Org. Synth. 1943, 23, 55
DOI: 10.15227/orgsyn.023.0055
[Acetyl chloride, (menthyloxy)-, l-]
Submitted by M. T. Leffler and A. E. Calkins.
Checked by R. L. Shriner and C. H. Tilford.
1. Procedure
A 1-l. three-necked round-bottomed flask is mounted on a steam cone and is fitted with a 250-ml. separatory funnel and a reflux condenser connected to a trap (Note 1) for absorbing gases. In the flask is placed 325 g. (198 ml., 2.73 moles) of thionyl chloride (Note 2), and to it is added, during the course of 1 hour, 125 g. (0.58 mole) of l-menthoxyacetic acid (p. 544). The flask is shaken frequently during the addition of the acid and, if necessary, is warmed to start the reaction. When all the acid has been added (Note 3), the reaction mixture is refluxed gently for 5 hours. After the reaction is complete, the excess of thionyl chloride is removed by distillation on the steam bath (Note 4) and the residue is distilled under reduced pressure. The yield of l-menthoxyacetyl chloride boiling at 117–120° /3 mm. (120–125° /5 mm.), [α]25D −89.6°, amounts to 115–118 g. (Note 5) (85–87%). The product turns dark on standing; it should be stored in a glass-stoppered amber bottle.
2. Notes
1. The gas-absorption trap shown in Org. Syntheses Coll. Vol. 1, 97 (1941) may be used.
2. The commercial grade (b.p. 74–78°) of thionyl chloride was used.
3. Owing to the high viscosity of the acid, it is desirable to rinse the separatory funnel with a little thionyl chloride which is then added to the reaction mixture.
4. The recovered thionyl chloride may be redistilled for future runs. It is best to remove the last traces of thionyl chloride by heating the crude product to about 140° under the vacuum of the water pump.
5. The submitters report the same yields (per cent) when twice the amounts of materials are used.
3. Discussion
The procedure given above is adapted from that described by Read and Grubb.1 No other methods for the preparation of l-menthoxyacetyl chloride have been described.

References and Notes
  1. Read and Grubb, J. Soc. Chem. Ind., 51, 330T (1932).

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

thionyl chloride (7719-09-7)


L-Menthoxyacetyl chloride,
Acetyl chloride, (menthyloxy)-, l- (15356-62-4)