Excess volumes of binary mixtures of ethylbenzene with octanol,nonanol and dodecanol from 50 to 100°C and 0.1 to 7.5 MPa

The excess volume V ^E of binary mixtures of octanol, nonanol and dodecanol in ethylbenzene have been calculated from the densities measured with a vibrating tube densimeter at temperatures from 50 to 100 °C and at pressures from 0.1 to 7.5 MPa. The values of V ^E are positive for all the three mixtures in the complete temperature, pressure and mole fraction ranges studied. The maxima in V ^E is observed at 0.4 mole fraction of alkanol. The results are discussed in terms of specific interactions present in the binary mixtures. The second order thermodynamic quantities (V ^E /T)_p,(V ^E /P)_T and (V _E /P)_T which have been derived from the effect of temperature and pressure on V ^E , indicate an overall net creation of order in the binary mixtures of ethylbenzene with higher homologues of alkanols.     

Integrated lithographic membranes and surface adhesion chemistry for three-dimensional cellular stimulation

The complex spatiotemporal organization of cellular and molecular interactions dictates the physiological function of cells. These behaviors are indications of an integrated response to a three-dimensional cellular environment and anchored in cell adhesion on scaffolds. Here, we are able to control interconnected structural, mechanical, and chemical stimuli by dictating the cellular environment through chemical surface modifications, soft lithography, and mechanical deformation. Control of these variables is obtained through the use of an elastomeric membrane chemically modified for cell adhesion with a pressure-driven cell-stretching device which creates a pattern of forces similar to those encountered in physiological environments. Further, the integration of lithographic methods and chemical patterning allows the introduction of space- and time-dependent parameters by combining mechanical stimulation, biochemical regulation, and scaffolding design. The method is applied to stimulate single cells and cell populations to examine cellular response with spatiotemporal control. This research provides the capacity to probe biological patterns and tissue formation under the influence of mechanical stress.     

Effect of alkaline earth metal dopants on the thermal decomposition of the CaCO3-SiO2 system: Part II. Formation of dicalcium silicate

Mixtures of calcium oxide (taken as carbonate) and silica in 2:1 molar ratio containing varying amounts of MgO, SrCO₃ and BaCO₃ as dopants were subjected to thermal treatment up to 1450°C. The exothermic peaks at 1200°C and above (beyond the decomposition temperature of calcium carbonate) have been examined to elucidate the phases formed. The exothermic peak at 1210°C without dopant was found to conform to the β-dicalcium silicate phase with a significant amount of free lime and cristobalite along with small amounts of the γ-C₂S phase. MgO at 0.1–1% leads to the formation of β- and γ-dicalcium silicate phases at 1420–1430°C, while 5% MgO results in the formation of the β-C₂ S phase at 1360°C. SrCO₃, in the concentration range studied, leads to the stabilization of β-C₂S, but does not lower its temperature of formation. BaCO₃ at 0.1–1% assists in the formation of the β-dicalcium silicate phase, but 5% BaO forms a mixture of β- and α'_H-C₂S phases at a lower temperature.     

A Convenient One Step Synthesis of 1,3-Diaryl-6-methyl-4-oxo-1,2,3,4-tetrahydro-2-thioxofuro [2,3-d] Pyrimidines

1,3-Diaryl-6-methyl-4-oxo-1,2,3,4-tetrahydro-2-thioxofuro (2,3-d) pyrimidines have been synthesised in one step in good yield by the reaction of 1,3-diaryl-1,3-dihydro-2-thioxo-2H,5H-pyrimidine-4,6-diones with chloroacetone in presence of triethylamine.     

Simultaneous quantification of diterpenoids in Premna integrifolia using a validated HPTLC method

A sensitive, selective and robust densitometric high‐performance thin layer chromatographic method was developed and validated for the determination of diterpenoids in the root bark of Premna integrifolia. Diterpenoids 1β,3α,8β‐trihydroxy‐pimara‐15‐ene ( A ), 6α,11,12,16‐tetrahydroxy‐7‐oxo‐abieta‐8,11,13‐triene ( B ) and 2α,19‐dihydroxy‐pimara‐7,15‐diene ( C ) were used as chemical markers for the standardization of P. integrifolia plant extracts. The separation was performed on silica gel 60F₂₅₄ high‐performance thin layer chromatography plates using hexane/acetone/ethylacetate (60:20:20 v/v) as mobile phase. The quantitation of diterpenoids was carried out using densitometric reflection/absorption mode at 475 nm after post‐chromatographic derivatization using vanillin–sulfuric acid reagent. A precise and accurate quantification can be performed for compounds A , B and C in the linear working concentration range of 1–10 μg/spot with good correlations (r²=0.9985, 0.9996 and 0.9992, respectively). The method was validated for peak purity, precision, robustness, limit of detection (LOD) and quantitation (LOQ) etc., as per the International Conference on Harmonization (ICH) guidelines. Specificity of quantitation was confirmed using retention factor (R_f) and spectra correlation of markers in standard and sample tracks. The method reported here is simple and reproducible which may be applied for quantitative analysis of above diterpenoids in the root bark of P. integrifolia.     

Cobalt(III)‐Catalyzed Dehydrative [4+2] Annulation of Oxime with Alkyne by CH and NOH Activation

Efficient, scalable cobalt‐catalyzed redox‐neutral [4+2] annulation of readily available oximes and alkyne is reported. The developed synthetic methodology is widely applicable and tolerates various functional groups including heterocycles. A stable Cp*Co^III neutral complex is employed as the catalyst for this redox‐neutral [4+2] annulation reaction, which progresses smoothly by way of a reversible cyclometallation without any external oxidizing agent, and produces only water as the side product.     

A facile synthesis of 4-aryl-2H-1-benzopyran-2-ones

Reaction of 2-hydroxybenzophenones (1,3,7,8) with ethoxycarbonyl-methylenetriphenylphosphorane affords 4-aryl-2H-1-benzopyran-2-ones (2,4–6) in excellent yields.

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Eine einfache Synthese für 4-Aryl-2H-1-benzopyran-2-one

Zusammenfassung Die Reaktion der 2-Hydroxybenzophenone1,3,7 und8 mit Ethoxycarbonyl-methylentriphenylphosphoran ergab die 4-Aryl-2H-1-benzopyran-2-one2 und4–6 in ausgezeichneten Ausbeuten.