Journal articles: 'Macrocycles'

1

Abdelraheem, Eman, Shabnam Shaabani, and Alexander Dömling. "Artificial Macrocycles." Synlett 29, no. 09 (May 7, 2018): 1136–51. http://dx.doi.org/10.1055/s-0036-1591975.

Full text

Abstract:

Artificial macrocycles recently became popular as a novel research field in drug discovery. As opposed to their natural twins, artificial macrocycles promise to have better control on synthesizability and control over their physicochemical properties resulting in druglike properties. Very few synthetic methods allow for the convergent, fast but diverse access to large macrocycles chemical space. One synthetic technology to access artificial macrocycles with potential biological activity, multicomponent reactions, is reviewed here, with a focus on our own work. We believe that synthetic chemists have to acquaint themselves more with structure and activity to leverage the design aspect of their daily work.1 Introduction2 Macrocycle Properties and Receptor Binding3 Synthetic Approaches towards Artificial Macrocycles Using MCR4 Design Rules for Membrane Crossing Macrocycles5 Design Rules for Libraries of Macrocycles6 Computational Macrocyclic Methods7 Future View

APA, Harvard, Vancouver, ISO, and other styles

2

Singh, Kartikey, and Rama Pati Tripathi. "An Overview on Glyco-Macrocycles: Potential New Lead and their Future in Medicinal Chemistry." Current Medicinal Chemistry 27, no. 20 (June 7, 2020): 3386–410. http://dx.doi.org/10.2174/0929867326666190227232721.

Full text

Abstract:

Macrocycles cover a small segment of molecules with a vast range of biological activity in the chemotherapeutic world. Primarily, the natural sources derived from macrocyclic drug candidates with a wide range of biological activities are known. Further evolutions of the medicinal chemistry towards macrocycle-based chemotherapeutics involve the functionalization of the natural product by hemisynthesis. More recently, macrocycles based on carbohydrates have evolved a considerable interest among the medicinal chemists worldwide. Carbohydrates provide an ideal scaffold to generate chiral macrocycles with well-defined pharmacophores in a decorated fashion to achieve the desired biological activity. We have given an overview on carbohydrate-derived macrocycle involving their synthesis in drug design and discovery and potential role in medicinal chemistry.

APA, Harvard, Vancouver, ISO, and other styles

3

Zhong, Chunxiao, Yong Yan, Qian Peng, Zheng Zhang, Tao Wang, Xin Chen, Jiacheng Wang, Ying Wei, Tonglin Yang, and Linghai Xie. "Structure–Property Relationship of Macrocycles in Organic Photoelectric Devices: A Comprehensive Review." Nanomaterials 13, no. 11 (May 27, 2023): 1750. http://dx.doi.org/10.3390/nano13111750.

Full text

Abstract:

Macrocycles have attracted significant attention from academia due to their various applications in organic field-effect transistors, organic light-emitting diodes, organic photovoltaics, and dye-sensitized solar cells. Despite the existence of reports on the application of macrocycles in organic optoelectronic devices, these reports are mainly limited to analyzing the structure–property relationship of a particular type of macrocyclic structure, and a systematic discussion on the structure–property is still lacking. Herein, we conducted a comprehensive analysis of a series of macrocycle structures to identify the key factors that affect the structure–property relationship between macrocycles and their optoelectronic device properties, including energy level structure, structural stability, film-forming property, skeleton rigidity, inherent pore structure, spatial hindrance, exclusion of perturbing end-effects, macrocycle size-dependent effects, and fullerene-like charge transport characteristics. These macrocycles exhibit thin-film and single-crystal hole mobility up to 10 and 26.8 cm2 V−1 s−1, respectively, as well as a unique macrocyclization-induced emission enhancement property. A clear understanding of the structure–property relationship between macrocycles and optoelectronic device performance, as well as the creation of novel macrocycle structures such as organic nanogridarenes, may pave the way for high-performance organic optoelectronic devices.

APA, Harvard, Vancouver, ISO, and other styles

4

Fan, Linmeng, Min Du, Lichun Kong, Yan Cai, and Xiaobo Hu. "Recognition Site Modifiable Macrocycle: Synthesis, Functional Group Variation and Structural Inspection." Molecules 28, no. 3 (January 31, 2023): 1338. http://dx.doi.org/10.3390/molecules28031338.

Full text

Abstract:

Traditional macrocyclic molecules encode recognition sites in their structural backbones, which limits the variation of the recognition sites and thus, would restrict the adjustment of recognition properties. Here, we report a new oligoamide-based macrocycle capable of varying the recognition functional groups by post-synthesis modification on its structural backbone. Through six steps of common reactions, the parent macrocycle (9) can be produced in gram scale with an overall yield of 31%. The post-synthesis modification of 9 to vary the recognition sites are demonstrated by producing four different macrocycles (10–13) with distinct functional groups, 2-methoxyethoxyl (10), hydroxyl (11), carboxyl (12) and amide (13), respectively. The 1H NMR study suggests that the structure of these macrocycles is consistent with our design, i.e., forming hydrogen bonding network at both rims of the macrocyclic backbone. The 1H-1H NOESY NMR study indicates the recognition functional groups are located inside the cavity of macrocycles. At last, a preliminary molecular recognition study shows 10 can recognize n-octyl-β-D-glucopyranoside (14) in chloroform.

