[C:1]([C:3]1[S:7][C:6]2[CH:8]=[CH:9][C:10]([CH:12]=[CH:13][C:14]([O:16][CH3:17])=[O:15])=[CH:11][C:5]=2[CH:4]=1)#[N:2]>C1COCC1.[Pd]>[C:1]([C:3]1[S:7][C:6]2[CH:8]=[CH:9][C:10]([CH2:12][CH2:13][C:14]([O:16][CH3:17])=[O:15])=[CH:11][C:5]=2[CH:4]=1)#[N:2]Methyl 3-(2-cyanobenzo[b]thiophen-5-yl)acrylate (2.5 g) was hydrogenated in THF (20 ml) using 10% palladium on carbon (0.5 g) as catalyst until the majority of the starting material had disappeared by thin layer chromatography (silica plates eluting with ethyl acetate/hexane 1:4). The mixture was filtered and evaporated to give methyl 2-cyanobenzo[b]thiophene-5-propionate (1.45 g) contaminated with ~20% of starting material. Sodium hydroxide (0.23 g) was added to a mixture of this product (1.4 g) in THF (10 ml) and uater (3 ml) and the mixture was stirred for 2 hours. The mixture was adjusted to ~pH 5 with concentrated hydrochloric acid and concentrated by evaporation to remove the THF present.
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