Menthol → (-)-Menthyl acetoacetate

HRID 963262Notes

Reaction equation

HRID 963262 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.[C:12](OCCCC)(=[O:17])[CH2:13][C:14]([CH3:16])=[O:15]>C1(C)C=CC=CC=1>[C:12]([O:10][C@H:3]1[C@H:4]([CH:7]([CH3:8])[CH3:9])[CH2:5][CH2:6][C@@H:1]([CH3:11])[CH2:2]1)(=[O:17])[CH2:13][C:14]([CH3:16])=[O:15]

Participants

4

Reactant 2

HCID 1254MentholHCID 11576Butyl acetoacetate2×

Product 1

HCID 11413787(-)-Menthyl acetoacetateYield 114.5%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Conditions

Temperature
23 °C

Procedure

A solution of (-)-menthol (23.0 g, 147 mmol, 1 equiv) and 1-butyl acetoacetate (20.0 ml, 121 mmol, 0.80 equiv) in toluene (50 mL) was heated at reflux for 12 h, then was cooled to 23° C. Volatiles were removed in vacuo and toluene (20 mL) and 1-butyl acetoacetate (12.2 mL, 73.5 mmol, 0.50 equiv) were added to the residue. The resulting solution was heated at reflux for 12 h, then was cooled to 23° C. The cooled reaction mixture was concentrated in vacuo and the residue was purified by distillation under reduced pressure (bp 90° C., 30 mmHg) to afford (1R,3R,4S)-p-menth-3-yl acetoacetate (1) as a low-melting solid (33.3 g, 94%). ##STR14##

Workup

  1. temperatureat reflux for 12 h
  2. additionwere added to the residue
  3. temperatureThe resulting solution was heated
  4. temperatureat reflux for 12 h
  5. temperaturewas cooled to 23° C
  6. customThe cooled reaction mixture
  7. concentrationwas concentrated in vacuo
  8. distillationthe residue was purified by distillation under reduced pressure (bp 90° C., 30 mmHg)

Sources & evidence

ORD record
ord-49e109631b9549f6b649f9cc75d04290
Source dataset
uspto-grants-1998_06
Patent number
US05763451

Reaction notes

Loading…