Smart Electrospun Nanofibers from Short Peptidomimetics Based on Pyrrolo-pyrazole Scaffold

Abstract

We prepared a small library of short peptidomimetics based on 3-pyrrolo-pyrazole carboxylate, a non-coded γ-amino acid, and glycine or alanine. The robust and eco-friendly synthetic approach adopted allows to obtain the dipeptides in two steps from commercial starting materials. This gives the possibility to shape these materials by electrospinning into microand nanofibers, in amounts required to be useful for coating surfaces of biomedical relevance. To promote high quality of electrospun fibers, different substitution patterns were evaluated, all for pure peptide fibers, free of any polymer or additive. The best candidate, which affords a homogeneous fibrous matrix, was prepared in larger amounts, and its biocompatibility was verified. This successful work is the first step to develop a new biomaterial able to produce pristine peptidebased nanofibers to be used as helpful component or stand-alone scaffolds for tissue engineering or for the surface modification of medical devices.

Stereochemical Behavior of Pyrrolo-Pyrazole Peptidomimetics Promoting Phase-Selective Supramolecular Organogels

“…Yields and spectroscopic analyses for 4a,b,d are in agreement with the data recently reported by our group [25].…”

“…Compounds 3a-d, characterized by different ester functionalities (i.e., Et, tBu, Bn) and N-phenyl or -benzyl groups in imide function, were prepared by exploiting the known 1,3-dipolar cycloaddition reaction from commercially available diazoalkanes 1a-c (toluene solution) and compounds 2a,b, operating in Et 2 O at 25 • C (12 h) [25,27]. As expected, single ∆ 2 -pyrazoline regioisomers 3a-d were obtained in good-to-excellent yields (Scheme 1).…”

“…The reaction mixture was stirred at room temperature overnight and monitored by TLC (AcOEt/hexane, 4:6). A solid was formed that was filtered and washed with a few drops of Et 2 O. Cycloadducts 3a,b,d were recently prepared by our group [25].…”

“…Continuing our research on non-coded amino acids able to generate specific secondary structures when inserted into peptides [23] and enhancing the spectrum of fundamental materials [24], we recently synthesized 3-carboxylic-pyrrolo-pyrazole derivatives 3 (Scheme 1), which can be considered as mimetics of γ-amino acid [25]. This versatile scaffold can be obtained in one step from commercially available compounds and can be easily decorated at the carboxylic function, at the-nitrogen of the imide function and of pyrazoline, affording a small library of compounds.…”