2344
J . Org. Chem. 2000, 65, 2344-2349
Cop p er (II)-Ca ta lyzed Rea ction s of Activa ted Ar om a tics
A. Puzari and J ubaraj B. Baruah*
Department of Chemistry, Indian Institute of Technology, Guwahati 781 001 India
Received September 27, 1999
The catalytic reaction of cis-bisglycinato copper(II) monohydrate in the presence of hydrogen peroxide
leads to hydroxylation of phenol to give catechol and hydroquinone (1:1.2 ratio) in good yield. 2,6-
Dimethylphenol can be hydroxylated by hydrogen peroxide and a catalytic amount of cis-bisglycinato
copper(II) monohydrate to give an aggregate of 1,4-dihydroxy-2,6-dimethylbenzene and 2,6-
dimethylphenol. A similar reaction of o-cresol gives 2,5-dihydroxytoluene. The reactivity of cis-
bisglycinato copper(II) monohydrate in hydrogen peroxide with o-cresol is 4.5 times faster than
that of a similar reaction by trans-bisglycinato copper(II) monohydrate. A catalytic reaction of cis-
bisglycinato copper(II) monohydrate with aniline in aqueous hydrogen peroxide gives polyanilines
in the form of pernigraniline with different amounts of Cu(OH)2 attached to them. The two major
components of polyanilines obtained have Mn values of 1040 and 1500, respectively. Resistance of
films of these polyanilines increases with temperatures from 40 °C to a maximum value at 103 °C
and then decreases in the region of 103-150 °C, showing the property of a thermoelectric switch.
The aggregate prepared from hydroxylation of 2,6-dimethylphenol shows a similar property in the
region of 30-180 °C.
In tr od u ction
thesis of polyphenols. Recently, success has been made
in mimicking galactose oxidase by radical-containing
copper(II) phenoxo complexes.7 Copper(I) catalyst to-
gether with nitrogen bases in the presence of oxygen
gives linear polymer of 2,6-dimethylphenol having an
ether-type of linkage.8 Oxidation of copper(I) phenoxides
passes through hydroxylation.9 In stoichiometric reac-
tions copper(II) complexes can effectively cause selective
hydroxylation on aromatic rings.10 In contrast to these,
the anilinic compounds easily oligomerize under oxidative
conditions by transition metal catalysts to give poly-
anilines.11 These oxidative oligomerizations are usually
performed with the anilinium salts.11d,e There are differ-
ent types of polyanilines such as leucoemeraldine, emer-
aldine, and pernigraniline, depending on the extent of
oxidation of the chain.12 Thus, the properties of the
polyanilines are dependent on the method of preparation.
From the foregoing discussion it is clear that there is a
need to develop biorelated mild, catalytic, efficient meth-
ods for the oxidative transformation of aromatic com-
Aromatic hydroxylation finds important place in bio-
logical chemistry.1 Such a hydroxylation process can be
achieved by transition metal complexes.2 Preparation of
model compounds for selective catalytic hydroxylation
constitutes the backbone of this research.3 Biochemical
processes such as tyrosinase4a activity and biosynthesis
of lignin1 involve copper(II)-catalyzed aromatic hydroxy-
lation. The cleavage of DNA by copper(II) complexes
having phenolic groups as a part of the ligand is well
established.4b Oxidative polymerization5 and biochemi-
cal methods6 are commonly used methods for the syn-
* To whom correspondence should be addressed. e-mail: juba@
iitg.ernet.in.
(1) (a) Bioinorganic Catalysis; Reedjik, J ., Ed.; Mercel Dekker: New
York, 1993. (b) Magnus, K. A.; Ton-That, H.; Carpenter, J . E. Chem.
Rev. 1994, 94, 727. (c) Solomon, E. I.; Sundaran, V. M.; Machonkin, T.
E. Chem. Rev. 1996, 96, 2563. (d) Margernum, D. W.; Scheper, W. M.;
McDonald, M. R.; Frederick, F. C.; Wang, L.; Lee, H. D. In Bioorganic
chemistry of copper; Karlin, K. D., Tyeklar, Z., Eds.; Chapman and
Hall: New York, 1993; p 213. (e) Margerum, D. W. In Oxidase and
related redox systems; King, T. E., Mason, H. S., Morrison, M., Eds.;
Pergamon Press: Oxford, 1982; p193. (f) Ito, N.; Phillips, S. E. V.;
Stevens, L.; Ogel, Z. B.; Knowles, P. F. Nature 1991, 350, 87. (g)
Sokolowski, A.; Muller, J .; Weyhermuller, T.; Schept, R.; Hildebrandt,
P.; Hildenbrand, K.; Brothe, E.; Weigenhardt, K. J . Am. Chem. Soc.
