Synthesis of Dibenzotrisdehydro[16]annulene-1,4-dione and the Related Compounds

Synthesis of 7,8:13,14-dibenzo-2,9,11-trisdehydro[16]annulene-1,4-dione is described. Attempts to prepare diaza[18]annulene derivatives by ring expansion of the dibenz[16]annulenedione and its dimethyl analog are also described. Examination of 1H NMR spectra indicates that the dibenz[16]annulenedione shows no ring current effect.