Dihydro-1,2,3-tricarbalkoxycyclopenta[b] quinoxalines

4,9-Dihydro-3aH-1,2,3-tricarbalkoxycyclopenta[b]quinoxalines, the structure of which was established on the basis of the absorption, fluorescence, PMR, and IR spectra, were synthesized by condensation of o-phenylenediamine with tricarbalkoxycyclopentane-1,2-diones.