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We report the synthesis and characterization of a series of donor–acceptor TADF emitters with a new architecture, where the donor moiety and the dibenzazepine-based acceptor moiety are separated by a phenylene linker in a V-shaped spatial arrangement.

In the present paper, twelve Schiff bases derived from 3-amino-1H-1,2,4-triazole (ATz) and various benzaldehydes, and salicylaldehydes were synthesized. The 1H, 13C, and 15N NMR data are discussed in relation to the structure of ATz and its imine products. In addition, X-ray, ATR-FTIR, and UV–Vis analytical techniques are used for structure elucidation of ATz-based Schiff bases. It was found that the starting material, 3-amino-1H-1,2,4-triazole, exists as tautomeric mixture of three forms (Graphical Abstract) in solution, whereas in the solid state (13C and 15N CPMAS data) potentially tautomeric proton is located on nitrogen atom traditionally marked as N-2 (Graphical Abstract, 2N H structure). All investigated Schiff bases derived from salicylaldehydes exist in both phases as tautomeric equilibrium mixtures, where enol-imine forms are dominated structures. The positions of those equilibria only very slightly depend on substituents in phenol ring. Generally, the contributions of keto-amine forms in the solid state are higher comparing with DMSO solutions.

(1) Background: Natural peptides supporting the innate immune system studied at the functional and mechanistic level are a rich source of innovative compounds for application in human therapy. Increasing evidence indicates that apart from antimicrobial activity, some of them exhibit selective cytotoxicity towards tumor cells. Their cationic, amphipathic structure enables interactions with the negatively-charged membranes of microbial or malignant cells. It can be modeled in 3D by application of dendrimer chemistry. (2) Methods: Here we presented design principles, synthesis and bioactivity of branched peptides constructed from ornithine (Orn) assembled as proline (Pro)- or histidine (His)-rich dendrons and dendrimers of the bola structure. The impact of the structure and amphipathic properties of dendrons/dendrimers on two glioblastoma cell lines U87 and T98G was studied with the application of proliferation, apoptosis and cell migration assays. Cell morphology/cytoskeleton architecture was visualized by immunofluorescence microscopy. (3) Results: Dimerization of dendrons into bola dendrimers enhanced their bioactivity. Pro- and His-functionalized bola dendrimers displayed cytostatic activity, even though differences in the responsiveness of U87 and T98G cells to these compounds indicate that their bioactivity depends not only on multiple positive charge and amphipathic structure but also on cellular phenotype. (4) Conclusion: Ornithine dendrons/dendrimers represent a group of promising anti-tumor agents and the potential tools to study interrelations between drug bioactivity, its chemical properties and tumor cells&rsquo, phenotype.

In this study, we synthesized novel sulfonamides with a 1,2,4-triazine moiety according to pharmacophore requirements for biological activity. All the synthesized compounds were tested in vitro to verify whether they exhibited anticancer activity against the human breast cancer cell lines MCF-7 and MDA-MB-231. Among them, two most active ones, having IC50 values of 50 and 42 &micro, M, respectively, were found to show higher anticancer activity than chlorambucil used as the reference in the in vitro tests. In addition, two other compounds, which had IC50 values of 78 and 91 &micro, M, respectively, exhibited a similar level of activity as chlorambucil. X-ray analysis carried out for two of the compounds confirmed their synthesis pathway as well as their assumed molecular structures. Furthermore, a conformational analysis was performed, and electronic parameters of molecules were characterized using theoretical calculations at AM1 and DFT level. Moreover, molecular docking revealed the mode of binding of the investigated 1,2,4-triazine sulfonamides with the human estrogen receptor alpha (ER&alpha, ).

A new homochiral metal–organic framework (MOF) with an expanded open cage based on the (R)-3,3′-bis(6-carboxy-2-naphthyl)-2,2′-dihydroxy-1,1′-binaphthyl ligand was synthesized and utilized as a novel chiral stationary phase for high-performance liquid chromatography. Twelve racemates including sec-alcohols, sulfoxides, epoxides, lactone, 1,3-dioxolan-2-one, and oxazolidinone were used as analytes for evaluating the separation properties of the chiral-MOF-packed column. Experimentally, the homochiral MOF offered good molecular recognition ability, which suggests good prospects for the application of chiral MOFs as stationary phases for enantioseparation.

The reaction between primary amine and aldehyde usually leads to a Schiff base. In this work, we present the results of research (NMR, ATR-FTIR, UV–Vis, and X-ray) of products obtained in the reaction of 5-methyl-3-aminoisoxazole (3AMI) or 3-methyl-5-aminoisoxazole (5AMI) with 17 different aldehydes. Based on the results, we prove that this simple and well-known reaction does not always leads to the obtaining of typical products. In addition, we present a discussion on tautomeric forms preferred by the investigated o‑hydroxy imine compounds in solution and in the solid state. Knowledge of the tautomeric form which given Schiff base exists in the solution and in the solid state is very important in the development of medicine and pharmacy as well as coordination chemistry.

An efficient asymmetric ring-opening (ARO) reaction of meso-epoxides with aromatic amines catalysed by a series of homochiral metal–organic frameworks (MOFs) was carried out. Excellent results (up to 95% ee) for the ARO of cyclohexene oxide with several aromatic amines were achieved with a homochiral MOF derived from the ligand (R)-2,2′-dihydroxyl-1,1′-binaphthalene-5,5′-dicarboxylic acid. Furthermore, homochiral MOFs based on (R)-2,2′-dihydroxy-1,1′-binaphthyl-4,4′-di(4-benzoic acid) and (R)-2,2′-diethoxy-1,1′-binaphthyl-4,4′-di(5-isophthalic acid) catalysed ARO reactions of cis-stilbene oxide with 1-naphthylamine in high yield (up to 95%) and excellent enantioselectivity (up to 97%) of the β-amino alcohol. The MOF catalysts were recoverable and recyclable with retention of their performance.

