DBDMH (20 mmol) was added in portions to a mixture of 1b (5 mmol) and methanol (30 mL). The reaction was carried out at room temperature. After stirring the mixture for 12 hours, the methanol was evaporated under vacuum. The residue was dissolved in methyl tert-butyl ether (MTBE) (30 mL) and washed with water (3 × 30 mL). The organic extract was dried over anhydrous MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography (silica gel, petroleum ether/ethyl acetate, 30:1) to give Methyl 6-chloronicotinate: a white solid.
