Pyrone series. Part XI. Reactivity of 4,6-diaryl-2-pyrones and cyclopropane derivatives obtained from 2-pyrazolines

Abstract

4,6-Diaryl-2-pyrones and ethyl 2-aroyl-3-arylcyclopropanecarboxylates have been prepared from 2-pyrazolines. The structure of the pyrones was established by fission with alkali. Treatment of the cyclopropane derivatives with hydrazine hydrate gave diazabicycloheptenones, from which N-acetyl and N-methyl derivatives were prepared. The 2-pyrazolines were also converted into pyrazine derivatives (III), which gave N-oxides. The pyrones could be converted into 2-pyridones, 1-methyl-2-pyridones, 2-methoxypyridines, 1-amino-2-pyridones, 2-thiopyrones, 1-methyl-2-thiopyridones, and 1-thio-2-pyrones. The structures assigned to the products were established by u.v. and i.r. spectroscopy.