α-Methyl-α-2-propen-1-ylbenzeneethanol → Menthol

HRID 1414688Notes

Reaction equation

HRID 1414688 reaction equation
C(C([OH:13])(CC=C)C)C1C=CC=CC=1.C(=O)([O-])O[C:16]1([CH3:25])[CH2:21][CH2:20][CH:19]([CH:22]([CH3:24])[CH3:23])[CH2:18][CH2:17]1>>[CH:16]1([CH3:25])[CH2:21][CH2:20][CH:19]([CH:22]([CH3:24])[CH3:23])[CH:18]([OH:13])[CH2:17]1

Participants

3

Reactant 2

HCID 14223528α-Methyl-α-2-propen-1-ylbenzeneethanolHCID 86734388HCID 86734388, compound

Product 1

HCID 1254MentholYield 18%

Procedure

The method of Grignard and Chambret, Compt. rend. 182, 299(1926) was used to prepare 2-benzylpent-4-en-2-ol. The alcohol was converted to the 1-menthyl carbonate by a procedure like that of Example 4. Distillation of the extracted product through an 8-inch Vigreux column gave fractions boiling 25°-110°/0.04-0.6 mm, all having strong OH absorption in the infra-red. The residue was distilled through a short path and the fraction boiling 165°-6°/0.6-0.7 mm showed the following IR absorptions: no OH, strong carbonate (1750 and 1255 cm-1), vinyl (1655, 978, 913 cm-1), monosubstituted aromatic (750 shoulder, 697 cm-1). NMR analysis indicated 80% of the expected mixed ester, a yield of 18.0% from the alcohol. This product had very little odor, but on heating produced a menthol odor.

Workup

  1. distillationDistillation of the extracted product through an 8-inch Vigreux column
  2. customgave fractions
  3. customboiling 25°-110°
  4. customOH absorption in the infra-red
  5. distillationThe residue was distilled through a short path
  6. customboiling 165°-6°
  7. additionexpected mixed ester
  8. temperatureon heating

Sources & evidence

ORD record
ord-8aa5bafd59a14d419d8505b6ea2061b5
Source dataset
uspto-grants-1977_01
Patent number
US04002179

Reaction notes

Loading…