Synthesis and spectral characterization of some new thiazolopyrimidine derivatives

Thiazolopyrimidnes are considered one of the most interesting classes in heterocyclic chemistry due to their pharmaceutical importance. Herein, we report the synthesis of some new heterocyclic compounds containing thiazolopyrimidine starting from compound (1) which was previously prepared in literature. The starting compound was allowed to react with different alkylating agents such as chloroacetone, chloroacetyl chloride, and phenacyl bromide to afford derivatives (2-4). Compound (5), benzylidene derivative, was obtained by the reaction of compound (2) with benzaldehyde while amino-dicarbonitrile compound (6) can be obtained by the reaction of compound (5) and malononitrile. Acetylation of amino group in compound (6) with chloroacetyl chloride led to formation of compound (7). Nucleophilic substitution of chlorine in compound (7) by aniline gave compound (8) which further subjected the Munich reaction to form compound (9). All new synthesized compounds were characterized using different elemental and spectral analysis.

On the Single-Crystal Structure of Tenofovir Alafenamide Mono-Fumarate: A Metastable Phase Featuring a Mixture of Co-Crystal and Salt

Tenofovir alafenamide (TAF) is a prodrug of tenofovir as a potent nucleotide reverse transcriptase inhibitor. It serves as the key component of Genvoya® for the first-line treatment of human immunodeficiency virus infection (HIV) and is the active component of Vemlidy® for the treatment of chronic hepatitis B. Vemlidy® is also a monotherapeutic regimen formulated as TAF hemifumarate (1; TAF:fumarate = 2:1). In this work, we report for the first time the single-crystal structure of TAF fumarate hemihydrate (2, TAF:fumarate:H2O = 2:2:1). Compound 2 is initially documented as a salt in which one proton of the fumaric acid migrates to the amine group of the adenine moiety in TAF. It was recently proposed that ca. 20–30% proton is transferred to the N atom on the aromatic adenine backbone. We herein provide definitive single-crystal X-ray diffraction results to confirm that 2, though phase pure, is formed as a mixture of co-crystal (75%) and salt (25%). It features two pairs of TAF fumarates, wherein one of the four H atoms on the fumaric acid is transferred to the N atom of the adjacent adenine moiety while the other three carboxylates remain in their intrinsic acid form. Compound 2 is a metastable phase during the preparation of 1 and can be isolated by halting the reaction during the refluxing of TAF and fumaric acid in acetonitrile (MeCN). Our report complements the previous characterizations of TAF monofumarate, and its elusive structural patterns are finally deciphered.

Synthesis, Characterization, and Electrochemistry of Diferrocenyl β-Diketones, -Diketonates, and Pyrazoles

The synthesis of FcC(O)CH(R)C(O)Fc (Fc = Fe(η5-C5H4)(η5-C5H5); R = H, 5; nBu, 7; CH2CH2(OCH2CH2)2OMe, 9), [M(κ2O,O′-FcC(O)CHC(O)Fc)n] (M = Ti, n = 3, 10; M = Fe, n = 3, 11; M = BF2, n = 1, 12), and 1-R′-3,5-Fc2-cC3HN2 (R′ = H, 13; Me, 14; Ph, 15) is discussed. The solid-state structures of 5, 7, 9, 12, 13, 15, and 16 ([TiCl2(κ2O,O′-PhC(O)CHC(O)Ph)2]) show that 7 and 9 exist in their β-diketo form. Compound 13 crystallizes as a tetramer based on a hydrogen bond pattern, including one central water molecule. The electrochemical behavior of 5–7 and 9–16 was studied by cyclic and square-wave voltammetry, showing that the ferrocenyls can separately be oxidized reversibly between −50 and 750 mV (5–7, 9, 12–15: two Fc-related events; 10, 11: six events, being partially superimposed). For complex 10, Ti-centered reversible redox processes appear at −985 (TiII/TiIII) and −520 mV (TiIII/TiIV). Spectro-electrochemical UV-Vis/NIR measurements were carried out on 5, 6, and 12, whereby only 12 showed an IVCT (intervalence charge-transfer) band of considerable strength (νmax = 6250 cm−1, Δν½ = 4725 cm−1, εmax = 240 L·mol−1·cm−1), due to the rigid C3O2B cycle, enlarging the coupling strength between the Fc groups.

Characteristics Of Treating Arabic Grammar In Educational Books For Russian Orientalists/ خصائص معالجة النحو العربي في كتب تعليمية للمستشرقين الروس

This study aimed to identify the characteristics of grammatical rules treatment in educational books of Russian orientalists in teaching the Arabic language. Because of the rare study, this topic. This paper analyzes and evaluates one of the books of teaching Arabic grammar to non-Arabic speakers. It aims to reveal its different aspects in organizing and using grammatical rules, determining what is useful for them in teaching Arabic grammar to help in using the target language, and making some recommendations that contribute to this. The results are indicating that the book's treatment of grammatical rules is distinctly different. That follows the functional progression and focuses on the treatment of the similarities and differences between the grammatical of Arabic and Russian languages. Furthermore, it is interesting to provide how to use the rules, so that the learner can gradually form compound and straightforward sentences, which helps him use the target language.

