New amphipathic lipopeptides, 1. Synthesis and mesomorphic structures of lipopeptides with polysarcosine peptidic chains

Abstract

AbstractAmphipathic lipopeptides CnSarp with a hydrophobic aliphatic chain, Cn, and a hydrophilic peptidic chain of polysarcosine, Sarp, were synthesized by two methods, a step‐by‐step method and a polymerization method. In the step‐by‐step method, the sarcosine residues are added one by one at the end of a fatty amine (n‐alkylamine, n = 12,14,16,17,18). In the polymerization method, sarcosine N‐carboxyanhydride is polymerized initiated by the amino end of a fatty amine. In concentrated water solution, lipopeptides CnSarp exhibit mesophases whose structure was determined by means of X‐ray diffraction. Three types of mesomorphic structures (lamellar, cylindrical hexagonal, and body‐centred cubic) and two types of polymorphism (one as a function of the length of the peptidic chains, the other as a function of the water content of the mesophases) were established. Furthermore, the respective influence of the factors, governing the type of structure of the mesophases and the values of their geometrical parameters, were analysed.