645-00-1Relevant articles and documents
Low-temperature and highly efficient liquid-phase catalytic nitration of chlorobenzene with NO2: Remarkably improving the para-selectivity in O2-Ac2O-Hβ composite system
Deng, Renjie,Liu, Pingle,Luo, He'an,Ni, Wenjin,You, Kuiyi,Zhao, Fangfang
, (2020/02/26)
In this work, we developed a low-temperature and efficient approach for the highly selective preparation of valuable p-nitrochlorobenzene from the liquid-phase catalytic nitration of chlorobenzene with NO2 in O2-Ac2O-Hβ composite system. The results demonstrated that the introduction of molecular oxygen remarkably enhanced the chlorobenzene conversion and the cooperation catalysis of Hβ zeolite and Ac2O envidently improved the selectivity to para-nitro product. Under the optimized reaction conditions, 93.6 % of the selectivity to p-nitrochlorobenzene with 84.0 % of chlorobenzene conversion was obtained, and the ratio of p-nitrochlorobenzene to o-nitrochlorobenzene could reach up to 20.3. Furthermore, the selectivity distribution of nitration products was reasonably explained by the density functional theory (DFT) calculation. Finally, the possible nitration reaction pathway of chlorobenzene with NO2 was suggested in O2-Ac2O-Hβ composite catalytic system. The present work affords a new and mild nitration approach for highly selective preparation of valuable para-nitro products, and has potential industrial application prospects.
Pd-Catalyzed Decarboxylative Ortho-Halogenation of Aryl Carboxylic Acids with Sodium Halide NaX Using Carboxyl as a Traceless Directing Group
Fu, Zhengjiang,Jiang, Yongqing,Wang, Shuiliang,Song, Yuanyuan,Guo, Shengmei,Cai, Hu
, p. 3003 - 3007 (2019/05/10)
A highly regioselective Pd-catalyzed carboxyl directed decarboxylative ortho-C-H halogenation of cheap o-nitrobenzoic acids with NaX (X = I, Br) under aerobic conditions has been established. The utility of the method has been demonstrated by the gram-scale reaction and derivatization of the product. Experimental results have confirmed Pd and Bi played critical roles in the transformation and indicated the transformation might proceed via 2-halo-6-nitrobenzoic acid derivative intermediate.
Rapid Iododeboronation with and without Gold Catalysis: Application to Radiolabelling of Arenes
Webster, Stacey,O'Rourke, Kerry M.,Fletcher, Conor,Pimlott, Sally L.,Sutherland, Andrew,Lee, Ai-Lan
supporting information, p. 937 - 943 (2017/12/26)
Radiopharmaceuticals that incorporate radioactive iodine in combination with single-photon emission computed tomography imaging play a key role in nuclear medicine, with applications in drug development and disease diagnosis. Despite this importance, there are relatively few general methods for the incorporation of radioiodine into small molecules. This work reports a rapid air- and moisture-stable ipso-iododeboronation procedure that uses NIS in the non-toxic, green solvent dimethyl carbonate. The fast reaction and mild conditions of the gold-catalysed method led to the development of a highly efficient process for the radiolabelling of arenes, which constitutes the first example of an application of homogenous gold catalysis to selective radiosynthesis. This was exemplified by the efficient synthesis of radiolabelled meta-[125I]iodobenzylguanidine, a radiopharmaceutical that is used for the imaging and therapy of human norepinephrine transporter-expressing tumours.
