Hydrochloric Acid → 6-Bromo-4-hydroxyquinolin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

The product of Step 2 (14.7 g) was added to polyphosphoric acid (55.3 mL) and mixture was heated to 140° C. for 3 hrs. The reaction mixture was cooled slightly and poured into 3N HCl (168 mL). The pH was adjusted to 4 with 3N NaOH and resulting solid was filtered after cooling the reaction mixture to 10° C. The cake was washed with water and then slurried in 400 mL of 50% isopropanol/water for 18 hours. The solids were filtered, air dried to give a pasty solid which was dried in vacuo at 90° C. for 4 hours, ground in mortar/pestle and re-dried at 90° C. for another 18 hours to give 15 g of the desired product.

Provenance & Evidence