•Determination of the crystal structures of five benzyloxy substituted (2E)-phenyl-C(C=O)-CH=CH-benzene derivatives.•Determination of the Hirshfeld surfaces of five benzyloxy substituted ...(2E)-phenyl-C(C=O)-CH=CH-benzene derivatives.•A PIXEL study of five benzyloxy substituted (2E)-phenyl-C(C=O)-CH=CH-benzene derivatives.•Evidence of the importance of anti-parallel layered motifs in benzyloxy substituted compounds.
X-ray crystallographic, Hirshfeld surface and PIXEL study is reported on five benzyloxy substituted compounds, namely (E)-3-2 methoxy‑5-benzyloxyphenyl-1-(2‑hydroxy-4-methoxyphenyl)-2-ene-1-one, compound 1, (E)-3-2,5-bis(benzyloxy)phenyl-1-(2-hydroxyphenyl)-2-ene-1-one, compound 2, (E)-3-2,5-bis(benzyloxy)phenyl-1-(2‑hydroxy-4-methoxyphenyl)-2-ene-1-one, compound 3, (E)-3-2,5-bis(benzyloxy)phenyl-1-(2‑hydroxy-3,4-dimethoxyphenyl)-2-ene-1-one, compound 4, and (E)-3-2,5-bis(benzyloxy)phenyl-1-(2‑hydroxy-4,5-dimethoxyphenyl)-2-ene-1-one, compound 5. All five compounds exhibit intramolecular O—H(hydroxyl)···O(carbonyl) classical hydrogen bonds, (E)-arrangements about the olefinic bond and near planar chalcone cores, with the interplanar angles between chalcone rings A and B all less than 10°. The phenyl groups in the benzyloxy substituents make much greater interplanar angles with the chalcone core rings, A and B. The linker units, -C(O)-CH=CH-, between the terminal phenyl rings in the chalcone cores, exhibit electronic delocalization as indicated by the bond lengths being between single and double bonds. Motifs having molecules aligned in antiparallel arrangements in layers, with perpendicular distances between the two layers of ca.3.5 Å are amongst the most important motifs. The molecular slippage of the antiparallel molecules in these motifs varies significantly, which results in different functionality, e.g., the terminal phenyl rings, or segments in the linker unit, such as the carbonyl or the olefinic groups, in one layer being suitably placed to interact with functionality in the other. This series of motifs illustrate a great range of slippage distances which is reflected in the variety of interactions present in the motifs, including off-set, face-to-face π···π, π(CO)···π, π(CO)···π(CO) and π(C=C)···π(C=C) interactions. PIXEL calculations reveal the important motifs and their energies, and generally indicate the much greater importance of the dispersive contribution than Coulombic and polarization contributions to the overall energies of these molecules.
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•The determination of the crystal structures of two chalcone derivatives.•Study of the Hirshfeld surfaces of two chalcone derivatives.•PIXEL calculations on two chalcone derivatives.•Identification ...of the important motifs in crystalline chalcone derivatives.•Data base search of structures of (E)-alkoxy-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one derivatives.
The crystal structures, Hirshfeld surface analysis and PIXEL calculations are reported for (E)-3-(4-methoxyphenyl)-1-(2-hydroxy-5-isoproproxyphenyl)prop-2-en-1-one, 1, and (E)-3-(3-methoxy-4-isopropoxyphenyl)-1-(2-hydroxy-4,6-diisoproproxyphenyl)prop-2-en-1-one, 2. Different sets of C—H···O, C—H···π, off-set, face-to-face π ···π and/or C=O··· π intermolecular interactions are displayed by each compound. Due to the bulk of the isoproproxy unit and the consequent steric hindrance in forming aggregates in the solid state, compounds 1 and 2 exhibit larger interplanar angles than do corresponding chalcones with methoxy units. The total stabilization energies of the crystal packing, Etot distributed as Coulombic (Ecoul), polarization (Epol), dispersion (Edisp), and repulsion (Erep) have been computed by PIXEL. For compound 1, six motifs (molecule pairs) and for compound 2, with two independent molecules in the asymmetric unit, thirteen motifs are identified by the PIXEL calculations to have energies, -Etot, above the cut-off value of 10 kJ.mol−1. For each of these motifs, the largest contributor to the Etot value is the Edisp term, irrespective of the type(s) of interaction(s) connecting the two molecules, if any, in the motifs.
