Toluene → 4-(5-Bromo-2-chlorophenyl)-2,2,6,6-tetramethylpyran-3,5-dione

HRID 1191569Notes

Reaction equation

HRID 1191569 reaction equation
[CH3:1][C:2]1([CH3:12])[C:7](=[O:8])[CH2:6][C:5](=[O:9])[C:4]([CH3:11])([CH3:10])[O:3]1.C(Cl)(Cl)Cl.C1(C)C=CC=CC=1.C([O-])(=O)C.C([O-])(=O)C.C([O-])(=O)C.[Br:36][C:37]1[CH:38]=[CH:39][C:40]([Cl:44])=[C:41]([Pb+3])[CH:42]=1>ClCCl.Cl>[Br:36][C:37]1[CH:42]=[CH:41][C:40]([Cl:44])=[C:39]([CH:6]2[C:7](=[O:8])[C:2]([CH3:12])([CH3:1])[O:3][C:4]([CH3:11])([CH3:10])[C:5]2=[O:9])[CH:38]=1

Participants

7

Reactant 4

HCID 1140TolueneHCID 6212ChloroformHCID 199092752,2,6,6-Tetramethyloxane-3,5-dioneHCID 178476543[Diacetyloxy-(5-bromo-2-chlorophenyl)plumbyl] acetate

Product 1

HCID 684878854-(5-Bromo-2-chlorophenyl)-2,2,6,6-tetramethylpyran-3,5-dioneYield 7.5%

Reagents, catalysts & solvents 2

HCID 313Hydrochloric AcidSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
80 °C

Procedure

To a mixture of 2,2,6,6-tetramethylpyran-3,5-dione (2.78 g, 16.3 mmol) and N,N-dimethylaminopyridine (9.97 g, 81.6 mmol) is added anhydrous chloroform (120 ml). To this solution is added anhydrous toluene (30 ml), followed by 5-bromo-2-chlorophenyllead triacetate (10.32 g, 18 mmol) in one portion and the reaction mixture is heated at 80° C. overnight. The mixture is allowed to cool to room temperature, then diluted with dichloromethane (120 ml) and 2M aqueous hydrochloric acid (250 ml), followed by filtration through diatomaceous earth to remove inorganic residues. The filter cake is washed with dichloromethane, and all organic fractions are combined, washed with 2M hydrochloric acid, water and brine, dried over anhydrous magnesium sulfate then concentrated in vacuo. This material is finally purified by flash column chromatography on silica gel to afford 4-(5-bromo-2-chlorophenyl)-2,2,6,6-tetramethylpyran-3,5-dione (0.44 g) of sufficient purity to use directly in the next step.

Workup

  1. temperatureto cool to room temperature
  2. filtrationfollowed by filtration through diatomaceous earth
  3. customto remove inorganic residues
  4. washThe filter cake is washed with dichloromethane
  5. washwashed with 2M hydrochloric acid, water and brine
  6. dry with materialdried over anhydrous magnesium sulfate
  7. concentrationthen concentrated in vacuo
  8. customThis material is finally purified by flash column chromatography on silica gel

Sources & evidence

ORD record
ord-60ee0b9bfdf34abc8572b41d19ad058e
Source dataset
uspto-grants-2014_03
Patent number
US08680012B2

Reaction notes

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