248919-96-2

To a suspension of 5,6-diamino-nicotinic acid methyl ester (1 eq., 5.1 g) in cyclohexanone (50 ml) bromobutanone (1.2 equiv., 3.9 ml) was added over 10 min. The mixture was heated to 100° C. (inner temperature) and stirred 2.5 h at this temperature. The mixture was cooled to room temperature and the pale solid methyl 8-amino-2,3-dimethylimidazo[1,2-a]pyridine-6-carboxylate was filtered off and was washed with TBME (3×10 ml). Drying under reduced pressure at 45° C.