Turning Around theL-Phe-D-Oxd Moiety for a Versatile Low-Molecular-Weight Gelator

We have prepared a small library of 13 peptidomimetics containing the L-Phe-D-Oxd unit (or the isosteric L-Phe-D-pGlu unit), which is a privileged scaffold for the preparation of supramolecular materials. These compounds were prepared in solution in excellent yields and tested as organogelators and/or hydrogelators at 10 mM concentration with a plethora of solvents and solvent mixtures. Two molecules were very efficient gelators: one is a organogelator and the other is a hydrogelator. As these compounds have quite different skeletons, a rationale to explain the different behaviour of these molecules as gelators takes into consideration their hydrophobicity, expressed as logP. Finally, Fmoc-L-Phe-D-pGlu-OH (6b) efficiently gelated phosphate-buffered saline (PBS 1X) at 1.5% w/w concentration and is an excellent candidate for the preparation of novel materials for applications in, for example, drug release, biological assays, and tissue engineering.