[OH:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[C:4](=[O:14])[C:5](=[C:11]([CH3:13])[CH3:12])[O:6]2.C(=O)([O-])[O-].[K+].[K+].[Cl:21][CH2:22][C:23]#[C:24][CH2:25]Cl>CN(C)C=O>[Cl:21][CH2:22][C:23]#[C:24][CH2:25][O:1][C:2]1[CH:10]=[CH:9][CH:8]=[C:7]2[C:3]=1[C:4](=[O:14])[C:5](=[C:11]([CH3:12])[CH3:13])[O:6]2A mixture of 5.0 g 4-hydroxy-2-isopropylidenecoumaran-3-one, 4.6 g potassium carbonate, 3.3 ml 1,4-dichloro-but-2-yne and 100 ml dimethylformamide is warmed to 50° C. for 3 hours, then evaporated, mixed with water and extracted with dichloromethane. After evaporation of the extract, the residue (9.2 g) is purified by silica gel chromatography (eluent isohexane/ethyl acetate 9:1) to give 2.2 g of the desired intermediate.
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