Hydrochloric Acid → 2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-7-ol

HRID 1902839Notes

Reaction equation

HRID 1902839 reaction equation
[CH3:1][C:2]1([CH3:14])[O:7][C:6]2[CH:8]=[C:9]([OH:12])[CH:10]=[CH:11][C:5]=2[C:4](=O)[CH2:3]1.Cl>[Zn].C(O)(=O)C>[CH3:1][C:2]1([CH3:14])[O:7][C:6]2[CH:8]=[C:9]([OH:12])[CH:10]=[CH:11][C:5]=2[CH2:4][CH2:3]1

Participants

5

Reactant 2

HCID 313Hydrochloric AcidHCID 6009027-hydroxy-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

Product 1

HCID 110412812,2-dimethyl-3,4-dihydro-2H-1-benzopyran-7-olYield 45.6%

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 176Acetic AcidSolvent

Procedure

2,3-Dihydro-2,2-dimethyl-7-hydroxy-4H-benzo[b]pyran-4-one (9.98 g), amalgamated zinc dust (50.0 g), 5 N hydrochloric acid (400 ml) and glacial acetic acid (100 ml) were stirred and refluxed for 4 hours then stirred at room temperature for 18 hours. The reaction mixture was extracted with diethyl ether, washed with water, dried and evaporated in vacuo to afford a dark red oil which was distilled to give 2,3-dihydro-2,2-dimethyl-7-hydroxy-4H-benzo[b]pyran (4.22 g) as an orange oil, bp 138°-146° C. (0.02 mm).

Workup

  1. temperaturerefluxed for 4 hours
  2. extractionThe reaction mixture was extracted with diethyl ether
  3. washwashed with water
  4. customdried
  5. customevaporated in vacuo
  6. customto afford a dark red oil which
  7. distillationwas distilled

Sources & evidence

ORD record
ord-e8955d70f168460aadd32d943819b860
Source dataset
uspto-grants-1982_12
Patent number
US04366163

Reaction notes

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