APA, Harvard, Vancouver, ISO, and other styles

5

Guo, Hao, Yu-Fei Ao, De-Xian Wang, and Qi-Qiang Wang. "Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions." Beilstein Journal of Organic Chemistry 18 (May 2, 2022): 486–96. http://dx.doi.org/10.3762/bjoc.18.51.

Full text

Abstract:

A series of tetraamino-bisthiourea chiral macrocycles containing two diarylthiourea and two chiral diamine units were synthesized by a fragment-coupling approach in high yields. Different chiral diamine units, including cyclohexanediamines and diphenylethanediamines were readily incorporated by both homo and hetero [1 + 1] macrocyclic condensation of bisamine and bisisothiocyanate fragments. With the easy synthesis, gram-scale of macrocycle products can be readily obtained. These chiral macrocycles were applied in catalyzing bioinspired decarboxylative Mannich reactions. Only 5 mol % of the optimal macrocycle catalyst efficiently catalyzed the decarboxylative addition of a broad scope of malonic acid half thioesters to isatin-derived ketimines with excellent yields and good enantioselectivity. The rigid macrocyclic framework and the cooperation between the thiourea and tertiary amine sites were found to be crucial for achieving efficient activation and stereocontrol. As shown in control experiments, catalysis with the acyclic analogues having the same structural motifs were non-selective.

APA, Harvard, Vancouver, ISO, and other styles

6

Sun, Dianqing. "Recent Advances in Macrocyclic Drugs and Microwave-Assisted and/or Solid-Supported Synthesis of Macrocycles." Molecules 27, no. 3 (February 2, 2022): 1012. http://dx.doi.org/10.3390/molecules27031012.

Full text

Abstract:

Macrocycles represent attractive candidates in organic synthesis and drug discovery. Since 2014, nineteen macrocyclic drugs, including three radiopharmaceuticals, have been approved by FDA for the treatment of bacterial and viral infections, cancer, obesity, immunosuppression, etc. As such, new synthetic methodologies and high throughput chemistry (e.g., microwave-assisted and/or solid-phase synthesis) to access various macrocycle entities have attracted great interest in this chemical space. This article serves as an update on our previous review related to macrocyclic drugs and new synthetic strategies toward macrocycles (Molecules, 2013, 18, 6230). In this work, I first reviewed recent FDA-approved macrocyclic drugs since 2014, followed by new advances in macrocycle synthesis using high throughput chemistry, including microwave-assisted and/or solid-supported macrocyclization strategies. Examples and highlights of macrocyclization include macrolactonization and macrolactamization, transition-metal catalyzed olefin ring-closure metathesis, intramolecular C–C and C–heteroatom cross-coupling, copper- or ruthenium-catalyzed azide–alkyne cycloaddition, intramolecular SNAr or SN2 nucleophilic substitution, condensation reaction, and multi-component reaction-mediated macrocyclization, and covering the literature since 2010.

APA, Harvard, Vancouver, ISO, and other styles

7

Li, Yu, Wei Zhao, and Biao Wu. "Tetraurea Macrocycles: Template-Directed One-Pot Synthesis and Anion Binding Properties." Advances in Engineering Technology Research 6, no. 1 (June 19, 2023): 228. http://dx.doi.org/10.56028/aetr.6.1.228.2023.

Full text

Abstract:

Given the significance of anion in life, study of anion recognition attracted great attentions in the past decades. Macrocyclic receptors display intriguing anion binding properties; however, the synthesis of macrocycles is challenging. Here, we reported a new strategy of making tetraurea in one-step. By using 1-butyl-3-methylimidazolium ([hmim][X], X = anion) as the solvent and template reagent, tetraurea macrocycle comprised of bis(urea) binding moiety and hexyl chain spacers is selectively formed with high yield. The obtained macrocycles displayed interesting anion binding properties as indicated by single crystal X-ray diffraction structures and computational modelling.

APA, Harvard, Vancouver, ISO, and other styles

8

Chia, PSK, A. Ekstrom, I. Liepa, LF Lindoy, M. Mcpartlin, SV Smith, and PA Tasker. "New Macrocyclic Ligands. II. Pendant Hydroxyethyl, Cyanoethyl and Carbamoylethyl Arm Systems Derived From O2N2-Donor Rings: the X-Ray Structure of a Pendant Hydroxyethyl Derivative." Australian Journal of Chemistry 44, no. 5 (1991): 737. http://dx.doi.org/10.1071/ch9910737.

Full text

Abstract:

The syntheses and characterization of 12 new 14- to 17-membered macrocycles incorporating pendant hydroxyethyl cyanoethyl or carbamoylethyl groups are reported. The macrocyclic ring in each of these new ligands contains an O2N2-donor set. The X-ray structure of the di(hydroxyethyl) derivative of the 14-membered macrocycle is described.

APA, Harvard, Vancouver, ISO, and other styles

9

Boyd, Simon, Nuno M. Cabral, Kenneth P. Ghiggino, Martin J. Grannas, W. David McFadyen, and Peter A. Tregloan. "Nickel complexation and photophysics of alkylanthracenyl dioxocyclam macrocycle derivatives." Australian Journal of Chemistry 53, no. 8 (2000): 651. http://dx.doi.org/10.1071/ch00106.

