Sodium hypochlorite/Dowex 1X8-200: An effective oxidant for the oxidation of aromatic amines to quinones

Article abstract of DOI:10.1039/a905598c

Polymer supported hypochlorite ion is a useful oxidant for the oxidation of aromatic amines to the corresponding quinones.

Full text of DOI:10.1039/a905598c

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672 J. CHEM. RESEARCH (S), 1999
J. Chem. Research (S),
1999, 672^673y
Sodium Hypochlorite/Dowex 1X8-200: an
Effective Oxidant for the Oxidation of Aromatic
Amines to Quinones
Mohammed M. Hashemi* and Yousef A. Beni
Department of Chemistry, Sharif University of Technology, P. O. BOX 11365-9516 Tehran, Iran
Polymer supported hypochlorite ion is a useful oxidant for the oxidation of aromatic amines to the corresponding
quinones.
Organic reactions on supported reagents have received
recently considerable attention from synthetic chemists
require tedious work up,17 give low yields15;16 or long
reaction times.14;19
because of their high e¤ciency, environmental safety and
We report here the use of hypochlorite ion on Dowex
1X8-200 as an inexpensive alternative for oxidation of aro-
matic amines with total selectivity to the corresponding
quinones. Table 1 lists a variety of aromatic amines
oxidized with supported ClO on Dowex 1X8-200 anion
exchanger resin to the corresponding quinones.
3
convenient work up procedures.1
Polymer supported
reagents have emerged as a complementary approach to
solid phase organic synthesis.4;5 Reagents supported on
insoluble polymers are particularly convenient for solving
8
many problems in organic chemistry.6
Sodium hypochlorite is a readily available and inexpen-
sive oxidant and has been used for the oxidation of variety
of compounds.9 Unfortunately, the traditional NaClO
oxidation methods in this transformation are limited by
the very low solubility of NaClO in most organic solvents.
In order to overcome this limitation, milder NaClO
oxidation methods such as oxidation under phase transfer
catalyst have been developed.10;11 However these methods
possess disadvantages, e.g., long reaction times, high tem-
peratures and use of expensive polar aprotic solvents.
We have now found that it is possible to obtain in a
simple way a polymer supported ClO reagent for the
oxidation of aromatic amines to quinones utilizing a com-
mercial anion exchanger resin.
Oxidation of aromatic amines to quinones is an important
reaction in organic chemistry and a variety of oxidizing
reagents such as potassium dichromate,12 potassium
nitrosodisulfonate,13 ferric chloride,14 sodium nitrate,15 sil-
ver oxide and lead dioxide,16 lead tetraacetate17 and
hydrogen peroxide18 have been developed. Most of the
reported reagents require vigorous conditions,12;13;15 some
Experimental
All melting points are uncorrected. IR spectra were recorded (KBr)
on an FT-IR Unicam Mattson 1000 spectrophotometer. 1H NMR
spectra were recorded on a Bruker AC-80 (80 MHz) spectrometer
in CDCl3 and chemical shifts are indicated in d. Chemicals were pur-
chased from Merck, Aldrich and Riedel AG and were used without
further puri¢cation. All products are known compounds and were
identi¢ed by their mp, IR and 1H NMR spectroscopic properties.
All yields refer to isolated products.
Preparation of ClO Supported on an Anion Exchanger Resin.öTo
prepare the reagent, 55 g of the chloride form of Dowex 1X8-200, a
macroreticular anion exchanger resin containing quaternary
ammonium group, was added under stirring to a 200 ml solution
of 1.85 M NaOCl. Chloride ions were readily displaced and the ClO
form of the resin was qualitatively obtained in 2 h. The resin was then
successively rinsed with water, acetone and absolute ethanol and
¢nally dried in vacuo at 65 8C for 5 h. The capacity of the resin
was determined by stirring 1.0 g of the resin overnight with 20 ml
of 2 M aqueous potassium hydroxide, ¢ltering o¡ and titrating
iodometrically. In the obtained hypochlorite solution, the determined
average capacity of the dried resin was 2.2 mmol ClO
1
g
of resin.
Table 1 Oxidation of aromatic amines to quinones
NH2
O
ClO– / Dowex 1X8-200
R
R
O
Mmol
substrate: g
resin
Reaction
time/min
Amine
Product
Solvent
Yield(%)
Aniline
2-Toluidine
1,4-Benzoquinone
1: 1.5
1: 2
1 : 1.8
1 : 2
Tetrahydrofuran
Tetrahydrofuran
Tetrahydrofuran
Dichloromethane
Ethyl acetate
1,2-Dimethoxyethane
Tetrahydrofuran
1,2-Dimethoxyethane
1,2-Dimethoxyethane
1,2-Dimethoxyethane
30
30
45
150
150
45
30
45
150
85
88
93
85
95
91
97
95
90
89
93
2-Methyl-5-benzoquinone
2-Chloro-1,4-benzoquinone
1,2-Benzoquinone
1,2-Benzoquinone
1,4-Benzoquinone
2-Methyl-1,4-benzoquinone
1,4-Naphthoquinone
1,2-Naphthoquinone
1,4-Naphthoquinone
3-Chloroaniline
1,2-Phenylenediamine
2-Aminophenol
4-Aminophenol
2-Toluidine
1-Aminonaphthalene
1-Amino-2-naphthole
1-Amino-4-naphthole
1: 2
1 : 2
1: 1.5
1: 1.8
1: 2
1 : 2
Oxidation of Aromatic Amines into Quinones: General Pro-
cedure.öAromatic amine (2 mmol) and the dry ClO form of the
resin (1.5 g) were re£uxed in 25 ml of dry tetrahydrofuran under vig-
orous stirring for 30 min, then the reaction mixture was ¢ltered
through a sintered glass and the ¢ltrate concentrated and worked up
* To receive any correspondence (e-mail: mhashemi@ch.sharif.ac.ir).
This is a Short Paper as de¢ned in the Instructions for Authors,
Section 5.0 [see J. Chem. Research (S), 1999, Issue 1]; there is
therefore no corresponding material in J. Chem. Research (M).

