CC(C)([O-])C.[K+].CC1C=CC(S([CH2:17][N+:18]#[C-])(=O)=O)=CC=1.[O:20]1[CH2:24][CH2:23][O:22][CH:21]1[C:25]1[CH:29]=[CH:28][S:27][C:26]=1[CH:30]=O.[Cl-].[NH4+]>CO.C1COCC1>[O:22]1[CH2:23][CH2:24][O:20][CH:21]1[C:25]1[CH:29]=[CH:28][S:27][C:26]=1[CH2:30][C:17]#[N:18]20 ml of a THF solution of 4.49 g (40.0 mmol) of potassium tert-butoxide was cooled to −45 to −30° C., and 20 ml of a THF solution of 3.90 g (20.0 mmol) of TOSmic and 20 ml of a THF solution of 3.68 g (20.0 mmol) of 3-(1,3-dioxolan-2-yl)-2-thiophenecarboaldehyde were successively added thereto. After 40 minutes, 60 ml of methanol was added at −15° C. After heating under reflux for 15 minutes, an aqueous saturated ammonium chloride was added, and the mixture was extracted with ethyl acetate. The extract was washed with brine, and then dried over anhydrous magnesium sulfate. The solvent was evaporated, to give a crude product. The crude product was subjected to Cromatorex NH silica gel (ethyl acetate:hexane=1:4), to give 1.43 g (7.32 mmol, 36.6%) of the title compound as a yellow oil.
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