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Summary
Phosphatidylserine (PS) exposure increases as red cells age, and is an important signal for the removal of senescent cells from the circulation. PS exposure is elevated in red cells from ...sickle cell anaemia (SCA) patients and is thought to enhance haemolysis and vaso‐occlusion. Although precise conditions leading to its externalisation are unclear, high intracellular Ca2+ has been implicated. Red cells from SCA patients are also exposed to an increased oxidative challenge, and we postulated that this stimulates PS exposure, through increased Ca2+ levels. We tested four different ways of generating oxidative stress: hypoxanthine and xanthine oxidase, phenazine methosulphate, nitrite and tert‐butyl hydroperoxide, together with thiol modification with N‐ethylmaleimide (NEM), dithiothreitol and hypochlorous acid (HOCl), in red cells permeabilised to Ca2+ using bromo‐A23187. Unexpectedly, our findings showed that the four oxidants significantly reduced Ca2+‐induced PS exposure (by 40–60%) with no appreciable effect on Ca2+ affinity. By contrast, NEM markedly increased PS exposure (by about 400%) and slightly but significantly increased the affinity for Ca2+. Dithiothreitol modestly reduced PS exposure (by 25%) and HOCl had no effect. These findings emphasise the importance of thiol modification for PS exposure in sickle cells but suggest that increased oxidant stress alone is not important.
Hydrazonylsulfones such as Bt-NHNHSO2R and their iminotautomers have been studied as optical materials and for their biological potential. In this work, a structural study has been carried out on ...N-(1,3-benzothiazol-2-yl)-4-(halogenobenzenesulfonyl)-hydrazides (1: X = F, Cl, Br). For (1: X = F), single-crystal X-ray diffraction, Hirshfeld surface analysis, and PIXEL calculations were conducted, while in (1: X = Cl) and (1: X = Br), only single-crystal X-ray diffraction studies were successfully conducted due to the disordering of the solvent. Each compound crystallises with two independent but similar amino tautomers in the asymmetric units: compound (1: X = F) crystallises in the monoclinic P21/c, and the isostructural pair (X: 1 = Cl and Br) crystallises in the tetragonal P-421c space group. In the most stable motif of the supramolecular arrangement, the molecules of the asymmetric unit are connected by classical N–H(hydrazinyl)···N(thiazoyl) hydrogen bonds and several face-to-face, offset π···π interactions. This motif has a very powerful influence on the crystal structure due to its direct links with the other weaker motifs. Other significant intermolecular interactions found in the structure include N–H(hydrazonyl)···O(sulfonate) bonds. Analogous intermolecular interactions were found in similar compounds, leading to the conclusion that those interactions are the most important instabilizing the solid state of hydrazonylsulfones.
•The determination of the crystal structures of isomeric three benzothiazolylhydrazones.•Study of the hirshfeld surfaces of three benzothiazolylhydrazones.•PIXEL calculations on three ...benzothiazolylhydrazones.•Identification of the important motifs in crystalline benzothiazolylhydrazones.•Comparison of structures with those of previously reported related compounds.
Detailed structural analyses, utilizing crystal structure determinations, Hirshfeld surface analysis and PIXEL calculations have been carried out on the three isomeric (E)-2-((pyridin-X-ylmethylidene)hydrazinyl)-benzodthiazoles: 1: 2-py (X = 2), 1: 3-py (X = 3), and 1: 4-py (X = 4). All compounds are near planar with the largest deviation from planarity experienced by the pyridin-2-yl derivative. The bond lengths in the linker units between the terminal aromatic groups indicate a degree of electionic delocalisation is occurring, which thus points to an extended π system being present for each complete molecule. Hirshfeld surface analysis and the PLATON analysis provided information on the close contacts and intermolecular interactions. Each compound has its own set of intermolecular hydrogen bonds and stacking interactions. The total stabilization energies of the crystal packing, Etot, distributed as Coulombic (Ecoul,), polarization (Epol), dispersion (Edisp) and repulsion (Erep) components, are calculated by PIXEL. The energy contributions (kJ.mol−1) for each molecule, in the order, Edisp, Ecoul, Epol and Erep, are for compound 1: 2-py -86.2, -43.8, -180.8 and 165.3 kJmol−1, for compound 1: 3-py -98.4, -50.1, -188.4, 187.8 kJ.mol−1, and for compound 1: 4-py – 88.9, -40.8, -194.9 and 164.5 kJ.mol−1 respectively. For 1: 2-py, 1: 3-py and 1: 4-py, the number of motifs (molecule pairs) indicated by PIXEL to have energies above the cut-off value of -10 kJ.mol−are six, seven and seven, respectively. While the most energetically favourable motif in each compound is formed from N—H···N hydrogen bonds, with the ECoul term being the biggest contributor to Etot., different intermolecular hydrogen bonds are involved: the hydrogen bonds in 1: 2-py and 1: 4-py, involve hydrazonyl moieties, ie. N—H(hydrazonyl)···N(hydrazonyl) with formation of R22(8) dimers, and in compound, 1: 3-py, C(7) chains are formed from N—H(hydrazonyl) ···N(pyridinyl) hydrogen bonds. The remaining motifs for all three compounds have Edisp as the biggest contributor to their stabilities. The percentage atom··· atom contacts were obtained from partial analysis of the PIXEL calculations: for both compounds 1: 2-py, 1: 3-py and 1: 4-py, the three highest percentage atom···atom contacts were H···H (ca. 37%), H···C / C···H (ca.23%) and H···N/ N···H (ca. 17)%.
