Chloroacetaldehyde → 8-(Benzyloxy)-5-bromoimidazo[1,2-a]pyridine
Reaction equation
[CH2:1]([O:8][C:9]1[C:10]([NH2:16])=[N:11][C:12]([Br:15])=[CH:13][CH:14]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.Cl[CH2:18][CH:19]=O>>[CH2:1]([O:8][C:9]1[C:10]2[N:11]([CH:18]=[CH:19][N:16]=2)[C:12]([Br:15])=[CH:13][CH:14]=1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1Participants
3
Procedure
A mixture of 3-benzyloxy-6-bromopyridin-2-ylamine (1.0 g, 3.6 mmol) and chloroacetaldehyde (1.2 mL, 50 wt. % in water) in IMS (12 mL) was stirred at reflux for 1 hour, then concentrated under reduced pressure. The residue was partitioned between an aqueous saturated solution of sodium bicarbonate and EtOAc. The organic layer was separated and washed with brine, dried over Na2SO4, filtered and concentrated. The residue was purified by flash chromatography (Si—PPC, MeOH:Et2O, gradient 0:100 to 1:99) to give 8-Benzyloxy-5-bromo-imidazo[1,2-a]pyridine as an beige solid (960 mg, 88%). LCMS (Method H) RT 3.08 min; [M+H]+ 303 (79Br) and 305 (81Br)
Workup
- temperatureat reflux for 1 hour