Chromone studies. Part 10.1Substituent effects on the basicity of 2-(N,N-dimethylamino)chromones†

The pKavalues for a series of 12, substituted 2-(N,N-dimethylamino)chromones have been determined by potentiometric titration and found to lie within a narrow range (1.92–2.52), protonation of the carbonyl oxygen being supported by 13C NMR data and semi-empirical and ab initio calculations.