Hydrochloric Acid → Menthyl bromoacetate

To a solution of (−) Menthol (2.75 mmoles) in anhydrous THF (5 ml), Et3N (2.75 mmoles) is added under stirring. The solution temperature is lowered to 0° C. and bromo-acetylbromide (2.5 mmoles) added. The solution temperature is then allowed to raise to room temperature and the reaction mixture is stirred for 2 hours. An HCl 1N (2 ml) aqueous solution is added and the organic phase is extracted with ethyl acetate (3×5 ml). The pooled organic phases are washed with a saturated aqueous NaCl solution (1×15 ml), dehydrated on Na2SO4 and filtered. The solvent is evaporated under a reduced pressure and the crude product is purified by flash chromatography in n-hexane/ethyl acetate 97/3 volume/volume. 388 mg of 2-isopropyl-5-methyl-cyclohexyl ester of the bromo acetic acid (51% yield) are recovered.

1. customis lowered to 0° C.
2. stirringthe reaction mixture is stirred for 2 hours
3. extractionthe organic phase is extracted with ethyl acetate (3×5 ml)
4. washThe pooled organic phases are washed with a saturated aqueous NaCl solution (1×15 ml)
5. filtrationfiltered
6. customThe solvent is evaporated under a reduced pressure
7. customthe crude product is purified by flash chromatography in n-hexane/ethyl acetate 97/3 volume/volume

ORD record

ord-253674b0829845ddbdc9e69de36d131b

Source dataset

uspto-grants-2013_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08580820B2