Background and Overview[1]
3-Aminodibenzofuran can be used as a pharmaceutical synthesis intermediate.
Preparation[1]
1) Synthesis of 3-nitrodibenzofuran:
Add 150ml trifluoroacetic acid to the reaction bottle, then add dibenzofuran (14.2g, 82mmol), stir vigorously at room temperature to dissolve it, cool it in ice-water bath, and add 70% HNO3 (9.1g, 101mmol) to 50ml Trifluoroacetic acid, slowly added to the reaction bottle, stirred for 40 minutes, then poured the reaction solution into 300ml ice water and stirred for 30 minutes, filtered, to obtain an off-white solid, washed with 2M sodium hydroxide solution and water, respectively, to obtain the solid Then recrystallize with ethanol to obtain 14.7g of light yellow solid.
2) Synthesis of 3-aminodibenzofuran:
3-Nitrodibenzofuran (12.6g, 60mmol) was dissolved in 800ml ethyl acetate, purged with nitrogen for 5 minutes, 1000mgPd/C was added, hydrogenation started, pressurized hydrogen 60psi, when the pressure was 60psi The reaction is complete when it can be maintained stably for 15 minutes and no longer decreases. The reaction solution is filtered with a sand core funnel, and the filtrate is spin-dried to obtain a white solid (10.9g, 58mmol).
Apply[1]
3-Aminodibenzofuran can be used as a pharmaceutical synthesis intermediate, such as the preparation of 3-bromodibenzofuran:
Sodium nitrite (4.4g, 65mmol) was dissolved in 40ml of concentrated sulfuric acid at ℃, and 3-aminodibenzofuran (10.6g, 58mmol) was dissolved in a small amount of glacial acetic acid and slowly dripped into the reaction solution, keeping The temperature is lower than 5°C. After the dropwise addition, keep it at 0°C and continue stirring for 2 hours. Add 200ml of ether to the reaction solution and stir. Diazonium salt will precipitate. Filter to obtain a brown solid; add CuBr (12.5g) to another reaction bottle. , 87mmol), 300ml48% HBr, finally add the obtained brown diazonium salt, heat to 66°C and hold for 2 hours, cool to room temperature, filter, wash the filter cake with water twice, use petroleum ether: methylene chloride = The eluent of 10:1 was passed through the column to obtain 9.6 g of solid.
Main reference materials
[1](CN105481903) A phosphorescent iridium complex containing a 3-phenylpyridazine structure and its application
