodium hydroxide in water to the rearranged amine.
With pyridine as a base and solvent, refluxing conditions are required. [7] However, with the addition of 4-dimethylaminopyridine (DMAP) as a catalyst, the reaction can take place at room temperature. [8] With some acids, this reaction can take place even in the absence of an α-amino group. This reaction should not be confused with the Dakin ...