Tofacitinib citrate synthesizing method

The invention belongs to the field of medicine synthesis and particularly relates to a Tofacitinib citrate synthesizing method. The Tofacitinib citrate synthesizing method comprises steps as follows: TFTB-1(N-methyl-N-((3R,4R)-4-methyl-1-benzyl-3-piperidyl)-7-((4-methyl phenyl) sulfonyl)7H-pyrrolo[2,3-D] pyrimidine-4-amine), sodium hydroxide, ethyl alcohol and water have a heating reaction, and TFTB-2 is prepared; TFTB-2, ammonium acetate and ethyl alcohol react in the presence of a Pd(OH)2/C catalyst and H2, and TFTB-3 hydrochloride is obtained; TFTB-3 hydrochloride, triethylamine and ethyl acetate are mixed, DCC (dicyclohexylcarbodiimide) and DMAP (dimethylaminopyridine) are added, the components are heated and stirred, and cyanoacetic acid is added for reaction; citric acid monohydrate and n-butyl alcohol are added and heated for reaction, and Tofacitinib citrate is obtained after refining. A product is directly prepared from the TFTB-3 hydrochloride, a finished product is prepared with a one-pot process, and the yield and the purity are high.