Crystal Structures of 1,5,9,18,22,26-Hexaaza[11.11]-p-cyclophane Adducts; Two-dimensional Supramolecular Networks

Two newly identified supramolecular structures arise from self-assembly of the macrocyclic 1,5,9,18,22,26- hexaaza[11.11]-p-cyclophane salts with o-nitrophenol (C₂₈H₅₀N₆)⁴⁺·4(C₆H₄NO₂O)⁻ (1) and with HCl (C₂₈H₅₂N₆)⁶⁺·6Cl^-·4H₂O (2). In both cases two-dimensional supramolecular sheets are formed.     

The Effect of the Catalyst Used on the Kinetics of Di-2-Ethylhexyl Maleate Synthesis

Kinetics of the esterification of maleic anhydride with 2-ethylhexanol in the presence of sulfuric acid, amphoteric tetrabutyl titanate or in the absence of external catalyst has been studied. The kinetic equations and kinetic parameters have been determined.     

Cyclopentathiadiazines, new heterocyclic materials from cyclic enaminonitriles

Indene and cyclopentene enaminonitriles were reacted with SCl2, iBu3N and NCS to give the first cyclopenta[1,2,6]thiadiazines that showed unusual characteristics, one as a NIR dye and another as a liquid crystal.     

Synthesis of new fluorinated 1,5-benzoxazepine derivatives

A simple approach to the fluorinated 1,5-benzoxazepine ring system is described. By reacting commercially accessible aminophenols 1 and the trifluoroacetylvinyl ether 2, high yields of enaminones 3 were obtained. Functionalization of methyl group of compounds 3 gave rise to dieneamines 4 that were cyclized in acidic environment to benzoxazepine derivatives 5.     

Electrochemical monitoring of indigo preparation using Maya’s ancient procedures

The preparation of indigo from Indigofera suffruticosa following the procedures attributed to ancient Mayas was electrochemically monitored using the voltammetry-of-microparticles approach. The mechanism formation of indigotin and indirubin from its precursors, indican and isatan, is discussed. Comparison of voltammetric profiles for differently prepared and commercial indigos and genuine Maya Blue samples suggests that the preparation procedure of indigo changed during the Late Classical Maya period. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A short synthesis of C-glycosyl pyrazoles and pyrroles

The sodium salt of TOSMIC reacted with (E)-3,4,5,6,7-penta-O-acetyl-1,2-dideoxy-1-C-nitro-D-galacto- (1) and -D-manno-hept-1-enitol (2) to give 3-(D-galacto- (3) and 3-(D-manno-penta-O-acetylpentitol-1-yl)-4-nitropyrrole (4) , respectively. Compound 1 reacted with diaryl nitrile imines, affording 1,3-diaryl-4-(1,2,3,4,5-penta-O-acetyl-D-galacto-pentitol-1-yl)pyrazoles 5 and 6 .     

Do proficiency tests always verify laboratories’ performance? The case of FAPAS PT 0270

In this paper, the case of FAPAS PT 0270 “Doramectin and Oxfendazole in Sheep Liver” is discussed. During evaluation of the data received from participants (determination of total, oxidised oxfendazole residue and calculation of the sum of oxfendazole and oxfendazole sulfone residues), significant differences were observed between the results obtained by use of two analytical approaches. This phenomenon can be explained by the route of oxfendazole metabolism, which results in the presence of fenbendazole in the sample. This was not predicted by the provider; consequently, not all the necessary tests on the material were conducted. Due to the high uncertainty of the z-scores in this test, the results of the PT cannot be used for purposes of evaluation, and the benefits of participation in PT 0270 are questionable.     

Isobaric vapor–liquid equilibria for the quaternary reactive system: Ethanol + water + ethyl lactate + lactic acid at 101.33 kPa

Isobaric vapor–liquid equilibrium (VLE) data of the reactive quaternary system ethanol (1) + water (2) + ethyl lactate (3) + lactic acid (4) have been determined experimentally. Additionally, the reaction equilibrium constant was calculated for each VLE experimental data. The experimental VLE data were correlated using the UNIQUAC equation to describe the chemical and phase equilibria simultaneously. For some of the non-reactive binary systems, UNIQUAC binary interaction parameters were obtained from the literature. The rest of the binary UNIQUAC parameters were obtained by correlating the experimental quaternary VLE data obtained in this work. A maximum pressure azeotrope at high water concentration for the binary reactive system ethyl lactate + water has been calculated.