Pelizza G, Nebuloni M, Ferrari P, Gallo G G, Pelizzi G, Tarasconi P
Farmaco Sci. 1978 Jan;33(1):3-13.
Three polymorphic forms of 1-methyl-2-nitro-5-vinylimidazole, a potential antimicrobial drug, have been isolated and characterized by thermomicroscopy, differential scanning calorimetry, infrared spectroscopy and X-ray powder diffraction. On the basis of some infrared bands, the hypothesis has been made that the different packing of forms I and II was due to the existence of the molecule in two different conformations in the two forms. The direct confirmation of the hypothesis has been sought by X-ray diffraction of single crystals, but a suitable crystal was obtained only for form II. Form II is orthorhombic, space group Pbca, with unit-cell dimensions: a = 13.05, b = 10.83, c = 10.21 A; Z = 8. From the X-ray analysis, carried out by direct methods, the molecule is planar and the vinyl group is cisoid to the heterocyclic CH group. Then, the existence of the molecule as transoid conformation in form I still remains a hypothesis.
已分离出一种潜在抗菌药物1-甲基-2-硝基-5-乙烯基咪唑的三种多晶型物，并通过热显微镜、差示扫描量热法、红外光谱和X射线粉末衍射对其进行了表征。基于一些红外谱带，有人提出假设，I型和II型的不同堆积是由于两种晶型中分子以两种不同构象存在。已通过单晶X射线衍射寻求对该假设的直接证实，但仅获得了适合II型的晶体。II型为正交晶系，空间群Pbca，晶胞参数：a = 13.05，b = 10.83，c = 10.21 Å；Z = 8。通过直接法进行的X射线分析表明，分子是平面的，乙烯基与杂环CH基团呈顺式。那么，I型中分子以反式构象存在这一假设仍然成立。
