Hydrogen Bromide → 3-Phenyl-4,8-dihydroxy-coumarin

HRID 904303Notes

Reaction equation

HRID 904303 reaction equation
C[O:2][C:3]1[CH:4]=[CH:5][CH:6]=[C:7]2[C:12]=1[O:11][C:10](=[O:13])[C:9]([C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)=[C:8]2[OH:20].Br.C(OC(=O)C)(=O)C>C(O)(=O)C>[OH:20][C:8]1[C:7]2[C:12](=[C:3]([OH:2])[CH:4]=[CH:5][CH:6]=2)[O:11][C:10](=[O:13])[C:9]=1[C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][CH:19]=1

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 7918Acetic AnhydrideHCID 547213328-Methoxy-4-hydroxy-3-phenylcoumarin

Product 1

HCID 547213333-Phenyl-4,8-dihydroxy-coumarinYield 38.1%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent

Procedure

37.6 g. (0.14 mol) of 8-methoxy-4-hydroxy-3-phenylcoumarin are brought to reflux for 1 hour in a mixture of 750 ml. of 62% hydrobromic acid, 375 ml. of glacial acetic acid and 375 ml. of acetic anhydride. The mixture is poured on to 5.3 kg. of ice, filtered and dried. 25.3 g. of a solid are obtained, which is recrystallised from a mixture of dioxane and diisopropyl ether (50:50). Weight 13 g., yield 38.1% (theoretical yield 34.2 g.); M.P. 220° C.

Workup

  1. temperatureto reflux for 1 hour in a mixture of 750 ml
  2. additionThe mixture is poured on to 5.3 kg
  3. filtrationof ice, filtered
  4. customdried
  5. customof a solid are obtained
  6. customwhich is recrystallised from a mixture of dioxane and diisopropyl ether (50:50)

Sources & evidence

ORD record
ord-eecef8a08442429bb828092e1625e605
Source dataset
uspto-grants-1980_10
Patent number
US04230850

Reaction notes

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