A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1942, 22, 30
DOI: 10.15227/orgsyn.022.0030
[o-Toluic acid, α-cyano-]
Submitted by Charles C. Price and Richard G. Rogers.
Checked by W. E. Bachmann and Richard D. Morin.
1. Procedure
A mixture of 100 g. of phthalide (Note 1) and 100 g. of powdered potassium cyanide is placed in a 2-l. round-bottomed flask fitted with a stirrer and a thermometer. The stirred mixture is heated to 180–190° (internal temperature) for 4–5 hours in an oil bath (Note 2). One liter of water is added to the cooled mass, and the mixture is stirred until the solid salts are dissolved (Note 3). Any insoluble material that separates is removed by filtration (Note 4). Under a hood, 6 N hydrochloric acid (20–60 ml.) is added to the dark aqueous solution until it becomes turbid (Note 5). The solution is carefully neutralized with sodium bicarbonate (Note 6), a few grams of Norit is added, and the mixture is stirred for several minutes and filtered. The nearly colorless filtrate is acidified with 40–50 ml. of concentrated hydrochloric acid and, after cooling in an ice bath, is filtered with suction. The yield is 80–100 g. (67–83%) of white crystals which melt at 113–115° (Note 7).
2. Notes
1. The submitters used phthalide obtained from E. I. du Pont de Nemours and Company, Wilmington, Delaware. The checkers prepared it according to Org. Syntheses Coll. Vol. 2, 526 (1943).
2. At the end of the reaction, the mixture should be dark brown and nearly solid. The temperature must not rise above 200°; the checkers kept it at 180°.
3. About 1 hour is required to disintegrate the mass.
4. In some runs 5–15 g. of phthalide is recovered at this point.
5. Occasionally a small amount of crystalline homophthalimide separated from the alkaline solution at this point; m.p. 235°.1
6. The checkers found it advisable to acidify the solution slightly at this stage in order to precipitate dark impurities.
7. This material is satisfactory for most purposes. It can be purified by recrystallization from benzene or acetic acid, though with considerable loss.
3. Discussion
o-Carboxyphenylacetonitrile has been prepared by the reaction of phthalide with potassium cyanide.2,3,4 The above procedure is essentially that of Wislicenus.2,3

References and Notes
  1. Gabriel, Ber., 19, 1655 (1886).
  2. Wislicenus, Ann., 233, 102 (1886).
  3. Price, Lewis, and Meister, J. Am. Chem. Soc., 61, 2760 (1939).
  4. Johnston, Kaslow, Langsjoen, and Shriner, J. Org. Chem., 13, 477 (1948).

Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

hydrochloric acid (7647-01-0)

acetic acid (64-19-7)

Benzene (71-43-2)

sodium bicarbonate (144-55-8)

potassium cyanide (151-50-8)

Norit (7782-42-5)

Phthalide (87-41-2)


o-Toluic acid, α-cyano- (6627-91-4)