[C:1]([C:4]1[C:9](=[O:10])[CH:8]=[C:7]([CH3:11])[O:6][C:5]=1[CH3:12])([OH:3])=[O:2].[C:13](Cl)(=O)C.CO.C(=O)([O-])[O-].[Na+].[Na+]>C(Cl)Cl>[C:1]([C:4]1[C:9](=[O:10])[CH:8]=[C:7]([CH3:11])[O:6][C:5]=1[CH3:12])([O:3][CH3:13])=[O:2]42 g of 3-carboxy-2,6-dimethylpyr-4-one is dissolved in 250 ml of methylene chloride. In a second flask, 20 ml of acetyl chloride is cautiously added to 400 ml of methanol. The two solutions are mixed and refluxed for five hours. Solid sodium carbonate is added and the solvent removed after a water wash. The residue is distilled (115°-125° at 0.1 mm) to give 40 g of 3-carbomethoxy-2,6-dimethylpyr-4-one as a waxy solid.
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