TY - JOUR A1 - He, Jing A1 - Wei, Yueting A1 - Feng, Yijiao A1 - Li, Chuntian A1 - Dai, Bin A1 - Liu, Ping T1 - Halogenations of 3-aryl-1H-pyrazol-5-amines JF - Beilstein Archives Y1 - 2021/// SN - M3 - doi:10.3762/bxiv.2021.66.v1 N2 - A direct C-H halogenation of 3-aryl-1H-pyrazol-5-amines with NXS (X = Br, I, Cl) as cheap and safe halogenating reagents at room temperature has been developed. This transformation provides an effective metal-free protocol towards the synthesis of novel 4-halogenated pyrazole derivatives with moderate to excellent yields. The method represents simple and mild reaction conditions, broad substrate scope as well as gram-scale synthesis. The utility of this procedure is established by further transformations of the 4-halogenated products. Mechanism studies show that DMSO plays a dual role of catalyst and solvent. ER -