Aminolysis and Ammonolysis of Esters

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

The strategy described here explains the different possibilities of enzymatic ammonolysis and aminolysis reaction for resolution of esters or preparation of enantiomerically pure amides, which are important synthons in organic chemistry. This methodology has been also applied for the synthesis of pyrrolidinol derivatives that can be prepared via enzymatic ammonolysis of a polyfunctional ester, such as ethyl ( )-4-chloro-3-hydroxybutanoate [30]. In addition, it is possible in the resolution of chiral axe instead of a stereogenic carbon atom. An interesting enzymatic aminolysis of this class of reaction has been recently reported by Aoyagi et al. [31[. The side chain of binaphthyl moiety plays an important role in the enantiodis-crimination of the process (Scheme 7.14). 

Noting the fairly pronounced reactivity of phenyl esters in aminolysis Bodanszky concluded [21] that the enhanced aminolysis rates observed with thiophenyl esters [4] are due only in part to their thiol ester character and perhaps to a major extent to the fact that they are aryl esters. This conclusion was based on the fundamental studies of Gordon, Miller and Day [22] who found extremely high rates in the ammonolysis of phenyl and vinyl esters. To further increase the electronic effect operative in phenyl esters, their nitro-derivatives were prepared and examined. For practical application p-nitrophenyl esters were... 

FVom the point of view of the application of ester, amide, and urethane polymers, hydrolysis, alcoholysis/glycolysis and ammonolysis/aminolysis reactions are the most important. These processes are often used for recycling to feedstocks and offer raw materials, mainly for virgin polymer/resin syntheses. The schemes of the respective reactions with brief comments on the practical importance of the particular processes are presented in Figures 2 to 4. A description of the important solvolytic degradation processes for ester, amide, and urethane polymers is also given in this chapter. 

Theoretical studies of the ester enolate-imine reaction <98MI1826>, the effects of solvation on barriers of reaction <99JPC8628>, interactions of P-lactams in aqueous solution <99MI1401> and their ammonolysis and aminolysis <99JOC3281,99MI1045> are available. 

Classical reactions involving nucleophiles such as saponification ("OH as the nucleophile), aminolysis (with amines also ammonia in ammonolysis reactions), transesterification (alkoxides, "OR) and others (hydrazinolysis, hydroxamic acid synthesis, etc.) have been adapted to solid phane and used to obtain, for instance, carboxylic acids, amides and esters. Internal or intramolecular nucleophilic attack has been employed to obtain cyclic products such as lactones, lactams (including cyclic peptides) and a great variety of heterocycles (hydantoins, diketopiperazines, benzodiazepinones, etc.). 

Figure 1. (a) Ammonolysis/aminolysis of resin-bound esters, (b) Synthesis of peptidyl amides and peptidyl Aralkyl amides using amine-based linkers. 

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