NOVELTY - Imatinib is prepared by dissolving 3-methyl-4-bromoaniline in dichloromethane, adding 4-(N,N-dimethylamino)pyridine, cooling to 3-5 degrees C, adding 4-(chloromethyl)benzoyl chloride in dichloromethane solution dropwise, stirring reaction mixture for 5-8 hours, stirring reaction liquid in ice for 10-30 minutes, layering, extracting aqueous layer with dichloromethane, combining dichloromethane layers and washing successively with 1 N hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated salt water, drying organic phase by anhydrous sodium sulfate, and filtering.    USE - Preparation of imatinib (claimed).    ADVANTAGE - Raw material is cheap, environmental impact is low, and yield is high.    DETAILED DESCRIPTION - Imatinib is prepared by dissolving 3-methyl-4-bromoaniline in dichloromethane, adding 4-(N,N-dimethylamino)pyridine, cooling to 3-5 degrees C, adding 4-(chloromethyl)benzoyl chloride in dichloromethane solution dropwise, stirring reaction mixture for 5-8 hours, stirring reaction liquid in ice for 10-30 minutes, layering, extracting aqueous layer with dichloromethane, combining dichloromethane layers and washing successively with 1 N hydrochloric acid, saturated sodium bicarbonate aqueous solution, and saturated salt water, drying organic phase by anhydrous sodium sulfate, filtering, concentrating filtrate to dry, obtaining compound II, adding compound II, N-methylpiperazine, anhydrous potassium carbonate, dichloromethane, and N,N-dimethylformamide (DMF) in reaction bottle, heating to 60-80 degrees C for 6-10 hours, pouring reaction liquid into water, stirring for 15-30 minutes, extracting aqueous layer with dichloromethane, combining dichloromethane layers and washing with water, drying organic phase over anhydrous sodium sulfate, filtering, concentrating solution to dry, recrystallizing residue with ethyl acetate and petroleum ether, obtaining yellow crystal powder (compound III), reacting 3-acetylpyridine, DMF, and methanol in reaction bottle at 100 degrees C until methanol is distilled off, concentrating reaction solution under reduced pressure after adding toluene-petroleum ether, freezing for 1-3 hours, filtering, washing filter cake with petroleum ether, drying, obtaining yellow solid (compound IV), adding sodium ethoxide ethanol solution and guanidine hydrochloride in reaction bottle, stirring for 1-2 hours, adding compound IV in solution to dissolve, refluxing and reacting for 6-10 hours, cooling to room temperature, freezing overnight, filtering, washing filter cake with cold ethanol and water, washing, drying, recrystallizing crude product with ethanol to obtain yellow acicular crystal (compound V), adding compound V, compound II, cesium carbonate, copper iodide, 8-hydroxyquinoline, and DMF in reaction bottle, heating overnight at 100 degrees C, cooling to room temperature, pouring in ice water, stirring for 20-40 minutes, filtering, washing filter cake with water, drying crude product, and recrystallizing with methanol to obtain light yellow powder (compound I).