Preparation method of Ticagrelor and intermediates thereof

A method for preparing Ticagrelor (I),

• wherein the preparation method comprises the following steps:
• a cyclization reaction of 5-amino-1,4-di-substituted-1,2,3-triazole (II) and dialkyl carbonate (HI), to obtain 9-substituted-2,6-dihydroxy-8-azapurine (IV);
• chlorination of intermediate (IV), to obtain 9-substituted-2,6-dichloro-8-azapurine (V);
• an amination reaction of intermediate (V) and trans-(1R,2S)-2-(3,4-difluorophenyl)cyclopropanamine (VI) generates 9-substituted-6-amino-substituted-2-chloro-8-azapurine (VII);
• and a propanethiolation reaction of intermediate (VII) and propanethiol (VIII), to obtain Ticagrelor (I);
• Wherein the chemical formula of 5-amino-1,4-disubstituted-1,2,3-triazole is shown as below (II):
• Of which, R is hydrogen (H), alkyl acetate (—CH2COOR1) or 2-alkoxy ethyl(—CH2CH2OR2);
• Of which, R3 is formamido(—CONH2), formyl(—COOH), cyano(—CN) or alkyl carbamate group (—COOR4);
• Wherein the chemical formula of dialkyl carbonate is as shown in the following formula (III),
• Of which, R5 and R6 are independently selected from methyl, ethyl, n-propyl, isopropyl, allyl, t-butyl, n-butyl, phenyl, substituted phenyl, benzyl or substituted benzyl.