[C:1]([C:4]1[CH:9]=[CH:8][C:7]([CH2:10][C:11]([O:13][CH2:14][CH3:15])=[O:12])=[CH:6][CH:5]=1)(=O)[CH3:2].II.[NH2:18][C:19]1[CH:24]=[CH:23][CH:22]=[CH:21][N:20]=1>C(O)C>[N:18]1[C:1]([C:4]2[CH:9]=[CH:8][C:7]([CH2:10][C:11]([O:13][CH2:14][CH3:15])=[O:12])=[CH:6][CH:5]=2)=[CH:2][N:20]2[CH:21]=[CH:22][CH:23]=[CH:24][C:19]=12A mixture of 6 g of ethyl 4-acetylphenylacetate, 20 ml of ethanol, 7.5 g of iodine and 5.7 g of 2-aminopyridine is heated under reflux for 3 hours. The ethanol is distilled off under reduced pressure, and the residue is extracted with ethyl acetate. The extract is washed with water, dried, and concentrated to give a reddish brown oil. The oil is column chromatographed over silica gel with chloroform as eluent, and the colorless crystals obtained from the chloroform eluate are recrystallized from a mixture of benzene and petroleum ether to give 3.0 g of ethyl 4-(imidazo[1,2-a]pyridin-2-yl)phenylacetate melting at 92°-93°C.
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