3-Acetylimidazo[1,2-a]pyridine

To a solution of imidazo[1, 2-a]pyridine (8.0 g, 67.7 mmol) in carbon disulfide (80 mL), was added powdered anhydrous AlClThe imidazo [1, 2-aM piperidine (59.3 mmoles) was dissolved in carbon disulfide (70 ml) under ice-cooling, Aluminum chloride (148.2 mmol) was added slowly, and repeatedly purged with nitrogen. At room temperature, after stirring for 30 minutes under reflux conditions Acetic anhydride (59.3 mmol) was slowly dropwise added to the system was added dropwise over 30 minutes period. The reaction in the reaction system under reflux for 5 hours, cooled. The solvent was removed by distillation under reduced pressure, the resulting residue was washed with a saturated aqueous sodium bicarbonate, washed with water and brine, dried over anhydrous sodium sulfate, and column chromatography (ethyl acetate: petroleum ether = 1: 8) afforded 2.9 g of the title compound. 12.9 g.2-Aminopyridine (1.88 g, 20 mmol) in 1, 1-dimethoxyN, N-dimethylmethanamine (3.82 g, 32 mmol) was refluxed for 23 h and then evaporated. The resulting residue was dissolved in EtOH (35 mL), 1-bromoacetone (3.12 g, 22.75 mmol) was added and the reaction mixture was stirred at room temperature for 24 h. The reaction mixture was concentrated and the residue was purified by column chromatography (eluent: dichloromethane/methanol = 40:1) to afford 12s as a pale yellow solid (2.06 g, 64percent). Mp: 95-96 °C (Lit.Mp [20] 98-99 °C). A solution of intermediate 1 (20 g, 0.21 mol) and DMF-DMA (38 g, 0.32 mol) was stirred at 90° C. for 3 hrs. The mixture was concentrated in vacuum, the residue was dissolved in EtOH (200 ml), 1-bromopropan-2-one (32 g, 0.23 mol) was added dropwise, and the mixture was stirred at room temperature for 4 hrs. The solvent was concentrated in vacuum and purified by flash column chromatography to give intermediate 23 (4.1 g, 12percent) as a yellow solid. (0384) The 2-aminopyridine (1. 88g, 20mmol) wasdissolved in N, N-Dimethyl formamide Dimethyl Acetal(3.82g32mmol)and refluxed the reaction for 23h. The reaction solution was concentrated, intothe residue added 35mL ethanol and Bromoacetone(3. 12g, 22. 7mmol) andat room temperature keep the reaction for 24h. The reaction solution wasconcentrated and the residue was separated and purified with columnchromatography (Eluent, petroleum ether: ethyl acetate = 40: 1, v / v) toobtain pale yellow solid 2.06g, yield64percent.

Molecular Weight:160.17
XLogP3:1.8
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:160.063662883
Monoisotopic Mass:160.063662883
Topological Polar Surface Area:34.4
Heavy Atom Count:12
Complexity:193
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes