Novel heterocycles from 5-methyldibenz[b,f]azocin-6,12-dione and its derivatives

The multifunctional dibenzazocine 2 and its benzylidene derivative 3 have been shown to take part in a variety of rearrangement reactions to produce novel heterocycles. Heterochrysenes 5 and 6 are formed from 3 on treatment with hydroxylamine and ethylamine respectively. The novel spiro-compounds 7 and 9 are obtained from 2 with aniline (at 120 °C) and NaIO4 (or SeO2) oxidation respectively, and acid and amine treatment of 2 gives the isocoumarin 10 and isoquinolines 8(a–c) respectively. Alkaline hydrolysis of 2 gives the deoxybenzoin 11 from which 5, 7, 8(a–c), 9 and 10 are also obtainable leading to mechanistic suggestions for the formation of these compounds. Treatment of 10 with Lawesson’s reagent gives the thionoisocoumarin 13.