TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The process comprises cleaning and drying the reaction bottle, 20% of adding ammonia water (50 ml), N,N-dimethyl amino pyridine (20 g), P-toluene sulfonic acid (20 g) and potassium thiocyanate (25 g) to the bottle, stirring at constant temperature and dissolving completely, and then slowly adding the mixture to zirconium sulfate powder (50 g), stirring and obtaining paste, solidifying into blocks, crushing, legivating and drying at 50-60 degrees C. The process comprises (a) adding ammonia water (20%) to the reaction bottle and then adding with DT4, heating the mixture at 60-80 degrees C, insulating until the reaction liquid is cleaned gradually, and then heating continuously and condensing until it is extracted and thickened to obtain the DT4-ammonium salt, (b) cooling the DT4-ammonium salt at below 60 degrees C, adding with excessive dimethylbenzene for changing the distillation condensing device into a backflow water trip instrument, heating, performing the water trip reaction until the distillate is clean, heating and condensing until a lot of substances are extracted and thickened, cooling at room temperature, and filtering to obtain the white crystals (DT4-amide), and (c) adding acetonitrile, purified water, DT4-amide and BTFMA into the bottle, stirring, heating at 30-60 degrees C, and dissolving completely to obtain a clean transparent solution, adding catalyst, stirring, heating and reacting for 18-24 hours, monitoring the terminal point by thin layer chromatography, after the reaction, filtering the mixture for removing the catalyst, condensing the filter liquor, recycling, thickening, cooling the acetonitrile at below 60 degrees C, adding methylbenzene, washing by the 6N of hydrochloric acid for 2-3 times, pure water for 2-3 times, sodium hydroxide (5%) for 2-3 times, finally washed by the pure water for 3-4 times until it is neutral, decompressing and condensing for recycling the methylbenzene, condensing the mixture by the absolute ethyl alcohol for 2 times, adding absolute ethyl alcohol, heating, dissolving completely, stirring and cooling at the room temperature, extracting crystal for 3 hours, filtering, washing the filter cake for multiple times by a little absolute ethyl alcohol, and filtering and drying at 80-90 degrees C to obtain the white dutasteride crystallizing powder. The filter cake is washed and dried at 60-80 degrees C.Preferred Components: The reaction bottle is cleaned by dimethylbenzene (100 ml). The catalyst is present at 30 mass%. ACTIVITY - Cytostatic; Uropathic.    MECHANISM OF ACTION - None given.