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Three closely related 1-[(1,3-benzodioxol-5-yl)methyl]-4-(halobenzo-yl)piperazines: similar mol-ecular structures but
Ninganayaka Mahesha1, Belakavadi K Sagar1, Hemmige S Yathirajan1
1Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysuru-570 006, India.
Abstract:
In each of the compounds 1-[(1,3-benzodioxol-5-yl)methyl]-4-(3-fluoro-benzo-yl)piperazine, C19H19FN2O3 (I), 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,6-di-fluoro-benzo-yl)piperazine, C19H18F2N2O3 (II), and 1-[(1,3-benzodioxol-5-yl)methyl]-4-(2,4-di-chloro-benzo-yl)piperazine, C19H19Cl2N2O3 (III), the piperazine rings adopt a chair conformation with the (1,3-benzodioxol-5-yl)methyl substituent occupying an equatorial site: the five-membered rings are all slightly folded across the O⋯O line leading to envelope conformations. The dihedral angle between the planar amidic fragment and the haloaryl ring is 62.97 (5)° in (I) but 77.72 (12)° and 75.50 (5)° in (II) and (III), respectively. Despite their similarity in constitution and conformation, the supra-molecular inter-actions in (I)-(III) differ: in (I), a combination of C-H⋯O and C-H⋯π(arene) hydrogen bonds links the mol-ecules into a three-dimensional framework structure, but there are no hydrogen bonds of any sort in either (II) or (III), although the structure of (III) contains a short Cl⋯Cl contact between inversion-related pairs of mol-ecules.
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