Sodium Hydroxide → Laquinimod Sodium

Participants

Reaction Conditions

Reaction Steps

N-Ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide (35 gm) was suspended in ethanol (140 ml) at 20-25° C. under stirring followed by the addition of freshly prepared sodium hydroxide solution (4.13 gm of sodium hydroxide in 11 ml of water) at 20-25° C. and then stirred for 15-30 minutes at 25-30° C. The resulting solution was filtered through a hyflow super cell bed and the bed was washed with ethanol (105 ml) at 25-30° C. The resulting filtrate was seeded with pure laquinimod sodium (0.175 gm) and then stirred for 4 hours at 25-30° C. The resulting mass was cooled to 0-5° C. followed by stirring for 2 hours at the same temperature. The resulting white colored solid was filtered, washed with chilled ethanol (38 ml) and then dried under vacuum at 60-65° C. to yield 28 gm of laquinimod sodium in crystalline Form A1 (HPLC Purity: 99.9%; Bulk density: 0.333 g/ml; Tapped density: 0.476 g/ml; and Particle size distribution: d(0.9)=26.3 microns).

Provenance & Evidence