Structure-Based Designing,Solvent Less Synthesis of 1,2,3,4-Tetrahydropyrimidine-5-carboxylate Derivatives: A Combined In Vitro and In Silico Screening Approach

Objective: In this study, small molecules possessing tetrahydropyrimidine derivatives have been synthesized having halogenated benzyl derivatives and carboxylate linkage. As previously reported, FDA approved halogenated pyrimidine derivatives prompted us to synthesize novel compounds in order to evaluate their biological potential. Methodology: Eight pyrimidine derivatives have been synthesized from ethyl acetoacetate, secondary amine, aromatic benzaldehyde by adding catalytic amount of CuCl₂·2H₂O via solvent less Grindstone multicomponent reagent method. Molecular structure reactivity and virtual screening were performed to check their biological efficacy as an anti-oxidant, anti-cancer and anti-diabetic agent. These studies were supported by in vitro analysis and QSAR studies. Results: After combined experimental and virtual screening 5c, 5g and 5e could serve as lead compounds, having low IC₅₀ and high binding affinity.     

A Comprehensive Outlook of Synthetic Strategies and Applications of Redox‐Responsive Nanogels in Drug Delivery

Increasing recognition of the role of oxidative stress in the pathogenesis of many clinical conditions and the existence of defined redox potential in healthy tissues has led to extensive research in the development of redox‐responsive materials for biomedical applications. Especially, considerable growth has been seen in the fabrication of polymeric nanogel–based drug delivery carriers utilizing redox‐responsive cross‐linkers bearing a variety of functional groups via various synthetic strategies. Redox‐responsive polymeric nanogels provide an advantage of facile chemical modification post synthesis and exhibit a remarkable response to biological redox stimuli. Due to the interdisciplinary nature of the subject, a more profound combined conceptual knowledge from a chemical and biological point of view is imperative for the rational design of redox‐responsive nanogels. The present review provides an insight into the design and fabrication of redox‐responsive nanogels with particular emphasis on synthetic strategies utilized for the development of redox‐responsive cross‐linkers, polymerization techniques being followed for nanogel development and biomedical applications. Cooperative effect of redox trigger with other stimuli such as pH and temperature in the evolution of dual and triple stimuli‐responsive nanogels is also discussed.     

Ultrasonic velocity, density, viscosity and their excess parameters of the binary mixtures of tetrahydrofuran with methanol and o-cresol at varying temperatures

The ultrasonic velocity, density and viscosity of binary mixtures of tetrahydrofuran (THF) with methanol and o-cresol were measured at 293, 303 and 313 K over the entire range of composition. Using these experimental data, various thermo-acoustic parameters such as deviation in isentropic compressibility Δκ_s, excess molar volume , viscosity deviation Δη and excess Gibb’s free energy of activation for viscous flow ΔG^∗E have been calculated and fitted to Redlich-Kister polynomial equation. The deviation/excess parameter were plotted against the mole fraction of THF over the whole composition range. The observed negative and positive values of deviation/excess thermo-acoustic parameters were explained on the basis of the intermolecular interactions present in these mixtures. Since methanol is less acidic than o-cresol, the removal of proton from methanol is less likely than the removal of proton from o-cresol which is more acidic than methanol. Hence the intermolecular interaction in the mixture of THF with o-cresol is found to be stronger than mixture of THF with methanol, which is reflected from the observed positive and negative values of excess thermo-acoustic parameters. Thus it may be concluded that THF + o-cresol mixture exhibits strong intermolecular interaction. However, dispersive forces are responsible for THF + methanol mixture due to weak interaction. Further, Nomoto, Junjie, CFT and Flory’s theory were applied for evaluating the ultrasonic velocity theoretically. The theoretical evaluation of ultrasonic velocity based on molecular models in liquid mixtures has been used to correlate with the experimental findings and to know the thermodynamics of the mixtures. The comparison of theoretical and experimental results provides better understanding about the validity of the various thermodynamic, empirical, semi empirical and statistical theories.     

