Esters with carboxylic acid anhydrides

Ethers of benzenepentol have been obtained by Dakin oxidation of the appropriately substituted acetophenone. Thus, the oxidation of 2-hydroxy-3,4,6-ttimethoxyacetophenone and 2-hydroxy-3,4,5-ttimethoxyacetophenone with hydrogen peroxide ia the presence of alkali gives l,2-dihydroxy-3,4,6-ttimethoxybenzene and l,2-dihydroxy-3,4,5-ttimethoxybenzene, respectively further methylation of these ethers yields the pentamethyl ether of benzenepentol (mp 58—59 degC) (253). The one-step aromatization of myoinositol to produce esters of pentahydroxybenzene is achieved by treatment with carboxylic acid anhydrides ia DMSO and ia the presence of pyridine (254) (see Vitamins). 6-Alkyl- or... 

Esterification with carboxylic acid anhydrides (Section 15.8) Carboxylic acid anhydrides react with alcohols to form esters in the same way that acyl chlorides do. 

Similar additions have been successfully carried out with carboxylic acids, anhydrides, acyl halides, carboxylic esters, nitriles, and other types of compounds. These reactions are not successful when the alkene contains electron-withdrawing groups such as halo or carbonyl groups. A free-radical initiator is required, usually peroxides or UV light. The mechanism is illustrated for aldehydes but is similar for the other compounds ... 

Similar additions have been successfully carried out with carboxylic acids, anhydrides,561 acyl halides, carboxylic esters, nitriles, and other types of compounds.562... 

It is possible to prepare esters of phenols with carboxylic acid anhydrides or acid halides, and phenyl ethers by reaction of benzenolate anion with halides, sulfate esters, sulfonates, or other alkyl derivatives that react well by the SN2 mechanism ... 

A cyclization reaction involving the sulfonamide 267 finalized an efficient synthetic approach to the COX-inhihitor 268 after subsequent simultaneous ester hydrolysis and detosylation (Equation 82) <2003JOC4104>. Indoles have also been prepared by reaction of (2-aminobenzyl)triphenylphosphonium salts with carboxylic acid anhydrides in the presence of a base <2002TL2885>. Exposure of o-(benzoylamino)benzonitriles to a-bromoketones under basic conditions gives 3-aminoindole derivatives <2001BML2169>. 

In general, salt-free solutions of ylides do not react with methyl or ethyl esters of carboxylic acids. Better results can be obtained when activated esters (e.g. phenyl or pyridyl esters) are used for acyl-ation. " Acylation with carboxylic acid anhydrides also requires only one mole of starting ylide (equation 73). ... 

It should finally be pointed out that trimethylsilyl ethers can also be transformed directly into other functionalities. Oxidation with NBS leads to ketones and aldehydes, treatment with LiAllWAlCb results in deoxygenation of the alcohol, reaction with carboxylic acid anhydrides in the presence of BF3-OEt2 produces esters and on treatment with PhsP Brj acid bromides are foimed directly from TMS esters. ss... 

Scheme 2.63 Reaction of aldehydes, esters, and carboxylic acid anhydrides with SF4 [125a, 137, 138).

Activated acyl donors such as vinyl esters, halogenated methyl or ethyl ester, oxime esters or carboxylic acid anhydrides are often preferred for acylation of alcohols. With vinyl esters, acylation is in general fast and quantitative, as the equilibrium is driven by the release of vinyl alcohol, which will spontaneously tautomerize to volatile acetaldehyde. Amine nucleophiles will typically react spontaneously with these acyl donors, which hence cannot be used for resolution of amines. Vinyl acetate and ethyl acetate are common reagents (and often also solvents) for enzymatic kinetic resolution of alcohols and amines, respectively [9],... 

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. 

The Fries rearrangement is the acid-catalyzed transformation of aryl esters into hydroxy ary Iketones [1] and often plays an important role in the production of hydro-xyarylketones by acylation of phenols with carboxylic acids, anhydrides, or acyl chlorides. 

Phenols react with carboxylic acid anhydrides and acid chlorides to form esters. These reactions are quite similar to those of alcohols (Section 17.7). 

Amines are convert ed to amides on reaction with acyl chlorides Other acylating agents such as carboxylic acid anhydrides and esters may also be used but are less reactive... 

The alcohol groups of carbohydrates undergo chemical reactions typical of hydroxyl functions They are converted to esters by reaction with acyl chlorides and carboxylic acid anhydrides... 

Esters from the reaction of alcohols with carboxylic acids, acid halides and anhydrides. 

Much more important than these reactions, however, are the reactions of CDI and its analogues with carboxylic acids, leading to AAacylazoles, from which (by acyl transfer) esters, amides, peptides, hydrazides, hydroxamic acids, as well as anhydrides and various C-acylation products may be obtained. The potential of these and other reactions will be shown in the following chapters. In most of these reactions it is not necessary to isolate the intermediate AAacylazoles. Instead, in the normal procedure the appropriate nucleophile reactant (an alcohol in the ester synthesis, or an amino acid in the peptide synthesis) is added to a solution of an AAacylimidazole, formed by reaction of a carboxylic acid with CDI. Thus, CDI and its analogues offer an especially convenient vehicle for activation of... 

As with carboxylic acids obtained by palladium hydroxycarbonylation, their derivatives esters, amides, anhydrides and acyl halides are synthesized from alkenes, CO and HX (X = OR, NR2 etc.). The Pd-catalyzed methoxycarbonylation is one of the most studied reactions among this type of catalyzed carbonylations and has been reviewed and included in reports of homogeneous catalysis.625, 26 The methoxycarbonylation has been applied to many different substrates to obtain intermediates in organic syntheses as well as specific products. For instance, the reaction has been applied for methoxycarbonylation of alkynes666 Highly efficient homogeneous Pd cationic catalysts have been reported and the methoxycarbonylation of alkynes has been used to develop economically attractive and environmentally benign process for the production of methyl... 

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