Full text

Abstract:

Ligands H2L in which (10-R-anthracen-9-yl)methyl moieties (R = H, Me, Et) are covalently joined (6-position) to the 5,7-dioxocyclam macrocycle framework have been prepared and their nickel(II) complexes isolated and characterized. X-Ray crystal structures of NiIIL (R = H, Me) complexes show that in both structures the anthracene moieties are folded around towards the mean plane of the macrocycles; dihedral angles between the mean anthracene and macrocyclic planes of c. 22˚ are subtended. 1H n.m.r. spectrometry indicates that the folded conformations are retained in solution. Absorption and fluorescence spectra, fluorescence quantum yields and lifetimes of the anthracenyl macrocycles are reported. Absorption spectra of the metal complexes are red-shifted and the fluorescence is dramatically quenched compared to the metal-free compounds indicating a strong electronic interaction between the anthracene and the complexed dioxocyclam macrocycle.

APA, Harvard, Vancouver, ISO, and other styles

10

Hosseinzadeh, Parisa, Gaurav Bhardwaj, Vikram Khipple Mulligan, Matthew D. Shortridge, Timothy W. Craven, Fátima Pardo-Avila, Stephen A. Rettie, et al. "Comprehensive computational design of ordered peptide macrocycles." Science 358, no. 6369 (December 14, 2017): 1461–66. http://dx.doi.org/10.1126/science.aap7577.

Full text

Abstract:

Mixed-chirality peptide macrocycles such as cyclosporine are among the most potent therapeutics identified to date, but there is currently no way to systematically search the structural space spanned by such compounds. Natural proteins do not provide a useful guide: Peptide macrocycles lack regular secondary structures and hydrophobic cores, and can contain local structures not accessible with l-amino acids. Here, we enumerate the stable structures that can be adopted by macrocyclic peptides composed of l- and d-amino acids by near-exhaustive backbone sampling followed by sequence design and energy landscape calculations. We identify more than 200 designs predicted to fold into single stable structures, many times more than the number of currently available unbound peptide macrocycle structures. Nuclear magnetic resonance structures of 9 of 12 designed 7- to 10-residue macrocycles, and three 11- to 14-residue bicyclic designs, are close to the computational models. Our results provide a nearly complete coverage of the rich space of structures possible for short peptide macrocycles and vastly increase the available starting scaffolds for both rational drug design and library selection methods.

APA, Harvard, Vancouver, ISO, and other styles

11

Fainerman-Melnikova, Marina, Leonard F. Lindoy, Show-Yee Liou, John C. McMurtrie, Noel P. Green, Azizollah Nezhadali, Gholamhossin Rounaghi, and William N. Setzer. "Metal-Ion Recognition—Selective Bulk Membrane Transport of Silver(I) Using Thioether Donor Macrocycles as Ionophores, and X-Ray Structure of the Silver Complex of an S4-Donor Ring." Australian Journal of Chemistry 57, no. 2 (2004): 161. http://dx.doi.org/10.1071/ch03239.

Full text

Abstract:

Competitive metal-ion transport experiments, each involving transport from an aqueous source phase containing equimolar concentrations of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), silver(i), and lead(II) across a chloroform membrane phase to an aqueous receiving phase have been carried out. The membrane phase incorporated an ionophore chosen from a series of thioether-containing macrocycles. For those systems that displayed transport behaviour, sole selectivity for silver(I) was observed under the conditions employed. The effect of variation in the macrocyclic sulfur atom donor set and the presence of hydrophilic ring substituents on transport efficiency is presented. An X-ray structure of the 1 : 1 silver(I) nitrate complex of a 16-membered, S4-donor macrocycle shows the presence of four crystallographically independent macrocycles displaying conformational isomerism. Each silver(I) has an approximate tetrahedral geometry, being bound to three sulfur atoms from three different macrocycles and to one nitrato ligand to yield a three-dimensional network.

APA, Harvard, Vancouver, ISO, and other styles

12

Roberge, Jacques Y., Pierre Giguere, Pierre Soucy, Yves L. Dory, and Pierre Deslongchamps. "First transannular Diels–Alder reactions involving tetrasubstituted non-activated dienophiles." Canadian Journal of Chemistry 72, no. 8 (August 1, 1994): 1820–29. http://dx.doi.org/10.1139/v94-231.

Full text

Abstract:

Transannular Diels–Alder reactions of four 14-membered macrocyclic trienes (27, 28, 43, and 44) possessing a dimethyl tetrasubstituted dienophile have been investigated. Macrocycles having a cis-trans-cis (CTC) (27), a CTT (43), and a TTT (44) geometry produced the predicted trans-syn-cis (TSC) (45), cis-anti-cis (CAC) (48), and TAC (49) tricycles, respectively. The TTC macrocycle (28) gave exclusively the TST tricycle (46), no CSC tricycle (47) being observed. TTT macrocycle (44) underwent macrocyclization at a lower temperature than the TTC isomer (28).

APA, Harvard, Vancouver, ISO, and other styles

13

Nezhadali, A., and M. Akbarpour. "Selective Transport of Silver(I) Ion Through Polymer Membranes Containing Thioether Donor Macrocycles as Carriers." E-Journal of Chemistry 5, no. 2 (2008): 271–74. http://dx.doi.org/10.1155/2008/295413.

