ORGANIC
LETTERS
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005
Vol. 7, No. 14
097-3098
Lipase-Catalyzed Glucose Fatty Acid
Ester Synthesis in Ionic Liquids
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Franka Ganske and Uwe T. Bornscheuer*
Department of Technical Chemistry and Biotechnology, Institute of Chemistry and
Biochemistry, Greifswald UniVersity, Soldmannstr. 16, 17487 Greifswald, Germany
Received May 13, 2005
ABSTRACT
Glucose fatty acid ester synthesis with poly(ethylene glycol)-modified Candida antarctica lipase B (CAL-B) was performed in pure 1-butyl-3-
methyl imidazolium tetrafluoroborate [BMIM][BF ] (30% conversion) and in pure 1-butyl-3-methyl imidazolium hexafluorophosphate [BMIM]-
PF ] (35% conversion). In a solvent system composed of ionic liquid and 40% t-BuOH conversions up to 90% and isolated yields of up to 89%
were achieved using fatty acid vinyl esters as acyl donors and commercial CAL-B.
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[
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Sugar fatty acid esters are nonionic surfactants widely used
in the pharmaceutical, cosmetic, and food industry. A
synthesis directly from sugar and fatty acid is preferred, but
this is difficult to achieve because of the low solubility of
sugars in organic solvents. Only a few solvents (e.g.,
pyridine) are able to dissolve the highly polar sugar and the
Ionic liquids have no measurable vapor pressure and are
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able to dissolve compounds of varying polarity. In addition,
it was shown that lipase-catalyzed reactions can take place
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in ionic liquids. Kazlauskas and Park observed that lipase-
catalyzed acylation of glucose with vinyl acetate proceeded
with substantially higher regioselectively compared to con-
ventional solvents. Kim and co-workers described the
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nonpolar fatty acid. Major disadvantages are denaturation
of most lipases and incompatibility of the solvents for
products used in food applications. Alternatively, solubility
was increased by using protected sugars (e.g., isopropylidene,
selective enzymatic acylation of alkyl glycosides in ionic
liquids and noticed enhanced reactivity and regioselectivity.9
However, contradictory reports were published, in which the
same lipase was found active or inactive in ionic liquids,
making their straightforward application somehow unpredict-
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phenylboronic acid derivatives) or alkyl glycosides. How-
ever, either this requires extra protecting and deprotecting
steps or the products show different properties compared to
nonderivatized sugar fatty acid esters. Another method
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0
able.
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described by our group is based on a solid-phase system,
(4) (a) Cao, L.; Bornscheuer, U. T.; Schmid, R. D. Fett/Lipid 1996, 98,
32. (b) Cao, L.; Fischer, A.; Bornscheuer, U. T.; Schmid, R. D. Biocatal.
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which enabled up to quantitative sugar ester yields. However,
problems arise during up-scaling and reactions cannot be run
continuously.
Biotransform. 1997, 14, 269. (c) Cao, L.; Bornscheuer, U. T.; Schmid, R.
D. Biocatal. Biotransform. 1998, 16, 249. (d) Cao, L.; Bornscheuer, U. T.;
Schmid, R. D. J. Mol. Catal. B: Enzym. 1999, 6, 279. (e) Yan, Y.;
Bornscheuer, U. T.; Cao, L.; Schmid, R. D. Enzyme Microb. Technol. 1999,
25, 725.
(
(
1) Therisod, M.; Klibanov, A. M. J. Am. Chem. Soc. 1986, 108, 5638.
2) (a) Ikeda, I.; Klibanov, A. M. Biotechnol. Bioeng. 1993, 42, 788. (b)
(5) Seddon, K. R. Nat. Mater. 2003, 2, 363.
Fregapane, G.; Sarney, D. B.; Vulfson, E. N. Enzyme Microb. Technol.
991, 13, 796. (c) Scheckermann, C.; Schlotterbeck, A.; Schmidt, M.; Wary,
M. Enzyme Microb. Technol. 1995, 17, 157.
3) (a) Theil, F.; Schick, H. Synthesis 1991, 533. (b) Bj o¨ rkling, F.;
Godtfredsen, S. E.; Kirk, O. Trends Biotechnol. 1991, 9, 360. (c) Adelhorst,
K.; Bj o¨ rkling, F.; Godtfredsen, S. E.; Kirk, O. Synthesis 1990, 112.
(6) Cull, S. G.; Holbrey, J. D.; Vargas-Mora, V.; Seddon, K. R.; Lye,
G. J. Biotechnol. Bioeng. 2000, 69, 227.
(7) (a) Kragl, U.; Eckstein, M.; Kraftzik, N. Curr. Opin. Biotechnol. 2002,
13, 565. (b) Van Rantwijk, F.; Madeira Lau, R.; Sheldon, R. A. Trends
Biotechnol. 2003, 21, 131.
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(
(8) Park, S.; Kazlauskas, R. J. J. Org. Chem. 2001, 66, 8395.
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0.1021/ol0511169 CCC: $30.25
© 2005 American Chemical Society
Published on Web 06/14/2005