Synthesis,anticancer, molecular docking and QSAR studies of benzoylhydrazone

To find out effective anticancer compounds we synthesized (1–30) derivatives of 4-isopropylbenzoylhydrazone and evaluated for anticancer potential. The compounds 3, 9, 12, 23, 26 and 28 showed better activities ranging (0.39–1.1 µg/ml) than the standard (1.53 ± 0.01 µg/ml). In line with this, compounds 2, 6, 24, 25 and 29 exhibited better activities compared to the second standard (5FU 4.60 ± 0.01 µg/ml). The best molecular docked complex between the BRCA1 structure and the 1–30 derivatives were analyzed based on the Glide docked score and binding orientation for both the SP and XP mode. The 2D-QSAR analysis reflected a significant correlation between the experimental and the predicted biological activities. The above-mentioned compounds were also assessed by various spectroscopic techniques.     

Phase Time for the Tunneling of Ultracold V-Type Atoms Through a Mazer Cavity

We study the tunneling time of ultracold V-type atoms interacting a high quality microwave cavity. Here atomic coherence is introduced in the system by a strong driving field which couples the two lower states of the three-level atom. It is found that in the presence of coherence, mazer action or the scattering like nature of the interaction may be examined for extended energies of the incident cold atoms. Our results show that position and amplitudes of the peak values of the phase time(traversal time) may be very effectively controlled by the coherent driving field. Further, here we obtained superclassical values of the phase time corresponding to much higher values of the transmission amplitudes of the tunneling atoms which may be advantageous in the possible experimental realization of the superclassical tunneling time of the traversing cold atoms. In addition, we examine a mirror reflection type symmetry in the phase time curve for a judicious choice of the external driving field.     

Intermolecular transition metal-catalyzed [4 + 2 + 2] cycloaddition reactions: a new approach to the construction of eight-membered rings

Transition metal-catalyzed cycloaddition reactions represent powerful methods for the construction of complex polycyclic systems. We have developed a new intermolecular metal-catalyzed [4 + 2 + 2] cycloaddition of heteroatom-tethered enyne derivatives with 1,3-butadiene. This study demonstrates that excellent selectivity can be obtained for the heterocycloaddition adducts through the judicious choice of silver salt. The development of the tandem rhodium-catalyzed allylic substitution [4 + 2 + 2] cycloaddition provides a convenient three-component coupling that circumvents the prior formation of the enyne derivative. Finally, the introduction of a stereogenic center at C-2 leads to a diastereoselective cycloaddition, which provides a powerful new method for the construction of bicyclic octanoid ring systems applicable to target directed synthesis.     

Khyberine and the biogenesis of dimeric aporphine-benzylisqoquinoline alkaloids

The new aporphine-benzylisquinoline khyberine ($\text{4b}$) is present in $\text{Berberis}$$\text{calliobotrys}$ Aitch. ex Bienert in about one part per million. An effort is made to present a complete scheme for the biogenesis of aporphine-benylisoquinoline dimers which arise from the condensation of two coclaurine units.     

Development of bis-thiobarbiturates as successful urease inhibitors and their molecular modeling studies

Bis-thiobarbiturate derivatives 1–15 have been synthesized, characterized by1 HNMR and EI-MS and screened for urease inhibition. All compounds showed various degree of urease inhibitory activity with IC_(50) values ranging 7.45 0.12 74.24 0.81 mmol/L while the standard thiourea behaved normally(IC_(50) = 21.10 0.12). Compounds 1(IC_(50) = 7.45 0.12 μmol/L), 9(IC_(50) = 18.17 1.03 μmol/L) and 13(IC_(50) = 8.61 0.45 μmol/L) showed excellent urease inhibitory activity in the series. Molecular modeling studies were performed to understand the binding site with the bimetallic nickel center of the enzyme.Structure-activity relationship has also been established for these compounds. This study identified bisthiobarbiturate as a novel class of urease inhibitors.     

Elicitation of Submerged Adventitious Root Cultures of Stevia rebaudiana with Cuscuta reflexa for Production of Biomass and Secondary Metabolites

