Structural elucidation of the red dye obtained from reaction of 1,8-naphthalenediol with 1,1-diphenylprop-2-yn-1-ol. A correction

The structure of the intensely coloured red product obtained through the reaction of 1,8-naphthalenediol with 1,1-diphenylprop-2-yn-1-ol was reinvestigated. Instead of the expected permanent open form of the naphthopyran, the dye presents the α,β-unsaturated chain at a different position of the naphthalene nucleus. The structure of this compound was elucidated on the basis of detailed spectral analysis, including 2D NMR experiments.