General procedure for the synthesis of imidazo[1,2-a]pyridine-8-carboxylic acid from 2-aminonicotinic acid and 2-bromo-1,1-dimethoxyethane: To a suspension of 2-aminonicotinic acid (0.69 g, 5.00 mmol) in acetonitrile (20 mL) was added 2-bromo-1,1-dimethoxyethane (0.59 mL, 5.00 mmol). The resulting mixture was heated to 150 °C in a microwave reactor and kept for 2 hours. After completion of the reaction, the precipitate was collected by filtration and washed sequentially with acetonitrile and hexane to afford imidazo[1,2-a]pyridine-8-carboxylic acid (0.924 g) as a gray solid.