Dichloromethane → Laquinimod

Participants

Reaction Conditions

Reaction Steps

The mixture of 1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxo-quinoline-3-carboxylic acid (1 gm) and methylene chloride (20 ml) was cooled to 5-10° C. under nitrogen atmosphere. Triethylamine (1.15 gm) was added to the resulting mass at 5-10° C. to form a clear solution. The solution was followed by addition of N-ethyl aniline (0.45 gm) in one portion at 5-10° C. and then thionyl chloride (0.48 gm) was added at 5-10° C. The resulting mixture was stirred for 4 hours followed by evaporation of methylene chloride under vacuum. The resulting residue was dissolved in ethyl acetate (100 ml) followed by washings with 5% sodium hydroxide solution (30 ml) at 25-30° C. The resulting aqueous layer was cooled to 10-15° C. and pH was adjusted to 2 by using 18% aqueous hydrochloric acid solution (20 ml). The resulting mass was stirred for 2 hours at 15-20° C. The resulting white colored solid was filtered and dried at 55-60° C. to yield 0.73 gm of laquinimod (HPLC Purity: 84.31%).

Provenance & Evidence