Effect of unsaturated electron-withdrawing substituents on the tautomerism of 2-hydroxypyridines: 6-hydroxy-2,3-bis(methoxycarbonyl)-pyridine and 5-cyano-2,3-dihydro-6-hydroxy-4-methylfuro[2,3-b]pyridine
Abstract
5,6-Dimethoxycarbonyl substitution in the former title compound, though very strongly electron-withdrawing, has a disproportionately small effect in raising the proportion of pyridol. The cyano-substituent in the latter title compound, even though very strongly electron-withdrawing, actually reduces the pyridol content.