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Reaction mechanism for the amine formation from a carboxylic acid via Schmidt reaction. In the reaction mechanism for the Schmidt reaction of ketones, the carbonyl group is activated by protonation for nucleophilic addition by the azide, forming azidohydrin 3, which loses water in an elimination reaction to diazoiminium 5.
Alkaline hydrolysis of esters is also known as saponification. A base such as sodium hydroxide is required in stochiometric amounts. Unlike acid-catalyzed ester hydrolysis, it is not an equilibrium reaction and proceeds to completion. Hydroxide ion attacks the carbonyl carbon to give a tetrahedral intermediate, which then expels an alkoxide ion.
The classic example of a dehydration reaction is the Fischer esterification, which involves treating a carboxylic acid with an alcohol to give an ester RCO 2 H + R′OH ⇌ RCO 2 R′ + H 2 O. Often such reactions require the presence of a dehydrating agent, i.e. a substance that reacts with water.
Krapcho decarboxylation is a chemical reaction used to manipulate certain organic esters. [1] This reaction applies to esters with a beta electron-withdrawing group (EWG).. The reaction proceeds by nucleophilic dealkylation of the ester by the halide followed by decarboxylation, followed by hydrolysis of the resulting stabilized carbanion.
The Knorr pyrrole synthesis is a widely used chemical reaction that synthesizes substituted pyrroles (3). [1] [2] [3] The method involves the reaction of an α-amino-ketone (1) and a compound containing an electron-withdrawing group (e.g. an ester as shown) α to a carbonyl group (2). [4] The Knorr pyrrole synthesis
With highly activated phenols such as resorcinol, the reaction can be performed under much milder conditions. This provides a useful route to umbelliferone derivatives: The Pechmann condensation as applied to 7-hydroxy-4-methylcoumarin. For coumarins unsubstituted at the 4-position, the method requires the use of formylacetic acid or ester.
The Darzens reaction (also known as the Darzens condensation or glycidic ester condensation) is the chemical reaction of a ketone or aldehyde with an α-haloester in the presence of a base to form an α,β-epoxy ester, also called a "glycidic ester". [1] [2] [3] This reaction was discovered by the organic chemist Auguste Georges Darzens in 1904 ...
Acyloin condensation is a reductive coupling of two carboxylic esters using impure metallic sodium to yield an α-hydroxyketone, also known as an acyloin. [1] [2] [3] The acyloin condensation. The reaction is most successful when R is aliphatic and saturated, and typically performed with a silyl chloride reactant to trap the product as a ...