LETTER
Oxidation of Veratryl Alcohol with H O in Ionic Liquid
413
2
2
Table 2 Oxidation of Veratryl Alcohol with H O Catalyzed by Cl TPPFe(III) or HRP in Recycled Ionic Liquid [bmim][PF ]
2
2
8
6
Run
1
2
3
4
5
Yielda
2
3
2
3
2
3
2
3
8
7
2
3
7
5
1
-Cl TPPFe(III)-NMI
83
73
12
9
80
74
13
6
81
71
10
5
74
71
70
69
8
1-HRP
a
Based on HPLC analysis.
generated in the rate-determining step for cytochrome-c,
(5) (a) Labat, G.; Seris, J. L.; Meunier, B. Angew. Chem., Int.
Ed. Engl. 1990, 29, 1488. (b) Robert, A.; Meunier, B. New
J. Chem. 1988, 12, 885. (c) Higuchi, T.; Satake, C.; Hirobe,
M. J. Am. Chem. Soc. 1995, 117, 8879.
microperoxidase-11 and hemin has also been reported.15
The yields of oxidized products with HRP in ionic liquid
were comparable with those in aqueous solution but the
stability of HRP was higher in ionic liquids and it showed
good activity up to five cycles for the oxidation of 1
whereas it gets destroyed after second cycle in aqueous
solution. Similarly, water-soluble iron(III) porphyrin
(
6) Wood, J. M.; Folsom, B. R.; Eudy, E. W. In Proceedings of
the 3rd International Conference on Biotechnology in the
Pulp and Paper Industry, Stockholm, June 16–19, 1986.
(7) Turk, H.; Ford, W. T. J. Org. Chem. 1991, 56, 1253.
(8) (a) Labat, G.; Meunier, B. C. R. Acad. Sci. Paris 1990, 311,
625. (b) Crestini, C.; Saladino, R.; Tagliatesta, P.; Boschi, T.
[
Cl TPPS Fe(III)] was also recycled after extraction of
8 4
Bioorg. Med. Chem. 1999, 7, 1897.
the product from first cycle and it retained good catalytic
activity up to five consecutive cycles. The recycle experi-
(
9) Klibanov, A. M. Nature (London) 2001, 409, 241.
(
10) Klibanov, A. M. Trends Biotechnol. 1997, 15, 97.
ment for iron(III) porphyrin [Cl TPPS Fe(III)] and HRP
8
4
(11) (a) Jain, N.; Kumar, A.; Chauhan, S.; Chauhan, S. M. S.
Tetrahedron 2005, 61, 1015. (b) Dupont, J.; de Souza, R. F.;
Suarez, P. A. Z. Chem. Rev. 2002, 102, 3667.
in ionic liquids were studied by adding 1 and H O to ionic
2
2
liquid containing the catalyst or enzyme. The recycle ex-
periment showed that Cl TPPS Fe(III) and HRP can be
(
12) Kragl, U.; Eckstein, M.; Kaftzik, N. Curr. Opin. Biotechnol.
002, 13, 565.
8
4
2
reused with appreciable activity up to five cycles
(
13) Van Rantwijk, F.; Lau, R. M.; Sheddon, R. A. Trends
Biotechnol. 2003, 21, 131.
(
Table 2).
In conclusion, the water-soluble iron(III) porphyrins and
HRP demonstrated substantial ligninase activity in ionic
liquid. The activity of water-soluble iron(III) porphyrins
was significantly higher in ionic liquid than in aqueous
solution, which reflects the non-coordinating nature and
weak nucleophilicities of ionic liquids as compared to
water. Further, stability of HRP increased in ionic liquids
and it can be recycled. Thus, ionic liquids may be the
suitable media for the reactions catalyzed by HRP and
water-soluble iron(III) porphyrins. Oxidation of veratryl
alcohol with these catalysts immobilized in ionic liquids
can provide sufficient insight in the fundamental chemis-
try of lignin.
(14) Okrasa, K.; Guibe-Jampel, E.; Therisod, M. Tetrahedron:
Asymmetry 2003, 14, 2487.
(
(
(
15) Compton, D. L.; Laszlo, J. L.; Joseph, A. J. Electroanal.
Chem. 2002, 520, 71.
16) Srinivas, K. A.; Kumar, A.; Chuahan, S. M. S. Chem.
Commun. 2002, 2456.
17) Chauhan, S. M. S.; Kumar, A.; Srinivas, K. A. Chem.
Commun. 2003, 2348.
(18) Jain, N.; Kumar, A.; Chauhan, S. M. S. Tetrahedron Lett.
005, 46, 2599.
19) Gelpke, M. D. S.; Lee, J.; Gold, M. H. Biochemistry 2002,
1, 3498.
2
(
(
4
20) Costanzo, L. D.; Geremia, S.; Randaccio, L.; Purrello, R.;
Lauceri, R.; Sciotto, D.; Gulino, F. G.; Pavone, V. Angew.
Chem. Int. Ed. 2001, 40, 4245.
(
(
21) Li, Z.; Xia, C.-G. Tetrahedron Lett. 2003, 44, 2069.
22) Representative Procedure for Oxidation of Veratryl
Alcohol (1) with H O Catalyzed by Iron(III) Porphyrins
Acknowledgment
2
2
in Ionic Liquid: H O (30%; 113 mL, 100 mmol) was added
with stirring at r.t to a solution of water-soluble iron(III)
porphyrin (1 mmol, 10%) and veratryl alcohol (100 mmol)
The authors are grateful to Department of Biotechnology (DBT),
New Delhi, India, and Birla Institute of Technology and Science,
Pilani for financial assistance.
2
2
in the ionic liquid [bmim][PF ] (2.0 mL). The 20-mL aliquots
6
were taken at 30 min interval and analyzed by HPLC
analysis at 280 nm. After completion of the reaction the
References and Notes
reaction mixture was extracted with Et O and the ionic liquid
2
(
1) Part of the work was presented at: Modern Trends in
Inorganic Chemistry-X (MTIC-X), Bombay, India,
December, 2003.
containing iron(III) porphyrin was recovered. The Et O
2
layer was dried over anhyd Na SO and evaporated under
2
4
reduced pressure. The residue was column chromatographed
(
(
(
2) Chattopadhyay, K.; Mozumdar, S. Biochemistry 2000, 39,
1
over silica gel and the products were identified by H NMR,
263.
IR and MS spectral data.
3) Chauhan, S. M. S.; Mohapatra, P. P.; Kalra, B.; Kohli, T. S.;
Satapathy, S. J. Mol. Catal. A: Chem 1996, 113, 239.
4) Chauhan, S. M. S.; Sahoo, B. B. Bioorg. Med. Chem. 1999,
Representative Procedure for Oxidation of Veratryl
Alcohol (1) with H O Catalyzed by HRP in Ionic Liquid:
2
2
Veratryl alcohol (100 mmol) was dissolved in the ionic
7, 2629.
liquid [bmim][PF ] (2.0 mL) in a 5-mL round-bottomed
6
flask fitted with a magnetic stirrer. HRP [100 mL, 1.0 mg
Synlett 2007, No. 3, 411–414 © Thieme Stuttgart · New York