Full text

Abstract:

The Preparation of polymer membrane and it's selectivity to silver(I) ion from an aqueous solution containing seven metal cations, Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II) and Pb(II), was studied. The source phase contained equimolar concentrations of the above mentioned cations with the source and receiving phases being buffered at pH 5.0 and 3.0 respectively. The effect of variation in the number of the macrocyclic sulfur atom donor set anssd the size of ring 9 and 16 member macrocycles on transport efficiency is presented. Silver(I) ion transport occurred (at 25°C) from the aqueous source phase across the polymer membrane (derived from cellulos triacetate) containing ligands 9-membered, S3-donor and16-membered S4-donor macrocycles as the ionophors in separate experiments into the aqueous receiving phase. Clear transport selectivity for silver(I) ion was observed using both thioether donor macrocycles. The efficiency of transport rate for silver(I) ion with using 9-membered S3-donor macrocycle as carrier was better than 16-membered S4-donor .

APA, Harvard, Vancouver, ISO, and other styles

14

Boden, Britta N., Amir Abdolmaleki, Cecily T. Z. Ma, and Mark J. MacLachlan. "New diformyldihydroxyaromatic precursors for luminescent Schiff base macrocycles: Synthesis, characterization, and condensation studies." Canadian Journal of Chemistry 86, no. 1 (January 1, 2008): 50–64. http://dx.doi.org/10.1139/v07-136.

Full text

Abstract:

With the goal of preparing luminescent, fully conjugated Schiff base macrocycles, a series of precursors based on benzene, phenanthrene, and triphenylene with formylhydroxy functionalization have been prepared and characterized. The condensation of these compounds with substituted phenylenediamines to afford conjugated [2+2] or [3+3] Schiff base macrocycle has been investigated. Although the [3+3] Schiff base macrocycles could not be isolated, two new soluble and luminescent [2+2] Schiff base macrocycles with N2O2 binding pockets have been prepared and characterized.Key words: Schiff base, macrocycle, condensation, salicylaldehyde, conjugated.

APA, Harvard, Vancouver, ISO, and other styles

15

Duckworth, PA, LF Lindoy, M. Mcpartlin, and PA Tasker. "New Macrocyclic Ligands. IV. Dibenzo-Substituted Rings Incorporating Five Donor Atoms. X-Ray Structures of an N4O-Donor Macrocycle, Its Protonated Form, and Its Complex With Barium Perchlorate." Australian Journal of Chemistry 46, no. 11 (1993): 1787. http://dx.doi.org/10.1071/ch9931787.

Full text

Abstract:

The syntheses and characterization of four dibenzo-substituted macrocycles incorporating N5-, N4O-or N4S-donor sets are reported. The new systems extend the range of related (potentially pentadentate ) macrocyclic systems of this general structure reported previously. For the 17-membered macrocycle incorporating an N4O-donor set, X-ray structure determinations of the free ligand and its salt of type [LH]ClO4 confirm the structure of this compound predicted from physical measurements. The diperchloratobarium complex of this macrocycle is shown to have the barium nine-coordinate; the coordination sphere is composed of the N4O-donors of the macrocycle and four oxygen atoms derived from a monodentate as well as a bidentate perchlorate group and an ethanol molecule.

APA, Harvard, Vancouver, ISO, and other styles

16

Mishra, Purti, Pooja Sethi, and Anjana Kumari. "Emerging applications and host- guest chemistry of synthetic macrocycles." Research Journal of Chemistry and Environment 26, no. 7 (June 25, 2022): 153–57. http://dx.doi.org/10.25303/2607rjce153167.

Full text

Abstract:

Synthetic macrocycles offer variety of biologically significant properties e.g. antibacterial, antifungal, anti-fertility, anticancerous, anti-inflammatory, anti-diabetic, anti-malarial, antiviral and antioxidant. DNA binding and cleaving agents are thoroughly used in area of medicinal chemistry. Host-guest chemistry is the one of most fascinating parts of macrocycles. Literature suggests various macrocycles with the potential therapeutic properties. Magnetic resonance imagining (MRI) contrast agent, dopamine detection, photochemical properties as sensor and catalytic activities of macrocycle are most attracting and growing fields of naturally mimic synthetic macrocycles. In recent years, interest has aroused on Schiff based macrocycles and synthetic strategies were employed to develop novel macrocycles with engrossed properties and applications.

APA, Harvard, Vancouver, ISO, and other styles

17

Yampolska, H., S. Kharchenko, A. Kozytskyi, A. Kyrylchuk, Z. Voitenko, and O. Grygorenko. "SYNTHESIS OF A 1,2,3-TRIAZOLE-CONTAINING MACROCYCLE BASED ON THE "CLICK CHEMISTRY" REACTION AND ANALYSIS OF ITS PLANAR CHIRALITY USING NMR AND DFT CALCULATIONS." Bulletin of Taras Shevchenko National University of Kyiv. Chemistry, no. 1 (57) (2020): 55–61. http://dx.doi.org/10.17721/1728-2209.2020.1(57).14.

