TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The reductant is lithium borohydride, sodium borohydride, potassium borohydride, calcium borohydride, hydrazine hydrate or hydrazine monohydrate. The inorganic acid is hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, perchloric acid or hydrobromic acid. The Lewis acid is anhydrous aluminum trichloride, boron trifluoride, anhydrous zinc chloride or phosphorus pentoxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The reaction temperature of the step (a) is controlled at -20 degrees C to 20 degrees C. The step (b) is carried out by dissolving (a2) into dichloromethane or ethyl acetate, controlling the pH of the reaction solution at 1-5 by the acid and controlling the reaction temperature at 10 degrees C to a backflow temperature of the solvent. The step (c) is carried out at 10-60 degrees C, and for 2-48 hours. The step (d) comprises: dissolving (c2) into the solvent, adding the reductant and reacting for 1-24 hours at -50 degrees C to 20 degrees C; dropping the methylation reagent at -50 degrees C to 20 degrees C and keeping the original temperature till finishing the reaction; adding water which is 0.5-4 times of the total volume of the reaction solution; mixing and adjusting the pH to 2-6 and using the ether or the ethyl acetate to extract the mixed solution to obtain an organic solution; depressurizing and concentrating to obtain (d1). Preferred Components: The solvent for dissolving (a1) is tetrahydrofuran, 1,4-dioxane, ethanol, methanol or methyl tertiary butyl ether. The molar ratio of the reductant to (a1) is 1-15 to 1. The organic acid is glacial acetic acid, trifluoroacetic acid, sulfonic acid, camphorsulfonic acid, p-toluenesulfonic acid, citric acid or tartaric acid. The organic solvent used in step (c) is methanol, ethanol, tetrahydrofuran or 1,4-dioxane. The amount of water added in step (c) is 0.5-4 times the total volume of the reaction solution. The methylation reagent is iodomethane, dimethyl sulfate or dimethyl carbonate.