[Synthesis]
The general procedure for the synthesis of methyl [2,3'-bipyridine]-6-carboxylate from 2-trimethylsilylpyridine and methyl 5-bromopyridine-2-carboxylate was as follows: according to the method modified from the literature by Tye et al. (Tet. Lett., 2008, 49, 3939), methyl 5-bromo-2-pyridinecarboxylate (0.25 g, 1.16 mmol) was prepared by adding methyl 5-bromo-2-pyridinecarboxylate (0.25 g, 1.16 mmol) in stirred and 2-(trimethylmethylsilyl)pyridine (0.48 mL, 3.48 mmol) in an anhydrous N,N-dimethylformamide (7.5 mL) suspension in turn. methylmethylsilyl)pyridine (0.48 mL, 3.48 mmol) in a suspension in anhydrous N,N-dimethylformamide (7.5 mL), silver(I) oxide (0.27 g, 1.16 mmol), allylpalladium chloride dimer (21 mg, 5 mol%), and tetrabutylammonium fluoride (1 M solution in THF, 0.116 mL) were added in sequence. The reaction mixture was heated at 90 °C for 18 hours. After completion of the reaction, the mixture was filtered and washed with EtOAc. The filtrate was concentrated under reduced pressure and purified by column chromatography (silica gel, eluent DCM, 0-2% MeOH gradient) to give 0.12 g (48% yield) of methyl 2,3'-bipyridine-6'-carboxylate. Mass spectrometry analysis showed m/z = 215 [M+ + H]. |