1997, 119, 8889. (h) Baesjou, P. J .; Driessen, W. L.; Challa, G.; Reedijk,
J . J . Am. Chem. Soc. 1997, 119, 12590. (i) Steinhagen, H.; Helmchen,
G. Angew. Chem., Int Ed. 1998, 35, 2339.
(7) (a) Wang, Y.; Dubois, J . L.; Heman, B.; Hodgson, K. O.; Stack,
T. P. D. Science 1998, 279, 537. (b) Chaudhuri, P.; Hess, M.; Florke,
U.; Wieghardt, K. Angew. Chem., Int. Ed. 1998, 37, 2217. (c) Kruger,
H.-J . Angew. Chem., Int. Ed. 1999, 38, 1433.
(8) (a) Hay, A. S.; Balchand, H. S.; Endrer, G. F.; Eustance, J . E. J .
Am. Chem. Soc. 1959, 81, 6335. (b) Schoten, A. J .; Noordergraaf, D.;
J ekel, A. P.; Challa, G. J . Mol. Catal. 1979, 5, 5331.
(2) (a) Metal Catalysed Oxidation of Organic Compounds; Sheldon,
R. A., Kochi, J . K., Eds.; Academic Press: New York, 1981. (b) Conte,
V.; Furia, F. D.; Modena, G. In Organic peroxides; Ando, W., Ed.;
Wiley: New York, 1992. (c) Funabashi, T.; Yokomizo, T.; Suzuki, S.;
Yoshida, S. J . Chem. Soc., Chem. Commun. 1997, 151. (d) Strukul, G.
La Chemica & L’Industria 1990, 72, 421.
(3) (a) Tyklar, Z.; Karlin, K. D. Acc. Chem. Res. 1989, 22, 241. (b)
Steinhagen, H.; Helmchen, G. Angew. Chem., Int. Ed. Engl. 1996, 35,
2339.
(4) (a) Pidcock, E.; Debeer, S.; Obias, H. V.; Hedman, B.; Hodgson,
K. O.; Karlin, K. D.; Solomon, E. I. J . Am. Chem. Soc. 1999, 121, 1870.
(b) Lamour, E.; Routier, S.; Bernier, J .-L.; Catteau, J .-P.; Bailly, C.;
Vezin, H. J . Am. Chem. Soc. 1999, 121, 1862.
(5) Yamamoto, K.; Nishida, H.; Tscusida, E. J . Chem. Soc. J pn. 1986,
152.
(9) Karlin, K. D.; Gultneh, Y. Progress in inorganic chemistry;
Lippard, S. J ., Ed.; J ohn Wiley: New York, 1987; Vol. 35, p 219.
(10) (a) Reinaud, O.; Capdevielle, P.; Maumy, M. J . Chem. Soc.,
Chem. Commun. 1990, 566. (b) Capdivielle, P.; Sparfel, D.; Lafort, J .
B.; Cuong, N. K.; Maumy, M. J . Chem. Soc., Chem. Commun. 1990,
565.
(11) (a) MacDiarmid, A. G.; Chian, J . C.; Halporn, M.; Huang, W.
S.; Mu, S. L.; Somasiri, N. L.; Wu, W.; Yaniger, S. I. Mol. Cryst. Liq.
Cryst. 1985, 121, 173. (b) Kim, S.-B.; Harada, K.; Yamamoto, T.
Macromolecules 1998, 31, 988. (c) Trivedi, D. C. Bull. Mater. Sci. 1999,
22, 447. (d) Moon, D. K.; Osakada, K.; Maruyama, T.; Kubota, K.;
Yamamoto, T. Macromolecules 1993, 26, 6992. (e) Moon, D. K.;
Osakada, K.; Maruyama, T.; Yamamoto, T. Makromol. Chem. 1992,
192, 1723.
(12) Pethrick, R. A. In Desk reference of functional polymers:
synthesis and application; Arshahy, R., Ed.; American Chemical
Society: Washington D. C., 1996; Ch. 3.4, pp 463-487.
(6) Tsuchida, E.; Yamamoto, K. In Bioinorganic catalysis; Reedjik,
J ., Ed.; Mercel Dekker: New York, 1993; pp 29-87.
10.1021/jo991509j CCC: $19.00 © 2000 American Chemical Society
Published on Web 03/22/2000