dialkyl 2-(4,4-diaryl-2-mercapto-5-oxo-4,5-dihydro-1H-imidazol-1-yl)fumarate, 7. Single crystal X-ray diffraction study on 4b and 7b proved the structures unambiguously with C=O and SH functionality at the 2-position of the imidazole ring, respectively. Dynamic effects were observed in the NMR spectra of these compounds and were attributed to restricted rotation around the carbon-nitrogen single bonds
在乙内酰
脲或
硫代乙内酰
脲的存在下,
化学计量的二烷基
乙炔二
羧酸酯与
三苯基膦的反应提供了稳定的结晶
磷叶立德。这些化合物经历 PPh3 的平滑消除以产生二烷基 2-(4,4-diaryl-2,5-dioxoimidazolidin-1-yl)fumarate、4 或二烷基 2-(4,4-diaryl-2-mercapto-5-oxo -4,5-dihydro-1H-imidazol-1-yl)fumarate, 7. 4b 和 7b 的单晶 X 射线衍射研究清楚地证明了在
咪唑环的 2-位具有 C=O 和 SH 官能团的结构, 分别。在这些化合物的 NMR 光谱中观察到动态效应,这归因于围绕碳 - 氮单键的受限旋转。旋转异构体的相互转化过程的旋转能垒 (ΔG#) 等于 (53.6 和 17.2) ± 2 kcal mol-1。