Abstract text

The present invention provides a method for preparing an antiulcer agent, 2-(2-pyridylmethylsulphinyl)benzimidazoles, such as Omeprazole, Lansoprazole and Pantoprazole, which includes oxidizing an intermediate having a linkage of methylthio group (—CH₂S—) to methylsulfinyl (—CH₂S(O)—) in the presence of an oxidation catalyst of acetyl acetonate of molybdenium (II) [(CH₃C(O)CH₂C(O)CH₂)₂Mo].