Search results
Results From The WOW.Com Content Network
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 the Hofmann elimination, treatment of a quaternary ammonium iodide salt with silver oxide produces hydroxide ions, which act as a base and eliminate the tertiary amine to give an alkene. [11] In the Hofmann elimination, the least substituted alkene is typically favored due to intramolecular steric interactions.
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.
In effect, Hofmann elimination is a retro-Michael addition chemical process. It is important to note here that the physiological process of Hofmann elimination differs from the non-physiological Hofmann degradation process: the latter is a chemical reaction in which a quaternary ammonium hydroxide solid salt is heated to 100 °C, or an aqueous ...
Consequently, the elimination product is always syn and rarely occurs with 6-membered rings. ( Rings with 5 or 7 or more members undergo the reaction just fine.) [ 6 ] [ 7 ] [ 8 ] This organic reaction is closely related to the Hofmann elimination , [2] but the base is a part of the leaving group .
The Cope rearrangement is the prototypical example of a concerted sigmatropic rearrangement. It is classified as a [3,3]-sigmatropic rearrangement with the Woodward–Hoffmann symbol [π 2 s + σ 2 s + π 2 s] and is therefore thermally allowed.
Quinine's vinyl group is then constructed by Hofmann elimination with sodium hydroxide in water at 140 °C. This process is accompanied by hydrolysis of both the ester and the amide group but it is not the free amine that is isolated but the urea 14 by reaction with potassium cyanate.
Metabolism and Hofmann elimination . Fig.3 A simple illustration of how vecuronium binds to the nicotinic receptor. Its D-ring binds to the receptor at two points and the lipophillic side of the molecule repels cations from flowing through the ion-channel. Deacetylating vecuronium at position 3 results in a very active metabolite. [23]