Water → (+/-)-Frontalin

HRID 981885Notes

Reaction equation

HRID 981885 reaction equation
[C:1]([C:5]1([CH3:12])[CH2:10][CH2:9][CH:8]=[C:7]([CH3:11])[O:6]1)(OC)=[O:2].[H-].[Al+3].[Li+].[H-].[H-].[H-].O.[OH-].[Na+]>CCOCC>[CH3:12][C:5]12[CH2:1][O:2][C:7]([CH3:11])([O:6]1)[CH2:8][CH2:9][CH2:10]2

Participants

6

Reactant 4

HCID 962Water2×HCID 14798Sodium HydroxideHCID 10899110HCID 10899110, compoundHCID 21226445Aluminium lithium hydride

Product 1

HCID 34235(+/-)-FrontalinYield 81%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent2×

Procedure

A solution of 2-carbomethoxy-2,6-dimethyl-3,4-dihydro-2 H-pyran (11.2 gm, 0.066 mol) in dry ether was added dropwise with stirring to lithium aluminum hydride (3 gm, 0.079 mol) in dry ether. The reaction mixture was heated under reflux for 4 hours, cooled and decomposed with water (3 ml), aqueous 15% NaOH solution (3 ml) and finally water (9 ml). It was stirred at room temperature for 2 hours and filtered. The ether solution containing the resulting alcohol was treated with a catalytic amount of p-toluenesulfonic acid, stirred at room temperature for 2 hours and neutralized with K2CO3. The solvent was removed using a 40 cm Vigreux column and the residue was distilled to give 7.6 gm (75.6%) of frontalin.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureunder reflux for 4 hours
  3. temperaturecooled
  4. filtrationfiltered
  5. additionThe ether solution containing the resulting alcohol
  6. additionwas treated with a catalytic amount of p-toluenesulfonic acid
  7. stirringstirred at room temperature for 2 hours
  8. customThe solvent was removed
  9. distillationthe residue was distilled

Sources & evidence

ORD record
ord-e4fb25280db94393881fbce9aa8e5cb1
Source dataset
uspto-grants-1991_02
Patent number
US04994268

Reaction notes

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