Chloroform → 4-(5-Chloro-2-methylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione

HRID 1191542Notes

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.C([O-])(=O)C.C([O-])(=O)C.C([O-])(=O)C.[Cl:29][C:30]1[CH:31]=[CH:32][C:33]([CH3:37])=[C:34]([Pb+3])[CH:35]=1>C(OCC)(=O)C>[Cl:29][C:30]1[CH:35]=[CH:34][C:33]([CH3:37])=[C:32]([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:31]=1

Participants

Conditions

Temperature: 40 °C

Procedure

To a mixture of 2,2,6,6-tetramethylpyran-3,5-dione (described in U.S. Pat. No. 5,089,046A) (0.504 g, 2.96 mmol) and N,N-dimethylaminopyridine (1.45 g, 11.84 mmol) is added anhydrous chloroform (40 ml). To this solution is added crude 5-chloro-2-methylphenyllead triacetate (2.26 g, 4.44 mmol) in one portion, and the mixture is then heated at 40° C. for 17 hours (analysis), then for a further 23 hours at 45-50° C. The mixture is allowed to cool to room temperature, then diluted with ethyl acetate (100 ml) and washed with dilute aqueous hydrochloric acid (3×30 ml). The organic phase is dried over anhydrous magnesium sulfate, then concentrated to give a yellow gum which is purified by column chromatography (ethyl acetate/hexane/acetic acid 8:18:1 ratio) then triturated with hexanes to afford 4-(5-chloro-2-methylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione (0.53 g) as a white solid.

Workup

temperatureto cool to room temperature
washwashed with dilute aqueous hydrochloric acid (3×30 ml)
dry with materialThe organic phase is dried over anhydrous magnesium sulfate
concentrationconcentrated
customto give a yellow gum which
customis purified by column chromatography (ethyl acetate/hexane/acetic acid 8:18:1 ratio)
customthen triturated with hexanes

Sources & evidence

ORD record: ord-4c8ec70b00c54fa5ac897cf52fa9f01e
Source dataset: uspto-grants-2014_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08680012B2

Reaction notes

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