2,3,8,12,13-Penta­meth­oxy-5H-dibenzo­[c,n]acridin-7(6H)-one toluene solvate

Abstract

The title compound, C26H25NO6·C7H8, formed by an unexpected tandem reaction of Beckmann rearrangement, electrophilic aromatic addition and subsequent demethyl­ation, was crystallized as its toluene solvate. The crystal under investigation was found to be nonmerohedrally twinned by a rotation around the reciprocal axis [100]; the twin ratio refined to 0.688 (2):0.312 (2). The mol­ecule exhibits an unusual helical arrangement of three six-membered rings that are all connected at one central C atom. The helix effectively performs one full turn around this atom, and the thread pitch, as defined by the distance of the terminal C atoms of the helix, is 4.98 (3) Å. The angles around the central atom are between 104.7 (2) and 115.2 (2)°. The middle ring, a cyclo­hexa-2,4-dienimine ring containing only one saturated C atom, is essentially planar, with an r.m.s. deviation from the mean plane of only 0.035 Å. The other two rings have conformations best described as between envelope and screw-boat, with puckering amplitudes of 0.527 (2) and 0.544 (2) Å, respectively. The packing appears to be dominated by a combination of simple dispersion forces, weak C-HO hydrogen bonds and C-H inter­actions