Ligand Effects of 2-(2-Pyridyl)benzazole−Pd Complexes on the X-ray Crystallographic Structures, 1H NMR Spectra, and Catalytic Activities in Mizoroki−Heck Reactions

Palladium-Catalyzed Remote Hydrosulfonamidation of Alkenes: Access to Primary N-Alkyl Sulfamides by the SuFEx Reaction

Herein, we establish a remote hydrosulfonamidation (HSA) of alkenes using palladium catalysis, where N-fluoro-N-(fluoro-sulfonyl)-carbamate with a sulfur(VI) fluoride moiety is demonstrated as a good amidation reagent. The anti-Markovnikov HSA reaction of terminal alkenes and the remote HSA of internal alkenes are achieved to efficiently yield primary N-alkyl-N-(fluorosulfonyl)-carbamates. In addition, this protocol enables the high-value utilization of alkane by combining the dehydrogenation process. The generated N-alkyl products exhibit a unique reactivity of sulfur(VI) fluorides, which can be directly transferred to N-alkyl sulfamides or amines via the sulfur(VI) fluoride exchange reaction, thereby streamlining their synthesis. Moreover, a (pyridyl) benzazole-type ligand proved to be vital for the excellent chemo- and regioselectivities.

Ruthenium(II) polypyridyl complexes with benzothiophene and benzimidazole derivatives: Synthesis, antitumor activity, solution studies and biospeciation

With the aim to incorporate pharmacophore motifs into the Ru(II)-polypyridyl framework, compounds [Ru(II)(1,10-phenantroline)₂(2-(2-pyridyl)benzo[b]thiophene)](CF₃SO₃)₂ (1) and [Ru(II)(1,10-phenantroline)₂(2-(2-pyridyl)benzimidazole)](CF₃SO₃)₂ (2) were prepared, characterized and tested for their antitumor potential. The solid-state structure of the compounds was confirmed by single-crystal X-ray diffraction analysis. The solution behavior of both complexes was investigated, namely their solubility, stability, and lipophilicity in physiological mimetic conditions, as well as an eventual uptake by passive diffusion. In vitro anticancer activity of the complexes on ovarian and different colon cancer cells and apoptosis induction by the complexes were studied. A slow transformation process was observed for complex 1 in aqueous solution when exposed to sunlight, while complex 2 undergoes deprotonation (pK_a = 7.59). The lipophilicity of this latter complex depends strongly on the pH and ionic strength. In contrast, 1 is rather hydrophilic under various conditions. Complex 1 was highly cytotoxic on Colo-205 human colon (IC₅₀ = 7.87 μM) and A2780 ovarian (IC₅₀ = 2.2 μM) adenocarcinoma cell lines, while 2 displayed moderate anticancer activity (30.9 μM and 18.0 μM, respectively). The complexes induced late apoptosis and necrosis. Only a weak binding of the complexes to human serum albumin, the main transport protein in blood serum, was found. However, a more significant binding to calf thymus DNA was observed in UV-visible titrations and fluorometric dye displacement studies. Detailed analysis of fluorescence lifetime data collected for the latter systems reveals not only the partial intercalation of the complexes, but goes beyond the usual simplified interpretations.

Effect of the aniline fragment in Pt(II) and Pt(IV) complexes as anti-proliferative agents. Standard reduction potential as a more reliable parameter for Pt(IV) compounds than peak reduction potential

The problems of resistance and side effects associated with cisplatin and other chemotherapeutic drugs have boosted research aimed at finding new compounds with improved properties. The use of platinum(IV) prodrugs is one alternative, although there is some controversy regarding the predictive ability of the peak reduction potentials. In the work described here a series of fourteen chloride Pt(II) and Pt(IV) compounds was synthesised and fully characterised. The compounds contain different bidentate arylazole heterocyclic ligands. Their cytotoxic properties against human lung carcinoma (A549), human breast carcinoma (MCF7) and human colon carcinoma (HCT116 and HT29) cell lines were studied. A clear relationship between the type of ligand and the anti-proliferative properties was found, with the best results obtained for the Pt(II) compound that contains an aniline fragment, (13), thus evidencing a positive effect of the NH₂ group. Stability and aquation studies in DMSO, DMF and DMSO/water mixtures were carried out on the active complexes and an in-depth analysis of the two aquation processes, including DFT analysis, of 13 was undertaken. It was verified that DNA was the target and that cell death occurred by apoptosis in the case of 13. Furthermore, the cytotoxic derivatives did not exhibit haemolytic activity. The reduction of the Pt(IV) compounds whose Pt(II) congeners were active was studied by several techniques. It was concluded that the peak reduction potential was not useful to predict the ability for reduction. However, a correlation between the cytotoxic activity and the standard reduction potential was found.