Full text

Abstract:

Macrocycles represent previously unexplored promising drug candidates, that can be useful for treating protein-protein interactions. Atropoisomerism is an inherent feature of the natural macrocyclic peptides that is significant for their activity and selectivity, and, therefore, should be introduced into newly synthesized macrocycles. Synthesis of the libraries of artificial macrocycles faces many challenges due to their structure and size. Herein we report on the preparation of a 16-membered macrocycle containing 1,2,3-triazole ring, spiro-piperidine, and phenyl moieties, as well as a chiral carbon atom. Our approach to the macrocycle was inspired by the "build/couple/pair" (B/C/P) strategy, a part of diversity-oriented synthesis methodology. We have employed readily accessible starting materials and robust synthetic procedures which allowed us to obtain the target macrocycle in a high yield. Standard methods of amide bond formation were used for the coupling of macrocycle building blocks. Click chemistry azide-alkyne cycloaddition was exploited at the final ring closure step. The assignment of signals in 1H and 13C NMR spectra of the macrocycle was performed using a series of 2D NMR techniques. The macrocycle displayed planar chirality, which, in a combination with a stereocenter with the known configuration, was sufficient to propose possible structures of diastereomers. The diastereomers could differ by the relative position of triazole ring. Their racemization could occur through a "rope skipping" motion involving the cyclic chain crossing the plane of 1,2,3-triazole ring. The supposed structures of diastereomers were corroborated by means of a various NMR spectroscopy techniques and DFT calculations. Analysis of the amide NH chemical shift temperature coefficients coupled with the data on optimized geometries obtained by DFT convincingly demonstrated that the intramolecular hydrogen bonds play a major role in stabilization of the diastereomer structures. According to the variable temperature NMR experiment, the interconversion of two diastereomers did not occur even at heating up to 70 °C.

APA, Harvard, Vancouver, ISO, and other styles

18

Liang, Yan, Ru Fang, and Qiu Rao. "An Insight into the Medicinal Chemistry Perspective of Macrocyclic Derivatives with Antitumor Activity: A Systematic Review." Molecules 27, no. 9 (April 29, 2022): 2837. http://dx.doi.org/10.3390/molecules27092837.

Full text

Abstract:

The profound pharmacological properties of macrocyclic compounds have led to their development as drugs. In conformationally pre-organized ring structures, the multiple functions and stereochemical complexity provided by the macrocycle result in high affinity and selectivity of protein targets while maintaining sufficient bioavailability to reach intracellular locations. Therefore, the construction of macrocycles is an ideal choice to solve the problem of “undruggable” targets. Inspection of 68 macrocyclic drugs on the market showed that 10 of them were used to treat cancer, but this structural class still has been poorly explored within drug discovery. This perspective considers the macrocyclic compounds used for anti-tumor with different targets, their advantages and disadvantages, and the various synthetic methods of them.

APA, Harvard, Vancouver, ISO, and other styles

19

Zuo, Minzan, Krishnasamy Velmurugan, Kaiya Wang, Xueqi Tian, and Xiao-Yu Hu. "Insight into functionalized-macrocycles-guided supramolecular photocatalysis." Beilstein Journal of Organic Chemistry 17 (January 18, 2021): 139–55. http://dx.doi.org/10.3762/bjoc.17.15.

Full text

Abstract:

Due to the unique characteristics of macrocycles (e.g., the ease of modification, hydrophobic cavities, and specific guest recognition), they can provide a suitable environment to realize photocatalysis via noncovalent interactions with different substrates. In this minireview, we emphasized the photochemical transformation and catalytic reactivity of different guests based on the binding with various macrocyclic hosts as well as on the role of macrocyclic-hosts-assisted hybrid materials in energy transfer. To keep the clarity of this review, the macrocycles are categorized into the most commonly used supramolecular hosts, including crown ethers, cyclodextrins, cucurbiturils, calixarenes, and pillararenes. This minireview not only summarizes the role that macrocycles play in photocatalytic reactions but also clarifies the photocatalytic mechanisms. Finally, the future research efforts and new pathways to apply macrocycles and supramolecular hybrid materials in photocatalysis are also discussed.

APA, Harvard, Vancouver, ISO, and other styles

20

Merner, Bradley, Nirmal Mitra, and Caroline Merryman. "Highly Strained para-Phenylene-Bridged Macrocycles from Unstrained 1,4-Diketo Macrocycles." Synlett 28, no. 17 (August 22, 2017): 2205–11. http://dx.doi.org/10.1055/s-0036-1589081.

Full text

Abstract:

The conversion of macrocyclic 1,4-diketones to highly strained para-phenylene rings has recently been reported by our laboratory. This synthetic strategy represents a non-cross-coupling-based approach to arene-bridged macrocycles, and an alternative to palladium- and nickel-mediated processes. In this Synpacts article we discuss the development of endgame aromatization protocols for the synthesis of increasingly strained arene systems, as well as potential advantages of the macrocyclic 1,4-diketone approach to selectively functionalized benzenoid macrocycles for future complexity building reactions.1 Introduction2 A Non-Cross-Coupling-Based Approach to Arene-Bridged Macro cycles3 Macrocyclic 1,4-Diketones: Streamlined Synthesis and Size-Dependent Diastereoselective Grignard Reactions4 Dehydrative Aromatization Reactions: A Powerful Tool for Synthesizing Highly Strained para-Phenylene Units5 Conclusion

APA, Harvard, Vancouver, ISO, and other styles

21

Kallert, Uwe, and Rainer Mattes. "Komplexe 17-gliedriger Dibenzo-Makrocyclen mit N3O2- bzw. N3S2-Donorzentren Strukturen von [Zn(′N3O2′)Cl]2ZnCl4 und [Hg(′N3S2′)Br2] / Complexes of 17-Membered Dibenzo Macrocycles with N3O2 or N3S2 Donor Sets Crystal and Molecular Structures of [Zn(′N3O2′)Cl]2ZnCl4 and [Hg(′N3S2′)Br2]." Zeitschrift für Naturforschung B 47, no. 9 (September 1, 1992): 1271–75. http://dx.doi.org/10.1515/znb-1992-0910.

