2-Aminopyridine → 6-Aminopyridine-3-sulfonyl chloride

Participants

Reaction Conditions

Reaction Steps

Under ice-cooling, 10.00 g (0.106 mol) of 2-aminopyridine was added little by little to 123.8 g (1.06 mol) of chlorosulfonic acid. To the mixture was added 50.56 g (0.425 mol) of thionyl chloride. The mixture was heated under reflux for 2.5 hours, and further stirred at 150° C. for 7 hours. The reaction solution was poured into ice-water, neutralized by adding sodium bicarbonate and extracted with ethyl acetate. The organic layer was successively washed with an aqueous saturated sodium bicarbonate, water and brine, dried over magnesium sulfate, and then concentrated to dryness. The residue was suspended in ethyl ether and the insoluble matters were filtered off. The filtrate was concentrated to dryness and the residue was recrystallized from ethyl ether/hexane, to give 6.58 g of the title compound.

Provenance & Evidence