Acetic Acid → Lansoprazole

Participants

Reaction Steps

2 g of 2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]thio]-1H-benzimidazole was suspended in 36 ml of methanol at room temperature, to which 1.76 g of 45% NaOH in 14 ml water was added while stirring. 0.09 g of Na2WO4·2H2O oxidation catalyst was dissolved in 0.77 g H2O2 (50% aqueous solution), and further diluted with 10 ml of water. The oxidant/catalyst solution was added to the reactant/base solution dropwise so that the addition was completed in about 30 minutes while stirring at room temperature. The reaction was continued for additional 10 minutes while stirring. 10 ml of 10% Na2S2O3 aqueous solution was then added, and the resulting mixture was subjected to a reduced pressure to remove methanol therefrom. Finally, a precipitate was formed after adding a diluted acetic acid aqueous solution to a pH value of about 8, which was filtered, water washed, and dried in vacuo to obtain Lansoprazole with a yield of about 90.8% (LC purity>95%).

Provenance & Evidence