Calix[4]Resorcinarene Carboxybetaines and Carboxybetaine Esters: Synthesis, Investigation of In Vitro Toxicity, Anti-Platelet Effects, Anticoagulant Activity, and BSA Binding Affinities

Base-Catalyzed Reaction of Isatins and (3-Hydroxyprop-1-yn-1-yl)phosphonates as a Tool for the Synthesis of Spiro-1,3-dioxolane Oxindoles with Anticancer and Anti-Platelet Properties

An approach to the synthesis of phosphoryl substituted spiro-1,3-dioxolane oxindoles was developed from the base-catalyzed reaction of various isatins with (3-hydroxyprop-1-yn-1-yl)phosphonates. It was found that various aryl-substituted and N-functionalized isatins with the formation of appropriate products with high yields and stereoselectivity when using t-BuOLi are able to react. Cytotoxic activity evaluation suggests that the most significant results in relation to the HuTu 80 cell line were shown by N-benzylated spirodioxolanes. 5-Cloro-N-unsubstituted spirooxindoles exhibit antiaggregational activity exceeding the values of acetylsalicylic acid.

Dual Brønsted acidic-basic function immobilized on the 3D mesoporous polycalix [4]resorcinarene: As a highly recyclable catalyst for the synthesis of spiro acenaphthylene/indene heterocycles

In this study, a novel dual Brønsted acidic-basic nano-scale porous organic polymer catalyst, PC4RA@SiPr-Pip-BuSO3H, was synthesized through various steps: preparation of a 3D network of polycalix, modification with (3-chloropropyl)-trimethoxysilane, then functionalization of polymer with piperazine and n-butyl sulfonic acid under the provided conditions. The catalyst characterization was performed by FT-IR, TGA, EDS, elemental mapping, PXRD, TEM, and FE-SEM analyses, confirming high chemical stability, activity, recoverability, and excellent covalent anchoring of functional groups. So, the designed catalyst was utilized for preparing spiro-acenaphthylene and amino-spiroindene heterocycles, providing good performance with a high yield of the corresponding products. Accordingly, this catalyst can be used in different organic transformations. Necessary experiments were conducted for the recyclability test of the polymeric catalyst, and the results showed the PC4RA@SiPr-Pip-BuSO3H catalyst can be reused 10 times without any decrease in its activity or quality with excellent stability. The structure of resultant spiro heterocycles was confirmed using 1H NMR, 13C NMR, and FT-IR.

Thiacalixarene Carboxylic Acid Derivatives as Inhibitors of Lysozyme Fibrillation

Amyloid fibroproliferation leads to organ damage and is associated with a number of neurodegenerative diseases affecting populations worldwide. There are several ways to protect against fibril formation, including inhibition. A variety of organic compounds based on molecular recognition of amino acids within the protein have been proposed for the design of such inhibitors. However, the role of macrocyclic compounds, i.e., thiacalix[4]arenes, in inhibiting fibrillation is still almost unknown. In the present work, the use of water-soluble thiacalix[4]arene derivatives for the inhibition of hen egg-white lysozyme (HEWL) amyloid fibrillation is proposed for the first time. The binding of HEWL by the synthesized thiacalix[4]arenes (logKa = 5.05-5.13, 1:1 stoichiometry) leads to the formation of stable supramolecular systems capable of stabilizing the protein structure and protecting against fibrillation by 29-45%. The macrocycle conformation has little effect on protein binding strength, and the native HEWL secondary structure does not change via interaction. The synthesized compounds are non-toxic to the A549 cell line in the range of 0.5-250 µg/mL. The results obtained may be useful for further investigation of the anti-amyloidogenic role of thiacalix[4]arenes, and also open up future prospects for the creation of new ways to prevent neurodegenerative diseases.

Pillar[5]arene/albumin biosupramolecular systems for simultaneous native protein preservation and encapsulation of a water-soluble substrate

The growing resistance of pathogens, bacteria, viruses, and fungi to a number of drugs has encouraged researchers to use natural and synthetic biomimetic systems to overcome this challenge. Multicomponent systems are an attractive approach for drug design and multitarget therapy. In this study, we report the assembly of a three-component (pillar[5]arene, bovine serum albumin, and methyl orange) biosupramolecular system as a potential drug delivery system. We estimated the cytotoxic activity and transfection ability of pillar[5]arene derivatives and investigated the effect of the nature of macrocycle functions (L-phenylalanine, glycine, L-alanine) on the native conformation of serum albumin in a three-component system. NMR, UV-vis, fluorescence, CD spectroscopy, DLS, and molecular docking studies were performed in order to confirm the structure and possible pillar[5]arene/bovine serum albumin/methyl orange interactions occurring during the association process. Results indicate that pillar[5]arene with L-phenylalanine fragments retains the native form of BSA to the maximum extent and forms more stable associates.

Carboxybetaine and Carboxybetaine Ester Derivatives of Tetra(dodecyloxyphenyl)-calix[4]resorcinarene: Synthesis, Self-Assembly and In Vitro Toxicity

Amphiphilic calix[4]resorcinarenes are a class of macrocyclic compounds with broad potential utility including nanomedicine. Here the synthesis of new carboxybetaine and carboxybetaine ester calix[4]resorcinarene bearing 4-(dodecyloxy)phenyl groups on the lower rim is presented. The compounds were characterized by 1H-NMR, 13C-NMR, 2D NMR, IR, ESI and elemental analysis. The critical association concentration values are 1.00 × 10−5 and 1.18 × 10−5 mol·L−1 for carboxybetain and ester, respectively. The hemolytic activity of the macrocycles and their cytotoxicity against normal (WI-38, Chang liver) and tumor cells (M-HeLa) are also estimated.