6-Bromo-7-methylimidazo[1,2-a]pyridine

Uses

6-Bromo-7-methylimidazo[1,2-a]pyridine is used as an intermediate in pharmaceuticals and synthetic materials.

Synthesis

A solution of 5-bromo-4-methylpyridin-2-amine (8 g, 42.78 mmol) and chloroacetaldehyde (~50% wt aqueous solution, 27.52 mL, 214 mmol) in ethanol (50 mL) was heated to 100°C under nitrogen protection and reacted for 16 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was dissolved in ethyl acetate (100 mL) and the organic phase was washed sequentially with saturated sodium bicarbonate solution (2 x 50 mL), water (2 x 50 mL) and saturated saline (2 x 100 mL). The organic layer was dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 6-bromo-7-methylimidazo[1,2-a]pyridine (8.5 g, 94% yield) as a brown solid. The product was characterized by 1H NMR (400 MHz, DMSO-d6) and LC-MS: 1H NMR δ 8.93 (s, 1H), 7.85 (s, 1H), 7.57 (d, J = 7.56 Hz, 2H), 2.38 (s, 3H); LC-MS (95%) m/z 211 [C8H7BrN2 + H]+.

References

[1] Patent: WO2013/147711, 2013, A1. Location in patent: Page/Page column 207
[2] Patent: US2014/371199, 2014, A1. Location in patent: Paragraph 0729
[3] Patent: WO2010/108074, 2010, A2. Location in patent: Page/Page column 68-69