Nano silver particles catalyzed synthesis,molecular docking and bioactivity of α-thiazolyl aminomethylene bisphosphonates

Abstract

A new series of α-thiazolyl aminomethylene bisphosphonates were synthesized by a three component reaction of 4-aryl substituted thiazol-2-amine with different dialkyl/aryl phosphites and triethyl orthoformate in the presence of Ag NPs (nano particles) as a catalyst under solvent free conditions. All the synthesized target compounds were characterized by ¹H, ¹³C, ³¹P, mass and elemental analysis. The target compounds were screened for their in vitro antioxidant, antibacterial and antifungal activity. Molecular docking studies were also performed. The results revealed that among the synthesized compounds tetramethyl(((4-(4-methoxyphenyl)thiazol-2-yl)amino) methylene)bis(phosphonate) (5d), tetramethyl(((4-(4-fluorophenyl)thiazol-2-yl)amino) methylene) bis(phosphonate) (5h), and tetramethyl(((4-(4-bromophenyl)thiazol-2-yl)amino)methylene) bis (phosphonate) (5j) showed remarkably higher antioxidant activity by DPPH and H₂O₂ than the standard ascorbic acid. Compounds tetramethyl(((4-phenyl thiazol-2-yl)amino) methylene) bis(phosphonate) (5a), 5d, 5h and tetraethyl(((4-(4-bromophenyl)thiazol-2-yl) amino)methylene)bis (phosphonate) (5k) showed good antibacterial activity. 5a, 5d, and 5h also showed rather higher antifungal activity than the standard flucanozole. Computational docking methods have been used to predict how several aminomethylene bisphosphonate derivatives compete against the inhibitor BPH-1330 at the crystal enzyme structure of the 4H3A protein active site and how R and R₁ influence their binding ability.     

Enantioselective reduction of 2-substituted tetrahydropyran-4-ones using Daucus carota plant cells

Enzymatic reduction of 2-substituted tetrahydropyran-4-ones with Daucus carota, plant cells as biocatalyst occurred in water under extremely mild and environmentally benign conditions giving a 1:1 mixture of diastereoselectively (2R,4S)- and (2S,4S)-2-aryl- or 2-alkyl-tetrahydropyranols in high yields.     

Study of electron pairs below the Z0 mass produced in pp collisions at √s = 540 GeV

From an integrated luminosity of $\text{∫}\text{L}\text{d}\text{t = 116}\text{nb}{}^{-1}$, 10events are found which contain an electron pair of mass in the range $\text{12 < M}{}^{\mathrm{<mtext>ee</mtext>}}\text{< 26}\text{GeV}\text{c}{}^2$ and electron transverse momenta $\text{p}{}_{\mathrm{<mtext>T</mtext>}}{}^{\mathrm{<mtext>e</mtext>}}\text{> 5}\text{GeV}\text{c}$. THe sample are described, as well as some featruyres of the The production characteristics of this sample are described, as well as some features of the estimated to be 2.2±0.6 events. The production characteristics of this sample are described, as well as some features of the associated event topology. Comparisons are made with the expectations for such electron pair production from the Drell-Yan mechanism and from the semi-leptonic decay of heavy flavours.     

Nano CuO–Ag-catalyzed synthesis of some novel pyrano[2,3-d] pyrimidine derivatives and evaluation of their bioactivity

A simple, highly efficient, and green method is developed for the synthesis of pyrano[2,3-d] pyrimidine derivatives via Knoevenagel and Michael addition in the presence of nano CuO–Ag as a catalyst. The structures of synthesized target compounds 5a–l were confirmed by spectral and elemental analysis and were screened for their antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH), H₂O₂, and NO methods. Their antibacterial activity against Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli, against Gram-positive bacteria such as Bacillus subtilis and Staphylococcus aureus, and antifungal activity against Candida albicans and Candida glabrata was also evaluated. The compounds showed higher bacterial activity than the standard used. Compounds 5b , 5d , 5g , 5h , and 5i exhibited higher free radical scavenging activity than the standard butylated hydroxy toluene (BHT). Compounds 5b , 5d , and 5h showed higher activity on Gram-positive bacteria, and compounds 5b , 5d , 5h , and 5i showed higher activity on Gram-negative bacteria than that of standard tetracycline. Compounds 5b , 5j , and 5l showed much higher antifungal activity against Candida globrata and C. albicans than that of standard Griseofulvin.     

