Synthesis and Stacked Conformations of Symmetrical and Unsymmetrical Oligo-ureas of Metaphenylenediamine
作者:Jonathan Clayden、Loïc Lemiègre、Madeleine Helliwell
DOI:10.1021/jo061989w
日期:2007.3.1
The addition of substituted anilines to nitro-substituted isocyanates followed by reduction generates new aniline-substituted ureas, which can be further extended in a one- or two-directional iterative manner to form oligomeric ureas based on a m-phenylenediamine monomer. Oligo-ureas with up to eight urea linkages are reported. Fully N-substituted oligo-ureas are crystalline, and the X-ray crystal structures display ring-stacked conformations. H-1 NMR studies indicate that the stacked conformation persists in solution.