Preparation method and intermediate of brexpiprazole and preparation method of intermediate

The invention relates to the technical field of medicinal chemical synthesis and in particular relates to a preparation method and an intermediate of brexpiprazole and a preparation method of the intermediate. The preparation method of the brexpiprazole is shown in the following flow chart (described in the specification), wherein X1 and X2 are halogen, X1 is bromine preferably, and X2 is chlorine preferably. The invention provides a preparation method of a new compound 1 by providing new compounds 2 and 3. The preparation method of the new compound 1 mainly comprises two-step reaction, namely substitution and cyclization. Byproducts produced in the preparation method of the new compound 1 are less and are easy to separate, and column chromatography treatment does not need to be carried out. Meanwhile, the invention also provides a preparation method of the compound 2. The preparation method of the compound 2 has the advantages that generation of byproducts is greatly reduced, overall yield of reaction is improved, column chromatography treatment does not need to be carried out and production time is shortened while production cost is reduced, so that the preparation method of the compound 2 is applicable to industrial production.