(Phen-yl)(3-phenyl-sulfonyl-1,2-dihydro-pyrrolo-[1,2-a]quinoxalin-1-yl)methanone.

In the title mol-ecule, C(24)H(18)N(2)O(3)S, the 13-atom ring system comprising the quinoxaline and fused five-membered ring exhibits an r.m.s. deviation from coplanarity of 0.039†à , with a maximum deviation of 0.0710†(10)†à for the PhCO-bearing C atom of the five-membered ring. The 10-membered C(8)N(2) quinoxaline ring system has an r.m.s. deviation from coplanarity of 0.022†à , with a maximum deviation of 0.0403†(9)†à for the C atom involved in the C=C bond in the five-membered ring. The three atoms of the five-membered ring fused to the quinoxaline ring system show deviations of up to 0.118†(2)†à for the PhCO-bearing C atom. C-N bond distances in the quinoxaline ring system of the title mol-ecule deviate from those in unsubstituted quinoxaline. In particular, the two C-N distances to the N atom involved in the five-membered ring are essentially equal, with values of 1.3786†(17) and 1.3773†(16)†à , unlike the difference of nearly 0.06†à in quinoxaline.