The ultraviolet spectra of aniline, 2-, 3-, and 4-aminopyridines and of some of their derivatives in n-hexane, 1,4-dioxan, ethanol, and water solutions

Abstract

The u.v. spectra of aniline, 2-, 3-, and 4-aminopyridines, and certain of their derivatives have been determined in n-hexane, 1,4-dioxan, ethanol, and water solutions. N-Methylation of the amino-group increases its electrondonating ability and the introduction of a methyl group or halogen atom into the phenyl or pyridyl ring also produces a bathochromic shift. In dioxan and ethanol solutions the amine forms hydrogen bonds to the solvent; this also occurs with 4-aminopyridines in water; with the other solutes hydrogen bonding by the water predominates.