Crystal structure of the biclotymol–<Emphasis Type="Italic">N,N</Emphasis>-dimethylacetamide solvate 1:1: experimental and theoretical conformational analysis of biclotymol molecule

The crystal structure of the N,N-dimethylacetamide–biclotymol 1:1 solvate has been determined at room temperature by X-ray single-crystal diffraction. The molecular geometry of the biclotymol molecule is compared to the geometries observed in the N,N-dimethylformamide and dimethylsulfoxide solvates, and in the unsolvated form Phase-I. Rotational energy profile of the isolated molecule was obtained by semi-empirical AM1 calculations with respect to two selected torsional angles, which were rotated from 0° to 360° by steps of 10°. Not only, we find the two conformations experimentally observed, but also the conformation proposed by simple force fields calculations 30 years ago. Moreover, we propose three additional possible conformations that may offer potential candidates for the structure biclotymol Phase-II, which remains to be solved.     

Synthesis of a New Ditopic Ligand Possessing Linear and Cyclic Tetraaza Subunits

An easy‐to‐run route to a new ditopic ligand possessing linear and cyclic tetraaza subunits is described. In the first step, the reaction consists in the preparation of a triprotected cyclam bearing a 3‐bromopropyl pendant side chain. A subsequent reaction with a bisaminal protected linear tetraamine gives, after deprotection, the desired ditopic ligand.     

Extraction mechanism of Tc(IV) by Di-(2-ethylhexyl)phosphoric acid (HDEHP)

Journal of Radioanalytical and Nuclear Chemistry - Di-(2-ethylhexyl)phosphoric acid, HDEHP, is a well-known extractant used for metal ion extraction in an industrial scale and for research work....     

Development and validation of capillary zone electrophoresis and high-performance liquid chromatography methods for the determination of oral anticoagulant edoxaban in pharmaceutical tablets

The incidence of thrombotic complications in SARS-CoV-2 infections has become a global concern; thus, anticoagulants are an integral part of the treatment. Edoxaban (EDX) is an oral anticoagulant suitable for pharmacologic thromboprophylaxis. Herein, two novel analytical methods for EDX determination in tablets are developed and validated using capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC). Operating conditions such as the electrolyte's concentration and pH value, injection time, volume, and the capillary temperature, were optimized. The methods were successfully validated by establishing the linearity, intra- and inter-day precisions (relative standard deviation [%]), accuracy, and robustness. Adequate separation of excipients and degradation products of EDX generated by stress degradation conditions demonstrated the stability-indicating capability of the methods. The analytical procedures were linear in the range of 25–125 µg/ml (r > 0.999), with the limits of detection and quantification of 3.26 and 10.87 µg/ml for CZE and 0.740 and 2.78 µg/ml for HPLC. Although both methodologies are suitable for determining EDX in tablets, CZE provides a greener alternative due to low-cost analysis using less organic solvents and minimizing waste generation.     

Reductive Elimination at Pb(II) Center of an (Amino)plumbylene-Substituted Phosphaketene: New Pathway for Phosphinidene Synthesis

A stable (amino)plumbylene-substituted phosphaketene 3 was synthesized by the successive reactions of PbCl₂ with two anionic reagents (lithium amidophosphine and NaPCO). Of particular interest, the thermal evolution of 3 , at 80 °C, leads to the transient formation of corresponding amino- and phosphanylidene-phosphaketenes ( 6 and 7 ), via a reductive elimination at the Pb^II center forming new N−P and P−P bonds. Further evolution of 6 gives a new cyclic (amino)phosphanylidene phosphorane 4 , which shows a unique reactivity as a phosphinidene. This result provides a new synthetic route to phosphinidenes, extending and facilitating further their access.     

Elasticity and ramification

Let A ? Bbe an extension of domains and Xbe an indeterminate over B. In this paper, we study the elasticity of atomic domains of the form A+ XB[X] where A ? Bis an integral extension. First, we study the case where A = Zand, show that, whatever B, this elasticity is infinite. Finally, we investigate the case where Ais a discrete valuation ring with quotient field Kand Bits integral closure in a finite extension of K.