Ammonolysis of esters

The reaction mechanism is very much like that of saponification. The unshared electron pair on the ammonia nitrogen initiates nucleophilic attack on the ester carbonyl group. 

PROBLEM 10.20 The first step in eq. 10.26 really involves two reactions, addition of ammonia to the carbonyl carbon to form an ammonium alkox-ide followed by a proton transfer from the nitrogen to the alkoxide oxygen. Illustrate this process with equations using the arrow-pushing formalism. The second step in eq. 10.26 also involves two steps, elimination of an alkoxide (R O ) followed by deprotonation of the hydroxyl group. Write a detailed mechanism for these steps. 

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Effect of somme soults on the hydrolysis and ammonolysis of ester groups express Rh nnd Ra... 

Ammonolysis. Reactions involving ammonia. Ammonolysis of esters, acyl chlorides, and anhydrides give amides aniline is produced by ammonolysis of chlorobenzene. The reaction is analogous to hydrolysis, with ammonia substituted for water. 

A further example of the preparation of amides by the ammonolysis of esters (cf. succinamide, Expt 5.155) is provided by the preparation of nicotinamide described in Expt 6.169 as a stage in the synthesis of 3-cyanopyridine. 

Saponification is the base-mediated hydrolysis of an ester, yielding its component carboxylate salt and alcohol. Ammonolysis of esters gives amides. Esters react with Grignard reagents to give tertiary alcohols. With lithium aluminum hydride, on the other hand, they are reduced to primary alcohols. 

I) Ammonolysis of Esters. (1) To 5 ml of saturated solution of ammonia in methanol add 2 ml of ethyl acetate. Cork, and allow to stand until the next laboratory period. Place the contents of the tube in an evaporating dish and evaporate the alcohol over a water bath. Determine the weight of the amide. 

Introduction. The general methods for the preparation of amides are (1) ammonolysis of esters, acyl halides, and anhydrides (2) the dehydration of the ammonium salts of carboxylic acids ... 

Studies of the kinetics of the reaction have been concerned principally with the liquid-phase ammonolysis of esters and aromatic chloro compounds, presumably because the reactions are more cleancut and there is less tendency to form by-products. For example, in the ammonolysis of esters, the amide is essentially the only product, whereas with the reaction of aliphatic alcohols and ammonia an equilibrium mixture of mono-, di-, and trialkylainines is obtained. 

M. Gordon, J.G. Miller, A.R. Day, Effect of structure on reactivity in ammonolysis of esters with special references to electron release effects of alkyl and aryl groups. J. Amer. Chem. Soc. 70 1946-1953 (1948)... 

Some new work in very classical procedures is also reported such as the ion-exchange catalyzed hydration of nicotinonitrile, the ammonolysis of esters of nicotinic acid, as well as of the free acid. ... 

As we have seen, most reactions of carboxylic acids, esters, and related compounds involve, as the first step, nucleophilic attack on the carbonyl carbon atom. Examples are Fischer esterification, saponification and ammonolysis of esters, and the first stage of the reaction of esters with Grignard reagents or lithium aluminum hydride. All of these reactions can be summarized by a single mechanistic equation ... 

The reaction is much more rapid than the ammonolysis of esters. Two equivalents of ammonia are required, however—one to form the amide and one to neutralize the hydrogen chloride. 

Yong KW, Cannon JG, Rose JG (1970) N-butyUithium in aminolysis and ammonolysis of esters. Tetrahedron Lett 11(21) 1791-1794... 

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