Hydrochloric Acid → 4-(3,5-dichloropyridin-4-ylamino)-8-hydroxy-7-methoxy-2H-chromen-2-one

Participants

Reaction Conditions

Reaction Steps

8-(Cyclopropylmethoxy)-4-(3,5-dichloropyridin-4-ylamino)-7-methoxy-2H-chromen-2-one (5.4 g, 13.3 mmol, Example 5) was added in one portion to conc. HCl (90 mL). After 1 h of vigorous stirring, the mixture was diluted with water (50 mL, 0° C.) and cooled to 0° C. The white precipitate was filtered, washed with water (100 mL, 0° C.), and then resuspended in water (100 mL, 0° C.). After 30 min of vigorous stirring, the white solid was filtered, washed with water (100 mL, 0° C.), and dried to give 4-(3,5-dichloropyridin-4-ylamino)-8-hydroxy-7-methoxy-2H-chromen-2-one: 1H NMR (400 MHz, DMSO-d6): δ 9.53 (br, 2H), 8.79 (s, 2H), 7.66 (d, 1H), 7.12 (d, 1H), 4.60 (s, 1H), 3.90 (s, 3H); MS (ESI): 352.9.

Provenance & Evidence