The Changing Relation between Atomicity and Elementarity

Early modern efforts to reconceptualize atomicity as a chymical notion fell by the wayside during the chemical revolution, as Antoine Lavoisier’s desire to transform chemistry into a strictly empirical and quantitative science led him to reject all metaphysical speculation about the fundamental nature of matter. Instead, Lavoisier focused on identifying elementary substances, which he defined operationally as the final products of chemical analysis. Our current understanding of the relation between atoms and elements, however, owes a great deal to the work of nineteenth-century chemist John Dalton. Dalton’s chemical atomic theory reconciled the concepts of “atomicity” and “elementarity” and rendered both as empirical and chemical notions, amenable to measurement and quantitative analysis. One of the central goals of Dalton’s theory was understanding how relative weights of chemical atoms determine the properties of elements and how the chemical atoms of different elements combine to form compound substances. Thus, Dalton’s theory provided a way of studying and measuring the properties of atoms and elements in a way that allowed chemists to finally understand the chemical relations between them.

Effect of potassium for cesium replacement in atomic level structure of potassium cobalt hexacyanoferrate(II)

Potassium cobalt hexacyanoferrate(II) [K2CoFe(CN)6] is an extremely selective ion exchanger for cesium ions. To examine the atomic level background for the selectivity a computational structural study using DFT modelling was carried out for K2CoFe(CN)6 and for products where Cs has replaced K in the elemental cube cages closest to the surface. In the K-form compound the potassium ions are not in the center of the Co–Fe–CN elementary cube cages closest to the surface but locate about 140 pm from the cube center towards the surface. When cesium ions are exchanged to these potassium ions they locate much deeper from the surface, being only about 70 pm upwards from the cube center. This apparently leads to much stronger bonding of cesium compared to potassium. Once taken up into the outermost cube cages on the surface of the crystallites cesium ions are not able to penetrate further since they are much larger than the electron window between the cubes. Furthermore, they are not able to return to the solution phase either leading to a practically irreversible sorption.

Simplicius on the Individuation of Material Substances

In his commentary on Physics I 9, Simplicius claims that individual forms individuate matter. Given that in the same text he calls the immanent form ‘universal,’ it seems reasonable to conclude that the individual forms are individual instances of one universal species–form. However, Simplicius also mentions accidental properties that are peculiar to form rather than to matter. On the basis of Simplicius’ commentaries on the Categories and on the Physics, I argue that the individuating accidents are not part of the individual forms, but that each individual’s form coordinates the individual’s accidental features. By belonging to a certain species, the individual form sets limits as to which accidents a matter–form compound can assume. This approach enables Simplicius to combine hylomorphism with a theory of individuation through properties. Furthermore, in his commentary on De Caelo I 9 Simplicius explains the uniqueness of each individual’s conglomeration of properties in light of his Neoplatonic cosmology: each individual corresponds to an individual cosmic disposition that determines its characteristic features.

Playful You in the Zhuangzi and Six Dynasties Literati Writing

This essay explores the notion of you 游in the Zhuangzi and Six Dynasties literati writing through a comparative reading. Used interchangeably with its variant you 遊, you 游has various uses and meanings, from the more literal “swim in water”, “move in an unobstructed way”, “wander”, and “travel afar”, to its extended meanings including “ramble in a carefree way”, “travel playfully”, “travel into foreign or unknown space”, or “enjoy a leisurely activity”. You is also, significantly, combined with other characters to form compound expressions specifying different playful activities, e.g. youxi 游戲: “play and frolic”, “amuse oneself”, or “game”; youwan 游玩: “play outdoors” (with an emphasis on movement); and lüyou 旅游: “travelling for leisure”, or “tourism”—which have very different connotations from lüxing 旅行, “journey”, or “travel (the main purpose of which is not pleasure)”. In these different uses and expressions of you, in both classical and modern Chinese, what we find in common is the connotation of an unhindered, playful movement that is closely connected to its spatial context. In the context of the Zhuangzi and Six Dynasties literature, therefore, can we find articulations of you as a playful activity? If yes, in what specific ways is you playful, especially in regard to the space and context in which it occurs? Finally, what do the differences and similarities between the Zhuangzi and Six Dynasties writing say about the evolution of the notion of you within the Daoist and Neo-Daoist discourse? At time of publication of this article, the journal operated under the old name. When quoting please refer to the citation on the left using British Journal of Chinese Studies. The pdf of the article still reflects the old journal name; issue number and page range are consistent.

INVESTIGATION AND OPTIMIZATION OF COMPLEXATION OF COBALT IONS WITH DIHYDROQUERCETIN IN AQUEOUS SOLUTIONS

We continue to study the reactions of complexation of biogenic metal ions with flavonoid dihydroquercetin (DHQ). The interaction of Co2+ ions with DHQ in aqueous solutions has been studied. It is established that complexes with different stoichiometry are formed at different pH values of the solution. Changing the pH of the solution from 6.0 to 7.0 leads to the formation of compounds 1–3 with a metal: flavonoid ligand (Met: L) ratio from 1: 2 at pH 6.0 (1) via 2: 3 at pH 6.4 -6.7 (2) to 1: 1 at pH 6.8-7.0 (3). Using the method of thermogravimetry with elemental analysis data, the most probable composition of compounds was established with the determination of the amount of bound water: [CoL2(H2O)4] for 1, [Co2L3(OH)(H2O)4] for 2 and [CoL(OH)(H2O)2] for 3. The conditions for the complexation of Co2+ ions with dihydroquercetin in aqueous solutions to form compound 2, optimized for the yield of the product, are proposed. pH of the solution is 6.7, the reaction time is 15 minutes, the temperature of the reaction solution is 90 °C, molar ratio of the initial reagents DHQ:Co2+ is 1: 1.5, initial concentrations are 0,020 M DHQ and 0,030 M Co2+, the source of Co2+ is CoSO4∙7H2O. The yield of the product is 81.8 %.