将苯环上的甲基氧化成羧基的问题？ 苯并吡嗪2位上的甲基氧化条件是氢氧化钾与高锰酸钾加热到90度反应2.5h，文献如下，可以参考一下，不过可要看请楚是氧化出了几个羧基 2-tetrahydroquinoxaline (15.0 g, 60.0 mmol) was placed in a 3-l three-neck round-bottom flask equipped with a mechanical stirrer, thermocouple and a solid addition funnel. the golden solid was suspended in distilled water (1500 ml), heated to 40ºc and the mixture basified with potassium hydroxide (7.50 g. 133 mmol) to yield a deep red solution. the solution was heated to 90ºc and treated with small portions of solid potassium permanganate (20 x 5.5 g, 696 mmol) over 1.5 h. slow addition was paramount, as the oxidation of the carbon skeleton was accompanied by strong effervescence due to the elimination of co2 from the solution at the elevated temperature. after stirring the solution for 1 h at 90ºc, any unreacted potassium permanganate was removed by the addition of methanol (10 cm3) and the suspension filtered hot to remove the brown manganese dioxide. the solids were washed with boiling water (5 x 50 cm3) and the combined filtrates were concentrated under reduced pressure ( ca. 30 cm3) to yield a pale yellow solution. the solution was brought to ph = 6 with the addition of conc. hno3 (s.g. 1.42, 70 %) and boiled for 15 min. to remove excess co2. the solution was left to cool to ambient temperature and treated with silver(i) nitrate (35 g, 205 mmol) in distilled water (50 cm3) to precipitate the yellow silver complex of the triacid. the complex was isolated by filtration and dried on the filter for 15 min. the material was light sensitive and unduly exposure to light caused decomposition by a colour change to grey, therefore this procedure was conducted in a darkened fumehood. the obtained solid was treated twice with hot aqueous hydrochloric acid (2 x 100 cm3, 2m), filtered to remove the precipitated silver chloride and the solid was washed once more with hot hydrochloric acid (100 cm3, 2m) to remove any residual product. the filtrates were combined, left to cool to ambient temperature and concentrated under reduced pressure to roughly half the starting volume (ca. 150 cm3), upon which the title compound began to separate out as a white crystalline solid. the solid was isolated by filtration and dried in a vacuum desiccator over p2o5 for several hours. (4.90 g, 30 %). two further crops of material were obtained upon further concentration to ca. 20 cm3 (2.32 g, 18.5 %) and prolonged storage of the filtrate at +4ºc (1.09 g, 9 %). the total yield was recorded as (8.31 g, 66 %).查看更多
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