[CH3:1][O:2][C:3]1[CH:4]=[C:5]([S:11][CH2:12][CH2:13][C:14](OC)=O)[CH:6]=[N:7][C:8]=1[O:9][CH3:10].CC(C)([O-])C.[K+].BrC[C:26]1C=C[CH:29]=[C:28]([Cl:32])[CH:27]=1>C1COCC1>[Cl:32][C:28]1[CH:29]=[C:13]([CH:14]=[CH:26][CH:27]=1)[CH2:12][S:11][C:5]1[CH:4]=[C:3]([O:2][CH3:1])[C:8]([O:9][CH3:10])=[N:7][CH:6]=1To a cooled solution of methyl 3-[(5,6-dimethoxypyridin-3-yl)sulfanyl]propanoate (Intermediate 7, 257 mg, 1 mmol) in THF (6 ml) at −45° C. was added potassium tert-butoxide (123 mg, 1.10 mmol). After stirring at −45° C. for 20 minutes, 1-(bromomethyl)-3-chlorobenzene (0.16 ml, 1.20 mmol) was added and the reaction mixture was stirred with warming to room temperature for 2 hours. The resulting mixture was partitioned between ethyl acetate (15 ml) and water (15 nil) and the resulting organic layer was washed with brine (15 ml), dried (MgSO4), filtered and concentrated in vacuo to give yellow oil. Purification by column chromatography (SiO2; 0-10% ethyl acetate in petrol) gave 5-(3-chlorobenzylthio)-2,3-dimethoxypyridine as a yellow oil (244 mg, 82%).
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