A phosphorus integrated strategy for supercapacitor: 2D black phosphorus–doped and phosphorus-doped materials

In the design and development of energy storage devices, two main factors are considered first high electrochemical performances and second low-cost materials. Phosphorus owns excellent properties such as high carrier mobility, tunable bandgap, anisotropic electronic properties, hydrophilicity, biocompatibility, good electrochemical activity, and high surface area. The interlayer distance of black phosphorus (BP) (0.55 nm) is higher than that of graphene which makes facile ion transportation for supercapacitor application. The phosphorus-based electrode obtained with top-down approaches such as exfoliation and bottom-up approach such as pulsed laser deposition. The BP has been investigated due to its small electronegativity of P which is beneficial to improve the electrical conductivity of the electrode and its abundance nature makes it a desirable candidate for the fabrication of low-cost device. Hence, this review covers the new BP material as the advanced materials for the commercial realization of advanced supercapacitors. This is the first review on phosphorus integrated supercapacitor devices. This review will give a brief idea about BP to researchers in search of outstanding supercapacitor configurations with different electrodes and electrolytes.     

Transannular 1,5-hydride shift in 5-hydroxycyclooctanone: an experimental and theoretical investigation

1H NMR measurements have shown that eight out of twelve methylene hydrogen atoms of 5-hydroxycyclooctanone (1HK) are exchanged for deuterium atoms under acidic and basic conditions. For the reaction in 7.9 M DCl/D2O, an activation energy Ea = 19.2 +/- 0.4 kcal mol(-1) is found. In order to explain these findings, a degenerate transannular 1,5-hydride shift is essential, and this reaction has been analyzed by quantum chemical calculations. Hydride transfer takes place via a tight transition state with a six-membered ring. The activation barrier is lowest in the presence of base. The molecular conformation of the eight-membered ring in the transition state resembles that of the starting structure. It is unlikely that solvent molecules such as water participate in the formation of the transition state.     

1H NMR, mass spectroscopic studies and color fastness properties of methyl-4,6-dihydroxy-2-oxo-1-phenyl-5-arylazopyridine-3-carboxylate, part III: new disperse dyes

1H NMR and mass spectroscopic studies of new disperse dyes synthesized from methyl-4,6-dihydroxy-2-oxo-1-phenyl pyridine-3-carboxylate. Application of the dyes on polyester fabric and color fastness properties are also studied. The dyes are also found to possess DPPH free radical scavenging activity.     

Anomeric effects in the symmetrical and asymmetrical structures of triethylamine. Blue-shifts of the C-h stretching vibrations in complexed and protonated triethylamine

Quantum mechanical calculations using density functional theory with the hybrid B3LYP functional and the 6-31++G(d,p) basis set are performed on isolated triethylamine (TEA), its hydrogen-bond complex with phenol, and protonated TEA. The calculations include the optimized geometries and the results of a natural bond orbital (NBO) analysis (occupation of sigma* orbitals, hyperconjugative energies, and atomic charges). The harmonic frequencies of the C-H stretching vibrations of TEA are predicted at the same level of theory. Two stable structures are found for isolated TEA. In the most stable symmetrical structure (TEA-S), the three C-C bond lengths are equal and one of the C-H bond of each of the three CH2 groups is more elongated than the three other ones. In the asymmetrical structure (TEA-AS), one of the C-C bonds and two C-H bonds of two different CH2 groups are more elongated than the other ones. These structures result from the hyperconjugation of the N lone pair to the considered sigma*(C-H) orbitals (TEA-S) or to the sigma*(C-C) and sigma*(C-H) orbitals of the CH2 groups (TEA-AS). The formation of a OH...N hydrogen bond with phenol results in a decrease of the hyperconjugation, a contraction of the C-H bonds, and blue-shifts of 28-33 cm-1 (TEA-S) or 40-48 cm-1 (TEA-AS) of the nus(CH2) vibrations. The nu(CH3) vibrations are found to shift to a lesser extent. Cancellation of the lone pair reorganization in protonated TEA-S and TEA-AS results in large blue-shifts of the nu(CH2) vibrations, between 170 and 190 cm-1. Most importantly, in contrast with the blue-shifting hydrogen bonds involving C-H groups, the blue-shifts occurring at C-H groups not participating in hydrogen bond formation is mainly due to a reduction of the hyperconjugation and the resulting decrease in the occupation of the corresponding sigma*(C-H) orbitals. A linear correlation is established between the C-H distances and the occupation of the corresponding sigma*(C-H) orbitals in the CH2 groups.