Hydrogen Peroxide → Lansoprazole

Participants

Reaction Conditions

Reaction Steps

In a 1-liter flask equipped with dropping funnel and mechanical stirring 50 g (0.142 moles) of Lansoprazole sulfide, 35.0 mg (0.00014 moles) of methyltrioxorhenium (Aldrich) and 500 ml of methanol are charged. The temperature of the solution is brought to 5° C., and then 17.8 g (0.173 moles) of a 33% (v/v) aqueous solution of hydrogen peroxide are added. The mixture is maintained at 5° C. for 4 hours, then 1000 ml of cold deionized water are added, whereby a dense precipitate forms. The mixture is stirred for 1 additional hour at 5° C. and is then filtered on a Buchner, the cake is washed with 3×100 ml of cold deionized water and is discharged. The wet solid weighs 59.5 g. A 1 g sample is collected and dried under vacuum (50 mmHg) at 40° C. for 12 hours, which loses 16.5% of its weight. The yield of crude product is thus 95%. The amount of residual water in the crystalline solid is calculated through the Karl-Fischer method and the solid is then recrystallised, talking into account the amount of residual water, from 8 volumes of a 9:1 mixture of ethanol and water. The yield of the crystallized, dried product starting from the sulfide is 75%, the purity of the product is >99.5% (HPLC).

Provenance & Evidence