利用硝酰氯或硝酸酯进行硝化反应

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NO2Cl(硝酰氯)以前是由发烟硝酸和氯磺酸制得,由于这个方法不方便以及危险性大,另一个替代方法是 NaNO3/TMSCl/AlCl3体系【Olah, G. A; Ramaiah, G, Synthesis,1994, 468.NaNO3 TMSCl 反应生成硝酰氯,然后再AlCl3 的作用下经过类似F-C反应的亲电取代过程得到硝化物, NaNO3也可用KNO3代替。这个硝化反应条件很温和,选择性很好,如果用其他硝化方法得到的选择性差,不妨试试这个硝化条件,其缺点是有时转化率不高。

 

 

To a suspension of KNO3 (60.6 g, 0.6 mol) in CHCl3 (500 mL) wasadded TMSCl (102 mL, 0.8mol) and carbonic acid 2,4-diisopropyl-phenyl esterisopropyl ester (105.6 g,0.4 mol) successively at 0oC, the mixture was stirred for 0.5hour.  Then AlCl3 (160 g, 1.2 mol) was added in one portionat 0 oC.  The mixture wasstirred for another 2 hours.  TLC showedmost of the starting material was consumed and the product was present.  The resulting mixture was poured intoice-water, extracted with CHCl3. The combined organic layers were washed with Sat.NaHCO3solution, brine successively, dried over Na2SO4 andevaporated under reduced pressure to give the crude product as an oil. To thecrude product was added 100 mL petroleum ether, the desired compound wasrecrystallized from the ether in the bath of dry ice-acetone, which wasfiltered and washed with petroleum ether to give the desired product as a paleyellow solid (27.2 g,22%).



硝酸酯,包括BuONO2/Nafion-H,MeONO2/BF3, Me3SiONO2作为硝化试剂,能使活化的苯环发生硝化。

 

   Asolutuion of 1, 2, 3, 4-tetramethylbenzene (1.34 g, 10 mmol) in nitromethane (20 mL) was addedmethyl nitrate (2.31 g,30 mmol).  The mixture was stirred at 25oCand saturated with boron trifluoride gas. The mixture was stirred for 1 h then washedwith Sat.NaHCO3 solution, extracted with CH2Cl2.  The combined organic layers were evaporatedunder reduced pressure, the residue was purified by column chromatography togive the product (1.62 g,90%). 


Olah, G. A; Lin, H.C. Synthesis1973, 488.


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