[Br:1][C:2]1[CH:3]=[CH:4][C:5](/[N:8]=[CH:9]/N(C)C)=[N:6][CH:7]=1.Cl[CH2:14][C:15](=[O:17])[CH3:16].C([O-])(O)=O.[Na+]>CC(O)C.O>[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[N:6]([C:14]([C:15](=[O:17])[CH3:16])=[CH:9][N:8]=2)[CH:7]=1(E)-N′-(5-Bromopyridin-2-yl)-N,N-dimethylformimidamide (2.0 g, 8.8 mmol), 1-chloropropan-2-one (1.2 mL, 1.4 g, 15 mmol), NaHCO3 (1.3 g, 15.5 mmol) in 2-propanol (30 mL) were heated at 90° C. under nitrogen for 12 h. The dark reaction mixture was cooled and the dense heterogeneous suspension was diluted with water. The solid was collected by filtration, washed with water and dried to obtain 1.0 g of 1-(6-bromoimidazo[1,2-a]pyridin-3-yl)ethan-1-one. 1H NMR (300 MHz, DMSO-d6) δ 9.62 (d, J=1.9 Hz, 1H), 8.61 (s, 1H), 7.81 (d, J=9.5 Hz, 1H), 7.75 (dd, J=9.5, 1.9 Hz, 1H), 2.55 (s, 3H). See Bioorg. Med. Chem. Lett. 15(1), 403-412 (2007); Int'l Pat. App. Pub, no. 2009/158011.
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