Diethyl Ether → (+/-)-6-Benzyloxy-2,5,7,8-tetramethylchroman2-acetic acid

HRID 580374Notes

Reaction equation

HRID 580374 reaction equation
C[O:2][C:3](=[O:31])[CH:4]([C:9]1([CH3:30])[CH2:14][CH2:13][C:12]2[C:15]([CH3:29])=[C:16]([O:21][CH2:22][C:23]3[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=3)[C:17]([CH3:20])=[C:18]([CH3:19])[C:11]=2[O:10]1)C(OC)=O.[OH-].[K+].C(O)CO.O.CCOCC>O>[CH3:30][C:9]1([CH2:4][C:3]([OH:31])=[O:2])[CH2:14][CH2:13][C:12]2[C:15]([CH3:29])=[C:16]([O:21][CH2:22][C:23]3[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=3)[C:17]([CH3:20])=[C:18]([CH3:19])[C:11]=2[O:10]1

Participants

6

Reactant 4

HCID 3283Diethyl EtherHCID 14797Potassium HydroxideHCID 10002579rac-3,4-dihydro-2,5,7,8-tetramethyl-6-(phenylmethoxy)-2H-1-benzopyran-2-ylpropanedioic acid dimethyl esterHCID 20437942Ethylene glycol water

Product 1

HCID 14368743(+/-)-6-Benzyloxy-2,5,7,8-tetramethylchroman2-acetic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A mixture of 0.43 g (1 mmole) of rac-3,4-dihydro-2,5,7,8-tetramethyl-6-(phenylmethoxy)-2H-1-benzopyran-2-ylpropanedioic acid dimethyl ester, 0.56 g (10 mmoles) of potassium hydroxide, and 25 ml of 9:1 ethylene glycol-water is stirred and refluxed for 8 hr. The mixture is cooled, diluted with water, and extracted with ether (the ether extract is discarded). The aqueous, alkaline solution is acidified with 3NHCl and the acid product isolated by ether extraction. The ether extracts are combined, washed with water and brine, dried (MgSO4), filtered and concentrated in vacuo. Recrystallization of the residue from aqueous ethanol gives rac-3,4-dihydro-2,5,7,8-tetramethyl-6-(phenylmethoxy)-2H-1-benzopyran-2-acetic acid which can be converted to Vitamin E by the procedures in Helv. Chim Acta 61, 837 (1978); Helv. Chim. Acta 59, 290(1976) and Helv. Chim. Acta 64, 1158 (1981).

Workup

  1. temperaturerefluxed for 8 hr
  2. temperatureThe mixture is cooled
  3. extractionextracted with ether (the ether
  4. extractionextract
  5. customisolated by ether extraction
  6. washwashed with water and brine
  7. dry with materialdried (MgSO4)
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo
  10. customRecrystallization of the residue from aqueous ethanol

Sources & evidence

ORD record
ord-f5e5766a9a8f482bb800300f865bbd07
Source dataset
uspto-grants-1988_06
Patent number
US04752646

Reaction notes

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