Inducing achiral aliphatic oligoureas to fold into helical conformations
作者:Romina Wechsel、Julien Maury、Juliette Fremaux、Scott P. France、Gilles Guichard、Jonathan Clayden
DOI:10.1039/c4cc06754a
日期:——
The ability of urea-linked oligomers of achiral diamines (achiral analogues of the well-established chiral oligourea foldamers) to adopt helical conformations was explored spectroscopically. Up to four achiral units were ligated either to a well-formed helical trimer or to a single chiral diamine, and the extent to which they adopted a screw-sense preference was determined by NMR and CD. In the best performing cases, a trimeric chiral oligourea and even a single cis-cyclohexanediamine monomer induced folding into a helical conformation.
A Nonpeptidic Reverse-Turn Scaffold Stabilized by Urea-Based Dual Intramolecular Hydrogen Bonding
作者:Amiya K. Medda、Chul Min Park、Aram Jeon、Hyunwoo Kim、Jeong-Hun Sohn、Hee-Seung Lee
DOI:10.1021/ol201247x
日期:2011.7.1
A novel nonpeptidic reverse-turn scaffold containing urea fragments that are connected by a conformationally constrained D-prolyl-cis-1,2-diaminocyclohexane (D-Pro-DACH) linker is reported. The scaffold adopts a well-defined reverse-turn conformation that is stabilized by dual intramolecular hydrogen bonding in both solution and solid states.