Chemo-selectivity of the N,O-enzymatic acylation in organic media and in ionic liquids

E. Husson (1) , C. Humeau (2) , Fabian Blanchard (1) , X. Framboisier (1) , I. Marc (1) , I. Chevalot (1)

1 LSGC - Laboratoire des Sciences du Génie Chimique
2 ENSAIA - Ecole Nationale Supérieure d'Agronomie et des Industries Alimentaires

The chemo-selectivity and the efficiency of the enzymatic acylation of 6-amino-1-hexanol have been studied in organic solvents distinct by their nature and their dissociation power, in solvent-free systems corresponding to free fatty acid or ethyl ester media and in different ionic liquids. In organic solvents and fatty acid ester media, a sequential reaction allowed the major production of the diacylated derivative at the equilibrium state. Conversely, the use of a solvent-free system with free fatty acid orientated the reaction exclusively towards the O-acylation by modifying the ionization state of the amino group and decreased the reaction time to reach the equilibrium state. Ionic liquids as 1-butyl-3-methyl imidazolium cation coupled with anions of low nucleophilicity significantly improved the efficiency of the reaction (substrate conversion and initial rate) and also led to the N,O-diacyl product. The nature of the reaction medium was shown to influence the ionization state of functional groups, then their capacity to react, and finally, the efficiency of the reaction.

Mots clés: Chemo-selectivity; Acylation; Lipase; Ionic liquid Ion-pair complex

Domaines: Génie des procédés

E. Husson, C. Humeau, Fabian Blanchard, X. Framboisier, I. Marc, et al.. Chemo-selectivity of the N,O-enzymatic acylation in organic media and in ionic liquids. Journal of Molecular Catalysis B: Enzymatic, 2008, 55 (3-4), pp.110-117. ⟨10.1016/j.molcatb.2008.02.004⟩. ⟨hal-00379725⟩