Stevia rebaudiana is an important medicinal plant that belongs to the Asteraceae family. The leaves of Stevia rebaudiana are a rich source of many health-promoting agents such as polyphenols, flavonoids, and steviol glycoside, which play a key role in controlling obesity and diabetes. New strategies such as the elicitation of culture media are needed to enhance the productivity of active components. Herein, the Cuscuta reflexa extracts were exploited as elicitors to enhance the productivity of active components. Cuscuta reflexa is one of the parasitic plants that has the ability to elongate very fast and cover the host plant. Consequently, it may be possible that the addition of Cuscuta reflexa extracts to adventitious root cultures (ADR) of Stevia rebaudiana may elongate the root more than control cultures to produce higher quantities of the desired secondary metabolites. Therefore, the main objective of the current study was to investigate the effect of Cuscuta reflexa extract as a biotic elicitor on the biomass accumulation and production of antioxidant secondary metabolite in submerged adventitious root cultures of Stevia rebaudiana. Ten different concentrations of Cuscuta reflexa were added to liquid media containing 0.5 mg/L naphthalene acetic acid (NAA). The growth kinetics of adventitious roots was investigated for a period of 49 days with an interval of 7 days. The maximum biomass accumulation (7.83 g/3 flasks) was observed on medium containing 10 mg/L extract of Cuscuta reflexa on day 49. As the concentration of extract increases in the culture media, the biomass gradually decreases after 49 days of inoculation. In this study, the higher total phenolics content (0.31 mg GAE/g-DW), total flavonoids content (0.22 mg QE/g-DW), and antioxidant activity (85.54%) were observed in 100 mg/L treated cultures. The higher concentration (100 mg/L) of Cuscuta reflexa extract considerably increased the total phenolics content (TPC), total phenolics production (TPP), total flavonoids content (TFC), total flavonoids production (TFP), total polyphenolics content (TPPC), and total polyphenolics production (TPPP). It was concluded that the extract of Cuscuta reflexa moderately improved biomass accumulation but enhanced the synthesis of phenolics, flavonoids, and antioxidant activities. Here, biomass’s independent production of secondary metabolites was observed with the addition of extract. The present study will be helpful to scale up adventitious roots culture into a bioreactor for the production of secondary metabolites rather than biomass accumulation in medicinally important Stevia rebaudiana.     

Synthesis of Ferrocene-based Esters as Burning Rate Catalysts and their Anti-migration Study

Ferrocene-based (Fc-based) burning rate catalysts (BRCs) play an essential role in the solid rocket propellants. However, the migration problem during curing and storage limits their applications. To retard the migration problems of Fc-based BRCs and to increase the burning rate (BR) of AP-based propellants, Fc-based esters compounds (Es-Fcs) were synthesized. The synthesized Es-Fcs were characterized by X-ray diffraction, proton nuclear magnetic resonance (¹H NMR),¹³C NMR and Fourier transform infrared (FT-IR) spectroscopy. The electrochemical behaviors of Es-Fcs were investigated by cyclic voltammetry (CV). The BR catalytic activity of Es-Fcs on thermal decomposition of AP were examined by thermogravimetry (TG). Thermal analysis results showed that these Es-Fcs had good BR catalytic effects on thermal decomposition of AP. It was found that the anti-migration performance of Es-Fcs were better than catocene and Fc.     

Carbon nanotubeben cuprous oxide composite based pressure sensors

In this paper, we present the design, the fabrication, and the experimental results of carbon nanotube (CNT) and Cu₂O composite based pressure sensors. The pressed tablets of the CNT-Cu₂O composite are fabricated at a pressure of 353 MPa. The diameters of the multiwalled nanotubes (MWNTs) are between 10 nm and 30 nm. The sizes of the Cu₂O micro particles are in the range of 3-4 μm. The average diameter and the average thickness of the pressed tablets are 10 mm and 4.0 mm, respectively. In order to make low resistance electric contacts, the two sides of the pressed tablet are covered by silver pastes. The direct current resistance of the pressure sensor decreases by 3.3 ×as the pressure increases up to 37 kN/m². The simulation result of the resistance-pressure relationship is in good agreement with the experimental result within a variation of ± 2%.     

Analytical substrate flux approximation for the Monod boundary value problem

We present an analytical approximation for the diffusive flux of a substrate into a reactive layer, in which the substrate is degraded according to Monod kinetics. This problem is described by a nonlinear two-point boundary value problem. The approximation is derived based on a Homotopy Analysis Method idea and verified computationally, by comparison against a numerical solution of the problem. The analytical approximation is easy to evaluate and depends only on model parameters.     

Thermal catalytic conversion of the used isobutyl isoprene rubber into valuable hydrocarbons

An environment friendly method, thermal catalytic pyrolysis of used isobutyl isoprene rubber was investigated. In this method, the used inner butyl tube rubbers were catalytically pyrolyzed into valuable hydrocarbons and carbon black. In this method, the tube rubber was pyrolyzed both thermally (with out catalyst) and catalytically in a batch reactor under atmospheric pressure. The effect of temperature, the amount of catalyst, and the reaction time on the yields of the pyrolyzed products were investigated. Char yield decreased with increase of pyrolysis temperature while total gas and liquid yields increased. The liquid fraction was obtained with boiling point up to 478 K. At optimum conditions, the liquid product was collected and analyzed for different fuel properties. Typical analysis of the used isobutyl isoprene rubber oil for both the cases of parent and refluxed oil has been performed. Phenols and carbonyls were quantitatively determined by spectrophotometric methods using folin-denis and phenyl hydrazine reagents, respectively. The distillation data showed that ~100% of oil has boiling point <473 K which is the boiling point for 80% of distilled product in commercial kerosene. Its specific gravity, viscosity, freezing point, Cetane number, and diesel index were also within the limits of kerosene.