Heterocycles as a Peptidomimetic Scaffold: Solid-Phase Synthesis Strategies

Parallel Synthesis of Piperazine Tethered Thiazole Compounds with Antiplasmodial Activity

Thiazole and piperazine are two important heterocyclic rings that play a prominent role in nature and have a broad range of applications in agricultural and medicinal chemistry. Herein, we report the parallel synthesis of a library of diverse piperazine-tethered thiazole compounds. The reaction of piperazine with newly generated 4-chloromethyl-2-amino thiazoles led to the desired piperazine thiazole compounds with high purities and good overall yields. Using a variety of commercially available carboxylic acids, the parallel synthesis of a variety of disubstituted 4-(piperazin-1-ylmethyl)thiazol-2-amine derivatives is described. the screening of the compounds led to the identification of antiplasmodial compounds that exhibited interesting antimalarial activity, primarily against the Plasmodium falciparum chloroquine-resistant Dd2 strain. The hit compound 2291-61 demonstrated an antiplasmodial EC50 of 102 nM in the chloroquine-resistant Dd2 strain and a selectivity of over 140.

Polyheterocyclic peptidomimetics: Parallel solid phase synthesis of oligo cyclic guanidines and their inhibition activity against Mycobacterium tuberculosis DNA gyrase

Polyheterocycles are one of the most desired synthetic targets due to their numerous and valuable applications in various fields. We report the design and the parallel synthesis of novel linear oligocyclic guanidine peptidomimetics from predesigned reduced polyamides. A screening of these compounds identified active Mycobacterium tuberculosis DNA gyrase inhibitors which do not inhibit human DNA topoisomerase IIα and topoisomerase I.

Neglected Zoonotic Diseases: Advances in the Development of Cell-Penetrating and Antimicrobial Peptides against Leishmaniosis and Chagas Disease

In 2020, the WHO established the road map for neglected tropical diseases 2021-2030, which aims to control and eradicate 20 diseases, including leishmaniosis and Chagas disease. In addition, since 2015, the WHO has been developing a Global Action Plan on Antimicrobial Resistance. In this context, the achievement of innovative strategies as an alternative to replace conventional therapies is a first-order socio-sanitary priority, especially regarding endemic zoonoses in poor regions, such as those caused by Trypanosoma cruzi and Leishmania spp. infections. In this scenario, it is worth highlighting a group of natural peptide molecules (AMPs and CPPs) that are promising strategies for improving therapeutic efficacy against these neglected zoonoses, as they avoid the development of toxicity and resistance of conventional treatments. This review presents the novelties of these peptide molecules and their ability to cross a whole system of cell membranes as well as stimulate host immune defenses or even serve as vectors of molecules. The efforts of the biotechnological sector will make it possible to overcome the limitations of antimicrobial peptides through encapsulation and functionalization methods to obtain approval for these treatments to be used in clinical programs for the eradication of leishmaniosis and Chagas disease.

Novel Approaches for the Solid-Phase Synthesis of Dihydroquinazoline-2(1H)-One Derivatives and Biological Evaluation as Potential Anticancer Agents

In the design of antineoplastic drugs, quinazolinone derivatives are often used as small molecule inhibitors for kinases or receptor kinases, such as the EGFR tyrosine kinase inhibitor gefitinib, p38MAP kinase inhibitor DQO-501, and BRD4 protein inhibitor PFI-1. A novel and convenient approach for the solid-phase synthesis of dihydroquinazoline-2(1H)-one derivatives was proposed and 19 different compounds were synthesized. Cytotoxicity tests showed that most of the target compounds had anti-proliferative activity against HepG-2, A2780 and MDA-MB-231 cell lines. Among them, compounds CA1-e and CA1-g had the most potent effect on A2780 cells, with IC₅₀ values of 22.76 and 22.94 μM, respectively. In addition, in an antioxidant assay, the IC₅₀ of CA1-7 was 57.99 μM. According to bioinformatics prediction, ERBB2, SRC, TNF receptor, and AKT1 were predicted to be the key targets and play an essential role in cancer treatment. ADMET prediction suggested 14 of the 19 compounds had good pharmacological properties, i.e., these compounds displayed clinical potential. The correct structure of the final compounds was confirmed based on LC/MS, ¹H NMR, and ¹³C NMR.

Peptidomimetics: An Overview of Recent Medicinal Chemistry Efforts toward the Discovery of Novel Small Molecule Inhibitors

The use of peptides as therapeutics has often been associated with several drawbacks such as poor absorption, low stability to proteolytic digestion, and fast clearance. Peptidomimetics are developed by modifications of native peptides with the aim of obtaining molecules that are more suitable for clinical development and, for this reason, are widely used as tools in medicinal chemistry programs. The effort to disclose innovative peptidomimetic therapies is recurrent and constantly evolving as demonstrated by the new lead compounds in clinical trials. Synthetic strategies for the development of peptidomimetics have also been implemented with time. This perspective highlights some of the most recent efforts for the design and synthesis of peptidomimetic agents together with their biological evaluation toward a panel of targets.