A NOVEL THREE-CARBON ANNELATION METHOD FOR PYRIDINE DERIVATIVES

Abstract

Cyclopentane ring annelation methods for 2-pyridone derivatives are provided by cyclobutane ring expansion of 1, 2-dihydrocyclobuta [c] pyridin-3 (4H)-ones having an appropriate function at the l-position. Since the latter compounds are readily accessible from 4-alkoxy-2-pyridones via our two-step procedure (Kaneko-Naito method), the methods seem to have wide applicability for the synthesis of cyclopenta [c] pyridines.