Sodium Hydroxide → Pantoprazole

Participants

Reaction Conditions

Reaction Steps

A flask equipped with a stirrer is charged with acetonitrile (40 ml). Under mixing, compound VI (5 g) is added followed by 2N NaOH (17.5 ml, 4.9 eq.). The flask is cooled to −10° C. A solution of N-chlorophthalimide (2.6 g, 1.1 eq.) in dimethylformamide (DMF) (10 ml) is added dropwise over 45 min. The two-phase mixture is stirred at room temperature over 1 h. Saturated aqueous Na2S2O5 (20 ml) is then added, and the pH is adjusted to 8.5 with acetic acid. The phases are separated. The organic phase is washed with brine, and the aqueous phase is extracted twice with ethyl acetate. The organic phases are combined, dried, and evaporated to dryness. The residue is taken up in a mixture of ethyl acetate (10 ml), toluene (10 ml), and hexane (30 ml). On standing, a precipitate forms in the solution which is separated by filtration to give pantoprazole (5.13 g, 98%) containing 0.3% compound VI and free of sulfone within the limit of UV detection.

Provenance & Evidence