Process for the production of antiulceratives

A method for the production of an antiulcerative of formula I:

• wherein
• R1, R2 and R3 are independently selected from the group consisting of hydrogen, C1-C8 alkyl, C3-C8 cycloalkyl, C2-C8 fluoroalkyl and C1-C8 alkoxy,
• R4 and R5 are independently selected from the group consisting of hydrogen, C1-C8 alkyl, C3-C8 cycloalkyl, CH2—C3-C8 cycloalkyl, C1-C8 alkoxycarbonyl, C1-C8 alkoxy, C1-C8 fluoroalkoxy, CF3, C2-C8 fluoroalkyl and C(O)O—C1-C8 alkyl, and
• R6 is hydrogen or C1-C2 alkyl,
• wherein the method comprises
• reacting a compound of formula II:
• wherein R1, R2, R3, R4, R5 and R6 are defined as above,
• with m-chloroperoxybenzoic acid in a solvent selected from the group consisting of acetone and acetone/water mixture to form a reaction mixture,
• raising the pH of the reaction mixture to above pH 7.0, whereby crystals of the compound of formula I are formed, and
• separating the crystals of the compound of formula I.