Chemical Properties
Pale Yellow Solid
Uses
Lansoprazole Sulfide (Lansoprazole EP Impurity C; USP Impurity B) is a metabolite of Lansoprazole, as gastric pump inhibitor.
Synthesis
2-Chloromethyl-3-methyl-4-(2,2,2-trifluoroethoxy)pyridine (91 g, 0.38 mol) and 1H-benzo[d]imidazole-2-thiol (57 g, 0.38 mol) were used as raw materials, suspended in methanol (1 L), and benzyltributylammonium bromide (2.15 g) was added as a phase transfer catalyst. A 30% NaOH solution (65 mL) was added slowly and dropwise over a period of 1 h, followed by stirring the reaction for 2 h at room temperature. Upon completion of the reaction, water (300 mL) was added to the reaction mixture and stirring was continued for 30 min. The mixture was cooled to 10 °C and the pH was adjusted to 9 with 35% HCl, at which point the target product 2-(((3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl)methyl)thio)-1H-benzo[d]imidazole precipitated as a precipitate. The precipitate was collected by filtration and washed sequentially with 50% methanol and water. Finally, the product was dried under vacuum at 50 °C to give 129 g in 96% yield.
References
[1] Organic Process Research and Development, 2013, vol. 17, # 10, p. 1272 - 1276
[2] Patent: CN106543146, 2017, A. Location in patent: Paragraph 0025; 0031; 0032; 0041; 0045; 0049; 0053-0069
[3] Synthetic Communications, 2002, vol. 32, # 8, p. 1211 - 1217