A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1945, 25, 69
DOI: 10.15227/orgsyn.025.0069
[Pelargonic acid, θ-cyano-, methyl ester]
Submitted by W. S. Bishop
Checked by C. F. H. Allen and J. VanAllan.
1. Procedure
Caution! Tetrachloroethane is toxic; the operations should be conducted in a hood.
In a 1.5-l. Erlenmeyer flask to which is attached a reflux condenser, 190 g. (0.88 mole) of methyl sebacamate (p. 613) is dissolved in 200 ml. of boiling tetrachloroethane. The solution is allowed to cool to 40–50° (Note 1), 95 g. (0.67 mole) of phosphorus pentoxide is added (Note 2), and the mixture is stirred well by means of a glass rod. The mixture is heated in an oil bath to 120° (thermometer in oil), and a second 95-g. portion of phosphorus pentoxide is added. After the mixture has been heated at 145° for 30 minutes with occasional hand stirring, the liquid is decanted. The residue is heated at 145° with 200 ml. of tetrachloroethane for 30 minutes with occasional stirring, and the liquid is decanted. This process is repeated once. The combined extracts are placed in a 1-l. flask, and most of the solvent is distilled under the reduced pressure of a water pump. The residue is transferred to a 300-ml. flask, and the remainder of the solvent is removed (Note 3). When no more distillate comes over, the receiver is changed, the water pump is replaced by an oil pump, and the residue is fractionated (Note 4). The yield of methyl ω-cyanopelargonate boiling at 121–124°/1 mm. (Note 5) is 119–124 g. (69–71%).
2. Notes
1. The slush that results on cooling is easily mixed with the phosphorus pentoxide.
2. The phosphorus pentoxide is weighed rapidly on a piece of paper, from which it can be slid quickly into the flask.
3. About 550–560 ml. of tetrachloroethane is recovered. Ground-glass equipment is preferable for the distillations.
4. There is no fore-run. At 1 mm., the thermometer reads about 118° when the first drop appears at the end of the side tube of the distilling flask. There is a 5- to 6-g. fraction, b.p. 124–135°/1 mm., and some residue.
5. Other boiling points are 154°/5 mm. and 170°/14 mm.
3. Discussion
Methyl ω-cyanopelargonate has also been prepared by esterification of ω-cyanopelargonic acid with methyl sulfate1 or methanol,2 and by dehydration of methyl sebacamate with phosphorus pentoxide3 or thionyl chloride.4 The procedure described appears in the literature.1,3

References and Notes
  1. Biggs and Bishop, J. Am. Chem. Soc., 63, 944 (1941).
  2. Biggs, U. S. pat. 2,339,672 [C. A., 38, 3990 (1944)].
  3. Bishop, U. S. pat. 2,277,033 [C. A., 36, 4636 (1942)].
  4. Soffer, Strauss, Trail, and Sherk, J. Am. Chem. Soc., 69, 1884 (1947).

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

Pelargonic acid, θ-cyano-, methyl ester

methanol (67-56-1)

thionyl chloride (7719-09-7)

methyl sulfate (75-93-4)

tetrachloroethane (630-20-6)

Methyl ω-cyanopelargonate (53663-26-6)

Methyl sebacamate (53663-35-7)


phosphorus pentoxide (1314-56-3)