Synthesis of 2-(5-Nitropyrid-2-yl)-3-(4-substitutedphenyl)amino-isoxazol-5(2H)-ones and Their Rearrangements to Imidazo12-a- pyridines and Indoles with Triethylamine

摘要

3-(4-Substitutedphenyl)aminoisoxazol-5(2H)-ones, substituted on nitrogen with a nitropyridine group, react with triethylamine to give imidazo[1,2-a]pyridines and indoles. With 4-bromophenyl and 4-methylphenyl group substituents only imidazopyridines are formed, but the 4-methoxyphenyl derivative gave a 3:1 mixture of the corresponding imidazo[1,2-a]pyridine and 2-pyridylaminoindole, respectively.