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

HRID 1903169Notes

Reaction equation

HRID 1903169 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 3 N 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 3 N 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-dc1290840d9f46388ecac4d4175a6a8f
Source dataset
uspto-grants-1984_03
Patent number
US04435406

Reaction notes

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