Org. Synth.1972,52, 88
DOI: 10.15227/orgsyn.052.0088
USE OFDIPOTASSIUM NITROSODISULFONATE (FREMY'S SALT):4,5-DIMETHYL-o-BENZOQUINONE
[3,5-Cyclohexadiene-1,2-dione, 4,5-dimethyl-]
Submitted by H.-J. Teuber
1 Checked by P. A. Wehrli, F. Pigott, and A. Brossi.
1. Procedure
A solution of15 g. ofsodium dihydrogen phosphate(Note 1) in 5 l. of distilled water is placed in a6-l. separatory funnel. To this solution is added90 g. (0.33 mole) ofdipotassium nitrosodisulfonate (Fremy's salt)(Note 2). The mixture is shaken to dissolve the inorganic radical. A solution of16 g. (0.13 mole) of3,4-dimethylphenol(Note 3) in350 ml. ofdiethyl ether is added quickly to the purple solution. As the mixture is shaken vigorously for 20 minutes(Note 4), the color of the solution changes to red-brown. Theo-quinone thus formed is extracted in three portions with1.2 l. ofchloroform. The combined organic layers are dried over anhydroussodium sulfate(Note 5), filtered, and evaporated under reduced pressure at 20–23°(Note 6). The residual, somewhat oily, red-brown crystals are slurried twice with15 ml.-portions of ice-coldether and collected on a filter. The dark-red crystals, after air drying, weigh8.7–8.9 g. (49–50%), m.p.105–107°(Note 7).
2. Notes
1.
Monobasicsodium phosphate, NaH2PO4·H2O, obtained from Merck & Co., Inc., was used. This buffer was found to be satisfactory for this reaction.
2.
Fremy's salt may be purchased from Aldrich Chemical Company, Inc., or from Matheson, Coleman and Bell. The
Fremy's salt used by the checker was prepared electrolytically.
23.
3,4-Dimethylphenol was obtained from Eastman Organic Chemicals, m.p.
63–65°.
4. An
efficient stirrer may be substituted for the shaking.
5. The drying was accomplished in about 5 minutes.
6. Higher temperatures may accelerate dimerization of the product.
7. The product is reported to melt at
102°.
3 This material has
1H NMR peaks (CDCl
3) at δ 2.14 and 6.19 with relative intensities of 3 : 1. The IR spectrum (CHCl
3) shows the strongest absorption at 1670 cm
−1 accompanied, among others, by four more bands at 1390, 1280, 1005, and 835 cm
−1. The product has UV maxima, nm (ε), (CHCl
3) at 260 (2600), 400 (1120), and 572 (288). It is reported that the material undergoes slow Diels-Alder dimerization.
43. Discussion
o-Quinones exemplify a very important and reactive class of compounds for general organic synthesis. In the past they have been prepared from catechol derivatives by
silver oxide dehydrogenation.
3 The unique oxidizing properties of Fremy's salt allow a number of readily available phenols to be converted to
o-quinones in excellent yield.
4 The scope of this oxidation, the Teuber reaction, is the subject of numerous papers
5 which have been reviewed recently.
6
References and Notes
- H.-J. Teuber, Institut für Organische Chemie der Universität, Frankfurt/Main.
- P. A. Wehrli and F. L. Pigott,Inorg. Chem.,9, 2614 (1970).
- R. Willstätter and F. Müller,Ber. Dtsch. Chem. Ges.,44, 2171 (1911).
- H.-J. Teuber and G. Staiger,Chem. Ber.,88, 802 (1955); H.-J. Teuber, U.S. Pat. 2,782,210 (1957).
- H.-J. Teuber and S. Benz,Chem. Ber.,100, 2918 (1967) and earlier papers.
- H. Zimmer, D. C. Lankin and S. W. Horgan,Chem. Rev.,71, 229 (1971).
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
DIPOTASSIUM NITROSODISULFONATE (FREMY'S SALT)
Fremy's salt
ether,
diethyl ether (60-29-7)
chloroform (67-66-3)
silver oxide (20667-12-3)
sodium sulfate (7757-82-6)
3,4-dimethylphenol (95-65-8)
sodium dihydrogen phosphate (7558-80-7)
DIPOTASSIUM NITROSODISULFONATE
3,5-Cyclohexadiene-1,2-dione, 4,5-dimethyl-,
4,5-Dimethyl-o-benzoquinone (4370-50-7)
sodium phosphate (7601-54-9)
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