Lansoprazole → (4-{2-[3-Methyl-4-(2,2,2-trifluoro-ethoxy)-pyridin-2-ylmethanesulfinyl]-benzimidazole-1-sulfonyl}phenoxy)acetic Acid 2-(toluene-4-sulfonyl)ethyl Ester

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반응 단계

To a heterogeneous solution of 2-[3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-ylmethanesulfinyl]-1H-benzimidazole (900 mg, 2.44 mmol) in 30 mL of CH2Cl2 was added 70 mg of NaH (2.92 mmol) at room temperature, during which time the mixture became homogeneous. To this clear reaction mixture was added the 4-chlorosulfonylphenoxy)acetic acid 2-(toluene-4-sulfonyl)ethyl ester (Intermediate 4, 1.26 g, 2.92 mmol, 1.2 eq). About 1 g of solid NaHCO3 was added after the chlorosulfonate has dissolved completely in the reaction mixture. (Without addition of NaHCO3 the mixture became black when the reaction was complete.) Thereafter the solvent was removed by evaporation and the residual oil was purified by column chromatography (silica gel, CH2Cl2 to 4% MeOH in CH2Cl2) to give 1.75 g (94%) of the desired product (Intermediate 5) as an off-white foam.

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