Synthesis of Substituted 1H-Indazoles by Pyrazole Annelation to an Arene
摘要:
Substituted 1H-indazoles have been synthesized by reductive intramolecular heterocyclization of 2,4-di-aroyl-N-nitrosomethylanilines and 2,4-diacetyl-N-nitrosomethylaniline. The N-nitrosoanilines were obtained by nitrosation of N-methyl-2,4-diaroyl- and 2,4-diacetylanilines, the products of quaternary 3,5-diaroyl- and 3,5-diacetylpyridinium salt recyclization.