- Efficient synthesis of N-Oxide derivatives: Substituted 2-(2-(pyridyl-N-oxide)methylsulphinyl)benzimidazoles
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Different substituted 2-chloromethylpyridyl derivatives (6a-d) were oxidized with mCPBA to give the respective 2-chloromethylpyridine-N-oxide derivatives (7a-d) at low temperature, which on condensation with 2-mercapto-1H-benzimidazole (8a-c) in the presence of aprotic solvents give the 2-[[(pyridin-2-yl-1-oxide)methyl]sulfanyl]-1H-benzimidazole (9a-d) in good yield. Finally, 9a-d oxidized with mCPBA in chlorinated solvent gives a mixture of 2-[[(pyridin-2-yl-1-oxide)methyl]sulfonyl]-1H-benzimidazole (3a-d, 10%) and 2-[[(pyridin-2-yl-1-oxide) methyl]sulfinyl]-1H-benzimidazole (4a-d, 90%) derivatives. Copyright Taylor & Francis Group, LLC.
- Ray, Purna C.,Mittapelli, Vasantha,Rohatgi, Amit,Tyagi, Om Dutt
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- A process for the preparation of omeprazol
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The process starts by reacting 2,3,5 trimethylpyridine with hydrogen peroxide in the presence of catalysts, giving new reactive ionic species allowing the number of required steps to be substantially reduced. In the final important step, oxidation to omeprazol, there are used new salts of 5-methoxy-2-((3,5-dimethyl-4-methoxy-2-pyridine)methylthio)-1H-benzimidazole which, as the oxidation evolves, precipitate the omeprazol. The new oxidation method avoids superoxidations, provide for faster oxidation, high purity and yields of over 90%.
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