Full text

Abstract:

The macrocyclic complexes [Zn(′N3O2')Cl]2ZnCl4 (1) und [Hg(′N3S2')Br2] (2) have been prepared and their crystal structures determined. Zn(II) is incorporated into the macrocyclic cavity of the ′N3O2′ ligand and primarly coordinated to the three nitrogen donors of the macrocycle and to a chloride ion. Weaker interactions occur with the oxygen donors of the macrocycle. The Zn—O distances are 296,4(5) and 322,4(6) pm. In complex 2 Hg(II) lies outside the macrocyclic cavity. The donor set comprises two secondary amine nitrogen atoms and a thioether sulfur atom of the macrocycle, and two bromide anions. The coordination polyhedron can be described as a trigonal bipyramid. The conformational behaviour of the ′N3O2′ and the ′N3S2′ ligands within these and other complexes is discussed. ′N3O2′ and ′N3S2′ are 17-membered dibenzo macrocycles. Crystal data for [Zn(′N3O2')Cl]2ZnCl4 (1): monoclinic, space group C2/c, a = 2864(4), b = 951.0(2), c = 1986(4) pm, β = 118.5(1)°, Z = 4, 2499 reflections, R = 0.0581; [Hg(′N3S2′)Br2] (2): monoclinic, space group P21/c, a = 887.0(2), b = 1307.6(3), c = 2002.3(4) pm, β = 94.13(3)°, Z = 4,3123 reflections, R = 0.072.

APA, Harvard, Vancouver, ISO, and other styles

22

Nasri, Fariborz. "A Review of the Thermodynamics of Complexation of Crown Ethers With Metal Ion." Journal of Advances in Environmental Health Research 10, no. 4 (October 1, 2022): 263–72. http://dx.doi.org/10.32598/jaehr.10.4.1218.

Full text

Abstract:

Recently, macrocyclic and supramolecular chemistry has reached a hopeful area of research in the mutual interaction between chemistry, physics and biology. Charles J. Pedersen, at du Pont figure out a compound in the early 1960s famous for dibenzo-18-crown-6 (DB18C6) later on. The detection of the complex formation in solution, the designation of the stability of the consequence complex or complexes and the determination of the thermodynamic or the kinetic parameters of the complex formation can be attained by a manifold of physicochemical measurements. Conformational rigidity or flexibility of macrocycles has a considerable penetration on their selective behavior. The number, type, and arrangement of donor atoms in the macrocyclic rings play a main role in macrocycle selectivity. Based on chemistry terminology, this is known as “host-guest” chemistry where the ether plays the role as the host and the ionic species as the guest. In organic solutions, crown ethers take the role of phase-transfer catalysts and agents in order to enhance the solubility of inorganic salts. Macrocycles need to compete with solvent molecules for the cations during the process of complexation. Consequently, variation of the solvent makes a considerable change in the manifest binding characteristics of these ligands.

APA, Harvard, Vancouver, ISO, and other styles

23

Gagnon, Christina, Éric Godin, Clémentine Minozzi, Johann Sosoe, Corentin Pochet, and Shawn K. Collins. "Biocatalytic synthesis of planar chiral macrocycles." Science 367, no. 6480 (February 20, 2020): 917–21. http://dx.doi.org/10.1126/science.aaz7381.

Full text

Abstract:

Macrocycles can restrict the rotation of substituents through steric repulsions, locking in conformations that provide or enhance the activities of pharmaceuticals, agrochemicals, aroma chemicals, and materials. In many cases, the arrangement of substituents in the macrocycle imparts an element of planar chirality. The difficulty in predicting when planar chirality will arise, as well as the limited number of synthetic methods to impart selectivity, have led to planar chirality being regarded as an irritant. We report a strategy for enantio- and atroposelective biocatalytic synthesis of planar chiral macrocycles. The macrocycles can be formed with high enantioselectivity from simple building blocks and are decorated with functionality that allows one to further modify the macrocycles with diverse structural features.

APA, Harvard, Vancouver, ISO, and other styles

24

Srungavruksham, Nagarjuna Kumar, and Viswanathan Baskar. "Te4Se2O6 macrocycle stabilizing triangular planar and tetrahedral anions." Dalton Transactions 44, no. 10 (2015): 4554–59. http://dx.doi.org/10.1039/c4dt03911d.

Full text

Abstract:

The anion exchange reactions of Cl-macrocycle 1a with anions of varying geometry (NO₃⁻ trigonal planar, ClO₄⁻ and BF₄⁻ tetrahedral) have been investigated to yield macrocycles 2–4. Solid state molecular structures of these macrocycles are also retained in solution.

APA, Harvard, Vancouver, ISO, and other styles

25

Matsumoto, Toshihiko. "Simple One–Pot Synthesis of Hexakis(2-alkoxy-1,5-phenyleneimine) Macrocycles by Precipitation–Driven Cyclization." Macromol 4, no. 1 (January 3, 2024): 1–22. http://dx.doi.org/10.3390/macromol4010001.

