[C:1]([NH:4][C:5]1[CH:6]=[C:7]([OH:15])[C:8](=[CH:13][CH:14]=1)[C:9]([O:11][CH3:12])=[O:10])(=[O:3])[CH3:2].C(=O)([O-])[O-].[K+].[K+].[CH2:22](Br)[CH:23]=[CH2:24]>CN(C=O)C.C(OCC)(=O)C>[CH2:24]([O:15][C:7]1[CH:6]=[C:5]([NH:4][C:1](=[O:3])[CH3:2])[CH:14]=[CH:13][C:8]=1[C:9]([O:11][CH3:12])=[O:10])[CH:23]=[CH2:22]To a solution of 10 g (47.8 mmol) of methyl 4-acetylaminosalicylate in 30 ml of DMF is added 19.8 g (143.4 mmol) of finely ground potassium carbonate in a single portion at room temperature, followed by 8.3 ml (95.6 mmol) of allyl bromide in a similar fashion. The reaction mixture is heated to 60° C. and stirred at that temperature for 4 hours. After cooling to room temperature the reaction mixture is diluted with ethyl acetate and washed with water. The organic layer is dried over MgSO4, filtered and concentrated. Flash chromatography (10% ethyl acetate/hexane) provides methyl 2-allyloxy-4-acetylaminobenzoate which can be used directly in the next step.
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