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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.
Asymmetric ester hydrolysis with pig liver esterase is the enantioselective conversion of an ester to a carboxylic acid through the action of the enzyme pig liver esterase (EC 3.1.1.1). Asymmetric ester hydrolysis involves the selective reaction of one of a pair of either enantiotopic (within the same molecule and related by a symmetry plane of ...
[1] [2] In organic chemistry, ether cleavage is an acid catalyzed nucleophilic substitution reaction. Depending on the specific ether, cleavage can follow either S N 1 or S N 2 mechanisms. Distinguishing between both mechanisms requires consideration of inductive and mesomeric effects that could stabilize or destabilize a potential carbocation ...
Scheme 2. Hydrolysis of benzoic acid esters. Reaction constants are known for many other reactions and equilibria. Here is a selection of those provided by Hammett himself (with their values in parentheses): the hydrolysis of substituted cinnamic acid ester in ethanol/water (+1.267) the ionization of substituted phenols in water (+2.008)
Nefkens and Tesser developed a technique for generating active esters from N-hydroxyphthalimide [14] for use in peptide synthesis, [15] an approach later extended to using N-hydroxysuccinimide. [16] The ester linkage is formed between the N-hydroxyphthalimide and a carboxylic acid by elimination of water, the coupling achieved with N,N ...
The hydrolysis of the ester or peptide bond proceeds in two steps. First, the acyl part of the substrate (the acid part of an ester or the part of a peptide ending in a carboxyl group) is transferred to the serine, making a new ester or amide bond and releasing the other part of the substrate (the alcohol of an ester or the part of the peptide ...
Ortho esters are readily hydrolyzed in mild aqueous acid to form esters: . RC(OR ′) 3 + H 2 O → RCO 2 R ′ + 2 R ′ OH. For example, trimethyl orthoformate CH(OCH 3) 3 may be hydrolyzed (under acidic conditions) to methyl formate and methanol; [5] and may be further hydrolyzed (under alkaline conditions) to salts of formic acid and methanol.
Hormone-sensitive lipase (EC 3.1.1.79, HSL), also previously known as cholesteryl ester hydrolase (CEH), [5] sometimes referred to as triacylglycerol lipase, is an enzyme that, in humans, is encoded by the LIPE gene, [6] and catalyzes the following reaction: (1) diacylglycerol + H 2 O = monoacylglycerol + a carboxylate