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.     

Metastable Chiral Azobenzenes Stabilized in a Double Racemate

The self‐assembly of chiral organic chromophores is gaining huge significance due to the abundance of supramolecular chirality found in natural systems. We report an interdigitated molecular assembly involving axially chiral octabrominated perylenediimide (OBPDI) which transfers chiral information to achiral aromatic moieties. The crystalline two‐component assemblies of OBPDI and electron‐rich aromatic units were facilitated through π‐hole???π donor–acceptor interactions, and the charge‐transfer characteristics in the ground and excited states of the OBPDI cocrystals were established through spectroscopic and theoretical techniques. The OBPDI cocrystals entail a remarkable homochiral segregation of P and M enantiomers of both molecular entities in the same crystal system, leading to twisted double‐racemic arrangements. Synergistically engendered cavities with the stored chiral information of the twisted OBPDI stabilize higher‐energy P/M enantiomers of trans‐azobenzene through non‐covalent interactions.     

One‐Pot Protection‐Glycosylation Reactions for Synthesis of Lipid II Analogues

(2,6‐Dichloro‐4‐methoxyphenyl)(2,4‐dichlorophenyl)methyl trichloroacetimidate ( 3 ) and its polymer‐supported reagent 4 can be successfully applied to a one‐pot protection‐glycosylation reaction to form the disaccharide derivative 7 d for the synthesis of lipid II analogues. The temporary protecting group or linker at the C‐6 position and N‐Troc protecting group of 7 d can be cleaved simultaneously through a reductive condition. Overall yields of syntheses of lipid II ( 1 ) and neryl‐lipid II N^ε‐dansylthiourea are significantly improved by using the described methods.     

Preparation of Tetraoxadiphosphadiborocane-2,6-diones

Cyclization of aryl/alkyl phosphonic dichlorides (2a–f) with phenylboronic acid/K₂CO₃/I₂ in dry toluene at 60–70 °C afforded 2,6-diaryl/alkyl-4,8-diphenyl-1,3,5,7,2λ ⁵,6λ ⁵,4,8-tetraoxadiphosphadiborocane-2,6-diones (3a–f).     

What Difference Does a Methyl Group Make: Pentamethylbenzene?

The crystal structure of pentamethylbenzene has been obtained for the first time with the use of synchrotron radiation, whilst the low‐energy spectrum of lattice dynamics, dominated by the methyl group torsions, was obtained using inelastic neutron scattering. The effect of symmetry lowering by the removal of a single methyl group relative to hexamethylbenzene has been investigated, including the role that this plays in the charge‐transfer characteristics of complexes formed with tetracyanoethylene.     

Simple,Accurate and Rapid HPTLC Method for Analysis of Theophylline in Post-Mortem Blood and Validation of the Method

JPC – Journal of Planar Chromatography – Modern TLC - Theophylline (1, 3-dimethylxanthine) is used both in the prophylaxis of chronic asthma and chronic obstructive airways disease...     

Intrinsic paramagnetic defects probe superionic phase transition in Ag1−xCuxI (x=0, 0.05, 0.15 and 0.50) nanocrystals

EPR probed the zincblende (γ) to cubic (α) AgI structural phase transition in AgI at 423 K through two intrinsic paramagnetic centers: an Ag²⁺-based hole center (signal ‘A’) and an Ag⁰-based conduction electron center (signal ‘B’) associated with AgI nanocrystallites. Sudden drops in intensity (I_PP), <g>, and ΔH_PP observed at 423 K for pure AgI nanocrystals. Addition of Cu in AgI increases the thermal stability of the cation sublattice as seen from the increase in the transition temperature from 423 K (undoped AgI) to 453 K. Abrupt jumps in the number of spins (N) and reciprocal susceptibility (1/χ) observed at increased phase transition temperatures in Cu-substituted AgI relative to that in undoped AgI reflects progressively strengthened local bonding configuration of γ-AgI structure induced by Cu.     

Dynamic programming—neural network real-time traffic adaptive signal control algorithm

In this paper, an “intelligent” isolated intersection control system was developed. The developed “intelligent” system makes “real time” decisions as to whether to extend (and how much) current green time. The model developed is based on the combination of the dynamic programming and neural networks. Many tests show that the outcome (the extension of the green time) of the proposed neural network is nearly equal to the best solution. Practically negligible CPU times were achieved, and were thus absolutely acceptable for the “real time” application of the developed algorithm.