C(N1C=CN=C1)(N1C=CN=C1)=O.[I:13][C:14]1[CH:22]=[CH:21][C:17]([C:18]([OH:20])=O)=[CH:16][CH:15]=1.O[NH:24][C:25](=[NH:27])[CH3:26].C[O-].[Na+].CO>CN(C)C=O.O.C(OCC)(=O)C>[I:13][C:14]1[CH:15]=[CH:16][C:17]([C:18]2[O:20][N:27]=[C:25]([CH3:26])[N:24]=2)=[CH:21][CH:22]=11,1′-Carbonyldiimidazole (0.49 g, 3 mmol) was added to a solution of 4-iodobenzoic acid (0.5 g, 2 mmol) in dry dimethylformamide (4 ml) and stirred at room temperature for 30 minutes. N-hydroxy-acetamidine (0.224 g, 3 mmol) was added and stirring at room temperature continued for 16 hours. Sodium methoxide in methanol (25% wt solution; 1.1 ml, 5 mmol) was added and the mixture heated at 80° C. for 6 hours. Once cool, ethyl acetate (50 ml) and water (50 ml) were added. The organic layer was washed with water (50 ml), brine (50 ml), dried over magnesium sulfate, filtered and solvent removed in vacuo. The residue was purified by silica SPE cartridge (5 g) (100% cyclohexane, 20:1 cyclohexane/ethyl acetate v:v to 10:1 cyclohexane/ethyl acetate v:v) to yield the desired product as a white solid (0.15 g, 0.52 mmol).
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