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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.
The Hofmann–Martius rearrangement in organic chemistry is a rearrangement reaction converting an N-alkylated aniline to the corresponding ortho and / or para aryl-alkylated aniline. The reaction requires heat, and the catalyst is an acid like hydrochloric acid .
The Hofmann rearrangement is a decarbonylation reaction whereby an amide is converted to an amine by way of an isocyanate intermediate. It is usually carried out under strongly basic conditions. It is usually carried out under strongly basic conditions.
PIFA can be used to carry out the Hofmann rearrangement under mildly acidic conditions, [11] rather than the strongly basic conditions traditionally used. [ 12 ] [ 13 ] The Hofmann decarbonylation of an N -protected asparagine has been demonstrated with PIDA, providing a route to β-amino- L - alanine derivatives.
The Cope elimination is very similar to the Hofmann elimination in principle, but occurs under milder conditions. It also favors the formation of the Hofmann product, and for the same reasons. [3] An example of a Hofmann elimination (not involving a contrast between a Zaitsev product and a Hofmann product) is the synthesis of trans-cyclooctene. [4]
In organic chemistry, regioselectivity is the preference of chemical bonding or breaking in one direction over all other possible directions. [1] [2] It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base will abstract from an organic molecule, or where on a substituted benzene ring a further substituent will be added.
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The formation of the quinoline product is influenced by the interaction of both steric and electronic effects.In a recent study, Sloop [8] investigated how substituents would influence the regioselectivity of the product as well as the rate of reaction during the rate-determining step in a modified Combes pathway, which produced trifluoromethylquinoline as the product.