Menthol → Menthol

HRID 1794976Notes

Reaction equation

HRID 1794976 reaction equation
[CH:1]1([CH3:11])[CH2:6][CH2:5][CH:4]([CH:7]([CH3:9])[CH3:8])[CH:3]([OH:10])[CH2:2]1.[CH3:12][CH:13]1[CH2:18][C@H:17]([OH:19])[C@@H:16]([CH:20]([CH3:22])[CH3:21])[CH2:15][CH2:14]1.C(OC=C)(=O)C>CCCCCCC>[C:17]([O:10][CH:3]1[CH:4]([CH:7]([CH3:8])[CH3:9])[CH2:5][CH2:6][CH:1]([CH3:11])[CH2:2]1)(=[O:19])[CH3:16].[CH:13]1([CH3:12])[CH2:14][CH2:15][CH:16]([CH:20]([CH3:21])[CH3:22])[CH:17]([OH:19])[CH2:18]1

Participants

6

Reactant 3

HCID 1254Menthol2×HCID 7904Vinyl AcetateHCID 12285346HCID 12285346, compound

Product 2

HCID 1254MentholHCID 27867Menthyl acetate

Reagents, catalysts & solvents 1

HCID 8900HeptaneSolvent

Procedure

Lyophilised “AMANO AK” (a Pseudomonas fluorescens lipase enzyme) was obtained from Amano Pharmaceutical Co. (Japan). Concentrated liquid menthol was produced by the hydrogenation of thymol. The menthol contained four diastereomeric pairs of menthols, namely (+)-menthol (51%), (±)-isomenthol (14%), (±)-neomenthol (29%) and (±)-neoisomenthol (2%). A volume of 1 ml was added to sealed batch reactors. Vinyl acetate (54 μl) was added at a 2:1 molar ratio to (−)-menthol. Heptane was added as solvent to a final reaction volume of 5 ml. These reactors were incubated in silicon oil baths at 50° C. and stirred on a stirring hot plate. Batch times, unless otherwise stated were 24 hours. The reaction mixture was then centrifuged to separate the products from the enzyme. The supernatant was analysed by GC (% m/m analysis). Of the available (−)-menthol, 100% was converted to (−)-menthyl acetate, at an ee of 98%. The enzyme was recycled a total of 150 times by washing with heptane and adding fresh substrate (liquid menthol, vinyl acetate and heptane) after every recycle. An amount of menthyl acetate equivalent to 185 g of (−)-menthol was produced by this process.

Workup

  1. additionA volume of 1 ml was added
  2. customto sealed batch reactors
  3. customreaction volume of 5 ml
  4. customat 50° C.
  5. customto separate the products from the enzyme
  6. washby washing with heptane
  7. additionadding fresh substrate (liquid menthol, vinyl acetate and heptane) after every recycle

Sources & evidence

ORD record
ord-7f70e898410f41b0af961e7916a24754
Source dataset
uspto-grants-2006_04
Patent number
US07026144B2

Reaction notes

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