Chloroacetone → 8-Bromo-2-methylimidazo[1,2-a]pyridin-7-amine

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Reaction Steps

To a solution of 2,4-diamino-3-bromopyridine (17) (in Rauckman, B. S, and al. J. Med. Chem. 1980, 23, 384-391) (2.00 g, 10.6 mmol) in ethanol (40 mL) was added chloracetone (3.93 g, 42.5 mmol). The solution was stirred under reflux for 24 h. After cooling to room temperature, the solution was evaporated to dryness. The residue was diluted with water (40 mL) and the resulting solution made basic by the addition of Na2CO3. The solution was extracted with CH2Cl2 and the combinated extracts were dried (Na2SO4), filtered and evaporated under reduced pressure. The crude product was purified by chromatography using CH2Cl2/EtOAc (4/1, v/v) as eluent to afford compound 18 (yield: 90%); mp 158-160° C.; 1H NMR (200 MHz, DMSO-d6) δ 2.19 (s, 3H), 5.78 (brs, 2H), 6.41 (d, 1H, J=7 Hz), 7.36 (s, 1H), 8.07 (d, 1H, J=7 Hz); 13C NMR (100 MHz, DMSO-d6) δ 14.1, 86.2, 104.6, 109.1, 125.5, 140.8, 143.1, 144.0. Anal.

Provenance & Evidence