Anhydrides, alcoholysis with carboxylic acids

Esters are less reactive than acid chlorides and acid anhydrides. They are converted to carboxylic acid hy acid or base hydrolysis, and to another ester by acid or base alcoholysis (transesterification). The 1°, 2° or 3° amides are obtained from esters by treatment with ammonia or 1° or 2° amines, respectively. 

Alcoholysis of trihalides 0-6 Hydrolysis of ortho esters 0-20 Alcoholysis of acyl halides 0-21 Alcoholysis of anhydrides 0-22 Esterification of carboxylic acids 0-23 Transesterification 0-24 Alkylation of carboxylic acid salts 0-25 Cleavage of ethers with anhydrides 0-26 Alkylation of carboxylic acids with diazo compounds... 

The various ways in which esters of cellulose and phosphorous adds can be synthesized are esterification cellulose with free acids alcoholysis, with cellulose, of the esters and amides of phosphoric adds and esterification with mixed anhydrides df phosphoric adds and carboxylic adds. 

Polymers with pendant groups that are derivatives of carboxylic acid can he hydrolyzed to yield poly(acrylic acid). This includes polymers like polyacrylamide, polyacrylonitrile, and polyacrylates. When heated, poly(acrylic acid) form polymeric anhydrides, which undergo typical reactions of anhydrides, such as hydrolysis, alcoholysis, and amidation. 

One-carbon Homologation of Carboxylic Acids. l-[(Tri-methylsilyl)methyl]benzotriazole converts benzoyl chlorides to the corresponding (benzotriazol-l-yl)methyl aryl ketones in high yields (see eq 1). Treatment with triflic anhydride and 2,6-lutidine in CH2CI2 converts these ketones into their enolate triflates in 83-95% yields (eq 4). In the subsequent steps, the triflates are treated with sodium methoxide and then with ethanolic HCl to afford ethyl esters of the corresponding arylacetic acids in 89-98% yields (eq 5). The proposed reaction mechanism involves elimination of trifluoromethanesulfonic acid with sodium methoxide and final alcoholysis of the obtained l-(arylethynyl)benzotriazole intermediates with ethanolic HCl. A comparable classical method for one-carbon homologation of carboxylic acids, the Amdt-Eistert reaction, involves difficult to handle diazomethane and Q -diazoketones. ... 

Treatment of [2- C]malonic acid with acetone in the presence of acetic anhydride and catalytic amounts of concentrated sulfuric acids provides [5- C]Meldrum s acid (419). one of the most versatile low molecular weight building blocks . As summarized in Figure 6.124, its reactivity at C2 is analogous with that of the malonate diesters already discussed. However, the reactivity of the initial adducts differs. For example, hydrolysis or alcoholysis (including tert-BuOH) of the initial adducts with alkyl halides , aldehydes and acyl chlorides gives directly the [2- C]carboxylic acids/esters, a,/3-unsaturated acids/esters and /3-keto acids/esters, respectively, with simultaneous elimination of acetone and In contrast, the 2-(alkoxymethylene)[2- C]malonate... 

Esterification at room temp, with tetrachloroaluminic acid ether complex has been described The alcoholysis of a-mono-alkylacetoacetates to the corresponding esters and alkyl acetates has been accomplished with excellent yields A new modification of the Curtius degradation avoids the prepn. of acid chlorides by using in their place carboxylic alkoxyformic anhydrides intermediates well-known in peptide chemistry. Among recent developments in this latter field are the use of mixed anhydrides prepared with diphenylketene an improved peptide synthesis via azides prepared with nitrosyl chloride or butyl nitrite instead of aq. sodium nitrite and a rapid synthesis directly from acid hydrazides with N-bromosuccinimide Oligopeptides and /5-lactams have been synthesized from simple starting materials and isonitriles,... 

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