Be disclosed herein formula 4 nucleoside phosphoramidate and they as with what treat viral disease medicament purposes. These compounds are the inhibitor of RNA- dependence 5RNA virus replication, and can be used as the inhibitor of HCV NS5B polymerase, the inhibitor that HCV is replicated and treat hepatitis C infection in mammals with what. A kind of preparation method of compound indicated by formula 4 is also disclosed: (formula 4) wherein P* indicates chiral phosphorus atoms,This method comprises: a) make alanine isopropyl ester,(formula A),Two-X '-phenyl phosphate ester,(formula B),2 '-deoxidations -2 '-fluoro- 2 '-C- methyluridine,(formula 3) and alkali are reacted to obtain the first mixture comprising 4； Wherein X is the conjugation alkali of acid,N is 0 or 1,And X ' is halogen,B) make first mixture and protection compound reaction to obtain the second mixture comprising 4； And c) optionally,Crystallize second mixture,Chromatography or extraction are to obtain 4.本文公開式4的核苷氨基磷酸酯以及它們作爲用於治療病毒性疾病的藥劑的用途。這些化合物是RNA-依賴性5RNA病毒複製的抑制劑，並且可用作HCV NS5B聚合酶的抑制劑、HCV複製的抑制劑、以及用於在哺乳動物中治療丙型肝炎感染。還公開一種由式4表示的化合物的製備方法：(式4)其中P*表示手性磷原子，該方法包括：a)使丙氨酸異丙酯，(式A)，二-X′-苯基磷酸酯，(式B)，2′-脫氧-2′-氟-2′-C-甲基尿苷，(式3)和碱反應以獲得包含4的第一混合物；其中X是酸的綴合鹼，n是0或1，並且X′是鹵素，b)使所述第一混合物和保護化合物反應以獲得包含4的第二混合物；以及c)任選地，使所述第二混合物進行結晶、色譜分析或萃取以獲得4。
