Synthesis of malonamide pseudopeptidic compounds using a pseudo five-component reaction and evaluation of their gelation properties

Abstract

A new class of malonamide pseudopeptidic compounds (MPPCS) was prepared via an isocyanide-based pseudo five-component reaction. Amino acid esters, which were used in this reaction, were phenylalanine ethyl ester and glycine ethyl ester. MPPCS that were obtained from L-phenylalanine ethyl ester and glycine ethyl ester gave stable gels in the mixture of dimethyl sulfoxide (DMSO)/water as solvent while MPPCs derived from D-phenylalanine did not give gel. Also, when MPPCS of D- and L-form (1:1) were mixed, they could not create a gel in low and even high concentrations. The sol-gel phase transition temperature of the gels showed that they have agreeable thermal stability. Rheological results showed high mechanical strength for some of gels. Fourier transform infrared (FT-IR) spectra indicated that three types of driving forces have the key role in this self-assembly include hydrogen bondings, van der Waals, and π-π interactions. Moreover, morphology of the xerogel was clarified using the scanning electron microscope (SEM) image. © 2018