Abstract: The present disclosure relates to a synthesis method for halofuginone and its intermediates, with the reaction formulas as shown below, wherein, R1 is selected from: methyl, ethyl, propyl, isopropyl or tert-butyl:, R2 is selected from: methyl, ethyl:, R3 is selected from: methoxyformyl, ethoxyformyl, tert-butoxyformyl, benzyloxyformyl, trichloroethoxyformyl or benzyl. The synthesis method in the present disclosure has many advantages, such as simple process, low cost, few by-products in the synthesis process, simple purification process, no need for column chromatography purification, high product yield, few impurities, high purity, controllable product quality, easy to meet the requirements of ICH declaration, and it can be used for industrial production of halofuginone.

Abstract: The disclosure relates to an entecavir intermediate, a synthetic method therefor, and the synthetic method for entecavir by using the intermediate. According to the disclosure, the synthetic methods for entecavir and the intermediate thereof have the advantages of being controllable in chirality, high in yield and product purity, wide in source of raw materials, cheap and available in reagents, simple in reactions, convenient to operate, environmentally friendly, and suitable for industrial amplification production.