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The hepatitis B virus infection is characterized by a longer duration, the virus is difficult to remove, so most patients need long-term medication. Now used in clinical anti-HBV drugs are most of the interferon and the nucleoside drugs, nucleoside drugs can be taken orally, substantially no direct toxic effects are widely applied. Therefore, the development and research of nucleoside drugs is one of the hot spots of the current study. Is approved by the State Food and Drug Administration in 2006 for the treatment of chronic hepatitis B, telbivudine novel L-nucleoside analogues, its efficacy is superior to lamivudine has been widely used in clinical nucleoside drugs . Telbivudine of hepatitis B virus DNA polymerase have a specific inhibitory effect, whereas no effect on human DNA polymerase activity, thus the drug's toxicity. Reported the synthesis of alternate routes telbivudine complex synthesis. The purpose of this project is to choose a suitable for industrial production routes telbivudine. The article selection using D-xylose as a starting material, was synthesized by oxidation, bromo, hydrogenolysis for telbivudine key intermediates 5 - bromo-2 ,5 - dideoxy-D-xylose acid -1, 4 - lactone 33%, the total yield of the three-step, and the experimental conditions were optimized. The results show that the soluble in water of potassium carbonate to carry out the reaction in the oxidation of D-xylose with a decrease of the amount of solvent; after repeated experiments found that this step reaction without purification, but with acetic acid and water form an azeotropic to remove water in the reactants, and then directly to the second reaction, not only simplifies the post-treatment process, but also to avoid the influence on the reaction product was hydrolyzed. The second reaction the optimal conditions for the internal temperature was 45 ° C when the reaction for 1 hour. Solution method at the third step with hydrogen in place of sodium iodide in the literature, the method hydrogenolysis reagent is easy to get the advantages of simple steps, but also in the industrial use of hydrogen in the palladium on carbon catalyzed reduction is commonly used the reaction, the technology is more mature. Optimized method of cheap raw materials, pollution, simple operation, and post-processing does not require column chromatography and mild reaction conditions, in line with the requirements of industrial production. The pranlukast Is new anti-asthma drug, the drug is a leukotriene receptor antagonist. 3 - amino-2 - hydroxyacetophenone Synthesis Pranlukast important intermediates, has important applications in the study of new drugs and study the synthesis. This article also is the synthesis process of 3 - amino-2 - hydroxyacetophenone were optimized selection of p-chlorophenol as a starting material, after the esterification, Fries rearrangement, nitration and nitro reduction, four-step reaction synthesis experiment 3 - Amino-2 - hydroxyacetophenone, the objective compound physicochemical data consistent with the literature. The target compound purity higher than 97%, the total yield of 29%. This method is simple, mild reaction conditions, reagents, easy to get, and is suitable for industrial production.
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