Pyridine → 8-Bromo-5-methoxy-3-chromanone

HRID 1464694Notes

Reaction equation

HRID 1464694 reaction equation
N1C=CC=CC=1.[Br:7][C:8]1[CH:9]=[CH:10][C:11]([O:19][CH3:20])=[C:12]2[C:17]=1[O:16][CH2:15][CH:14]([OH:18])[CH2:13]2.C(OC(=O)C)(=O)C>C(Cl)Cl>[Br:7][C:8]1[CH:9]=[CH:10][C:11]([O:19][CH3:20])=[C:12]2[C:17]=1[O:16][CH2:15][C:14](=[O:18])[CH2:13]2

Participants

5

Reactant 3

HCID 1049PyridineHCID 7918Acetic AnhydrideHCID 147034238-Bromo-5-methoxy-3-chromanol

Product 1

HCID 147034268-Bromo-5-methoxy-3-chromanoneYield 81.6%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a solution consisting of dry pyridine and CH2Cl2 (120 ml, dried over P2O5) CrO3 (435 mg, 4.35 mmol) was added. The mixture was stirred for 15 min and 8-bromo-5-methoxy-3-chromanol (293 mg, 1.13 mmol) was dissolved in 10 ml dry CH2Cl2 was added and immediately thereafter acetic acid anhydride (0.41 ml, 4.35 mmol) was added to the solution. The mixture was stirred for 10 min and then sucked through a short silica column (13 g SiO2) with vacuum. The column was washed with CH2Cl2 and the solvent evaporated yielding 237 mg (81%) of the product. An analytic sample was obtained from recrystallization in light petroleum-ether, m.p. 97°-100° C. 1H NMR (CHCl3) δ 3.55 (s,2H), 3.80 (s,3H), 4.45 (s,2H), 6.5 (d,1H), 7.4 (d,1H). GC/M (HP-5970A) m/e=258 (64) M+1, 256 (57) M-1, 134 (100), 50 (11), 76 (11).

Workup

  1. additionwas added
  2. additionwas added
  3. stirringThe mixture was stirred for 10 min
  4. washThe column was washed with CH2Cl2
  5. customthe solvent evaporated

Sources & evidence

ORD record
ord-c043fa0b655c49808757c7a1b92737a3
Source dataset
uspto-grants-1994_04
Patent number
US05306830

Reaction notes

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