O-Ethynylphenylcarbonyl compds. undergo cyclization to 2-benzopyrylium salts on treatment with acid. Treatment of these compds. with NH3 gave isoquinolines. 1-Ethoxy-2-benzopyrylium salts were partially hydrolyzed to the hydroxy analogs and 1-dimethylaminoisoquinolines were accompanied by the amino analogs. [on SciFinder(R)]
