Characterization of Quinoline Derivatives. II. 7-(4-methyl-1-piperazinyl)-6H-[1]benzopyrano[3,4-c]quinoline

The title compound, C21H21N3O belongs to a new class of novel, potent and selective serotonin 5-HT3 receptor antagonists based on the arylpiperazine skeleton. The molecular topology is not flat, but the molecule is bent in a helicene-like manner. The pyran ring has a half-boat conformation. This, together with the fusion to the quinoline nucleus, determines the orientation of the fused benzene ring, the role of which is important for the biological activity of the compound. The piperazine ring has a chair conformation. The crystal packing is stabilized by stacking interactions between the quinoline nuclei.