Bromobenzene → 2,2-Dimethyl-4-phenyl-2H-1-benzopyran-7-ol

HRID 1577447Notes

Reaction equation

HRID 1577447 reaction equation
Br[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Mg].[CH3:9][C:10]1([CH3:22])[CH2:19][C:18](=O)[C:17]2[C:12](=[CH:13][C:14]([OH:21])=[CH:15][CH:16]=2)[O:11]1.[Cl-].[NH4+]>O1CCCC1>[CH3:9][C:10]1([CH3:22])[CH:19]=[C:18]([C:2]2[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=2)[C:17]2[C:12](=[CH:13][C:14]([OH:21])=[CH:15][CH:16]=2)[O:11]1

Participants

6

Reactant 4

HCID 7961BromobenzeneHCID 25517Ammonium ChlorideHCID 6009027-hydroxy-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-oneHCID 5462224Magnesium

Product 1

HCID 205704922,2-Dimethyl-4-phenyl-2H-1-benzopyran-7-olYield 57.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

Bromobenzene (141.3 g) in dry tethydrofuran (300 ml) was added to magnesium (23.7 g) in dry tetrahydrofuran (100 ml). 2,2-Dimethylchroman-4-one-7-ol (34.5 g) in dry tetrahydrofuran (250 ml) was then added and the solution refluxed for 48 hours. The mixture was poured into ammonium chloride solution, the tetrahydrofuran layer was separated and evaporated under reduced pressure. The aqueous layer was extracted with ethyl acetate and the organic layer and the residue from the tetrahydrofuran layer was shaken with 10% sodium hydroxide solution. The basic layer was acidified and re-extracted with ethyl acetate. The organic layers were dried (MgSO4). Removal of the solvent under reduced pressure gave an oil (26 g) which was chromatographed on silica. Elution with ether-petrol (1:1) gave the title compound (14 g).

Workup

  1. temperaturethe solution refluxed for 48 hours
  2. customthe tetrahydrofuran layer was separated
  3. customevaporated under reduced pressure
  4. extractionThe aqueous layer was extracted with ethyl acetate
  5. extractionre-extracted with ethyl acetate
  6. dry with materialThe organic layers were dried (MgSO4)
  7. customRemoval of the solvent under reduced pressure

Sources & evidence

ORD record
ord-c0f94963537944c8b9077b8083538f5c
Source dataset
uspto-grants-1981_09
Patent number
USRE030739

Reaction notes

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