Carboxylic acid anhydrides synthesis

In an alternate synthesis, the formation of thermoplastic vulcanizate (TPV) is accomplished with two polymers, wherein one polymer is grafted with a carboxylic acid anhydride, which then is reacted with an aminosilane, which reacts with the acid anhydride and then cross-links with moismre. The vulcanizates exhibit good mechanical properties and lower melt-flow index than the starting polymers. 

Synthesis of Acyl Nitronates The most general approach to the synthesis of acyl nitronates is based on the reactions of anions of the corresponding AN with acyl halides or carboxylic acid anhydrides in the presence of bases. Here, we will not consider a series of studies, where the formation of intermediate O-acyl nitronates was postulated without conclusive proof or by detection of their decomposition products. 

The T2 linker has recently been shown to be a versatile backbone amide anchor. Immobilized disubstituted triazenes were acylated with carboxylic acid anhydrides or chlorides to give amide derivatives. These amides were cleaved under very mild conditions using trimethyl chlorosilane. This sequence thus employs the T2 system as backbone amine linker and was demonstrated in the automated library synthesis of substituted amide derivatives.54... 

The synthesis of derivatives of quinoline from isatins and carboxylic acid anhydrides can also be realized without isolating the intermediate N-acyl derivatives. Thus, unsubstituted 2-quinolonecarboxylic acid containing the 14C isotope at position 3 was synthesized by the condensation of isatin 7 with the anhydride (H314CC0)20 [172], The unsubstituted acid 168 [163] and its 3-aryl derivatives 195 [173, 174] were obtained by heating the isatin 7 directly with the respective anhydrides. 

Acetic Anhydride Acetic anhydride is the most important carboxylic acid anhydride. It is produced at the rate of about 4 billion pounds per year, primarily for synthesis of plastics, fibers, and drags. (See the synthesis of aspirin on p. 1009.) Acetic anhydride consists of two molecules of acetic acid, minus a molecule of water. The most common industrial synthesis begins by dehydrating acetic acid to give ketene. 

Acetic anhydride [108-24-7], (CH3C0)20, is a mobile, colorless liquid that lias ail acrid odor and is a more piercing lacrimator than acetic acid [64-19-7]. It is the largest commercially produced carboxylic acid anhydride U.S. production capacity is over 900,000 t yeady. Its chief industrial application is for acetylation reactions it is also used in many other applications in oiganic synthesis, and it lias some utility as a solvent in chemical analysis. 

Table 11 Synthesis of Carboxylic Acid Anhydrides by Reaction with Trimethylsilylethoxyacetylene...

Adducts (6) and (7) from amides and chlorophosphoric acid aiyl esters or dichlorophosphoric acid aryl esters respectively are well known. - The adducts are formed in a 1 1 ratio. They have been applied to the synthesis of mixed anhydrides from diarylphosphoric acids and carboxylic acids, as well as mixed substituted esters of pyrophosphoric acid. The adduct formation between primary or secondary carboxamides and dichlorophosphates has been used to prepare nitriles and isonitriles respectively. The adduct from DMF and phenyldichlorophosphate is a useful reagent for the preparation of carboxylic acid esters from the corresponding acids and alcohols, 3-lactams from imines and carboxylic acids," carboxylic acid anhydrides, carboxylic acid esters and thiol esters. Adducts of amides with ester amides or diamides of chlorophosphoric acid have been studied. ... 

P-Diketones. The Nicer we in2 synthesis of /3-diketones (4) involves the reaction of carboxylic acid anhydrides (1) with ketones (2) with boron trifluoride as... 

A polymeric HOBt (132), which is soluble in dichloromethane, DMF or water and bears a poly (ethylene glycol) (PEG) chain (average molecular wt 4000), has been prepared from PEG-NH2 and l-hydroxybenzotriazole-5-carboxylic acid using DCC as coupling agent [135]. The corresponding active esters were prepared by reaction with an excess of carboxylic acid anhydrides and used for the synthesis of the model tetrapeptide Cbz-Leu-Ala-Gly-Val-OtBu [136]. 

The Perkin reaction involves the condensation of a carboxylic acid anhydride and an aldehyde in the presence of a weak base, often the sodium or potassium salt of the acid or triethylamine, to give unsaturated carboxylic acids (equation 1). The first example of this reaction was described by Perkin in 1868 and involves a synthesis of coumarin by heating the sodium salt of salicylaldehyde with acetic anhydride (equation 2). The reaction is generally applicable only to aromatic aldehydes and is particularly useful for the preparation of substituted cinnamic acids, as illustrated by equation (3). ... 

Amidines themselves also cyclize with carboxylic acid anhydrides or esters to give the corresponding 1,3,5-triazines 322 323 the reactions have a mechanism similar to the Pinner synthesis. 

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