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Compared to amines, amides are very weak bases. While the conjugate acid of an amine has a pK a of about 9.5, the conjugate acid of an amide has a pK a around −0.5. Therefore, compared to amines, amides do not have acid–base properties that are as noticeable in water. This relative lack of basicity is explained by the withdrawing of ...
Amine. In chemistry, amines (/ ə ˈ m iː n, ˈ æ m iː n /, [1] [2] UK also / ˈ eɪ m iː n / [3]) are compounds and functional groups that contain a basic nitrogen atom with a lone pair.Formally, amines are derivatives of ammonia (NH 3), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group [4] (these may respectively be called alkylamines ...
Most common imides are prepared by heating dicarboxylic acids or their anhydrides and ammonia or primary amines. The result is a condensation reaction: [5] (RCO) 2 O + R′NH 2 → (RCO) 2 NR′ + H 2 O. These reactions proceed via the intermediacy of amides. The intramolecular reaction of a carboxylic acid with an amide is far faster than the ...
The amide bond is synthesized when the carboxyl group of one amino acid molecule reacts with the amino group of the other amino acid molecule, causing the release of a molecule of water (H 2 O), hence the process is a dehydration synthesis reaction. The dehydration condensation of two amino acids to form a peptide bond (red) with expulsion of ...
It is commonly used as the hindered base in amide coupling reactions between a carboxylic acid (typically activated, for example, as an acid chloride, as illustrated below) and a nucleophilic amine. [5] As DIPEA is hindered and poorly nucleophilic, it does not compete with the nucleophilic amine in the coupling reaction.
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.
The lithium amides are more common and more soluble than the other alkali metal analogs. Potassium amides are prepared by transmetallation of lithium amides with potassium t-butoxide (see also Schlosser base) or by reaction of the amine with potassium, potassium hydride, n-butylpotassium, or benzylpotassium. [2]
Primary amines are usually not used for enamine synthesis due to the preferential formation of the more thermodynamically stable imine species. [11] Methyl ketone self-condensation is a side-reaction which can be avoided through the addition of TiCl 4 [12] into the reaction mixture (to act as a water scavenger).