Rabeprazole

117977-21-6

117976-89-3

The general procedure for the synthesis of 2-(((4-(3-methoxypropoxy)-3-methylpyridin-2-yl)methyl)sulfinyl)-1H-benzo[d]imidazole from 2-(((4-(3-methoxypropoxy)-3-methylpyridin-2-yl)methyl)sulfinyl)-1H-benzo[d]imidazole was as follows: Example 6: 2.0 g of 2-[[[4-(3-methoxypropoxy)-3-methyl-2-pyridinyl]methyl]sulfinyl]-1H-benzo[d]imidazole was suspended in 36 mL of methanol at room temperature. Subsequently, 1.93 g of a 14 mL aqueous solution of 45% NaOH was added with stirring. 0.09 g of Na2WO4-2H2O oxidizing catalyst was dissolved in 0.66 g of 50% H2O2 aqueous solution and further diluted with 10 mL of water. The oxidizer/catalyst solution was slowly added dropwise to the reactant/base solution, and the dropwise process was completed in about 30 minutes while maintaining room temperature and continuous stirring. After the dropwise addition was completed, the reaction was continued with stirring for 10 minutes. Then, 10 mL of 10% Na2S2O3 aqueous solution was added and the reaction mixture was concentrated under reduced pressure to remove methanol. Finally, the pH was adjusted to about 8 by adding dilute aqueous acetic acid to form a precipitate. The precipitate was filtered, washed with water, and dried under vacuum to give rabeprazole in about 88% yield (LC purity >95%).