13C NMR spectra and azoquinone hydrazone tautomerism of azo-2-naphthols and azo-1-naphthols

Conclusions The¹³C NMR spectra of 1-phenylazo-2-naphthols and 2-phenylazo-1-naphthols have been investigated. For both classes the azoquinone hydrazone tautomeric equilibrium is shifted as a result of the nature of the substituent in the benzene ring and a qualitative series of effects has been established. A quantitative measurement of the tautomer composition has been obtained for the arylazo-2-naphthols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2271–2277, October, 1988.The authors thank M. V. Gorelika for submitting samples for investigation and for an interesting discussion.