Carboxylic acid anhydrides: aliphatic derivatives

The classes of compounds that are conveniently considered together as derivatives of carboxylic acids include the acyl chlorides, carboxylic acid anhydrides, esters, and amides. In the case of simple aliphatic and aromatic acids, synthetic transformations... 

Anilino-553 and the three 3-tolylaminobenzo[6]thiophenes554 undergo the Bernthsen reaction when heated with an aliphatic carboxylic acid anhydride and zinc chloride 1o yield polycyclic compounds (e.g., 181 from 3-m-tolylaminobenzo[6]thiophene and acetic anhydride), They give analogous arsenic derivatives (e.g., 182 from 3-p-tolylaminobenzo[6]thiophene) when heated with arsenic trichloride in o-dichlorobenzene.553,554... 

Diorgano tellurium dicarboxylates were prepared from dialkyl and diaryl tellurium derivatives. Aliphatic carboxylic acids, aromatic carboxylic acids, their sodium or silver salts, and carboxylic acid anhydrides were used as reagents. Dicarboxylic acids such as succinic acid and phthalic acid were reported to give monomeric carboxylates when... 

The familiar substitution reactions of derivatives of carboxylic acids with basic reagents illustrate nucleophihc substitution at aliphatic sp carbons. (Substitution reactions of carboxylic acids, and their derivatives, with acidic reagents are covered in Chapter 4.) The mechanisms of these reactions involve two steps (1) addition of the nucleophile to the carbonyl group and (2) elimination of some other group attached to that carbon. Common examples include the basic hydrolysis and aminolysis of acid chlorides, anhydrides, esters, and amides. 

The reaction of aliphatic carboxylate esters or ethers with carbon monoxide in the presence of nickel or a nickel derivative, iodine or an iodine compound, and an organic trivalent Group VA element compound and DBU under pressure gave carboxylic acid anhydrides (79GEP2844371). 

A dispersant that can be used in drilling fluids, spacer fluids, cement slurries, completion fluids, and mixtures of drilling fluids and cement slurries controls the rheologic properties of and enhances the filtrate control in these fluids. The dispersant consists of polymers derived from monomeric residues, including low-molecular-weight olefins that may be sulfonated or phosphonated, unsaturated dicarboxylic acids, ethylenically unsaturated anhydrides, unsaturated aliphatic monocarboxylic acids, vinyl alcohols and diols, and sulfonated or phosphonated styrene. The sulfonic acid, phosphonic acid, and carboxylic acid groups on the polymers may be present in neutralized form as alkali metal or ammonium salts [192,193]. 

This chapter deals with the kinetics and mechanisms of the hydrolysis of carboxylic acid derivatives of general formula RCOX. These include carboxylic acid halides, amides, and anhydrides with small sections on carboxylic acid cyanides etc. Many recent developments in this field have been made with acid derivatives in which R is not an aliphatic or aromatic group, for example, carbamic acid derivatives, and these are reported where relevant, as are reactions such as ethanolysis, aminolysis, etc. where they throw light on the mechanisms of hydrolysis. 

The esterification of support-bound carboxylic acids has not been investigated as thoroughly as the esterification of support-bound alcohols. Resin-bound activated acid derivatives that are well suited to the preparation of esters include O-acylisoureas (formed from acids and carbodiimides), acyl halides [23,226-228], and mixed anhydrides (Table 13.15). A-Acylurea formation does not compete with esterifications as efficiently as it does with the formation of amides from support-bound acids. Esters can also be prepared from carboxylic acids on insoluble supports by acid-catalyzed esterification [152,229]. Alternatively, support-bound carboxylic acids can be esteri-fied by O-alkylation, either with primary or secondary aliphatic alcohols under Mitsu-nobu conditions or with reactive alkyl halides or sulfonates (Table 13.15). 

The simpler examples are readily hydrolysed in aqueous solution, and therefore react with sodium hydrogen carbonate and also give the ester test they may be confirmed by applying the hydroxamic ester test (Section 9.5.3, p. 1222). Carbonyl adsorption is apparent in the infrared spectrum at about 1820 cm-1 and at about 1760cm-1. It should be noted that aromatic anhydrides and higher aliphatic anhydrides are not readily hydrolysed with water and are therefore effectively neutral (Section 9.5.3, p. 1218). The final characterisation of the acid anhydride is achieved by conversion into a crystalline carboxylic acid derivative as for add halides. 

Activation of carboxylic acids by phosphoms acid halides in the form of different derivatives (3-7) has been used extensively in more recent years. These methods have been tested not only for saturated aliphatic or aromatic carboxylic acids but also for functionalized derivatives. In Table 6 some examples are collected where (3) and (4) were applied successfully. The reactions are carried out at room temperature in acetone or dichloromethane by treatment of the carboxylic acid with 1 equiv. of triethylamine or A -ethylpiperidine and 0.5 equiv. of the reagent (equation 25). The anhydrides are either collected by filtration or recovered by evaporation of the solvent after washing with water. 

A variety of acylation reactions of chitosan are possible by using different acyl-ating agents, such as aliphatic carboxylic acid chlorides (hexanoyl, dodecanoyl and tetradecanoyl chlorides), cyclic anhydrides and cyclic esters. The acylation reaction is not regioselective. When IV,0-acylated chitosans were prepared with acyl chlorides in methanesulfonic acid [62-63], the derivatives of 4-chlorobutyl and decanoyl chlorides showed higher fungidal activities than chitosan [64]. Selectively N-acylated chitosan have been obtained by Lee et al. [65-66] with butanoic, hexanoic and benzoic anhydride under homogeneous conditions... 

This reaction was initially reported by Granacher in 1922. It is the preparation of thionic acid by the treatment of Aldol Condensation product from an aldehyde and rhodanine with a base (e.g., NaOH). Therefore, this reaction is known as the Granacher synthesis or Granacher reaction." The prepared thionic acid in this reaction can be further converted into a variety of derivatives under different conditions. For example, it can be transformed into a-thiol acid under a basic sodium amalgam reduction, whereas aliphatic acid is formed under an acidic zinc amalgam reduction. In addition, when the thionic acid is treated with ammonia, a-keto acid is generated, and the thionic acid can be converted into af-carboxyl oxime in reaction with hydroxylamine, from which either cy-amino acid or aliphatic nitrile forms via the treatment of sodium amalgam reduction or acetic anhydride, respectively. 

A combination of free aliphatic carboxylic acids and benzoic anhydride derivatives may be employed to generate a variety of enantioenriched esters of benzylic alcohols via BTM-catalyzed KR (eq 2). ... 

Reactions.—Several pathways are open for the diborane reduction of carboxylic acids. The lower aliphatic acids in THF form triacyloxyboranes (21) which may be further reduced, whereas such intermediates derived from higher aliphatic acids rapidly dismute and may be reduced via the carboxylic anhydride (22) and mixed anhydride (23) formed. ... 

Carboxylic acid triethylamine salts yield mixed anhydrides which, when treated with ethoxymagnesiomalonic esters give the benzoylated malonate. Alternatively, treatment of the mixed anhydrides with sodium tetracarbonylferrate(II) produces the aldehyde derived from the parent aliphatic or aromatic carboxylic acid in good yield. ... 

With aliphatic acids, even in the absence of pyridine, considerable chlorosulfonation occurs on irradiation 150 with short chain acids, e.g., propionic, isobutyric acids, the products isolated are the cyclic sulfo-carboxylic anhydrides (XLVI) in which the sulfo groups are in the 8-or 8- and y-positions. No products derived from substitution at a-posi-... 

---