Synthesis and characterization of one impurity in esomeprazole, an antiulcerative drug

During drug synthesis, control of impurities is very important to get high-qualified drugs. A number of studies have devoted to synthesize the impurities and study the structures to support the method of purification. In this paper, we first synthesize one impurity in esomeprazole, rel-2-[[(3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-6-methoxy-1 H -benzimidazole, with readily available raw materials, simple operation procedures and relatively mild reaction. Besides, we characterized its structure by MS, IR, 1 H-NMR and HPLC analyses. The purity of target compound is as high as 99.58%, which can be used as the reference substance of the impurities of esomeprazole.