Crystal structure, Hirshfeld surface analysis and PIXEL calculations of the three isomeric (E)-2-((pyridinylmethylidene)hydrazinyl)benzodthiazoles: occurrence of π interactions. Display omitted
A series of forty-seven quinoxaline derivatives, 2-(XYZC6H2CHN–NH)-quinoxalines, 1, have been synthesized and evaluated for their activity against four cancer cell lines: potent cytotoxicities were ...found (IC50 ranging from 0.316 to 15.749μM). The structure–activity relationship (SAR) analysis indicated that the number, the positions and the type of substituents attached to the aromatic ring are critical for biological activity. The activities do not depend on the electronic effects of the substituents nor on the lypophilicities of the molecules. A common feature of active compounds is an ortho-hydroxy group in the phenyl ring. A potential role of these ortho-hydroxy derivatives is as N,N,O-tridentate ligands complexing with a vital metal, such as iron, and thereby preventing proliferation of cells. The most active compound was (1: X,Y=2,3-(OH)2, Z=H), which displayed a potent cytotoxicity comparable to that of the reference drug doxorubicin.
The 2‐hydrazinyl‐1,3‐benzothiazole derivatives are precursors for synthesis of several compounds of technological interest, including the Bt−NH−N=CHR1 (R1=alkyl, aryl, heteroaryl), derivatives. ...Usually when Bt−NH−NH2 is allowed to react with a benzenesulfonyl chloride the substitution is observed in the terminal nitrogen of the arenehydrazine unit, but when 4‐iodophenyl sulfonyl chloride (4‐IC6H4SO2Cl) was used, the product isolated was the title compound as confirmed by Rx‐analysis. Determination of the crystal structure revealed that the definition of the arrangement was driven by N−H⋅⋅⋅π, C−I⋅⋅⋅π and S2−O21⋅⋅⋅π interactions instead of the classic O⋅⋅⋅H−N hydrogen bonds. The interactions were confirmed by HS analysis. Interaction energy calculations showed that the π interactions‐based motifs play an important role in the supramolecular arrangement, contributing about 60 % to the total energy of the lattice. DFT calculations showed that the energy of the C−I⋅⋅⋅π dimer is complemented with contributions of π⋅⋅⋅π stacking and N−H⋅⋅⋅π interaction between the primary amine and the thiazole aromatic ring.
The Pokagon Band of Potawatomi Indians has been a part of Chicago since its founding. In very public expressions of indigeneity, they have refused to hide in plain sight or assimilate. Instead, ...throughout the city's history, the Pokagon Potawatomi Indians have openly and aggressively expressed their refusal to be marginalized or forgotten-and in doing so, they have contributed to the fabric and history of the city.Imprints: The Pokagon Band of Potawatomi Indians and the City of Chicagoexamines the ways some Pokagon Potawatomi tribal members have maintained a distinct Native identity, their rejection of assimilation into the mainstream, and their desire for inclusion in the larger contemporary society without forfeiting their "Indianness." Mindful that contact is never a one-way street, Low also examines the ways in which experiences in Chicago have influenced the Pokagon Potawatomi.Imprintscontinues the recent scholarship on the urban Indian experience before as well as after World War II.
2-(1,3-Benzothiazol-2-yl)-4
H
-chromen-4-one and spiro1,4-benzothiazine-2,2'-chromene-3,4'(3'
H
,4
H
)-dione have been synthesized from 4-oxo-4
H
-chromene-2-carboxylic acid. The course of the ...reaction that usually occurs between the activated carboxylic acid and aromatic amines was changed upon the use of different reaction conditions (acidic or basic) and 2-aminobenzenethiol. As a result, new heterocyclic derivatives were obtained. Structures of the compounds have been established on the basis of spectral (1D and 2D NMR spectra) and X-ray data.
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