The first synthetic approach to the core structure of cardiac glycoside oleandrin exhibiting a potent cytotoxic activity, starting from a common androstane derivative, has been accomplished. The synthesis is focused on stereoselective transformations in the densely substituted and sterically shielded five-membered ring (steroid ring D). The developed synthesis paves a route to the synthesis of related bufadienolides, i.e., constituents of traditional drug Ch'an Su, bufotalin, and cinobufagin.

A new unexpected product of condensation reaction of 1,8-diaminonaphthalene (DAN) and carbonyl compound (here: dehydroacetic acid (dha)) was synthesized. Discussion about the molecular structure of possible products of this reaction was done on the base of NMR studies. The structure of the titled product in both DMSO solution and in the solid state was resolved by analysis of its spectral data (X-ray structure analysis, multinuclear NMR in solution and solid state spectra) and MS measurements. The presented studies provided clear evidence that the titled product exists in diluted DMSO solution as the mixture of two kinetic free ionic species whereas in concentrated DMSO solution as well as in the solid state this system forms associated ionic pairs bonded together by hydrogen bonds.

A series of thiosemicarbazides with 4-nitrophenyl group was obtained in the reaction of carboxylic acid hydrazides with isothiocyanates. All compounds were checked for their antibacterial and antiproliferative activity. Our results have shown that derivatives 6-8 possessed antibacterial activity against S. aureus, S. epidermidis, S. mutans and S. sanguinis, moderate cytotoxicity and good therapeutic safety in vitro. Additionally, compounds 1 and 4 significantly inhibited A549, HepG2 and MCF-7 cell division. Moreover, PASS software indicated that newly obtained compounds are potential α-glucosidase inhibitors. This was confirmed by in vitro studies. To investigate the mode of interaction with the molecular target compounds were docked to glucose binding site of the enzyme and exhibited a similar binding mode as glucose.

The structural study of five Schiff bases derived from diaminomaleonitrile (DAMN) and 2-hydroxy carbonyl compounds was performed using 1H, 13C and 15N NMR methods in solution and in the solid state as well. ATR-FTIR and X-Ray spectroscopies were used for confirmation of the results obtained by NMR method. The imine obtained from DAMN and benzaldehyde was synthesized as a model compound which lacks intramolecular hydrogen bond. Deprotonation of all synthesized compounds was done by treating with tetramethylguanidine (TMG). NMR data revealed that salicylidene Schiff bases in DMSO solution exist as OH forms without intramolecular hydrogen bonds and independent on the substituents in aromatic ring. In the case of 2-hydroxy naphthyl derivative, the OH proton is engaged into weak intramolecular hydrogen bond. Two of imines (salDAMN and 5-BrsalDAMN) exist in DMSO solution as equilibrium mixtures of two isomers (A and B). The structures of equilibrium mixture in the solid state have been studied by NMR, ATR-FTIR and X-Ray methods. The deprotonation of three studied compounds (salDAMN, 5-BrsalDAMN, and 5-CH3salDAMN) proceeded in two different ways: deprotonation of oxygen atom (X form) or of nitrogen atom of free primary amine group of DAMN moiety (Y form). For 5-NO2salDAMN and naphDAMN only one form (X) was observed.

Traditional antimicrobial therapy used today at clinics is mainly focused on application of developed several decades ago several classes of small chemically modified organic compounds of natural origin, e.g. penicillins, cephalosporins, macrolides, fluoroquinolones, etc. The efficacy of these drugs is declining due to spreading of antibiotic resistance around the microbial world. Herein, we examine current strategies of designing new antimicrobials as nanotechnology-based pharmaceutical drug delivery platforms. We address several problems like synergistic action of β-lactams and nanoparticles, nanoparticles self-cytotoxicity, perspectives of targeted drug delivery and application of “green” chemistry, vital for the prospective production of β-lactams nanoformulations with enhanced efficacy and low toxicity.

C8H8BrNO2, orthorhombic, Pbca (no. 61), a = 10.1313(3) Å, b = 8.5416(4) Å, c = 20.4597(7) Å, V = 1770.53(12) Å3, Z = 8, R gt(F) = 0.0394, wR ref(F 2) = 0.1214, T = 296 K.

A new oxidizing system for olefins, consisting of benzeneseleninic anhydride and trimethylsilyl triflate, was studied. The highly reactive benzeneseleninyl cation is presumably formed under these conditions. It has been shown that different products are formed with this species depending on the specific structure of olefin. The 1,1-disubstituted olefins afforded mostly α,β-unsaturated carbonyl compounds. The sterically encumbered tri- or tetrasubstituted olefins yielded 1,2- or 1,4-dihydroxylated products, presumably via four-membered cyclic intermediates.

A new oxidizing system for olefins, consisting of benzeneseleninic anhydride and trimethylsilyl triflate, was studied. The highly reactive benzeneseleninyl cation is presumably formed under these conditions. It has been shown that different products are formed with this species depending on the specific structure of olefin. The 1,1-disubstituted olefins afforded mostly α,β-unsaturated carbonyl compounds. The sterically encumbered tri- or tetrasubstituted olefins yielded 1,2- or 1,4-dihydroxylated products, presumably via four-membered cyclic intermediates.

C12H13N3O, monoclinic, P21/c (no. 14), a = 11.0784(3) Å, b = 14.4910(4) Å, c = 7.1565(2) Å, β = 97.668(2)°, V = 1138.61(5) Å3, Z = 4, R gt (F) = 0.0432, wR ref (F 2 ) = 0.1328, T = 296 K.