Full text

Abstract:

Hexakis(2-alkoxy-1,5-phenyleneimine) macrocycles were synthesized using a simple one-pot procedure through precipitation-driven cyclization. The acetal-protected AB–type monomers, 2-alkoxy-5-aminobenzaldehyde diethyl acetals, underwent polycondensation in water or acid-containing tetrahydrofuran. The precipitation–driven cyclization, based on imine dynamic covalent chemistry and π–stacked columnar aggregation, played a decisive role in the one–pot synthesis. The progress of the reaction was analyzed using MALDI–TOF mass spectrometry. The macrocycles with alkoxy chains were soluble in specific organic solvents, such as chloroform, allowing their structures to be analyzed using NMR. The shape-anisotropic, nearly planar, and shape-persistent macrocycles aggregated into columnar assemblies in polymerization solvents, driven by aromatic π-stacking. The octyloxylated macrocycle OcO–Cm6 exhibited an enantiotropic columnar liquid crystal-like mesophase between 165 °C and 197 °C. In the SEM image of (S)-(–)-3,7-dimethyloctyloxylated macrocycle (–)BCO–Cm6, columnar substances with a diameter of 200–300 nm were observed. The polymerization solution for the 2-(2-methoxyethoxy)ethoxy)ethoxylated macrocycle (TEGO–Cm6) gelled, and showed thixotropic properties by forming a hydrogen bond network.

APA, Harvard, Vancouver, ISO, and other styles

26

Liu, Na, Xing Wang, Hui Cao, Chun Hai Chen, and Wan Jin Zhang. "Synthesis of a Novel Hollow Sphere Having Rigid Binaphthyl Macrocycle as Shell." Solid State Phenomena 121-123 (March 2007): 219–22. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.219.

Full text

Abstract:

A novel hollow sphere having rigid binaphthyl macrocycle as shell was prepared by means of sacrifice the silica core. The synthesis of hollow sphere from rigid colloidal silica particles occurs in three steps: a) modification of silica particles with vinyltriethoxysilane as coupling agent, b) immersion in the solution of monomer having rigid binaphthyl macrocycle and polymerization, and c) removal of silica particles. These macrocycles contained in the shell of hollow spheres belong to an important class of host-guest macrocyclic material in which the rigid backbone and C2 symmetry of the binaphthyl unit play an important role in complexing guest molecules. This will endow hollow sphere with new opportunities in molecular recognition and separation.The morphology of colloidal silica particles and hollow spheres was characterized by SEM and TEM.

APA, Harvard, Vancouver, ISO, and other styles

27

Helweh, Waleed, Nathan C. Flanders, Shiwei Wang, Brian T. Phelan, Pyosang Kim, Michael J. Strauss, Rebecca L. Li, et al. "Layered structures of assembled imine-linked macrocycles and two-dimensional covalent organic frameworks give rise to prolonged exciton lifetimes." Journal of Materials Chemistry C 10, no. 8 (2022): 3015–26. http://dx.doi.org/10.1039/d1tc05840a.

Full text

Abstract:

Excitonic dynamics studies of a 2D COF, its corresponding hexagonal macrocycle, and extended nanotubes comprised of stacked macrocycles reveal that layering of the macrocycle in the assembled COF and nanotube lead to a prolonged exciton lifetime.

APA, Harvard, Vancouver, ISO, and other styles

28

Dempsey, Janel M., Qi-Wei Zhang, Allen G. Oliver, and Bradley D. Smith. "New tetralactam hosts for squaraine dyes." Organic & Biomolecular Chemistry 16, no. 46 (2018): 8976–83. http://dx.doi.org/10.1039/c8ob02596g.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Li, Zheng, and Ying-Wei Yang. "Conjugated macrocycle polymers." Polymer Chemistry 12, no. 32 (2021): 4613–20. http://dx.doi.org/10.1039/d1py00759a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Sessler, Jonathan L., Won-Seob Cho, Stephen P. Dudek, Lindsay Hicks, Vincent M. Lynch, and Michael T. Huggins. "Synthesis and study of a calixpyrrole-texaphyrin chimera: A new oligopyrrolic chloride anion receptor." Journal of Porphyrins and Phthalocyanines 07, no. 02 (February 2003): 97–104. http://dx.doi.org/10.1142/s1088424603000136.

Full text

Abstract:

Reported here is the synthesis and characterization of a new class of macrocycle that represents a hybrid between texaphyrin and calixpyrrole. These polypyrrolic macrocycles were prepared in one step by the acid-catalyzed condensation between diformyl dipyrromethanes and o-phenylenediamines in high yields. The X-ray crystal structure of one of these new “chimeras” was solved. It reveals that the diprotonated Schiff-base macrocycle has a V-shape in which one chloride anion is bound. Isothermal titration calorimetry (ITC) studies served to confirm the ability of the hybrid macrocycles to bind chloride anion in acetonitrile solution. These compounds may be useful as easy-to-make anion receptors.

APA, Harvard, Vancouver, ISO, and other styles

31

Salveson, Patrick J., Adam P. Moyer, Meerit Y. Said, Gizem Gӧkçe, Xinting Li, Alex Kang, Hannah Nguyen, et al. "Expansive discovery of chemically diverse structured macrocyclic oligoamides." Science 384, no. 6694 (April 26, 2024): 420–28. http://dx.doi.org/10.1126/science.adk1687.

