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The successive addition of carboxylic acids and alcohols into a system containing aromatic carboxylic acid anhydride and catalyst produces corresponding carboxylic esters through the process shown in the following figure. In acidic Shiina esterification, Lewis acid catalysts are used, while nucleophilic catalysts are used for Shiina ...
All of the processes of Shiina macrolactonization consist of reversible reactions, with the exception of the last cyclization step.At the first stage of the reaction, mixed anhydride (MA) is produced quickly under mild conditions; at the second stage, a faster cyclization of the MA prevents an increase in MA concentration.
2-Methyl-6-nitrobenzoic anhydride is an organic acid anhydride also known as the Shiina reagent, [1] [2] having a structure wherein carboxylic acids undergo intermolecular dehydration condensation. It was developed in 2002 by Prof. Isamu Shiina ( Tokyo University of Science , Japan). [ 3 ]
The Yamaguchi esterification is the chemical reaction of an aliphatic carboxylic acid and 2,4,6-trichlorobenzoyl chloride (TCBC, Yamaguchi reagent) to form a mixed anhydride which, upon reaction with an alcohol in the presence of stoichiometric amount of DMAP, produces the desired ester. It was first reported by Masaru Yamaguchi et al. in 1979 ...
The natural esterification that takes place in wines and other alcoholic beverages during the aging process is an example of acid-catalysed esterification. Over time, the acidity of the acetic acid and tannins in an aging wine will catalytically protonate other organic acids (including acetic acid itself), encouraging ethanol to react as a ...
The synthesis of 6-acetyl-1,2,3,4-tetrahydropyridine, an important bread aroma compound, starting from 2-piperidone was accomplished using t-boc anhydride. [14] See Maillard reaction ). The first step in this reaction sequence is the formation of the carbamate from the reaction of the amide nitrogen with boc anhydride in acetonitrile using DMAP ...
Strong acids catalyze the reaction by donating a proton to the carbonyl group, thus making it a more potent electrophile. Bases catalyze the reaction by removing a proton from the alcohol, thus making it more nucleophilic. The reaction can also be accomplished with the help of enzymes, particularly lipases (one example is the lipase E.C.3.1.1.3 ...
The reaction mechanism of the Mitsunobu reaction is fairly complex. The identity of intermediates and the roles they play has been the subject of debate. Initially, the triphenyl phosphine (2) makes a nucleophilic attack upon diethyl azodicarboxylate (1) producing a betaine intermediate 3, which deprotonates the carboxylic acid (4) to form the ion pair 5.