168140-37-2Relevant academic research and scientific papers
SYNTHESIS OF DIMETHYLPYRAZOLOBENZOTRIAZOLES AND OF METHYLPYRAZOLOQUINOXALINES BY CYCLIZATION OF 3,5-DIMETHYL-1-(2-NITRENOPHENYL)PYRAZOLES
Albini, Angelo,Bettinetti, Gianfranco,Minoli, Giovanna
, p. 597 - 606 (2007/10/02)
The thermal and photochemical decomposition of a series of 5-substituted 1-(2-azidophenyl)-3,5-dimethylpyrazoles has been examined under a homogeneous set of conditions.Cyclization to pyrazolobenzotriazole (via singlet nitrene) is an efficient process except when the phenyl substituent induces intersystem crossing to the azide triplet or compensates for its electrophilicity.On the contrary, cyclization to pyrazoloquinoxaline (via triplet nitrene) is not a preparatively useful process, due to competition with dimerization to the azo derivatives and reduction to aminophenylpyrazoles.
