Rabeprazole Intermediates

Rabeprazole is a new type of Proton Pump Inhibitors, which is widely used in therapy for digestive system illness. Four kinds of intermediates are prepared, and the key factors are optimized in this paper. Four steps are discussed in detail.2,3-dimethylpyridine-N-oxide is prepared by oxidation from 2,3-dimethyl pyridine and acetic acid in the first step. The method of single factor is used and the condition is optimized. The yield is above 96.5%.Then 4- nitro-2,3-dimethylpyridine-N-oxide is gotten by the reaction of nitration using 2,3-dimethylpyridine-N-oxide, nitric acid and sulfate acid as the raw material. The condition of reaction and the disposition are optimized. The yield is more than 70% and the purity is more than 98.5%.The third step is the preparation of 4- chloro-2,3-dimethylpyridine. A new route using 4-nitro-2,3-dimethylpyridine oxide and acetic acid as the raw material is made. A new craftwork of solvent's method is adopted and the optimized result is obtained. Finally the yield is over 88% and the purity is over 96%.4-(3-methoxy-propoxy)-2,3-dimethylpyridine-N-oxide is prepared in the fourth step. The conditions are optimized using 4-chloro-2,3-dimethylpyridine -N-oxide as the aw material. A new method of natrium are used because of the disadvantage of the basification. collective is 80% and the content is 80% after optimizing the method of basification, In allusion to, it designs. The yield is 88% and the purity is over 90% after optimization.