In this work, we have designed an efficient and convenient method for the synthesis of novel spiro[indene-2,2'-[1,3,5]oxathiazine]-1,3-diones by the one-pot, three component condensation of tetramethyl guanidine, ninhydrin, and isothiocyanates in water. Easy purification, green reaction conditions, easy performance and good yields are some advantages of this procedure. 相似文献
A new straightforward method based on cloud‐point extraction has been developed, optimized, and validated for the determination of doxepin in human plasma by high‐performance liquid chromatography separation and UV detection. The nonionic surfactant Triton X‐114 was chosen as the extraction solvent. Chromatography separation was performed on a μBondapakR C18 column (4.6 mm id × 300 mm, 3 μm particle size), which was used for isocratic elution at a detection wavelength of 289 nm. Under the optimum conditions, the linear range of doxepin in human plasma was 0.1–0.9 μg/mL. Also, the detection limit, preconcentration factor, and enrichment factor were 0.08 μg/mL, 50, and 49.0, respectively. 相似文献
Phenylphosphinic acid is found to catalyze the three‐component condensation of an aldehyde, enaminone, and urea or thiourea to afford the corresponding 6‐unsubstituted dihydropyrimidinones in high to excellent yields. This methodology is simple and fast synthetic route for the preparation of interesting class of heterocycles. 相似文献
A simple and rapid method using coupled bioluminescent assay was developed to determine level of ADP. ADP is involved in many biological reactions and ADP assay can be used for assaying some reactions universally by monitoring ADP formation or depletion. ADP analysis involves incubation of ADP or extracts containing ADP with pyruvate kinase (PK) and PEP. The ATP formed by this reaction is determined by measuring the intensity of the initial light flash produced when luciferin-luciferase preparation injected into the reaction mixture. In regard to the main role of the PK in this assay, the gene of PK from a Geobacillus species has been cloned in expression vector pET28a (+), sequenced and overexpressed in Escherichia coli. Recombinant protein was purified using Ni-NTA column and then the purified PK was used in a coupled bioluminescent assay for ADP measurement. Kinetic properties of PK are determined according to a bioluminescent assay using firefly luciferase. 相似文献
Densities and viscosities of ternary mixtures of 2-pyrrolidone + 1,2-propanediol + water and corresponding binary mixtures of 1,2-propanediol + water, 2-pyrrolidone + water and 2-pyrrolidone + 1,2-propanediol have been measured over the whole composition range at 313.15 K. From the obtained data, the excess molar volumes (VE), the deviations in viscosity (Δη) and the excess Gibbs free energy of activation (ΔG?E) have been calculated. The VE, Δη and ΔG?E results were correlated and fitted by the Redlich–Kister equation for binary mixtures and by the Cibulka equation for ternary mixtures, as a function of mole fraction. Several predictive empirical relations were applied to predict the excess molar volumes of ternary mixtures from the binary mixing data. 相似文献
The interaction of arsenic trioxide with human insulin was investigated by circular dichroism (CD), cyclic voltammetry and electrophoresis techniques. The interfacial behavior of insulin in presence of As2O3 onto the Ag electrode surface was studied at 310 K in phosphate buffer solution (PBS). According to Far-UV CD spectroscopy results, As2O3 caused to decrease in structural compactness and variety of alpha helix into beta structures. Near-UV CD indicated that As2O3 dissociates disulfide linkage in insulin structure. The kinetic parameters, including charge-transfer coefficient and apparent heterogeneous electron transfer rate constant were also determined. The thermodynamic parameters of insulin denaturation in presence of arsenic trioxide were calculated and reported. The obtained results indicated strong adsorption of insulin in presence of arsenic trioxide onto the Ag surface via chemisorptions.
International Journal of Theoretical Physics - The presented work provides a procedure for optimizing the communication cost of a distributed quantum circuit (DQC) in terms of the number of qubit... 相似文献
Chemistry of Heterocyclic Compounds - A series of novel pyrazolo[1,2-b]phthalazine-2-carboxylate derivatives has been synthesized via one-pot four-component reaction of aromatic aldehyde, ethyl or... 相似文献
Summary. Alum (KAl(SO4)2 · 12H2O) catalyzed the efficient synthesis of mono- and disubstituted 1,3,4-oxadiazoles by the condensation of acyl hydrazides with
orthoesters under solvent-free conditions at 100°C. This methodology offers significant improvements for the synthesis of
oxadiazoles with regard to the yield of products, simplicity in operation, inexpensive reagents, and green aspects by avoiding
toxic catalysts and solvents. 相似文献