The Synthesis of Hydroxy- and Methoxy-derivatives of p-Benzoquinonetropides

Abstract
2-Methoxy- (10), 2-hydroxy- (15), and 2, 6-dimethoxy- (20) p-benzoquinonetropide were synthesized by the dehydrogenation of tropylated guaiacol, catechol, and pyrogallol dimethyl ether respectively. The electronic spectra of 10, 15, and 20 in water showed their long wavelength absorption maxima at 550–570 mμ. However, the spectra of these compounds in chloroform showed that the peaks had shifted to wavelengths shorter by 38–60 mμ than those in water. A solvent effect of this type can be understood as resulting from a transition to an excited state that is more polar than the ground state.