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J. CHEM. RESEARCH (S), 1999 673
with 1 M hydrochloric acid. Flash chromatography (hexane^ethyl
acetate 8 : 2 v/v. gave the corresponding quinone.
4
5
6
S. W. Kaldor, M. G. Siegel, J. E. Fritz, B. A. Dressman and P.
J. Hahn, Tetrahedron Lett., 1996, 37, 7193.
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(i) 1,4-Benzoquinone: yellow solid, mp 114^116 8C (lit.20
1
115^117 8C), IR(KBr) 3060, 1680, 1658, 1600, 1570, 1510 cm
dH (CDCl3) 6.8(s).
,
(ii) 1,2-Benzoquinone: red^purple solid, decomposed at 60 8C (lit.20
1
60^70 8C), IR(KBr) 3050, 2910, 1748, 1688, 1670, 1410, 1292 cm
(iii) 2-Methyl-1,2-benzoquinone: yellow^purple solid, mp 67^69 8C
(lit.20 115^117 8C), IR(KBr), 3333, 3030, 1672, 1610, 1447, 1351,
1300 cm 1, dH (CDCl3) 2.1(s), 6.6^6.8(m).
.
7
8
9
J. M. J. Frechot, Tetrahedron Lett., 1981,37, 663.
J. J. Parlow, Tetrahedron Lett., 1995, 9, 1359.
M. Hudlicky,
Oxidation in Organic Chemistry, ACS,
Washington DC, 1990.
(iv) 2-Chloro-1,4-benzoquinone: yellow^red solid, mp 55^57 8C
10 G. A. Lee and H. H. Freedman, Tetrahedron Lett., 1976, 20,
1641.
11 G. A. Mirafzal and A. M. Lozeva, Tetrahedron Lett., 1998, 39,
1641.
12 A. V. Rao, S. P. Chavan and L. Sivadasan, Tetrahedron, 1986,
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13 H. J. Teuber and M. Hasselbach, Chem. Ber., 1959, 92, 674.
14 L. F. Fieser, Org. Synth., 1943, Coll. Vol. II, 430.
15 E. I. Martin and L. F. Fieser, Org. Synth., 1955, Coll. Vol. III,
633.
1
(lit.20 57 8C), IR(KBr) 3050, 1691, 1662, 1590, 1370, 1330, 1290 cm
dH (CDCl3) 6.9(s), 6.4^6.8(m).
,
(v) 1,2-Naphthoquinone: yellow-red solid, mp 146^148 8C (lit.20
1
146 8C), IR(KBr) 3027, 1669, 1610, 1591, 1560, 1450, 1412 cm
.
(vi) 1,4-Naphthoquinone: yellow solid, mp 127 8C (lit.20 128.5 8C),
IR(KBr) 3030, 1675, 1610, 1590, 1610, 1485, 1330, 1320 cm 1, dH
(CDCl3) 7.0(s), 7.7^8.2(m).
Received, 12th July 1999; Accepted, 2nd August 1999
Paper E/9/05598C
16 R. Willstatter and M. Benz, Chem. Ber., 1906, 39, 3482.
17 R. Adam and A. S. Nagarkatti, J. Am. Chem. Soc., 1950, 72,
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18 S. Sakave, T. Tsubakino, Y. Nishiyama and Y. Ishi, J. Org.
Chem., 1993, 58, 3633.
19 W. J. Williams, Handbook of Anion Determination,
Butterworth & Co. Ltd., London, 1979.
20 R. C. Weast and J. G. Grasselli, CRC Handbook of Data on
Organic Compounds, CRC Press, Boca Raton, FL, 2nd edn.,
1989.
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