Synthesis and anticholinesterase activities of novel glycosyl benzoxazole derivatives

Eight glycosyl benzoxazole derivatives are synthesized by nucleophilic addition reactions of glycosyl isothiocyanate with o-aminophenol in tetrahydrofuran. The reaction conditions are optimized, and good yields (86%–94%) were obtained. The structures of all new products are confirmed by infrared, 1H nuclear magnetic resonance, and high-resolution mass spectrometry (electrospray ionization). In addition, the in vitro cholinesterase inhibitory activities of these new compounds are tested by Ellman’s method.

Copper-Catalyzed Synthesis, Bio-Evaluation, and in Silico Studies of 2-Aryl-N-alkylbenzimidazoles as Neuroprotective Agents

2-aryl-N-alkylbenzimidazole derivatives synthesized by CuI/PPh3 promoted direct coupling of N-alkylbenzimidazoles with aryl bromides. In vitro neurotoxicities of 20 compounds were evaluated, and the neuroprotective abilities of low-neurotoxic compounds (3b, 3g, 3h, 3i, 3j, 3k, 3o, 3q, 3s and 3t) were investigated against toxicity induced by 1-methyl-4-phenylpyridinium ion (MPP+) in SH-SY5Y neuronal cells. In silico studies revealed that compound 3g could have molecule docking with the following proteins: the bone morphogenetic protein receptor type 1B (BMPR1B), human cytochrome P450 1B1(CYP1B1), Metabotropic glutamate receptor 7 (GRM7), histone deacetylase 6 (HDAC6), 5-hydroxytryptamine receptor 5A (HTR5A), human topoisomerase II beta (TOP2B). A molecular docking simulation of model compound 3g and model protein CYP1B1 has been shown.

Lysozyme and DNA binding affinity of Pd(ii) and Pt(ii) complexes bearing charged N,N-pyridylbenzimidazole bidentate ligands

The 2-pyridylbenzimidazole Pt(ii) complex functionalized with triphenylphosphonium interacts covalently with lysozyme via the loss of labile ligands and the departure of the TPP⁺ part.

Copper-catalyzed Direct 2-Arylation of Benzoxazoles and Benzoimidazoles with Aryl Bromides and Cytotoxicity of Products

An efficient copper-catalyzed direct 2-arylation of benzoxazoles and benzoimidazoles with aryl bromides is presented. The CuI/PPh₃-based catalyst promotes the installation of various aryl and heteroaryl groups through a C-H activation process in good to excellent yields. The cytotoxicity of obtained 2-aryl benzoxazoles (benzoimidazoles) was also evaluated and 1-methyl-2-(naphthalen-1-yl)benzoimidazole showed potential cytotoxicity.

(Pyridyl)benzoazole palladium(ii) complexes as homogeneous catalysts in hydrogenation of alkenes and alkynes

Complexes 1–6 form “cocktail” catalysts in the hydrogenation and isomerization of alkenes and alkynes where the active species are homogeneous.

Synthesis and characterization of substituted Schiff-base ligands and their d10 metal complexes: structure-induced luminescence tuning behaviors and applications in co-sensitized solar cells

The structure-induced luminescence tuning behaviors of Schiff-base ligand based d¹⁰ metal complexes and their applications in co-sensitized solar cells.

Bis((E)-2-{5,5-dimethyl-3-[4-(1H-1,2,4-triazol-1-yl-κN4)styryl]cyclohex-2-enylidene}malononitrile)diiodidomercury(II)

In the title complex, [HgI₂(C₂₁H₁₉N₅)₂], the Hg^II ion is located on a twofold rotation axis and is coordinated by two I atoms and two N atoms from two (E)-2-{5,5-di­methyl-3-[4-(1H-1,2,4-triazol-1-yl)styr­yl]cyclo­hex-2-enyl­idene}malono­nitrile ligands in a distorted tetra­hedral geometry. In the crystal, the mol­ecules are linked by inter­molecular π–π inter­actions between the triazole and benzene rings [centroid–centroid distance = 3.794 (3) Å] into a band extending in [010]. These bands are further connected by C—H⋯N hydrogen bonds into a two-dimensional network parallel to (100).

A Zn2+ fluorescent sensor derived from 2-(pyridin-2-yl)benzoimidazole with ratiometric sensing potential

A fluorescent Zn(2+) sensor based on the 2-(2'-pyridinyl)benzoimidazole (2-PBI) fluorophore has been devised by incorporation with a Zn(2+) ionophore, bis(pyridin-2-ylmethyl)amine. The sensor (PBITA) demonstrates a Zn(2+)-specific emission shift and enhancement with a 1:1 binding ratio. Due to the Zn(2+)-induced coplanation of 2-PBI via reversion/rotation, PBITA is shown to behave as a ratiometric sensor. The intracellular Zn(2+) imaging ability of the sensor has been tested in HeLa cells using a confocal microscope.