3-(2,3,5,6,7,8-Hexahydro-1H-cyclopenta[b]quinolin-9-yl)-1,5-bis(4-methoxyphenyl)biuret

Ipidacrine (2,3,5,6,7,8-hexahydro-1H-cyclopenta[b]quinolin-9-amine) was reacted with 4-methoxyphenyl isocyanate to give the title compound, C28H30N4O4. An intramolecular N-H center dot center dot center dot O hydrogen bond results in an essentially planar [r.m.s. deviation from the mean plane is 0.126 (1) angstrom] conformation for the biuret unit. The central ring of the quinoline unit is twisted by 78.2 (1)degrees with respect to the biuret mean plane, whereas the two 4-methoxybenzene rings are twisted out of this plane by 24.3 (1)degrees and 48.5 (1)degrees, resulting in an overall propeller-like structure. An intermolecular N-H center dot center dot center dot N hydrogen bond between the biuret NH atom and the quinoline ring nitrogen defines the crystal packing.