The arylidene–imidazolone derivatives are a group of compounds of great interest in medicinal chemistry due to their various pharmacological actions. In order to study the possible conformations of an arylidene–imidazolone derivative, two new crystal structures were determined by X-ray diffraction, namely (Z)-5-(4-chlorobenzylidene)-2-(4-methylpiperazin-1-yl)-3H-imidazol-5(4H)-one, C15H17ClN4O, (6), and its salt 4-[5-(4-chlorobenzylidene)-5-oxo-4,5-dihydro-3H-imidazol-2-yl]-1-methylpiperazin-1-ium 3-5-[4-(diethylamino)benzylidene]-4-oxo-2-thioxothiazolidin-3-yl}propionate, C15H18ClN4O+·C17H19N2O3S2
−, (7). Both compounds crystallize in the space group P\overline1}. The basic form (6) crystallizes with two molecules in the asymmetric unit. In the acid form of (6), the N atom of the piperazine ring is protonated by proton transfer from the carboxyl group of the rhodanine acid derivative. The greatest difference in the conformations of (6) and its protonated form, (6c), is observed in the location of the arylidene–imidazolone substituent at the N atom. In the case of (6c), the position of this substituent is close to axial, while for (6), the corresponding position is intermediate between equatorial and axial. The crystal packing is dominated by a network of N—H...O hydrogen bonds. Furthermore, the crystal structures are stabilized by numerous intermolecular contacts of types C—H...N and C—H...Cl in (6), and C—H...O and C—H...S in (7). The geometry with respect to the location of the substituents at the N atoms of the piperazine ring was compared with other crystal structures possessing an N-methylpiperazine moiety.
芳基亚甲基咪唑啉酮衍生物是一类在药物化学中具有多种药理作用的化合物,因而备受关注。为了研究芳基亚甲基咪唑啉酮衍生物的可能构象,通过 X 射线衍射测定了两种新的晶体结构,即 (Z)-5-(4-氯亚苄基)-2-(4-甲基哌嗪-1-基)-3H-咪唑-5(4H)-酮、C15H17ClN4O, (6), and its salt 4-[5-(4-chlorobenzylidene)-5-oxo-4,5-dihydro-3H-imidazol-2-yl]-1-methylpiperazin-1-ium 3-5-[4-(diethylamino)benzylidene]-4-oxo-2-thioxothiazolidin-3-yl}propionate, C15H18ClN4O+·C17H19N2O3S2
-, (7).这两种化合物都在 P\overline1} 空间群中结晶。碱式 (6) 结晶时不对称单元中有两个分子。在 (6) 的酸性形式中,哌嗪环的 N 原子通过质子转移从罗丹宁酸衍生物的羧基中质化。(6)和它的质子化形式(6c)在构象上的最大区别在于 N 原子上芳基咪唑酮取代基的位置。对于 (6c),该取代基的位置接近轴向,而对于 (6),相应的位置介于赤道和轴向之间。晶体结构主要由 N-H...O 氢键网络构成。此外,(6)中的 C-H...N 和 C-H...Cl 以及(7)中的 C-H...O 和 C-H...S 分子间的大量接触也稳定了晶体结构。哌嗪环 N 原子上取代基位置的几何形状与其他具有 N-甲基哌嗪分子的晶体结构进行了比较。