Toluene → Montelukast Sodium

Participants

Reaction Steps

1.15 L of toluene were added to 115.2 g of Montelukast acid (e.e.: 99.9%). The mixture was cooled between 2 and 10° C. and 313.3 ml of 0.5M NaOH solution in methanol were added over 15 minutes. Then, the mixture was warmed to room temperature and stirred for 30 minutes. After this period of time, 1.5 L of the solvent were distilled off under reduced pressure at 30° C. Then, 2.4 L of toluene were charged to the crude and the distillation was resumed to obtain a final volume of 300 ml. The solution of crude obtained was added over 1 hour to 1 L of heptane under stirring at room temperature. 18 hours after the addition, an off white solid was filtered off under a nitrogen atmosphere and washed with 500 ml of heptane. The wet product was dried under vacuum at 75° C. for 3 days to yield 120 g of Montelukast sodium. Yield: 100%. e.e.: 99.9%.

Provenance & Evidence