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Organic Synthess - McKusick B.C.

McKusick B.C., Boekelheide V., Emmons W.D. Organic Synthess - New York, 1963. - 134 p.
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5. To make a peroxide test, place a few milligrams of sodium iodide, a trace of ferric chloride, and 2-3 ml. of glacial acetic acid in a test tube and carefully add 1-2 ml. of the ether solution.
When unconsumed perbenzoate is present, a yellow ring is immediately formed between the two phases. If this test indicates the presence of peroxide, the extract should not be concentrated and distilled until it has been extracted first with a solution of potassium iodide in acetic acid to remove peroxide and then with aqueous sodium ihiosulfate to remove iodine.
6. The decomposition is considered to be complete when the pressure is constant.
7. 2-Hydroxythiophene resinilles on prolonged exposure to air.
8. It has recently been shown that 2-hydroxythiophene exists mainly as 2(5H)-thiophenone at room temperature.3
3. Methods of Preparation
The procedure described is essentially that of Lawesson and Frisell.4 2-Hydroxythiophene has been prepared in low yields by Hurd and Kreuz s from 2-thienylmagnesium bromide and oxygen in the presence of excess isopropylmagnesium bromide.
4. Merits of the Preparation
The first step of the procedure illustrates a general way of preparing aryl ierl-hutyl ethers.4’6 The second step is the best way to prepare 2-hydroxythiophene, inasmuch as the yield is good and fenl-butyl perbenzoate is a readily available perester that is relatively stable. The same procedure has been used to convert several other haloaromatic compounds to hydroxyaromatic compounds in good yield4 and is probably quite general.
1 Department of Organic Chemistry, Chemical Institute, University of Aarhus, Aarhus, Denmark.
г К. В. Wiberg, Laboratory Technique in Organic Chemistry, p. 207, McGraw-Hill Book Company, Inc., New York, 1960.
3 S. Gronowitz and R. A. Hoffman, Arkiv Kemi, 15,499 (1960).
4 S. -0. Lawesson and C. Frisell, Arkiv Kemi, 17, 393 (1961).
6 C. D. Hurd and K. L. Kreuz, J. Am. Chem. Soc., 72, 5543 (1950).
' C. Frisell and S. -0. Lawesson, Org. Syntheses, 41, 91 (1961).
Submitted by H. M. Blatter, H. Lukaszewski, and G. de Stevens.1 Checked by Wayland E. Noland and Kent R. Rush.
1. Procedure
A mixture of 1.44 g. (0.0099 mole) of indole-3-carboxaldehyde,2 7.0 g. (0.053 mole) of diammonium hydrogen phosphate, 30 g. (30 ml., 0.34 mole) of 1-nitropropane, and 10 ml. of glacial acetic acid is refluxed for 12.5 hours. During the reflux period the pale-yellow mixture becomes dark red. The volatile reactants and solvent are removed under reduced pressure, and an excess of water is then added to the dark residue. After a short time, crude indole-3-carbonitrile precipitates rapidly. It is separated by filtration and dried under reduced pressure; weight 1.20-1.34 g. (85-95%). Crystallization from acetone-hexane, with decoloriza-tion by activated carbon, yields 0.68-0.89 g. (48-63%) of fairly pure indole-3-carbonitrile, m.p. 179.5-182.5° (Note 1).
2. Note
1. The checkers obtained pure indole-3-carbonitrile, m.p. 182-184°, by subliming the product at a pressure of 1.5 mm. (bath temperature 165-170°) and recrystallizing the sublimate from a mixture of acetone and light petroleum ether. The recovery was 84%.
3. Methods of Preparation
Indole-3-carbonitrile has been prepared by the dehydration of indole-3-carboxaldehyde oxime,3-5 indoIe-3-glyoxalic acid ox-ime,4'6 or indole-3-carboxamide;3 by the action of cyanogen
chloride on indolylmagnesium iodide;6 by the reaction of isoamyl formate with o-aminobenzyl cyanide in the presence of metallic sodium;7,8 by mild basic hydrolysis of l-acetylindole-3-carboni-trile;7 and by the present method.9
4. Merits of the Preparation
This synthetic process is applicable to the preparation of other aromatic nitriles from aldehydes. The submitters have used it to prepare 5-bromoindole-3-carbonitrile, 7-azaindole-3-carboni-trile, ^-chlorobenzonitrile, 3,4,5-trimethoxybenzonitrile, and p-N,N-dimcthylaminobenzonitriIe.9 There are several advantages to its use. They include (a) readily available and inexpensive reagents, (6) a simple, time-saving procedure, and (c) fair to good yields of nitrile obtained by a one-step method.
1 Research Department, Division of Chemistry, CIBA Pharmaceutical Company, Division of CIBA Corporation, Summit, New Jersey.
2 P. N. James and H. R. Snyder, Org. Syntheses, Coll. Vol. 4, 539 (1963).
8 F. P. Doyle, W. Ferrier, D. O. Holland, M. D. Mehta, and J. H. C. Nayler, J. Chem. So ., 1956, 2853.
4 K. N. F. Shaw, A. McMillan, A. G. Gudmundson, and M. D. Armstrong, J. Org. Chem., 23, 1171 (1958).
6 S. Swaminathan, S. Ranganathan, and S. Sulochana, J. Org. Chem., 23, 707 (1958).
• R. Majima, T. Shigematsu, and T. Rokkaku, Chem. Ber., 57, 1453 (1924).
7 R. Pschorr and G. Hoppe, Chem. Ber., 43, 2549 (1910).
8 N. I. Gavrilov, Invest. Petrov. Selskochos, Akad. (Russia), 1-4, 14 (1919) [C. A., 19, 505 (1925)].
9 H. M. Blatter, H. Lukaszewski, and G. de Stevens, J. Am. Chem. Soc., 83, 2203 (1961).
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