The transformations of readily available 4-chloro-3,5-dinitropyrazole and its N-methylated derivative under the action of anionic S-/O-nucleophiles and neutral N-nucleophiles were studied. Independent of the substrate's charge (anionic, R = H, or neutral, R = Me), the nucleophilic substitution proceeds exclusively at position 4 replacing the chlorine nucleofuge. As a result of this study, the effective synthetic method for the preparation of 4-substituted 3,5-dinitropyrazoles via the nucleophilic substitution in 4-chloro3,5-dinitropyrazole was elaborated.
The specific reactivity of 3,4,5-trinitro-1H-pyrazole
作者:Igor L. Dalinger、Irina A. Vatsadze、Tatyana K. Shkineva、Galina P. Popova、Svyatoslav A. Shevelev
DOI:10.1016/j.mencom.2010.09.003
日期:2010.9
Nitration of 3,5-dinitropyrazole with HNO3-H2SO4 mixture gives 3,4,5-trinitro-1H-pyrazole, which in reaction with ammonia, amines or thiols under mild conditions undergoes regioselective nucleophilic substitution of the 4-positioned nitro group