C. Crestini et al. / Bioorg. Med. Chem. 14 (2006) 5292–5302
5301
dehyde 7, 3,4-dimethoxybenzoic acid 8, and methyl
(2Z)-3-(5-oxo-2,5-dihydrofuran-3-yl)acrylate were
4.10. Oxidation of lignin. General procedure
9
recovered in appreciable amount after flash chromato-
graphy of the respective crude and characterized by
1H NMR and 13C NMR analyses.
Oxidations of hydrolytic sugar cane lignin (SCL) and
red spruce kraft lignin (RSL) were carried out in acetic
acid (5 mL), in the presence of 100 mg of lignin,
1.0 mg MTO (1.0% w/w of the active species), and
500 lL H2O2 (35% water solution). After 24 h, the reac-
tion mixtures were evaporated, washed with water,
centrifuged, and freeze-dried.
(2E)-3-(4-Ethoxy-3-methoxyphenyl)acrylaldehyde 17,
2-[2-hydroxy-5-(hydroxymethyl)-3-methoxybenzyl]-6-
methoxy-4-methylphenol
20,
2,20-methylenebis[4-
(hydroxymethyl)-6-methoxyphenol] 21, 4-hydroxy-3-
[2-hydroxy-5-(hydroxymethyl)-3-methoxybenzyl]-
5-methoxybenzaldehyde 22, 2-hydroxy-5-(hydroxy-
methyl)-3-methoxybenzoic acid 23, (2-hydroxy-3-meth-
oxy-5-methylphenyl)acetic acid 24, [2-hydroxy-5-
(hydroxymethyl)-3-methoxyphenyl]acetic acid 25, 4-
(hydroxymethyl)-2-[5-(hydroxymethyl)-2,3-dimethoxy-
References and notes
1. Kuwahara, M.; Shimada, M. In Biotechnology in the Pulp
and Paper Industry; Kuwahara, M., Shimada, M., Eds.;
Unipublishers: Tokyo, 1992.
2. Gierer, J. Holzforshung 1997, 51, 34.
benzyl]-6-methoxyphenol
31,
3-(2,3-dimethoxy-5-
3. Adam, W.; Herrmann, W. A.; Lin, J.; Saha-Mo¨ller, C. R.;
Fischer, R. W.; Correia, J. D. G. Angew. Chem., Int. Ed.
Engl. 1994, 33, 2475.
methylbenzyl)-4-hydroxy-5-methoxybenzaldehyde 32,
and (2,3-dimethoxy-5-methylphenyl)acetic acid 33
were identified on the basis of the fragmentation
spectra and comparison with literature data. The
fragmentation patterns are shown in Table 7. Select-
ed data for compounds 3, 4, 7, 8, and 9:
4. (a) Herrmann, W. A.; Fischer, R. W.; Marz, D. W. Angew.
Chem., Int. Ed. Engl. 1991, 30, 1638–1641; (b) Herrmann,
W. A.; Fischer, R. W.; Rauch, M. U.; Scherer, W. J. Mol.
Catal. 1994, 86, 243–266; (c) Saladino, R.; Neri, V.;
Pelliccia, A. R.; Mincione, E. Tetrahedron 2003, 59, 7403–
7408; For a recent review see (d) Owens, G. S.; Aries, J.;
Abu-Omar, M. M. Catal. Today 2000, 55, 317–363.
5. Zhu, Z.; Espenson, J. H. J. Org. Chem. 1995, 60, 7728–7732.
6. Adam, W.; Herrmann, W. A.; Saha-Mo¨ller, C. R.;
Shimizu, M. J. Mol. Catal. A: Chem. 1995, 97, 15–20.
7. Abu-Omar, M. M.; Espenson, J. H. J. Am. Chem. Soc.
1995, 117, 272–280.
4.5. 4-Hydroxy-3-methoxybenzoic acid (3)
dH (CDCl3 + DMSO-d6): 7.50 (2H, m, PhH), 6.80
(1H, m, PhH), 3.80 (3H, s, OCH3). dC (CDCl3):
166.6 (CO), 150.4 (C), 146.5 (C), 123.9 (CH), 121.3
(C), 114.3 (CH), 111.7 (CH), 51.7 (CH3); m/z (EI)
168 (M+).
8. (a) Herrmann, W. A.; Fischer, R. W.; Correira, J. D. G. J.
Mol. Catal. 1994, 94, 213–223; (b) Bernini, R.; Mincione,
E.; Cortese, M.; Aliotta, G.; Saladino, R. Tetrahedron
Lett. 2001, 42, 5401–5404.
