[OH:1][C:2]1[C:10]2[O:9][CH:8]([C:11]([O:13][CH3:14])=[O:12])[CH2:7][C:6]=2[CH:5]=[CH:4][CH:3]=1.CO[C:17]1[C:25]2OC(C(O)=O)CC=2C=C[CH:18]=1.O[C:30]1C=CC=C2C=1C=C1C(=C2)C(=O)CCC1.C(Br)C#C.C([O-])([O-])=O.[K+].[K+]>CC(=O)CC>[CH2:25]([O:1][C:2]1[C:10]2[O:9][CH:8]([C:11]([O:13][CH2:14][CH3:30])=[O:12])[CH2:7][C:6]=2[CH:5]=[CH:4][CH:3]=1)[C:17]#[CH:18]37.57 g (0.194 mol) of methyl 7-hydroxy-2,3-dihydro-benzofuran-2-carboxylate [prepared from the known 7-methoxy-2,3-dihydro-benzofuran-2-carboxylic acid, G. Goldenberg et al., Chim. Ther. 8 (3), 1973, 259-270] and 32.85 g (0.213 mol) of propargyl bromide (80% in toluene) are refluxed in the presence of 29.49 g (0.213 mol) of K2CO3 in 194 ml of dry butanone for 5 h. After cooling, the precipitate is filtered off and washed well with acetone, and the filtrate is evaporated. The residue is taken up in 200 ml of CH2Cl2, shaken twice with 10% strength NaOH solution, dried over Na2SO4 and evaporated. The residue is flash chromatographed on silica gel (eluent: petroleum ether/acetone 5:1).
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