[C:1]([C:3]1[O:4][C:5]2[CH:13]=[C:12]([OH:14])[CH:11]=[CH:10][C:6]=2[C:7](=[O:9])[CH:8]=1)#[N:2].[Cl:15][CH2:16][CH2:17][CH2:18]Br.C(=O)([O-])[O-].[K+].[K+]>CC(C)=O>[C:1]([C:3]1[O:4][C:5]2[CH:13]=[C:12]([O:14][CH2:18][CH2:17][CH2:16][Cl:15])[CH:11]=[CH:10][C:6]=2[C:7](=[O:9])[CH:8]=1)#[N:2]A mixture of 2.43 g (13 mmol) of 2-cyano-7- hydroxy-4-oxo-4H-1-benzopyran, 2.04 g (13 mmol) of 3-chlorobromopropane and 1.80 g (13 mmol) of potassium carbonate was refluxed in 250 ml dry acetone overnight with heating. After evaporating to dryness, the residue was extracted with chloroform (3×100 ml), and dried with sodium sulfate. The chloroform solution was evaporated to one-third of the original volume to which was added n-hexane. The white precipitate was collected by filtration, washed with n-hexane and dried in vacuum to obtain 2-cyano-7-(3-chloropropyloxy)-4-oxo-4H-1-benzopyran (yield 51%).
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