作者:Jonathan Clayden、Loïc Lemiègre、Mark Pickworth、Lyn Jones
DOI:10.1039/b802673d
日期:——
Except in the most hindered of cases, N,N'-diaryl N,N'-dimethyl ureas adopt a conformation with the two aryl rings disposed cis to one another. Variable temperature NMR studies reveal the rate at which the Ar-N bonds rotate as well as the conformational preference of ortho disubstituted ureas in which more than one cis orientation is possible. In general, a conformation in which the aryl rings lie
除非在最受阻碍的情况下,否则N,N′-二芳基N,N′-二甲基脲采用的构型是两个芳基环彼此顺式排列。可变温度NMR研究揭示了Ar-N键旋转的速率以及邻二取代脲的构象偏好,其中可能有多个顺式取向。通常,优选其中芳基环在空间上紧密但其最大的2-取代基反式排列的构象,但对于特别庞大的2-取代基,其中一个芳基环指向另一个的构象也可能是优选的。被填充。