Sulfuric Acid → 1-Chloroisoquinoline-5-sulfonic acid

Participants

Reaction Conditions

Reaction Steps

To an ice-cold solution of fuming sulphuric acid (20% SO3, 2 mL) was added 1-chloroisoquinoline (1.0 g, 6.1 mmol) portionwise with stirring. After stirring at room temperature for 3 hours, the reaction was heated at 80° C. for 18 h, then cooled in an ice bath, poured onto ice (70 g), washed with ether, and concentrated in vacuo. The residues were treated with isopropanol giving a white solid which was filtered and dried to give 1-chloro-5-isoquinolinesulphonic acid (1.16 g, 4.77 mmol).

Provenance & Evidence