Intermolecular Interactions in Crystalline Hydroxychloroquine Sulfate in Comparison with Those in Selected Antimalarial Drugs

Abstract The crystal structure of hydroxychloroquine sulfate (OHClQ) was determined in order to compare its conformation and intermolecular interactions to those in the crystalline chloroquine phosphate (ClQP) and quinine salicylate (QSal) monohydrate. The crystals of OHClQ are monoclinic with the space group P2₁/c and unit-cell dimensions: a = 10.4966(1) ?, b = 8.8056(1) ?, c = 21.8603(3) ?, β = 101.074(1)°. The quinoline antimalarial drugs may interact with their putative receptors by formation of characteristic hydrogen-bonded rings. The protonated nitrogen atoms and/or hydroxyl groups of the drug cation are proton donors, while the oxygen atoms of anions are proton acceptors. Water molecules may intermediate in these interactions. Graphical Abstract Hydroxychloroquine sulfate is a drug used in the treatment of malaria and rheumatic diseases. The X-ray structure analysis shows an important role of intermolecular hydrogen bonds in the crystal architecture. Comparison with chloroquine phosphate and quinine salicylate indicates that the organization of the drug cations is determined by the anions.      

Synthesis and theoretical characterization of some new 4‐substituted‐1,3‐diphenyl‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazoles with potential pharmacological activity

Synthesis of some new triazoles fused to triazoles 5a–c or thiadiazoles 6a–c and the thiol‐thione tautomeric equilibrium study of the title compounds are reported. The “rule of five” and complementary criteria of pharmacokinetic properties were determined to predict whether these compounds are orally bioavailable. Semiempirical parameterizations have been critically benchmarked for the thiol‐thione tautomeric equilibrium against the DFT calculations. It was shown that unlike the AM1 and PM3 Hamiltonians, which erroneously predict higher stability of the thiol tautomer, the newly developed RM1 Hamiltonian, on the other hand, predicts energetics of this equilibrium in excellent agreement with the DFT results. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:713–718, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20499     

A quantitative thermal analysis of cyclists’ thermo-active base layers

It is well known that clothes used in sporting activity are a barrier for heat exchange between the environment and athlete, which should help in thermoregulation improvement. However, it is difficult to evaluate which top is best for each athlete according to the characteristics of the sport. Researchers have tried to measure the athlete’s temperature distribution during exercise at the base layers of tops with different approaches. The aim of this case study was to investigate the use of thermography for thermo-active base layer evaluation. Six new base layers were measured on one cyclist volunteer during a progressive training on a cycloergometer. As a control condition, the skin temperature of the same volunteer was registered without any layer with the same training. A training protocol was selected approximate to cycling race, which started from the warm-up stage, next the progressive effort until the race finished and at the end “cool-down” stage was over. In order to show which layer provided the strongest and weakest barrier for heat exchange in comparison with environment, the temperature parameters were taken into consideration. The most important parameter in the studies was the temperature difference between the body and the layers, which was changing during the test time. The studies showed a correlation between the ergometer power parameter and the body temperature changes, which has a strong and significant value. Moreover, the mass of every layer was checked before and after the training to evaluate the mass of the sweat exuded during the test. From this data, the layer mass difference parameter was calculated and taken into consideration as a parameter, which may correspond with the mean heart rate value from each training. A high and positive correlation coefficient was obtained between the average heart rate and the mass difference for the base layers. Thermal analysis seems to have a new potential application in the objective assessment of sports clothing and may help in choosing the proper clothes, which could support heat transfer during exercising and protect the body from overheating.

     

Subdirectly irreducible medial quandles

We describe all subdirectly irreducible medial quandles. We show that they fall within one of four disjoint classes. In particular, in the finite case they are either connected (and therefore Alexander quandles) or reductive. Moreover, we provide a representation of all non-connected subdirectly irreducible medial quandles.     

Synthesis and biological activity of new derivatives with the preserved carane system

Abstract

Terpenoid derivatives, which contain a preserved carane system in their structure, exhibit a broad spectrum of biological activities. Among them, we can distinguish insecticides, structures with pharmacological application etc. In the presented paper, the substrate - (–)-cis-caran-trans-4-ol was transformed using the reactions of typical organic synthesis to obtain novel derivatives. Most importantly, bromolactone ((–)-(1R,4R,6S)-2'-(bromomethyl)-4,7,7-trimethylspiro[bicyclo[4.1.0]heptan-3,3'-furan]-5'(4'H)-one) with the preserved carane system was synthesized. This bromolactone was tested for antifeedant activity against the lesser mealworm, Alphitobius diaperinus Panzer, and peach potato aphid (Myzus persicae). In addition, its moderate antibacterial activity was observed against the Bacillus subtilis strain (with Minimal Inhibitory Concentration of 200 µg/mL).     

Phenoxy herbicidal ammonium ionic liquids

Ammonium ionic liquids with the 4-chloro-2-methylphenoxyacetate anion were synthesized and characterized. Physicochemical properties, such as thermal stability, phase transition temperatures, viscosity, density, refractive index, as well as surface activity and herbicidal activity were determined. Improved physicochemical properties suggest a reduced environmental impact of newly formed group of herbicidal ionic liquids (HILs). HILs with a longer substituent can be characterized with better herbicidal activity in comparison with commercial products.     

Helicenophyrins: Expanded Carbaporphyrins Incorporating Aza[5]helicene and Heptacyclic S‐Shaped Aza[5]helicene Motifs

Incorporation of phenanthrene into a hexaphyrin(1.1.1.1.1.0) frame resulted in intramolecular ring fusion, thus giving rise to chiral helicenophyrins. These molecules contain helicene and porphyrin features by incorporating either an aza[5]helicene or heptacyclic S‐shaped aza[5]helicene.