1,3-Dibromopropane → methyl 8-chloro-3,4-dihydro-2H-1,5-benzodioxepin-6-carboxylate

HRID 15017Notes

Reaction equation

HRID 15017 reaction equation
[CH3:1][O:2][C:3](=[O:13])[C:4]1[CH:9]=[C:8]([Cl:10])[CH:7]=[C:6]([OH:11])[C:5]=1[OH:12].Br[CH2:15][CH2:16][CH2:17]Br.C([O-])([O-])=O.[K+].[K+]>CC(=O)C>[Cl:10][C:8]1[CH:9]=[C:4]([C:3]([O:2][CH3:1])=[O:13])[C:5]2[O:12][CH2:17][CH2:16][CH2:15][O:11][C:6]=2[CH:7]=1

Participants

5

Reactant 3

HCID 80011,3-DibromopropaneHCID 11430Potassium CarbonateHCID 18613685Methyl 5-chloro-2,3-dihydroxybenzoate

Product 1

HCID 18613659methyl 8-chloro-3,4-dihydro-2H-1,5-benzodioxepin-6-carboxylateYield 94.8%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

A mixture of 5-chloro-2,3-dihydroxy-benzoic acid methyl ester (0.3 mol), 1,3-dibromopropane (0.42 mol) and K2CO3 (0.66 mol) in 2-propanone (500 ml) was stirred and refluxed for 20 hours, then filtered hot and the filtrate was evaporated. The residue was purified by column chromatography over silica gel (eluent: DCM). The desired fractions were collected and the solvent was evaporated. Toluene was added and azeotroped on the rotary evaporator, yielding 69 g of methyl 8-chloro-3,4-dihydro-2H-1,5-benzodioxepin-6-carboxylate (intermediate 5).

Workup

  1. temperaturerefluxed for 20 hours
  2. filtrationfiltered hot
  3. customthe filtrate was evaporated
  4. customThe residue was purified by column chromatography over silica gel (eluent: DCM)
  5. customThe desired fractions were collected
  6. customthe solvent was evaporated
  7. additionToluene was added
  8. customazeotroped on the rotary evaporator

Sources & evidence

ORD record
ord-7ab66d16e9c8458ca22df66b17239717
Source dataset
uspto-grants-2010_06
Patent number
US07732464B2

Reaction notes

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