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However, there also have been reported examples of base-free Stieglitz rearrangements of N-halogenated amines. An example for that can be found in the total synthesis of (±)-lycopodine by Paul Grieco et al. [6] [29] There, a ring formation takes place by a rearrangement on a secondary haloamine by subjecting it to silver tetrafluoroborate. [6]
In the reaction, thermal or photochemical decomposition of N-halogenated amine 1 in the presence of a strong acid (concentrated sulfuric acid or concentrated CF 3 CO 2 H) generates a nitrogen radical intermediate. The radical then abstracts an intramolecular hydrogen atom to give a cyclic amine 2 (pyrrolidine or, in some cases, piperidine).
Because primary and secondary amines react with aldehydes and ketones, the most common variety of these aminocarbonyl compounds feature tertiary amines. Such compounds are produced by amination of α-haloketones and α-haloaldehydes. [1] Examples include cathinones, methadone, molindone, pimeclone, ferruginine, and tropinone.
For example, reaction of 1-bromooctane with ammonia yields almost equal amounts of the primary amine and the secondary amine. [3] Therefore, for laboratory purposes, N-alkylation is often limited to the synthesis of tertiary amines. An exception is the amination of alpha-halo carboxylic acids that do permit synthesis of primary amines with ...
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In the Mannich reaction, primary or secondary amines or ammonia react with formaldehyde to form a Schiff base. Tertiary amines lack an N–H proton and so do not react. The Schiff base can react with α-CH-acidic compounds (nucleophiles) that include carbonyl compounds, nitriles, acetylenes, aliphatic nitro compounds, α-alkyl-pyridines or imines.
By reaction with tertiary amines, long-chain alkyl bromides such as 1-bromododecane, give quaternary ammonium salts, which are used as phase transfer catalysts. [ 9 ] With Michael acceptors the addition is also anti-Markovnikov because now a nucleophilic X − reacts in a nucleophilic conjugate addition for example in the reaction of HCl with ...
For example, in the three-component coupling of aldehydes, amines, and activated alkenes, the aldehyde reacts with the amine to produce an imine prior to forming the aza-MBH adduct, as in the reaction of aryl aldehydes, diphenylphosphinamide, and methyl vinyl ketone, in the presence of TiCl 4, triphenylphosphine, and triethylamine: [19]