Tautomerism of Representative Aromatic α-Hydroxy Carbaldehyde Anils as Studied by Spectroscopic Methods and AM1 Calculations. Synthesis of 10-Hydroxyphenanthrene-9-carbaldehyde

Article abstract of DOI:10.1016/0040-4020(95)00002-P

The synthesis of 10-hydroxyphenanthrene-9-carbaldehyde and its anil are described.The structure of the latter compound has been thoroughly studied by 1H and 13C NMR, UV-visible absorption, fluorescence and IR spectroscopies.All the experimental results support the existence of this anil mainly in the keto-enamine tautomeric form.A comparison is presented with previously studied anils derived from salicylaldehyde and 2-hydroxynaphthalene-1-carbaldehyde.Semiempirical calculations (AM1) concerning the relative stability of tautomers as well as the optimized molecular geometries are in good agreement with the experimental findings.