Computation of Galois groups associated to the 2-class towers of some quadratic fields

The p-group generation algorithm from computational group theory is used to obtain information about large quotients of the pro-2 group for with d=−445,−1015,−1595,−2379. In each case we are able to narrow the identity of G down to one of a finite number of explicitly given finite groups. From this follow several results regarding the corresponding 2-class tower.     

An improved synthesis of some 5-substituted indolizines using regiospecific lithiation

Various 2-substituted indolizines can be directly and selectively lithiated in the 5 position and subsequent reactions with different electrophiles lead to some novel classes of indolizines. In particular, previously unknown 5-formyl- and 5-iodoindolizine have been prepared by this way and the molecular structure of 5-formyl-2- phenylindolizine was confirmed by X-Ray analysis. The reactivity of the 5-CHO- and 5- COPh groups toward some nucleophiles has been examined, and some additional classes of derivatives (oximes and alcohols) have been obtained. The possibility of Suzuki cross- coupling of 5-iodoindolizines and boronic acids was proven.     

Improvements in glass capillary gas chromatographic polychlorobiphenyl analysis

Separation of a 1:1:1:1 calibration mixture of Aroclors 1221, 1016, 1254, and 1260 on soda glass capillaries coated with Apolane (C-87) or Apiezon L is described. Polychlorobiphenyl congener structures are assigned to 112 separated and partially separated zones. The quantitative composition of Aroclor 1221 is reported. The performance of the two stationary phases on different lengths of laboratory and commercially prepared capillaries is compared and found to be very similar. Aroclors 1221, 1016, 1254, and 1260 are employed (1:1:1:1) for the primary calibration mixture because they contain all components of the commercial materials which pollute the environment; they are also easily obtained from the U.S. EPA Repository so that the method can be used in any laboratory by employing the calibration data given here.     

Dakin-West trick in the design of novel 2-alkyl(aralkyl) derivatives of oxazolo[3,2-a]pyridines

A series of previously unavailable derivatives of 2-alkyl- and 2-benzylderivatives of oxazolo[3,2-a]pyridines III were obtained via tandem ring opening and ring closure from stable mesoionic 3-acyloxazolo[3,2-a]pyridinium-2-olates I. The key intermediates of this tandem transformation are N-(b-oxoethyl)pyridones-2 II obtained by Dakin-West acylation of (pyridone-2-yl-1)acetic acid. An example of further utilization of this strategy is illustrated by preparation of unknown 2-benzylimidazo[1,2-a]pyridine from the salt I and ammonia.     

Growth and morphological study of copper oxide single crystals

Experiments on the growth of CuO single crystals by crystallization from flux in the CuO-Bi₂O₃-PbO-PbF₂, CuO-Bi₂O₃-Li₂O, CuO-Bi₂O₃-B₂O₃, CuO-BaO-Y₂O₃, and CuO-MO_x systems (M = P, V, or Mo) have been performed. The best results were obtained in crystallization in the CuO-Bi₂O₃-PbF₂ system: prismatic single crystals of platelet-and needlelike or isometric habit with dimensions up to 1 × 10 × 10, 1 × 1 × 20, or 6 × 6 × 8 mm, respectively, have been grown. The CuO crystals show polysynthetic twinning in the form of numerous alternating light and dark bands bound by systems of parallel straight lines on the {110} and {111} faces. A possible model of twinning associated with the Cu₂O → CuO transformation is considered.     

Low-frequency dynamic response of the bismuth strontium ferrite (Bi,Sr)FeO3−x

Broad-range measurements of the dynamic response of polycrystalline samples of the (Bi,Sr)FeO_3?x perovskite-like solid solution are performed over a frequency range from 10 Hz to 1 GHz at temperatures of 100–300 K for the first time. The colossal dielectric constant effect and the influence of electric contacts on the results of measurements are considered. It is shown that the frequency dependences of the permittivity and dynamic conductivity of (Bi,Sr)FeO_3?x samples can be described within the universal dielectric response model.