1,3-Dipolar character of six-membered aromatic rings. Part III. 2-Methyl-3-oxidoisoquinolinium. A novel route to benzotropones

The title compound reacts as a 1,3-dipole across the 1- and 3-positions with acrylonitrile and methyl acrylate. The stereochemistry of the adducts is deduced from n.m.r. spectra. The methiodides of the adducts undergo base-catalysed elimination to form 2-aminobenzotropones.