Org. Synth. 1953, 33, 25
DOI: 10.15227/orgsyn.033.0025
DIETHYL γ-OXOPIMELATE
[Heptanedioic acid, 4-oxo-, diethyl ester]
Submitted by W. S. Emerson and R. I. Longley, Jr.
1.
Checked by William S. Johnson and I. A. David.
1. Procedure
A
3-l. three-necked flask equipped with a
stirrer,
reflux condenser, and
gas inlet tube is charged with
476 g. (3.45 moles) of furylacrylic acid2 and
1580 g. (about 33 moles) of 95% ethanol (Note 1). The mixture is heated to boiling, and anhydrous
hydrogen chloride is introduced at such a rate that the mixture becomes saturated after 90 minutes. The gas inlet tube is replaced by a stopper, and a
2-ft. Vigreux column is substituted for the reflux condenser. About 250 ml. of solvent is removed by distillation at atmospheric pressure; then another 300 ml. is removed while the pressure is slowly reduced (
water aspirator). The residue is cooled and stirred with a solution of about
260 g. of sodium carbonate in water
(Note 2). The mixture is extracted with two
250-ml. portions of benzene, and the combined extracts are washed with 100 ml. of water
(Note 3). Distillation of the organic portion through a 2-ft. Vigreux column yields, after a small fore-run,
579–657 g. (
73–83%) of
diethyl γ-oxopimelate, b.p.
116–121° /0.3 mm.,
nD25 1.4395–1.4400.
2. Notes
1.
If absolute
ethanol is used the yield is much lower.
2.
A slight excess of
sodium carbonate is used. The amount required depends on the amount of
hydrogen chloride remaining after the distillation.
3.
Sodium chloride may be added if the layers do not separate.
3. Discussion
Diethyl γ-oxopimelate has been prepared by saturating an
ethanol solution of
furylacrylic acid3,4,5,6,7 or
γ-oxopimelic acid dilactone with
hydrogen chloride5 or
sulfuric acid.
8 It was found as a by-product in the esterification of
furylacrylic acid with
ethanol in the presence of
p-toluenesulfonic acid.
9 A mechanism has been proposed for the formation of esters of
γ-oxopimelic acid from
furylacrylic acid.
10 The present procedure is a modification of the original Marckwald process.
3,4
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
γ-oxopimelic acid dilactone
ethanol (64-17-5)
sulfuric acid (7664-93-9)
hydrogen chloride (7647-01-0)
Benzene (71-43-2)
sodium chloride (7647-14-5)
sodium carbonate (497-19-8)
Furylacrylic acid (539-47-9)
DIETHYL γ-OXOPIMELATE,
Heptanedioic acid, 4-oxo-, diethyl ester (6317-49-3)
γ-oxopimelic acid (502-50-1)
p-toluenesulfonic acid (104-15-4)
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