From N–H Nitration to Controllable Aromatic Mononitration and Dinitration─The Discovery of a Versatile and Powerful <i>N</i>-Nitropyrazole Nitrating Reagent
Tao Yang, Xiaoqian Li, Shuang Deng, Xiaotian Qi, Hengjiang Cong, Hong‐Gang Cheng, Liangwei Shi, Qianghui Zhou, Lin Zhuang
Abstract
-nitro-type reagent library constructed using a practical N-H nitration method. This nitrating reagent behaves as a controllable source of the nitronium ion, enabling mild and scalable nitration of a broad range of (hetero)arenes with good functional group tolerance. Of note, our nitration method could be controlled by manipulating the reaction conditions to furnish mononitrated or dinitrated product selectively. The value of this method in medicinal chemistry has been well established by its efficient late-stage C-H nitration of complex biorelevant molecules. Density functional theory (DFT) calculations and preliminary mechanistic studies reveal that the powerfulness and versatility of this nitrating reagent are due to the synergistic "nitro effect" and "methyl effect".