NOVELTY - Flumioxazin preparation involves mixing 2,4-difluoro-nitrobenzene, sodium metal and tetrahydrofuran in a four-neck flask in methyl glycolate under stirring, and then heating at room temperature to 65 degrees C. The formed reaction mixture is stirred at 65 degrees C for 5 hours for evaporating solvent to give a solid, which is washed with water and then recrystallized from ethanol to give 2-(5-fluoro-2-nitrophenoxy) acetic acid methyl ester.    USE - Method for preparing flumioxazin (claimed).    ADVANTAGE - The method prepares flumioxazin in a simple, cost-effective and eco-friendly manner with high yield.    DETAILED DESCRIPTION - Flumioxazin preparation involves mixing 2,4-difluoro-nitrobenzene, sodium metal and tetrahydrofuran in a four-neck flask in methyl glycolate under stirring, and then heating at room temperature to 65 degrees C. The formed reaction mixture is stirred at 65 degrees C for 5 hours for evaporating solvent to give a solid, which is washed with water and then recrystallized from ethanol to give 2-(5-fluoro-2-nitrophenoxy) acetic acid methyl ester. Iron powder is added to a glacial acetic acid with stirring, and then heated at room temperature to 60 degrees C, where the obtained 2-(5-fluoro-2-nitrophenoxy) acetic acid methyl ester is added in the formed mixture at 110-120 degrees C. The resulting mixture is refluxed at 110-120 degrees C with stirring for 3 hours, and then cooled to 80-90 degrees C, where the formed mixture is filtered to obtain a filtrate. The solvent is evaporated to give a solid, which is recrystallized with ethanol to give 7-fluoro-benzo-2H-1,4-oxazine-3(4H)ketone. 80% of aqueous sulfuric acid is cooled to 0-5 degrees C in a four-necked flask, and then 7-fluoro-benzo-2H-1,4-oxazine-3(4H)ketone is added at 0-5 degrees C. 60% of nitric acid aqueous solution is added at 0-5 degrees C under stirring for 30 minutes, and then poured into ice water to precipitate a solid, which is filtered to give 6-nitro-7-fluoro-benzoxazin-2H-1,4-3(4H) ketone. The obtained 6-nitro-7-fluoro-benzoxazin-2H-1,4-3(4H) ketone is dissolved in tetrahydrofuran and placed in an autoclave with palladium on charcoal at 30-40 degrees C with stirring for 12 hours. The solvent is evaporated to give 6-amino-7-fluoro-benzoxazin-2H-1,4-3(4H) ketone. The obtained 6-amino-7-fluoro-benzoxazin-2H-1,4-3(4H) ketone and 4,5,6-tetrahydro-phthalic anhydride are added in a four necked flask at room temperature to 120 degrees C with stirring. The obtained mixture is poured into saturated aqueous sodium bicarbonate solution, and then ethyl acetate is added to form ethyl acetate layer. The formed layer is distilled to remove solvent to give 2-(3,4-dihydro-7-fluoro-3-oxo-2H-benzo(b) (1,4 )oxazine-6-yl)-4,5,6,7-tetrahydro-1H-isoindole-1,3(2H) dione. The obtained 2-(3,4-dihydro-7-fluoro-3-oxo-2H-benzo(b) (1,4 )oxazine-6-yl)-4,5,6,7-tetrahydro-1H-isoindole-1,3(2H) dione, dimethylformamide and sodium ethoxide are added to four-neck flask at 0-5 degrees C with stirring for 30 minutes. 3-Bromo-propyne is added dropwise in the resulti9ng mixture, and then allowed to warm at 25-30 degrees C with stirring for 12-16 hours. The formed mixture is poured into saturated aqueous ammonium chloride solution, in which ethyl acetate is added, and then allowed to stand for stratification, where the formed ethyl acetate layer is washed with saturated aqueous sodium chloride solution to give flumioxazin.