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At temperatures above its melting point, itaconic anhydride converts to citraconic anhydride. [12] Even at significantly lower temperatures, such as in boiling chloroform, isomerization can take place in the presence of tertiary amines. [16] Umlagerung von Itaconsäureanhydrid in Citraconsäureanhydrid
Citraconic acid is an organic compound with the formula CH 3 C 2 H(CO 2 H) 2. It is a white solid. The alkene is cis. The related trans alkene is called mesaconic acid. It is one of the pyrocitric acids formed upon the heating of citric acid. [1] Citraconic acid can be produced, albeit inefficiently, by oxidation of xylene and methylbutanols.
Hippuric acid, the benzamide derivative of glycine, cyclizes in the presence of acetic anhydride, condensing to give 2-phenyl-oxazolone. [3] This intermediate also has two acidic protons and reacts with benzaldehyde, acetic anhydride and sodium acetate to a so-called azlactone. This compound on reduction gives access to phenylalanine. [4]
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 ...
The reaction between the carbonyl and amine are in equilibrium, favouring the carbonyl unless water is removed from the system. reduction-sensitive intermediates may form in the reaction which can affect chemoselectivity. The amine substrate, imine intermediate, or amine product might deactivate the catalyst. Acyclic imines have E/Z isomers.
The reaction mechanism involves the acylation and activation of the acid 1 to the mixed anhydride 3. The amide will serve as a nucleophile for the cyclization forming the azlactone 4. Deprotonation and acylation of the azlactone forms the key carbon-carbon bond. Subsequent ring-opening of 6 and decarboxylation give the final keto-amide product.
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.
Another common example is the reaction of a primary amine or secondary amine with a carboxylic acid or with a carboxylic acid derivative to form an amide. This reaction is widely used, especially in the synthesis of peptides. On the simple addition of an amine to a carboxylic acid, a salt of the organic acid and base is obtained.