4.6. (2Z)-3-(5-Oxo-2,5-dihydrofuran-3-yl)acrylic acid (4)
9. (a) Murray, R. W.; Iyanar, K.; Chen, J.; Wearing, J. T.
Tetrahedron Lett. 1995, 36, 6415–6418; (b) Schuchardt, U.;
Mandelli, D.; Shul’pin, G. B. Tetrahedron Lett. 1996, 37,
6487–6490.
10. Adam, W.; Hermann, W. A.; Lin, J.; Saha-Moller, C. R.
J. Org. Chem. 1994, 59, 8281.
Characterized as methyl ester. dH (CDCl3): 6.75 (dd, 1H,
J = 12.4 Hz, J = 2 Hz, CH), 6.30 (m, 1H, HCO), 6.12 (d,
1H, J = 12.4 Hz, CH), 5.25 (m, 2H, CH2OOC), 3.78 (s,
3H, CH3COO) m/z (EI) 168 (M+).
4.7. 3,4-Dimethoxybenzaldehyde (7)
11. Crestini, C.; Pro, P.; Neri, V.; Saladino, R. Bioorg. Med.
Chem. 2005, 13, 2569–2578.
dH (CDCl3): 9.86 (1H, s, CHO), 6.90–7.42 (3H, m,
PhH), 3.86 (3H, s, OCH3), 3.82 (3H, s, OCH3). dC
(CDCl3): 190.4 (CO), 134.3 (C), 149.1 (C), 129.7 (C),
126.5 (CH), 110.4 (CH), 108.4 (CH), 55.7 (CH3), 55.5
(CH3); m/z (EI) 166 (M+).
12. Saladino, R.; Neri, V.; Pelliccia, A. R.; Caminiti, R.;
Sadun, C. J. Org. Chem. 2002, 67, 1323–1332.
13. Herrmann, W. A.; Fritz-Meyer-Weg, D. M.; Wagner, M.;
Kuchler, J. G.; Weichselbaumer, G.; Fischer, R. US
¨
Patent 5, 155, 247, 1992.
14. Donbrow, M. Microcapsules and Nanoparticles in Medi-
cine and Pharmacy; CRC: Boca Raton, 1992.
4.8. 3,4-Dimethoxybenzoic acid (8)
15. (a) Takaaki, S.; Chyongjin, P. Kawamura Rikagaku
Kenkyusho Hokoku 2000, 59–64; (b) Wang, T.-J.;
Li, D.-C.; Bai, J.-H.; Huang, M.-Y.; Jiang, Y.-Y. J.
Macromol. Sci., Pure Appl. Chem. 1998, A35, 531–538.
16. Adam, W.; Saha-Mo¨ller, C. R.; Weichold, O. J. Org.
Chem. 2000, 65, 2897–2899.
dH (CDCl3 + DMSO-d6): 7.60–6.80 (3H, m, PhH),
3.80 (3H, s, OCH3), 3.78 (3H, s, OCH3). dC
(CDCl3 + DMSO-d6): 167.1 (CO), 151.7 (C), 147.8
(C), 124.5 (CH), 111.7 (CH), 110.4 (CH), 111.7
(CH), 54.3 (CH3), 54.1 (CH3); m/z (EI) 182 (M+).
17. Bouh, A. B.; Espenson, J. H. J. Mol. Catal. A: Chem.
2003, 206, 37–51.
18. (a) Adam, W.; Hermann, W. A.; Saha-Moller, C. R.;
Shimizu, M. J. Mol. Catal. 1995, 97, 15–20; (b) Adam, W.;
Shimizu, M. Synthesis 1994, 560–562; (c) Adam, W.;
Ganeshpure, P. A. Synthesis 1993, 280–282.
19. (a) Saladino, R.; Neri, V.; Mincione, E.; Filippone, P.
Tetrahedron 2002, 58, 8493–8500; (b) Saladino, R.;
Mincione, E.; Attanasi, O. A.; Filippone, P. Pure Appl.
Chem. 2003, 75, 261–268.
4.9. Methyl (2Z)-3-(5-oxo-2,5-dihydrofuran-3-yl)acrylate
(9)
dH (CDCl3): 6.75 (dd, 1H, J = 12.4 Hz, J = 2 Hz, CH),
6.30 (m, 1H, HCO), 6.12 (d, 1H, J = 12.4 Hz, CH),
5.25 (m, 2H, CH2OOC), 3.78 (s, 3H, CH3COO) m/z
(EI) 168 (M+).