Janssen, Joseph W. A. M. published the artcileGeneration and reactivity of N-pyrazolyl radicals in benzene solution, SDS of cas: 53355-55-8, the publication is Journal of Organic Chemistry (1975), 40(7), 915-20, database is CAplus.
The preparations of tert-Bu 1-pyrazolepercarboxylate and its 3-Me derivative are described. Thermolysis of these compounds in benzene at ∼140° proceeds predominantly via homolysis and leads to N-phenylated pyrazoles without formation of isomeric C-Ph derivatives N-pyrazolyl radicals, which are proposed as intermediates, apparently are able to effect homolytic aromatic substitution. Judging from competition with p-dichlorobenzene (partial rate factor ∼0.25), 1-pyrazolyl has a marked electrophilic character. Photolysis of N-nitropyrazoles in benzene, also leading to N-phenylated derivatives, is another way to generate N-pyrazloyl radicals. The unpaired electron is delocalized over (at least) the two N atoms. A σ-type ground state is favored over a π-type electronic structure.
Journal of Organic Chemistry published new progress about 53355-55-8. 53355-55-8 belongs to pyrazoles-derivatives, auxiliary class Pyrazole,Chloride,acyl chloride,Amide, name is 1H-Pyrazole-1-carbonyl chloride, and the molecular formula is C4H3ClN2O, SDS of cas: 53355-55-8.
Referemce:
https://en.wikipedia.org/wiki/Pyrazole,
Pyrazoles – an overview | ScienceDirect Topics