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Titre du document / Document title

Amide and lactam hydrolysis of N-(2 -hydroxyacetyl )-2-pyrrolidone : effective catalysis

Auteur(s) / Author(s)

GARCIA BORBOA Lisaedy ; NUNEZ Oswaldo ;

Résumé / Abstract

When N-(2-hydroxyacetyl)-2-pyrrolidone (open form) is dissolved in water at pH > 8, irreversible cleavage of the exocyclic and endocyclic amide C-N bond occurs. The latter rupture corresponds to the lactam opening yielding N-(4-hydroxyacetyl)butanoic acid (NBA). NBA is produced from the ester hydrolysis of the ester-amide macrocycle that is in equilibrium with the cyclol form of the open form. We have previously reported this latter equilibrium for N-(2-aminoacetyl)-2-lactams. 2-pyrrolidone (lactam) and glycolic acid are produced from direct hydrolysis of the open form by means of the amide exocyclic cleavage. The [NBA]/[lactam] ratio increases at higher pH since the NBA production is second order with respect to [OH-] while the corresponding lactam formation is only first order. The obtained kobs is hence the sum of the rate constants that yield lactam and NBA, respectively. This kobs is uncatalyzed and specific base catalyzed with unusually high rate constants of 2.1 × 10-6s-1 and 0.025 M-1 s-1, respectively. The stability of the corresponding tetrahedral intermediate formed and the intramolecular alkoxy nucleophilic attack on the lactam carbonyl group combined with an effective protonation of the lactam nitrogen that promotes the C-N cleavage, contribute to increase the reaction rates and lactam opening. Rate constants for the two parallel reactions are obtained from kobs and [NBA]/[lactam] versus pH plots.

Revue / Journal Title

Journal of physical organic chemistry    ISSN  0894-3230   CODEN JPOCEE 

Source / Source

2006, vol. 19, no11, pp. 737-743 [7 page(s) (article)]

Langue / Language

Anglais

Editeur / Publisher

Wiley, Chichester, ROYAUME-UNI  (1988) (Revue)

Mots-clés d'auteur / Author Keywords

hydrolysis

;

catalysis

;

lactam

;

amide

;

stable tetrahedral intermediate

;

cyclol

;

macrocycle

;

open form

;

Localisation / Location

INIST-CNRS, Cote INIST : 21887, 35400014547823.0060

Nº notice refdoc (ud4) : 18504180



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