Bocitinib intermediate 4-(3,4-dichloro-2-fluorophenylamino)-7-methoxyquinazolin-6-ol (12 g, 34 mmol) and compound (CAS:1620740-65-9) 4-methylbenzenesulfonic acid 1-acryloylpiperidin-4-yl ester (16 g, 51 mmol) were added to K2CO3 prepared in step (1-1) ( 9.4 g, 68 mmol) and dimethylacetamide (DMAc, 300 mL) were mixed. The reaction mixture was heated to 70 °C and stirred at this temperature for 24 hours. Upon completion of the reaction, the mixture was cooled to room temperature and extracted with ethyl acetate (300 mL) followed by washing with water (300 mL). The organic layer was separated and concentrated under reduced pressure. Ethyl acetate was added to the residue to solidify it, and after filtration and drying, the target product 1-(4-((4-((3,4-dichloro-2-fluorophenyl)amino)-7-methoxy-6-quinazolinyl)oxy)-1-piperidinyl)-2-propen-1-one was obtained (12.8 g, Yield: 77%).1H-NMR (300 MHz, DMSO-d6) δ 9.65 (bs, 1H), 8.40 (s, 1H), 7.88 (s, 1H), 7.64-7.56 (m, 2H), 7.24 (s, 1H), 6.89-6.80 (m, 1H), 6.15-6.08 (m, 1H), 5.70-5.66 (m, 1H), 4.78 (m, 1H), 3.94 (s, 3H) , 3.87 (m, 2H), 3.48 (m, 2H), 2.03 (m, 2H), 1.70 (m, 1H).