Synthesis of Pyrazoles by the Condensation of C(α)- and Trianions with Esters

In addition to our previous papers^2,3 on the preparation of pyrazoles from the C(α), N-dianions of phenylhydrazones and C(α), N, N-trianions of hydrazones, we wish to report preliminary results on (I) the preparation and condensation of methylhydrazone dianions with methyl benzoate followed by acid cyclization, (II) the condensation of the dianions of phenylhydrazone with methylformate, and the preparation and condensation of the trianions of cyclopentanone (III) and α - tetralone (IV) hydrazones.     

Quantification of plasma lactate concentrations using capillary electrophoresis with contactless conductivity detection

The quantification of plasma lactate and evaluation of the lactate threshold by CE with capacitively coupled contactless conductivity is demonstrated. The only sample preparation needed was deproteinization with a ACN/methanol mixture. A solution of 10 mmol/L 2-morpholinoethanesulfonic acid monohydrate, 10 mmol/L DL-histidine, 70 μmol/L hexadecyltrimethylammonium bromide, pH 6.0 was found suitable as running buffer. Linearity was achieved for the concentration range of 10-1000 μmol/L with a correlation coefficient of 0.9994. The limit of detection (3 S/N) was determined as 3.2 μmol/L. Intra- and inter-day variabilities were less than 7% RSD. The suitability of the method could be demonstrated by analyzing various clinical samples, where the results correlated satisfactorily with those of an established enzymatic method.     

Scroll wave instabilities in an excitable chemical medium

Two kinds of scroll wave instabilities were studied experimentally in the excitable Belousov-Zhabotinsky reaction: three-dimensional meandering and negative line tension of the scroll wave filament. The filament displays a flat zigzag shape in the initial stages of the experiment. As the chemical medium ages, the filament assumes a wiggly shape while its length increases substantially. Numerical simulations underpin the experimental findings and their interpretation.     

New thermotropic cubic mesophases

1,2-Bis-[4-n-alkyloxybenzoyl]-hydrazines with the general formula possess smectic C phases and at lower temperatures additional optically isotropic phases. According to X-ray investigations these isotropic phases show cubic symmetry. The lattice units consist of aggregations with micellar dimensions. The substances were characterized by microscopic, dilatometric and calorimetric investigations. The new cubic mesophases do not exhibit complete miscibility with the “smectic D” phases.     

Polylactones, 46. Telechelic polylactones having amino acid,dipeptide or penicilline endgroups via macrocyclic polymerization

Using 2‐stanna‐1,3‐dioxepane (DSDOP) as cyclic initiator either neat ε‐caprolactone (ε‐CL) or mixtures of ε‐CL and L ‐lactide were polymerized in bulk. The resulting tin‐containing macrocyclic polylactones were reacted with an excess of N‐protected amino acid or dipeptide 4‐chlorothiophenyl esters. It was shown that the coupling of amino acid thioaryl esters and tin‐containing macrocycles does not involve any racemization. The cleavage of Boc groups with trifluoroacetic acid proved to be feasible but not the hydrogenolytic cleavage of the Z‐group.