Carboxylic acid anhydrides reaction with

In addition to acyl halides and acid anhydrides, there are a number of milder and more selective acylating agents that can be readily prepared from carboxylic acids. Imidazolides, the (V-acyl derivatives of imidazole, are examples.115 Imidazolides are isolable substances and can be prepared directly from the carboxylic acid by reaction with carbonyldiimidazole. 

The combination of carboxyl activation by a carbodiimide and catalysis by DMAP provides a useful method for in situ activation of carboxylic acids for reaction with alcohols.10 The reaction proceeds at room temperature. Carbodiimides are widely applied in the synthesis of polypeptides from amino acids. The proposed mechanism for this esterification reaction involves activation of the acid via isourea 28 followed by reaction with another acid molecule to form anhydride... 

Haptens containing amino groups can be coupled directly to carriers containing carboxyl groups, or the amino group can be converted to a carboxylic acid by reaction with succinic anhydride. - When a keto or an aldehyde group is present in the hapten, it can be converted to a carboxyl via reaction with 0-(carboxymethyl)hydroxylamine or with hydrazides. Haptens containing double bonds can be made to react directly with mer-captoacetic or mercaptopropionic acid, or a two-step reaction may be performed bromination followed by reaction with mercaptocarboxylic acid. ... 

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... 

Amides are prepared from carboxylic acid derivatives, either acid chlorides or acid anhydrides. Recall that acid chlorides are made from carboxylic acids by reaction with reagents such as PCI5. 

The anhydrides react with traces of moisture or with pendant hydroxyl groups first. This opens the anhydride groups and frees the carboxylic acids for reactions with the epoxy rings ... 

Iodine triacylates (29) are readily obtained by ozonization of solutions of iodine in aliphatic carboxylic acid anhydrides thermolysis with mercuric oxide affords the symmetrical esters (30) in good yield. Mercuric iodate can perform the same transformation by direct reaction with the anhydride. 

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... 

By virtue of their fused /3-lactam-thiazolidine ring structure, the penicillins behave as acylating agents of a reactivity comparable to carboxylic acid anhydrides (see Section 5.11.2.1). This reactivity is responsible for many of the properties of the penicillins, e.g. difficult isolation due to hydrolytic instability (B-49MI51102), antibacterial activity due to irreversible transpeptidase inhibition (Section 5.11.5.1), and antigen formation via reaction with protein molecules. 

Ion 21 can either lose a proton or combine with chloride ion. If it loses a proton, the product is an unsaturated ketone the mechanism is similar to the tetrahedral mechanism of Chapter 10, but with the charges reversed. If it combines with chloride, the product is a 3-halo ketone, which can be isolated, so that the result is addition to the double bond (see 15-45). On the other hand, the p-halo ketone may, under the conditions of the reaction, lose HCl to give the unsaturated ketone, this time by an addition-elimination mechanism. In the case of unsymmetrical alkenes, the attacking ion prefers the position at which there are more hydrogens, following Markovnikov s rule (p. 984). Anhydrides and carboxylic acids (the latter with a proton acid such as anhydrous HF, H2SO4, or polyphosphoric acid as a catalyst) are sometimes used instead of acyl halides. With some substrates and catalysts double-bond migrations are occasionally encountered so that, for example, when 1 -methylcyclohexene was acylated with acetic anhydride and zinc chloride, the major product was 6-acetyl-1-methylcyclohexene. ... 

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 ... 

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. 

Carboxylic acids were introduced by the reaction of the polysilane(II) with carboxylic acid anhydrides in the presence of an amine. Table 2 shows the results. In order to examine the effect of unsaturated bonds and halides in the side chain on photolysis, double bonds or chloride groups were introduced with the carboxylic acid. Polysilanes(III) were also soluble in polar solvents and basic aqueous solution. The solubility in tetramethyl ammonium hydroxide aqueous solution(TMAH) depended strongly... 

Hill, C.A.S. and Hillier, J. (1999). Kinetic studies of the reaction of carboxylic acid anhydrides with wood. Experimental determination and modelling of kinetic profiles. Physical Chemistry and Chemical Physics, 1, 1569-1576. 

Hill, C.A.S. and Jones, D. (1996a). The dimensional stabilisation of Corsican pine sapwood by reaction with carboxylic acid anhydrides. Holrforschung, 50(5), 457 62. 

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