Calix[4]arene alpha-aminophosphonic acids: asymmetric synthesis and enantioselective inhibition of an alkaline phosphatase

[structure: see text] Chiral calix[4]arene alpha-aminophosphonic acids were obtained through diastereoselective Pudovik-type addition of sodium ethyl phosphites to the chiral calixarene imines, removal of chiral auxiliary groups, and mild dealkylation of phosphonate fragments. The diacids obtained show inhibitory activity toward porcine kidney alkaline phosphatase that depends considerably on the absolute configuration of the alpha-carbon atoms.     

On the complete integrability and linearization of a Burgers– Korteweg–de Vries-type nonlinear equation

In this work, on the basis of the Bogolyubov–Prykarpats’kyi gradient–holonomic algorithm for the investigation of the integrability of nonlinear dynamical systems on functional manifolds, the exact linearization of a Burgers–Korteweg–de Vries-type nonlinear dynamical system is established. As a result, we describe the linear structure of the space of solutions and show its relation to the convexity of certain functional subsets. The bi-Hamiltonian property of the Burgers–Korteweg–de Vries dynamical system is also established, and the infinite hierarchy of functionally independent invariants is constructed.     

Polyfunctional pyrazoles. 1. Synthesis of 3-aryl-1-(2-cyanoethyl)-4-formylpyrazoles and their 3-(5-methylfur-2-yl)-substituted analog

Previously unknown substituted pyrazoles were obtained by the reaction of the 2-cyanoethylhydrazones of aryl methyl ketones and 5-methylfur-2-yl methyl ketone with the Vilsmeier-Haack reagent.Bukovina State Medical Academy, Chernovtsy. Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1219–1221, September, 1999.     

High-performance thin-layer chromatography method for monitoring norfloxacin residues on pharmaceutical equipment surfaces

This paper presents a high-performance thin-layer chromatography (HPTLC) method with direct fluorescence measurement for the determination of norfloxacin. The method was validated for the monitoring of norfloxacin residues on stainless steel surfaces at the allowed limit of 10 mg of norfloxacin per square meter. However, it can be adapted for lower amounts of residues owing to the low detection limit of norfloxacin (about 5 ng) and can also be used for other surface materials. Test solutions were analyzed by the new HPTLC method and the known HPLC method for comparison. Accuracy and precision of the new HPTLC method, with a subsequent quantification by densitometer or video system, are comparable with those of the HPLC method.     

Intramolecular Cyclization of 4-Isocyanato-3-(2-naphthyl)-1-phenylpyrazole Under Friedel-Crafts Reaction Conditions

4-Isocyanato-3-(2-naphthyl)-1-phenylpyrazole cyclized under the influence of AlCl₃ to give 2H-benzo[h]pyrazolo[4,3-c]isoquinoline.     

Separation of pectin methylesterase isoenzymes from tomato fruits using short monolithic columns

One of the main forms of tomato pectin methylesterase (PME; EC 3.1.1.1.1) that is applicable to the food industry was isolated from fresh tomato fruit. The extraction of the PME isoenzymes involved washing the fresh tomato flesh with water in order to remove sugars and than solubilizing the enzymes with a diluted HCl solution at pH 1.6. The extract was then neutralized to pH 7.4 using buffer solution. After filtration, the solution was directly fractioned using Convective Interaction Media (CIM) short monolithic disk column bearing sulfonyl (SO3) groups and using a linear gradient from 0 to 700 mM NaCl. The injection volume was 3 ml and the diameter of the column was 12 mm and length 3 mm. The isolated fractions were monitored for protein content and PME activity. The fraction with the targeted enzyme, which showed NaCl independent activity, was further purified and concentrated by ultrafiltration and finally purified by a second semi-preparative cation-exchange chromatography step using a CIM carboxymethyl (CM) disk monolithic column consisting of two disks and applying a step gradient. From 1 kg of fresh tomato fruits, 7.5 mg of purified PME with molecular mass estimated to be 26 000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was obtained. A fraction with mixed PME and polygalacturonase activity was also obtained. Compared to the published procedures for the isolation and purification of PME from plant materials, this new procedure is much faster and more efficient. The potential application of CIM disk short monolithic columns in the analysis and semi-preparative extraction and isolation of the PME isoenzyme is presented.     

Functionally Substituted 3-Heterylpyrazoles: X. Reaction of 3-Aryl-1-phenyl-4-pyrazolecarbonyl Isothiocyanates with 3-Amino-5-methylisoxazole

3-Aryl-1-phenyl-4-pyrazolecarbonyl isothiocyanates react with 3-amino-5-methylisoxazole to afford 3-aryl-N-(3-acetonyl-1,2,4-thiadizol-5-yl)-1-phenylpyrazole-4-carboxamides.