Spectral and ionisation constant studies of substituted 2-hydroxypyridines (1,2-dihydro-2-oxopyridines)

The ultraviolet and infrared spectra and the ionisation constants of the title compounds containing substituents (3-, 4-, 5-, and 6-Me; 3- and 5-Cl; 3,5-Cl2; 3- and 5-Br; 3,5-Br2; 5-I; 3,5-I2; 3- and 6-OH; 3- and 6-O–; 3- and 5-NO2) have been determined. For all the compounds examined the pyridone form predominates. A number of the corresponding 2-methoxypyridines were also studied for reference.