The chemistry of polycyclic arene imines. VII. Reactions of phenanthrene 9,10‐imine with aromatic carboxaldehydes, carboxylic acids and acetylenic esters

The reactions of phenanthrene 9,10‐imine ( 1 ) with aromatic aldehydes, benzoic acids and acetylenedi‐carboxylic esters were investigated. The aldehydes were shown to give 1‐[ N ‐(arylmethylidene)‐9‐phenanthreneamine‐10‐yl]‐1a,9b‐dihydrophenanthro[9,10‐ b ]azirine 2. The ‘dimeric’ structure of these products was established by X‐ray diffraction analysis. The carboxylic acids proved to form in the presence of dicyclohexylcarbodiimide, N ‐aroylphenanthrene 9,10‐imines 7 , that readily undergo rearrangement to N ‐aroyl‐9‐phenanthrenamines 8. Esters of acetylenedicarboxylic acid gave the corresponding esters of (Z)‐2‐(1a,9b‐dihydrophenanthro[9,10‐ b ]azirine‐1‐yl)‐2‐butendioic acid 10 .