The general procedure for the synthesis of 2-bromo-4-dimethylaminopyridine from 2,4-dibromopyridine and dimethylamine was as follows: 2,4-dibromopyridine (100 mg, 0.31 mmol) was dissolved in ethanol (2 mL), and 33% ethanol solution of dimethylamine was added. The reaction mixture was heated and stirred at 50 °C for 5 hours. After completion of the reaction, the mixture was concentrated under reduced pressure to remove the solvent. The crude product was purified by an ISCO? automated column chromatography system using a silica gel column eluting with a 0-70% ethyl acetate/pentane gradient. The target product 2-bromo-4-dimethylaminopyridine (51 mg, 0.25 mmol, 81% yield) was obtained. The structure of the product was confirmed by 1H-NMR (CDCl3, 400 MHz): δ 3.0 (s, 6H), 6.4 (m, 1H), 6.6 (s, 1H), 7.9 (d, 1H). Mass spectrometry (APCI) showed the molecular ion peak m/z 201 [MH]+.
