N-donor 2-(Sulfonamido)benzamide ligands, their palladium(II) coordination species and C–C coupling catalysis efficiencies

Meso bromination and derivatization of synthetic bacteriochlorins

Twelve bacteriochlorin building blocks featuring meso-substitution have been prepared including a set with finely tuned long-wavelength absorption (725–757 nm) for studies in photonics.

Synthesis, Structure and Evaluation of the N-(2-Acetyl-4-(styryl)phenyl)-4-benzenesulfonamide Derivatives for Anticholinesterase and Antioxidant Activities

N-(2-Acetyl-4-bromophenyl)-4-methylbenzenesulfonamide (2) was transformed into 5-(4-methoxymethylstyryl)-2-(p-tolylsulfonamido)acetophenone (3a) and 5-(4- trifluoromethylstyryl)-2-(p-tolylsulfonamido)acetophenone (3b). Their structures were determined using a combination of NMR (1H & 13C) and mass spectroscopic as well as single crystal X-ray diffraction techniques. These compounds and the corresponding precursor, 2-amino-5-bromoacetophenone (1), were evaluated through enzymatic assays in vitro for inhibitory effect against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities as well as antioxidant effect through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) free radical scavenging assays. Molecular docking was performed on 3a to determine plausible protein–ligand interactions on a molecular level. Their drug likeness properties (absorption, distribution, metabolism, and excretion) and ability to cross the blood–brain barrier (BBB) have also been predicted at theoretical level.

Spectroscopic, X-ray Diffraction and Density Functional Theory Study of Intra- and Intermolecular Hydrogen Bonds in Ortho-(4-tolylsulfonamido)benzamides

The conformations of the title compounds were determined in solution (NMR and UV-Vis spectroscopy) and in the solid state (FT-IR and XRD), complemented with density functional theory (DFT) in the gas phase. The nonequivalence of the amide protons of these compounds due to the hindered rotation of the C(O)–NH₂ single bond resulted in two distinct resonances of different chemical shift values in the aromatic region of their ¹H-NMR spectra. Intramolecular hydrogen bonding interactions between the carbonyl oxygen and the sulfonamide hydrogen atom were observed in the solution phase and solid state. XRD confirmed the ability of the amide moiety of this class of compounds to function as a hydrogen bond acceptor to form a six-membered hydrogen bonded ring and a donor simultaneously to form intermolecular hydrogen bonded complexes of the type N–H···O=S. The distorted tetrahedral geometry of the sulfur atom resulted in a deviation of the sulfonamide moiety from co-planarity of the anthranilamide scaffold, and this geometry enabled oxygen atoms to form hydrogen bonds in higher dimensions.

New Bidentate N-Sulfonyl-Substituted Aromatic Amines as Chelate Ligand Backbones: Pd Catalyst Generation in C–C Coupling via In Situ and Precatalyst Modes

A series of six new, bidentate ligands based on N-(2-(R-sulfonamido)benzyl)R-sulfonamide have been isolated as dianionic or monoanionic chelators via condensation of 2-(aminomethyl)aniline with sulfonyl chloride reagents; R=methyl (1 and 1′), tolyl (2 and 2′), 2,4,6-trimethylphenyl (3), or 2,4,6-triisopropylphenyl (4). Complexes of ligands 2–4 reacted at room temperature with palladium(ii) acetate in the presence of various monodentate N-donor co-ligands to form complexes Pd2(2dmap), Pd2′(OAc.py), Pd3(2acn), Pd3(2py), Pd4(2acn), and Pd4(2py), which were structurally confirmed by three X-ray crystal analyses. Results of catalysis studies in water showed high turnover frequencies and yields of up to 98% within 10min and at 0.2 mol-% palladium catalyst loading. Relative to ligand-free catalysis in the presence of only Pd(OAc)2, the ligand-supported palladium species clearly possess positive catalytic advantage. Furthermore, Suzuki coupling efficiencies by 1:1 ‘Pd(OAc)2+ligand’ yielded notably better outcomes than for the 1:2 ‘Pd(OAc)2+ligand’ insitu catalyst generation, which reveals that coordinative saturation is undesirable. The size of the complementing monodentate co-ligand was observed to influence the catalytic efficiency such that bulkier co-ligands consistently yielded improved turnover frequency values, which leads to the conclusion that steric repulsion between the synthesised ligands and the bulkier co-ligands aided the generation of vacant coordination sites for the more active complexes. Moderate Heck coupling activity was recorded for the complexes and better activities appear to correlate with moderate bulkiness of ligand 3.