Sodium Thiosulfate → Pantoprazole

Participants

Reaction Steps

0.4 g of 5-difluoromethoxy-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]thio]-1H-benzimidazole was suspended in 6 ml of methanol at room temperature. 0.02 g of Na2WO4·2H2O oxidation catalyst was dissolved in 0.109 g H2O2 (35% aqueous solution), and further diluted with 2 ml of water. The oxidant/catalyst solution was added to the reactant solution dropwise so that the addition was completed in about 30 minutes while stirring at room temperature. The reaction was continued for additional 5.5 hours 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, followed by adding a diluted acetic acid aqueous solution to a pH value of about 8. The resulting pH=8 mixture was extracted with ethyl acetate to obtain a crude product of Pantoprazole with a LC purity of about 52.5%.

Provenance & Evidence