Studies On The Nitration Of Aromatic Amines In Continuous Flow Reactor And Photocatalyzed Decarboxylative Nitration

Nitrocompounds are widely used in medicine, pesticides, explosives and so on. Here we studied the method of nitration aromatic amines in continuous flow reactor and synthesis β-nitrostyrene via photocatalyzed decarboxylation.In the section one, the nitration of aniline under the continuous flow microreactor with Bi(NO3)3·5H2O as catalyst was investigated. Compared with the mixed acid nitration, this method showed mild reaction, easy to control, high o/p selectivity.The nitration of aromatic primary amine as the model reaction, we investigated the effects of temperature, reservation time(the flow rate of pump), the concentration of acetic anhydride, nitric acid, bismuth nitrate on the on the conversion. The optimal reaction conditions were determined as following:using 10 mol % Bi(NO3)3·5H2O,2.0 equiv fuming nitric acid,9.0 equiv AC2O, methylene chloride as a solvent, the reaction at 30 ℃ for 50 minutes. Then the nitration of 14 substrates of o-nitro aromatic amines were carried out under continuous flow microreactor. At last, we chose aniline as raw material, the nitration reaction was scale-up five times and still got 93% isolated yield.In the section two, we explored to synthesis nitroolefins by decarboxylative nitration of cinnamic acid under photocatalytic conditions. With the cinnamic acid as raw material, we assess the effects of the photocatalyst, the type and amount of additives and solvent. After experiments, we ultimately determine the optimal conditions of reaction:cinnamic acid,0.2 mmol; t-BuONO,0.6 mmol; BI-OH,0.1 mmol; Ru(bpy)3(PF6)2,0.004mmol; CH3CN,2 mL; oxygen atmosphere at room temperature, blue LED irradiation of 17 h. With the optimal reaction conditions in hand, we next investigated the substrate scope of the substituted cinnamic acid. And we got (E)-1,2,3-trimethoxy-5-(2-nitrovinyl)benzene in 50% yield.