
{"publication_number": "US-9856215-B2", "abstract": "disclosed is a preparation method of nintedanib , comprising the following steps : carrying out a condensation reaction on 4 -- 3 - nitrobenzoate and trimethyl orthobenzoate to obtain - 4 - r acetate - 2 - yl ]- 3 - nitrobenzoate ; carrying out a substitution reaction on the compound and n -- n - methyl - 2 - acetamide under the action of an acid - binding agent to generate - 4 - acetamido - aniline ) benzylidene ] r acetate - 2 - yl 