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

Participants

Reaction Conditions

Reaction Steps

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

Provenance & Evidence