Syntheses and crystal structures of two piperine derivatives.

The title compounds, 5-(2-1,3-benzodioxol-5-yl)--cyclo-hexyl-penta-2,4-dienamide, CHNO (I), and 5-(2-1,3-benzodioxol-5-yl)-1-(pyrrolidin-1-yl)penta-2,4-dien-1-one CHNO (II), are derivatives of piperine, which is known as a pungent component of pepper. Their geometrical parameters are similar to those of the three polymorphs of piperine, which indicate conjugation of electrons over the length of the mol-ecules. The extended structure of (I) features N-H⋯O amide hydrogen bonds, which generate (4) [010] chains. The crystal of (II) features aromatic π-π stacking, as for two of three known piperine polymorphs.