Carboxylic acids, functional derivatives reaction with water

Acidity of Amides, Imides, and Sulfonamides Characteristic Reactions Reaction with Water Hydrolysis Reaction with Alcohols Reactions with Ammonia and Amines Reaction of Acid Chiorides with Salts of Carboxylic Acids Interconversion of Functional Derivatives Reactions with Organometallic Compounds 18.10 Reduction... 

Another useful and important type of condensation reaction is that between a carboxylic acid and a primary amine, which is an organic compound containing an —NHg functional group. Amines can be considered derivatives of ammonia (NH ), and most of them are weak bases, similar in strength to ammonia. An amine reacts with a carboxylic acid to split out a water molecule and form an amide, for example. 

In Section 13.6, it was suggested that the mechanism for the Fischer esterification of carboxylic acids would be a model for many of the reactions of the functional derivatives of carboxylic acids. One such reaction, the reaction of an acid halide with water, is the following ... 

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. 

Kamochi and Kudo have reported the use of the Sml2/THF-H20 system to reduce aromatic carboxylic acids to alcohols (Scheme 50). Furthermore, aromatic esters amides and nitriles were similarly reduced by this system in good yield [104]. As indicated above, reduction of carboxylic acids to primary alcohols is also effective with Sml2 in a THF-H20-NaOH mixture [105]. In contrast, without water these substrates remain unchanged. With the Sml2/THF-H20 system, pyridine was rapidly reduced to piperidine in similar reactions with pyridine derivatives bearing chloro, amino and cyano substituents, these functionalities were partly eliminated to afford pyridine or piperidine [107]. 

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