Search results
Results from the WOW.Com Content Network
Amides are stable to water, and are roughly 100 times more stable towards hydrolysis than esters. [citation needed] Amides can, however, be hydrolyzed to carboxylic acids in the presence of acid or base. The stability of amide bonds has biological implications, since the amino acids that make up proteins are linked with amide
Lithium amides are usually prepared in the laboratory through the addition of a titrated solution of n-butyllithium in hexanes to a solution of the amine in ether. Dry glassware and inert atmosphere are required for these reactions. Alternatively, lithium amides may be prepared by the direct action of lithium on the corresponding amine.
Acid–base-catalysed hydrolyses are very common; one example is the hydrolysis of amides or esters. Their hydrolysis occurs when the nucleophile (a nucleus-seeking agent, e.g., water or hydroxyl ion) attacks the carbon of the carbonyl group of the ester or amide. In an aqueous base, hydroxyl ions are better nucleophiles than polar molecules ...
While nucleophilic acyl substitution reactions can be base-catalyzed, the reaction will not occur if the leaving group is a stronger base than the nucleophile (i.e. the leaving group must have a higher pK a than the nucleophile). Unlike acid-catalyzed processes, both the nucleophile and the leaving group exist as anions under basic conditions.
In enzymology, an amidase (EC 3.5.1.4, acylamidase, acylase (misleading), amidohydrolase (ambiguous), deaminase (ambiguous), fatty acylamidase, N-acetylaminohydrolase (ambiguous)) is an enzyme that catalyzes the hydrolysis of an amide. In this way, the two substrates of this enzyme are an amide and H 2 O, whereas its two products are ...
The asymmetry of the intermediate results in two products of its hydrolysis, either aspartic acid (in black at left) or isoaspartic acid, which is a beta amino acid (in green at bottom right). However, there is a concern that aspartic acid can be isomerized after deamidation. [ 2 ]
Next, the carbanion resulting from the benzylic hydrogen extraction performs a nucleophilic attack on the electrophilic carbonyl carbon of the amide group. When this occurs, the pi-bond of the amide is converted into a lone pair, creating a negatively charged oxygen. After these initial steps, strong base is no longer required and hydrolysis ...
These possibilities have been used to account for the fact that, for certain substrates like α-tetralone, the group that migrates can sometimes change, depending on the conditions used, to deliver either of the two possible amides. [8] Two proposed reaction mechanisms for the amide formation from a ketone via Schmidt reaction