Dithienylethene-Based Single Molecular Photothermal Linear Actuator

By employing a mechanically controllable break junction technique, we have realized an ideal single molecular linear actuator based on dithienylethene (DTE) based molecular architecture, which undergoes reversible photothermal isomerization when subjected to UV irradiation under ambient conditions. As a result, open form (compressed, UV OFF) and closed form (elongated, UV ON) of dithienylethene-based molecular junctions are achieved. Interestingly, the mechanical actuation is achieved without changing the conductance of the molecular junction around the Fermi level over several cycles, which is an essential property required for an ideal single molecular actuator. Our study demonstrates a unique example of achieving a perfect balance between tunneling width and barrier height change upon photothermal isomerization, resulting in no change in conductance but a change in the molecular length, which results in mechanical actuation at the single molecular level.     

Characterization of the galectin-1 carbohydrate recognition domain in terms of solvent occupancy

Human galectin-1, a galactosil-terminal sugar binding soluble protein, is a potent multifunctional effector that participates in specific protein-carbohydrate and protein-protein interactions. Recent studies revealed that it plays a key role as a modulator of cellular differentiation and immunological response. In this work, we have investigated the solvation properties of the carbohydrate recognition domain of Gal-1 by means of molecular dynamics simulations. Water sites (ws) were identified in terms of radial and angular distribution functions, and properties such as water residence times, interaction energies, and free-energy contributions were evaluated for those sites. Our results allowed us to correlate the thermodynamic properties of the ws and their binding pattern with the N-acetilgalactoside ligand. These results let us further infer that the water molecules located at the ws, which exhibit much more favorable binding, are the ones replaced by -OH groups of the sugar.     

Molecular simulation studies of water physisorption in zeolites

We report a series of Grand Canonical Monte Carlo simulations of water adsorption in NaY and NaX faujasite, as well as in silicalite-1. Computed adsorption isotherms and heats of adsorption were in good agreement with the available experiments. The existence of cyclic water hexamers in NaX located in the 12-ring windows, recently disclosed by neutron diffraction experiments (Hunger et al., J. Phys. Chem. B, 2006, 110, 342-353) was reproduced in our simulations. Interestingly enough, such cyclic hexamer clusters were also observed in the case of NaY, in which no stabilizing cation is present in the 12-ring window. We also report cation redistribution upon water adsorption for sodium faujasite with varying cation contents (Si ratio Al ratio in the range 1.53-3). A simple and transferable forcefield was used, that enabled to reproduce the different aspects of water physisorption in stable zeolites. The high pressure water condensation in hydrophobic silicalite-1 was reproduced without any parameter readjustment. The method and forcefield used here should be useful for engineering oriented applications such as the prediction of multi-component mixture adsorptive separations in various stable zeolites. It allows to address the issue of the effect of the small amounts of water that are almost inevitably present in zeolite-based separation processes.     

A measurement of the production of massive e+e− pairs in proton-proton collisions at √s = 62.4 GeV

An apparatus consisting of a superconducting solenoid magnet, cylindrical drift-chambers, and two arrays of lead-glass ?erenkov counters has been used at the CERN ISR to study the production of e⁺e^? pairs of invariant mass above 6.5 GeV/c². Cross sections for the continuum and the ? family of resonances are presented, as well as the mean transverse momentum 〈p_T〉 of the electron-positron pairs in the continuum and resonance region.     

Observation of πo mesons with large transverse momentum in high-energy proton-proton collisions

Invariant cross-sections are presented for the inclusive reaction p + p → π^o + anything, Measurements of large transverse momentum π^o's (2.5 GeV/c<p_⊥<9 GeV/c) were made near 90° at the CERN ISR at five centre-of-mass energies (√s = 23.5, 30.6, 44.8, 52.7 and 62.4 GeV. At large p_⊥, the invariant cross-sections are seem to vary with s and p_⊥, in good agreement with a fit of the form Ap_⊥^?nF(p_⊥/√s), with n≈8 and F(p_⊥/√s)≈exp(?26p_⊥/√s).     

A measurement of the transverse momenta of partons,and of jet fragmentation as a function of √s in p-p collisions

A large solid-angle apparatus consisting of a superconducting solenoid magnet, cylindrical drift chambers and two arrays of lead-glass counters was used to examine particles associated with a high transverse momentum trigger in p-p collisions with three √s values at the CERN ISR. The trigger was given by energy deposition in lead-glass arrays centred at 90°. The trigger transverse momentum range covered was 3 < $\text{p}{}_{\mathrm{<mtext>T\; trig</mtext>}}\text{< 11}\text{GeV}\text{c}$. Results are given for p_out for both individual charged particles, and also for the sum of charged particle momenta in the hemisphere opposite to the trigger. Mean values are then deduced for the parton transverse momentum k_T, and for the jet fragmentation momentum j_T.