Linden Anthony, Iliev Boyan, Heimgartner Heinz
Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Acta Crystallogr C. 2006 Jun;62(Pt 6):o339-43. doi: 10.1107/S010827010601420X. Epub 2006 May 24.
The title macrocycle, C26H30N2O6, (VI), was obtained by ;direct amide cyclization' from the linear precursor 3-hydroxy-N-[1-methyl-1-(N-methyl-N-phenylcarbamoyl)ethyl]-2-phenylpropanamide, the N-methylanilide of rac-2-methyl-2-[(3-hydroxy-2-phenylpropanoyl)amino]propanoic acid, C13H17NO4, (IV). The reaction proceeds via the intermediate rac-2-(2-hydroxy-1-phenylethyl)-4,4-dimethyl-1,3-oxazol-5(4H)-one, C13H15NO3, (V), which was synthesized independently and whose structure was also established. Unlike all previously described analogues, the title macrocycle has the cis-diphenyl configuration. The 14-membered ring has a distorted rectangular diamond-based [3434] configuration and intermolecular N-H...O hydrogen bonds link the molecules into a three-dimensional framework. The propanoic acid precursor forms a complex series of intermolecular hydrogen bonds, each of which involves pairwise association of molecules and which together result in the formation of extended two-dimensional sheets. The oxazole intermediate forms centrosymmetric hydrogen-bonded dimers in the solid state.
标题大环化合物C26H30N2O6（VI）是通过线性前体3-羟基-N-[1-甲基-1-(N-甲基-N-苯基氨基甲酰基)乙基]-2-苯基丙酰胺（rac-2-甲基-2-[(3-羟基-2-苯基丙酰基)氨基]丙酸的N-甲基苯胺，C13H17NO4，（IV））的“直接酰胺环化”反应得到的。该反应通过中间体rac-2-(2-羟基-1-苯乙基)-4,4-二甲基-1,3-恶唑-5(4H)-酮，C13H15NO3，（V）进行，该中间体是独立合成的，其结构也已确定。与所有先前描述的类似物不同，标题大环化合物具有顺式二苯基构型。这个14元环具有扭曲的基于矩形菱形[3434]的构型，分子间的N-H...O氢键将分子连接成三维框架。丙酸前体形成一系列复杂的分子间氢键，每个氢键都涉及分子的成对缔合，共同导致形成扩展的二维片层。恶唑中间体在固态下形成中心对称的氢键二聚体。
