[N:1]1[CH:6]=[CH:5][CH:4]=[C:3]2[CH2:7][C:8]3[CH:14]=[C:13]([CH2:15][C:16](=[O:18])[CH3:17])[CH:12]=[CH:11][C:9]=3[O:10][C:2]=12.O.[CH3:20]I>[Na].C(O)(C)C>[N:1]1[CH:6]=[CH:5][CH:4]=[C:3]2[CH2:7][C:8]3[CH:14]=[C:13]([CH:15]([CH3:20])[C:16](=[O:18])[CH3:17])[CH:12]=[CH:11][C:9]=3[O:10][C:2]=1224 g of 5H-[1]benzopyrano[ 2,3-b]pyridin-7-yl-acetone is dissolved in a solution of 2.5 g of metallic sodium in 120 ml of isopropyl alcohol at 50°-60°C with stirring. The solution is cooled to 40°C with water, 17.2 g of methyl iodide is added, and the mixture is stirred under reflux for 1 hour. The isopropyl alcohol is distilled off under reduced pressure, and the residue is dissolved in chloroform. After water cooling, the solution is dried over anhydrous magnesium sulfate and concentrated, and the residue is recrystallized from isopropyl alcohol to give 19 g of 3-(5H-[1]benzopyrano[2,3-b]pyridin-7-yl)-2-butanone melting at 136°-136°C.
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