Methanol → 6H-Dibenzo(b,d)pyran-6-one, 3,4-dihydroxy-

HRID 1030223Notes

Reaction equation

HRID 1030223 reaction equation
C(N(C(C)C)[C:5]([C:7]1[C:8]([C:13]2[CH:18]=[CH:17][C:16]([O:19]C)=[C:15]([O:21]C)[C:14]=2[O:23]C)=[CH:9][CH:10]=[CH:11][CH:12]=1)=[O:6])(C)C.B(Br)(Br)Br.CO.C(Cl)(Cl)Cl.O>C(Cl)Cl.C(O)(=O)C>[OH:19][C:16]1[CH:17]=[CH:18][C:13]2[C:8]3[CH:9]=[CH:10][CH:11]=[CH:12][C:7]=3[C:5](=[O:6])[O:23][C:14]=2[C:15]=1[OH:21]

Participants

7

Reactant 4

HCID 887MethanolHCID 25134Boron tribromideHCID 14827045HCID 14827045, compoundHCID 22418719Chloroform water

Product 1

HCID 54880466H-Dibenzo(b,d)pyran-6-one, 3,4-dihydroxy-Yield 77%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
-78 °C

Procedure

N,N-Diisopropyl-2',3',4'-trimethoxy-2-biphenylcarboxamide (0.94 mmol) was dissolved in dry methylene chloride (40 ml). The solution was cooled down to -78° C., BBr3 (5.6 mmol) was added slowly. Reaction was allowed to warm to room temperature over a period of 22 hours. The mixture was again cooled down to -78° C. and methanol (3 ml) was added. The reaction was warmed to room temperature over a period of 2 hours. All solvent was evaporated. The solid was extracted with chloroform. Removal of solvent gave white fluffy solid which was dissolved in glacial acetic acid (10 ml) and refluxed over night. Removal of acetic acid gave a solid, which was worked up with chloroform-water, the aqueous layer was separated and was extracted several times with chloroform. The chloroform layer was washed with satd. NaHCO3 solution. Removal of chloroform gave 77% (0.72 mmol) of solid product, which was recrystallized from methanol (m.p. 252° C.-254° C.). NMR spectrum was analyzed to be: δ6.84 (d, 1H, J=8.7 Hz, Ar--H), 7.63 (d, 1H, J=8 Jz, Ar--H), 7.82-7.89 (m 1H, Ar--H), 8.17-8.24 (t, 2H, Ar--H), 9.27 (br s, 1H, OH [D2O exchangeable]), 9.89 (br s, 1H, OH [D2O exchangeable]); MS m/z (relative intensity) 229 (M+1, 13), 228 (M+, 100), 200 (6), 126 (11), 115 (26).

Workup

  1. customReaction
  2. temperatureto warm to room temperature over a period of 22 hours
  3. additionwas added
  4. temperatureThe reaction was warmed to room temperature over a period of 2 hours
  5. customAll solvent was evaporated
  6. extractionThe solid was extracted with chloroform
  7. customRemoval of solvent
  8. customgave white fluffy solid which
  9. temperaturerefluxed over night
  10. customRemoval of acetic acid
  11. customgave a solid, which
  12. customthe aqueous layer was separated
  13. extractionwas extracted several times with chloroform
  14. washThe chloroform layer was washed with satd
  15. customRemoval of chloroform

Sources & evidence

ORD record
ord-4ed0a9e8534e45b6bd2b91e9d35ce545
Source dataset
uspto-grants-1992_04
Patent number
US05104894

Reaction notes

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