Synthesis of β-amino alcohols using the tandem reduction and ring-opening reaction of nitroarenes and epoxides

B2(OH)4-Mediated Reductive Ring-Opening of N-Tosyl Aziridines by Nitroarenes: A Green and Regioselective Access to Vicinal Diamines

The nucleophilic ring-opening of aziridine derivatives provides an important synthetic tool for the preparation of various β-functionalized amines. Amines as nucleophiles are employed to prepare synthetically useful 1,2-diamines in the presence of various catalysts or activators. Herein, the B2(OH)4-mediated reductive ring-opening transformation of N-tosyl aziridines by nitroarenes was developed. This aqueous protocol employed nitroarenes as cheap and readily available amino sources and proceeds under external catalyst-free conditions. Control experiments and DFT calculations pointed to the in situ reduction of nitroarenes to aryl amines via N-aryl boramidic acid (E) and an SN1-type ring-opening of N-tosylaziridines by the resultant aryl amines with high regioselectivity.

Bis-Boric Acid-Mediated Regioselective Reductive Aminolysis of 3,4-Epoxy Alcohols

Herein we report a bis-boric acid-mediated regioselective reductive aminolysis of 3,4-epoxy alcohols, providing new access to prepare amino diols in high diastereofidelity directly starting from nitroarenes. Notably, this step-economical process is enabled by the essential dual function of bis-boric acid, which is engaged initially in the 4,4'-bipyridine-catalyzed reduction of nitro compounds as the reductant and subsequently promotes the ring opening reaction of 3,4-epoxy alcohols with the in situ-generated anilines.

Experimental and Molecular Docking Studies on the Interaction of a Water-Soluble Pd(II) Complex Containing β-Amino Alcohol with Calf Thymus DNA

The interaction of water-soluble and fluorescent [Pd (HEAC) Cl₂] complex, in which HEAC is 2-((2-((2-hydroxyethyl)amino)ethyl)amino) cyclohexanol, with calf thymus DNA (ct-DNA) has been studied. This study was performed using electronic absorption and fluorescence emission spectroscopies, cyclic voltammetry and circular dichroism analyses, dynamic viscosity measurements, and molecular docking theory. From hypochromic effect observed in ct-DNA absorption spectra, it was found that the Pd(II) complex could form a conjugate with ct-DNA strands through the groove binding mode. The K_b values obtained from fluorescence measurements clearly assert the Pd(II) complex affinity to ct-DNA. The fluorescence quenching of the DNA-Hoechst compound following the successive additions of the Pd(II) complex to the solution revealed that the Pd(II) complex is located in the ct-DNA grooves, and Hoechst molecules have been released into solution; moreover, the resulting measurements from relative viscosity authenticate the Pd(II) complex binding to the grooves. Negative quantities of thermodynamic parameters imply that the Pd(II) complex binds to ct-DNA mainly by the hydrogen bonds and van der Waals forces; also, the Gibbs-free energy changes show the exothermic and spontaneous formation of the Pd(II) complex-DNA system. The electrochemical behavior of the Pd(II) complex in the attendance of ct-DNA was investigated using the cyclic voltammetry method (CV). Several quasi-reversible redox waves were observed along with increasing the anodic/cathodic peak currents, as well as a shift in anodic/cathodic peak potentials. Circular dichroism (CD) observations suggested that the Pd(II)-DNA interaction could alter ct-DNA conformation. The results of molecular modeling confirmed that groove mechanism is followed by the Pd(II) complex to interact with ct-DNA.

Amino Alcohols from Eugenol as Potential Semisynthetic Insecticides: Chemical, Biological, and Computational Insights

A series of β-amino alcohols were prepared by the reaction of eugenol epoxide with aliphatic and aromatic amine nucleophiles. The synthesized compounds were fully characterized and evaluated as potential insecticides through the assessment of their biological activity against Sf9 insect cells, compared with a commercial synthetic pesticide (chlorpyrifos, CHPY). Three derivatives bearing a terminal benzene ring, either substituted or unsubstituted, were identified as the most potent molecules, two of them displaying higher toxicity to insect cells than CHPY. In addition, the most promising molecules were able to increase the activity of serine proteases (caspases) pivotal to apoptosis and were more toxic to insect cells than human cells. Structure-based inverted virtual screening and molecular dynamics simulations demonstrate that these molecules likely target acetylcholinesterase and/or the insect odorant-binding proteins and are able to form stable complexes with these proteins. Encapsulation assays in liposomes of DMPG and DPPC/DMPG (1:1) were performed for the most active compound, and high encapsulation efficiencies were obtained. A thermosensitive formulation was achieved with the compound release being more efficient at higher temperatures.

Anticancer activities of a β-amino alcohol ligand and nanoparticles of its copper(ii) and zinc(ii) complexes evaluated by experimental and theoretical methods

2-(2-(2-Hydroxyethylamino)ethylamino)cyclohexanol (HEAC) and copper and zinc complexes, [Cu(HEAC)Cl]Cl (1), [Cu(HEAC)Br]Br (2), [Zn(HEAC)Cl₂] (3), were prepared and identified by elemental analysis, FT-IR, UV-Vis, ¹H NMR spectroscopy and single-crystal X-ray diffraction. Also nanoparticles of 1–3 were prepared for anticancer studies by ultrasonic irradiation. Particle size and morphology of the nano particles are investigated by PXRD and SEM, respectively. X-ray analysis revealed that the ionic complexes 1 and 2 are isostructural. In the structure of complexes 1 and 2, the metal atom has a CuN₂O₂X (X: Cl (1), Br (2)) environment with square-pyramidal geometry, containing the tetradentate N₂O₂-donor HEAC. The bond length of the axial position in the square-pyramidal geometry of 1 and 2 is elongated. Complex 3 has a ZnN₂OCl₂ environment with trigonal bipyramidal geometry around the zinc atom in which the HEAC acts as mer-N₂O-donor. The ability of HEAC and nano particles 1–3 to interact with the nine biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) are investigated by docking calculations. For examination of the docking results, the in vitro activities of four compounds against the human leukemia cell line K562 were investigated by evaluation of IC₅₀ values and mode of cell death (apoptosis). The thermodynamic stability of the compounds along with the charge distribution pattern were studied by DFT and NBO analysis, respectively.

Nano particles of copper and zinc complexes with an amino alcohol ligand were prepared under ultrasonic irradiation and their anticancer activates were investigated along with the docking studies and DFT calculations.