title: 6-Acetonyldihydroavicine.
abstract: The title compound, 1-(5-methyl-5,6-dihydro[1,3]dioxolo[4',5':4,5]benzo[c][1,5]dioxolo[4,5-j]phenanthridin-6-yl)acetone, C(23)H(19)NO(5), isolated from the stem bark of Zanthoxylum rhoifolium, crystallizes as a racemate in space group P1. The structure shows two aromatic ring systems, each terminated by a five-membered dioxole ring, coupled by an N-containing ring. The core of the molecule is almost planar; the planes of the two ring systems form an angle of 18.42 (6) degrees. The packing shows the molecules parallel to each other and about 3.5 A apart with graphite-type interactions. The N-methyl and acetone groups, which are anti with respect to one another, lie out of the plane and pack in spaces between neighbouring molecules.