Sulfuric Acid → (S)-(+)-6-hydroxy-2,5,7,8-tetramethylchroman-2-methanol

HRID 224738Notes

Reaction equation

HRID 224738 reaction equation
O[CH:2]1[C:8]2=[C:9]([CH3:16])[C:10](=[O:15])[C:11]([CH3:14])=[C:12]([CH3:13])[C@:7]32[O:17][C@:4]([CH3:18])([CH2:5][O:6]3)[CH2:3]1.[H][H].S(=O)(=O)(O)O>Cl(O)(=O)(=O)=O.CO>[OH:15][C:10]1[C:9]([CH3:16])=[C:8]2[C:7](=[C:12]([CH3:13])[C:11]=1[CH3:14])[O:17][C@:4]([CH3:18])([CH2:5][OH:6])[CH2:3][CH2:2]2

Participants

6

Reactant 3

HCID 1118Sulfuric AcidHCID 57010753(3S,9aR)-(-)-2,3,4,5,7,9a-hexahydro-5-hydroxy-3,6,8,9-tetramethyl-3,9a-epoxy-1-benzoxepin-7-oneHCID 178418361HCID 178418361, compound2×

Product 1

HCID 9881178(S)-(+)-6-hydroxy-2,5,7,8-tetramethylchroman-2-methanolYield 111.3%

Reagents, catalysts & solvents 2

HCID 24247Perchloric AcidCatalystHCID 887MethanolSolvent

Procedure

A mixture of 0.59 g of (3S,9aR)-(-)-2,3,4,5,7,9a-hexahydro-5-hydroxy-3,6,8,9-tetramethyl-3,9a-epoxy-1-benzoxepin-7-one, 0.7 g of palladium-on-barium sulfate (5% by weight) and 3 drops of concentrated perchloric acid in 20 ml of methanol was hydrogenated with ca 120 ml of hydrogen under normal pressure. Subsequently, 2 ml of 2-N sulfuric acid were added and air was conducted into the mixture for 15 hours. The reaction mixture was again hydrogenated with ca 25 ml of hydrogen. After removal of the catalyst by filtration over Hyflo, the filtrate was treated with dilute sodium bicarbonate solution and extracted with ether. The combined organic phases were dried over magnesium sulfate. After distillation of the solvent on a rotary evaporator, there were obtained 0.62 g of brown crystals, which, for purification, was chromatographed on Kieselgel with acetic ester/toluene (1/1 parts by volume). The resulting (S)-(+)-6-hydroxy-2,5,7,8-tetramethylchroman-2-methanol crystallized from methylene chloride/hexane at a yield of 487 mg; melting point 126.5°- 128.5°.

Workup

  1. customAfter removal of the catalyst
  2. filtrationby filtration over Hyflo
  3. additionthe filtrate was treated with dilute sodium bicarbonate solution
  4. extractionextracted with ether
  5. dry with materialThe combined organic phases were dried over magnesium sulfate
  6. distillationAfter distillation of the solvent
  7. customon a rotary evaporator

Sources & evidence

ORD record
ord-d6c074ff3b2e4844818f1731ca4eb676
Source dataset
uspto-grants-1980_11
Patent number
US04234490

Reaction notes

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