The addition of acetic acid to pyridynes and quinolynes

Abstract

The oxidation of the aminotriazolopyridines (1) and (3) and the aminotriazoloquinolines (2) and (4) with lead tetra-acetate in the absence of tetracyclone is described. The products from 2,3-pyridyne and 2,3-quinolyne are 2-acetoxypyridine (5) and 2-acetoxyquinoline respectively. From 3,4-pyridyne, the identifiable organic products are acetic anhydride and a mixture of N-4′-pyridyl-4-pyridone (8) and N-3′-pyridyl-4-pyridone (9) with no detectable amount of 3- or 4-acetoxypyridine. 2,3-Pyridynes undergo ionic addition by acetic acid in preference to cycloaddition to tetracyclone; but 3,4-pyridynes undergo cycloaddition to tetracyclone in preference to ionic addition of acetic acid. There is no sign of bipyridylenes: pyridynes undergo both cycloaddition and ionic addition in preference to dimerisation.