Five BINOL-based hosts with a variable macroring size were synthesized in a two-step postfunctionalization protocol by double N-benzylation followed by BMS-mediated reduction of tertiary amide groups (53−93%). UV−vis titration in MeCN reveals that all hosts exhibit a preference for the (R)-enantiomer over the (S)-enantiomer of PEA−HCl. The enantioselectivity depends on the number of hydrogen bond (HB) acceptors and the size and flexibility of the macroring. The highest enantiodiscrimination was observed for the 20-membered host 10, containing six HB acceptors (K R /K S = 2.13).
We present an improvement of our own method for synthesising macrocyclic compounds via doubleamidation reactions of aromatic dimethyl esters with five oxa-aliphatic α,ω-diamines of different lengths, leading to a large library of potential ion receptors. We studied the influence of various inorganic salts (NaCl, KCl, CsCl, NH4Cl, MgSO4, CaCl2, CuSO4) on the macrocyclization reaction. The results were analyzed in terms of substrate conversion and distribution of products, using high performance liquid chromatography (HPLC).
Surface properties are crucial for medical device and implant research and applications. We present novel polycatecholamine coatings obtained by oxidative polymerization of L-tyrosine, L-phenylalanine, and 2-phenylethylamine based on mussel glue-inspired chemistry. We optimized the reaction parameters and examined the properties of coatings compared to the ones obtained from polydopamine. We produced polycatecholamine coatings on various materials used to manufacture implantable medical devices, such as polyurethane, but also hard-to-coat polydimethylsiloxane, polytetrafluoroethylene, and stainless steel. The coating process results in significant hydrophilization of the material's surface, reducing the water contact angle by about 50 to 80% for polytetrafluoroethylene and polyurethane, respectively. We showed that the thickness, roughness, and stability of the polycatecholamine coatings depend on the chemical structure of the oxidized phenylamine. In vitro experiments showed prominent hemocompatibility of our coatings and significant improvement of the adhesion and proliferation of human umbilical vein endothelial cells. The full confluence on the surface of coated polytetrafluoroethylene was achieved after 5 days of cell culture for all tested polycatecholamines, and it was maintained after 14 days. Hence, the use of polycatecholamine coatings can be a simple and versatile method of surface modification of medical devices intended for contact with blood or used in tissue engineering.
Three (R)-BINOL-based macrocyclic receptors obtained via double-amidation reaction were used for chiral recognition of four anions derived from α-hydroxy and α-amino acids. The structural factors of hosts and guests that affect chiral recognition processes were also investigated, indicating that the proper geometry of both receptor and guest molecules plays a crucial role in effective enantio-discrimination.
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