New thiophene-derived α-aminophosphonic acids: Synthesis under microwave irradiations, antioxidant and antifungal activities, DFT investigations and SARS-CoV-2 main protease inhibition.

Four new α-aminophosphonic acids containing thiophene ring have been synthesized using simple, neat and catalyst-free conditions, more convenient and eco-friendly method under microwave irradiations. The structures of the title molecules have been confirmed by UV-Vis, FT-IR, 1H NMR, 13C NMR and 31P NMR. Moreover, their antioxidant activity was evaluated using DPPH, ABTS and phenantroline methods; the obtained results indicate that the title molecules exhibit excellent activity better than standards BHT and BHA. Also, the synthesized compounds show a good antifungal activity against two fungi, Fusarium oxysporum and Alternaria alternata. In addition, molecular, electronic properties, stability and reactivity of the synthesized products were studied by the density functional theory (DFT). Furthermore, molecular docking investigations of the studied α-aminophosphonic acids showed a good inhibition of SARS-CoV-2 main protease (Mpro).

Synthesis, characterization, DFT, antioxidant, antibacterial, pharmacokinetics and inhibition of SARS-CoV-2 main protease of some heterocyclic hydrazones.

Three hydrazone derivatives have been synthesized using condensation reaction of 4-hydrazinylbenzoic acid with three aromatic aldehydes namely: thiophene-2-carbaldehyde, thiophene-3-carbaldehyde and 2-furaldehyde in ethanol at 78 °C reflux. The synthesized molecules have been characterized using spectroscopic and physicochemical methods including UV-Vis, IR, 1H NMR, 13C NMR, 15N NMR and melting point determination. Optimized molecular structures, UV-Vis and IR spectra modeling, the reactivity, the stability and some quantum chemical parameters of the synthesized molecules were modeled utilizing density functional theory (DFT). The obtained theoretical results were found in good agreement with the experimental results. On the other hand, the antioxidant and antibacterial activities of the molecules under study were evaluated to better understand the associated mechanisms of action specifically. Also, predicted ADME-T and pharmacokinetic parameters indicated that these compounds showed good oral bioavailability. Finally, molecular docking has been used to predict the inhibitory activity of the studied hydrazone derivatives on the SARS-CoV-2 main protease (Mpro).

New α-Hydrazinophosphonic acid: Synthesis, characterization, DFT study and in silico prediction of its potential inhibition of SARS-CoV-2 main protease.

A new α-Hydrazinophosphonic acid (HDZPA) has been synthesized and its molecular structure was determined using spectroscopic methods. The Density Functional Theory (DFT) at the B3LYP/6-31 G (d,p) level was utilized to determine the electronic properties, vibrational modes and active sites of the examined molecule. In this context, some quantum chemical parameters have been calculated in order to discuss the reactivity of the studied molecule. Also, the inhibition activity of the investigated α-Hydrazinophosphonic acid for SARS-CoV-2 main protease (Mpro) and RNA dependent RNA polymerase (RdRp) has been predicted using in silico docking.

Step by Step Assembly of Polynuclear Lanthanide Complexes with a Phosphonated Bipyridine Ligand.

The synthesis of the octadentate ligand L (LH8 = ((([2,2'-bipyridine]-6,6'-diylbis(methylene))bis(azanetriyl))tetrakis(methylene))tetrakis(phosphonic acid)) is reported. The coordination of L with various lanthanide cations was monitored by absorption and luminescence spectrophotometric titration experiments (Ln = Tb, Yb), potentiometry (Ln = La, Eu, Lu), and mass spectrometry (Ln = Tb). It was found that L forms very stable mononuclear (LnL) species in aqueous solutions (log K = 19.80(5), 19.5(2), and 19.56(5) for La, Eu, and Lu, respectively) with no particular trend along the series. Spectroscopic data showed the Ln cations to be enclosed in the cavity formed by the octadentate ligand, thereby shielding the metal from interactions with water molecules in the first coordination sphere. When more than one equivalent of cations is added, the formation of polynuclear [(LnL)2Lnx] complexes (x = 1-3) can be observed, the presence of which could be confirmed by electrospray and MALDI mass spectrometry experiments. DFT modeling of the mononuclear (LnL) complexes indicated that the coordination of the cation in the cavity of the ligand results in a very asymmetric charge distribution, with a region of small negative electrostatic potential on the hemisphere composed of the chromophoric bipyridyl moiety and an electron-rich domain at the opposite hemisphere around the four phosphonate functions. DFT further showed that this polarization is most likely at the origin of the strong interactions between the (LnL) complexes and the incoming additional cations, leading to the formation of the polynuclear species. 1H and 31P NMR were used to probe the possible exchange of the lanthanide complexed in the cavity of the ligand in D2O, revealing no detectable exchange after 4 weeks at 80 °C and neutral pD, therefore pointing out an excellent kinetic inertness.

1-{[4-(4-{[(2-Oxidonaphthalen-1-yl)methyl-idene]aza-nium-yl}phen-oxy)phen-yl]iminiumylmeth-yl}naphthalen-2-olate.

The title Schiff base compound, C34H24N2O3, was prepared by a condensation reaction of bifunctional aromatic diamine (4,4'-diamino-diphenyl ether) with hy-droxy-naphtaldehyde. The asymmetric unit contains two independent mol-ecules with similar conformations. The compound contains a central oxygen bridge and two functionalized [(E)-(phenyl-iminio)meth-yl]naphthalen-2-olate units. The dihedral angles between the benzene rings linking to the central O atom are 74.64 (19) and 69.85 (18)° in the two independent mol-ecules. Intra-molecular O-H⋯O hydrogen bonding occurs between the protonated imino N atoms and deprotonated hy-droxy O atoms in both mol-ecules. In the crystal, weak C-H⋯O hydrogen bonds are observed.