Catechol → 3,4-dihydro-2H-1,5-benzodioxepine

HRID 745592Notes

Reaction equation

HRID 745592 reaction equation
[C:1]1([C:3](=[CH:5][CH:6]=[CH:7][CH:8]=1)[OH:4])[OH:2].C(=O)([O-])[O-].[K+].[K+].Br[CH2:16][CH2:17][CH2:18]Br>CN(C)C=O>[O:2]1[C:1]2[CH:8]=[CH:7][CH:6]=[CH:5][C:3]=2[O:4][CH2:18][CH2:17][CH2:16]1

Participants

5

Reactant 3

HCID 289CatecholHCID 80011,3-DibromopropaneHCID 11430Potassium Carbonate

Product 1

HCID 816353,4-dihydro-2H-1,5-benzodioxepineYield 41.3%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

110 g of pyrocatechol, 276 g of potassium carbonate and 303 g of 1,3-dibromopropane were stirred at 120° C. for 48 hours in 800 ml of absolute dimethylformamide. The cooled suspension was filtered under suction, the residue was back-washed with ether and the filtrate was poured into 4 l of water. This was extracted with ether. The ether extract was washed twice with 3N sodium hydroxide and then neutral with water, dried over sodium sulfate and evaporated in vacuo. The residue (146.6 g) was distilled at 11 mm/118°-120° C. 61.9 g (41.2% of theory) of 3,4-dihydro-2H-1,5-benzodioxepine were obtained.

Workup

  1. filtrationThe cooled suspension was filtered under suction
  2. washthe residue was back-washed with ether
  3. additionthe filtrate was poured into 4 l of water
  4. extractionThis was extracted with ether
  5. extractionThe ether extract
  6. washwas washed twice with 3N sodium hydroxide
  7. dry with materialneutral with water, dried over sodium sulfate
  8. customevaporated in vacuo
  9. distillationThe residue (146.6 g) was distilled at 11 mm/118°-120° C

Sources & evidence

ORD record
ord-da18c57e9f1241ed938edcedf82a52e1
Source dataset
uspto-grants-1986_07
Patent number
US04599347

Reaction notes

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