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7743790 
Journal Article 
The control of Novozym (R) 435 chemoselectivity and specificity by the solvents in acylation reactions of amino-alcohols 
Le Joubioux, F; Bridiau, N; Ben Henda, Y; Achour, O; Graber, M; Maugard, T 
2013 
Yes 
Journal of Molecular Catalysis B: Enzymatic
ISSN: 1381-1177 
Elsevier B.V. 
95 
99-110 
English 
WOS:000322612100014 
The current work describes the differential behaviour of Novozym® 435 (immobilized Candida antarctica lipase B) in O-acylation and N-acylation catalysis of bifunctional amino-alcohols acyl acceptors. We performed acylation experiments on three amino-alcohols (alaninol, 4-amino-1-pentanol and 6-amino- 1-hexanol) using myristic acid as an acyl donor. Two organic solvents (tert-amyl alcohol and n-hexane) and one ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate: Bmim [PF6]) were used to determine the effect of the solvent. The influence of the amino-alcohol carbon chain length between the alcohol and amino groups on chemoselectivity C (k cat,app O-acylation/kcat,app N-acylation) was highlighted. N-acylation is improved using alaninol, a short chain amino-alcohol (no mono-O-acylation in tert-amyl alcohol and C = 0.12 in n-hexane) whereas O-acylation is improved using 4-amino-1-pentanol and 6- amino-1-hexanol which are amino-alcohols with longer chain (C = 10.5 in tert-amyl alcohol and C = 539 in n-hexane). On the other hand, the production of the acylated amino-alcohols after 96 h of reaction was shown to be strongly affected by the solvent nature and the amino-alcohol structure: starting from alaninol as an acyl acceptor, the yield of amide synthesis reaches up to 98% in tert-amyl alcohol using 0.7 equivalents of myristic acid while the yield of amido-ester synthesis reaches up to 88% in Bmim [PF6] using 1.75 equivalents of myristic acid. © 2013 Elsevier B.V. 
N-Acylation; O-Acylation; Novozym (R) 435; Organic solvent; Ionic liquid; Chemoselectivity