Full text

Abstract:

Small macrocycles with four or fewer amino acids are among the most potent natural products known, but there is currently no way to systematically generate such compounds. We describe a computational method for identifying ordered macrocycles composed of alpha, beta, gamma, and 17 other amino acid backbone chemistries, which we used to predict 14.9 million closed cycles composed of >42,000 monomer combinations. We chemically synthesized 18 macrocycles predicted to adopt single low-energy states and determined their x-ray or nuclear magnetic resonance structures; 15 of these were very close to the design models. We illustrate the therapeutic potential of these macrocycle designs by developing selective inhibitors of three protein targets of current interest. By opening up a vast space of readily synthesizable drug-like macrocycles, our results should considerably enhance structure-based drug design.

APA, Harvard, Vancouver, ISO, and other styles

32

Fairlie, David P., Giovanni Abbenante, and Darren R. March. "Macrocyclic Peptidomimetics Forcing Peptides into Bioactive Conformations." Current Medicinal Chemistry 2, no. 2 (August 1995): 654–86. http://dx.doi.org/10.2174/0929867302666220218001506.

Full text

Abstract:

Abstract: Cyclic peptides that are potent regulators of biological processes are rapidly emerging as important mechanistic probes and drug leads. Nature clearly uses macrocycles to. constrain peptides into conformations that can selectively bind proteins or. small molecules. Therapeutic effects of such macrocycles, often containing additional conformational constraints that fine tune structure (e.g. D-amino acids, N-methyl substituents, aromatic rings, to name a few), have so far been mainly discovered by accident. However it is now becoming possible to rationally design synthetic macrocycles to selectively recognize and inhibit a specific protein. A receptor-binding struc ture is more easily adopted by macrocyclic peptidomimetics than more flexible acyclic peptides because the former have less conformational entropy. Macrocycles are often stable to hydrolysis by peptidases that degrade acyclic peptides and hydrophobic side chains can protect peptide bonds in macrocycles from hydrolysis, as well as enhance lipophilicity, cell permeability and bioavailability. Synthetic efforts to obtain bioactive conformations of short peptides have so far been substrate-based, guided by molecular modelling predictions and structure-activity data for modified amino acid sequences of substrates. However, dramatic advances in molecular biology, X-ray crystallography, NMR spectroscopy and computing are rapidly producing three dimensional structures of proteins, promising direct observation of protein-bound conformations of small molecules and receptor-based design of peptidomimetics with surface complementarity for proteins. This perspective review highlights examples of both natural and synthetic bioactive macrocyclic peptides containing constraints that fix conformation, and briefly illustrates the promise that receptor-based design holds for structural and functional mimicry of peptides by macrocycles.

APA, Harvard, Vancouver, ISO, and other styles

33

Jie, Kecheng, Yujuan Zhou, Yong Yao, and Feihe Huang. "Macrocyclic amphiphiles." Chemical Society Reviews 44, no. 11 (2015): 3568–87. http://dx.doi.org/10.1039/c4cs00390j.

Full text

Abstract:

This review describes recent results in the investigation of macrocyclic amphiphiles, which are classified based on different macrocyclic frameworks including cyclodextrins, calixarenes, cucurbiturils, pillararenes, and other macrocycles involved.

APA, Harvard, Vancouver, ISO, and other styles

34

Olsson, Sandra, Óscar Benito Pérez, Magnus Blom, and Adolf Gogoll. "Effect of ring rize on photoisomerization properties of stiff stilbene macrocycles." Beilstein Journal of Organic Chemistry 15 (October 11, 2019): 2408–18. http://dx.doi.org/10.3762/bjoc.15.233.

Full text

Abstract:

A series of stiff stilbene macrocycles have been studied to investigate the possible impact of the macrocycle ring size on their photodynamic properties. The results show that reducing the ring size counteracts the photoisomerization ability of the macrocycles. However, even the smallest macrocycle studied (stiff stilbene subunits linked by a six carbon chain) showed some degree of isomerization when irradiated. DFT calculations of the energy differences between the E- and Z-isomers show the same trend as the experimental results. Interestingly the DFT study highlights that the energy difference between the E- and Z-isomers of even the largest macrocycle (linked by a twelve carbon chain) is significantly higher than that of the stiff stilbene unit itself. In general, it is indicated that addition of even a flexible chain to the stiff stilbene unit may significantly affect its photochemical properties and increase the photostability of the resulting macrocycle.

APA, Harvard, Vancouver, ISO, and other styles

35

Anders, Patrick, Mario Rapp, Michael Linseis, and Rainer Winter. "Tetraruthenium Metallamacrocycles with Potentially Coordinating Appended Functionalities." Inorganics 6, no. 3 (July 24, 2018): 73. http://dx.doi.org/10.3390/inorganics6030073.

Full text

Abstract:

We present four new tetraruthenium macrocycles built from two 1,4-divinylphenylene diruthenium and two isophthalic acid building blocks with peripheral, potentially mono- or tridentate donor functions attached to the isophthalic linkers. These macrocycles are characterized by multinuclear NMR spectroscopy, mass spectrometry and, in the case of the thioacetyl-appended complex 4, by X-ray crystallography. Cyclic and square wave voltammetry establish that the macrocycles can be oxidized in four consecutive redox steps that come as two pairs of two closely spaced one-electron waves. Spectroscopic changes observed during IR and UV/Vis/NIR spectroelectrochemical experiments (NIR = near infrared) show that the isophthalate linkers insulate the electroactive divinylphenylene diruthenium moieties against each other. The macrocycles exhibit nevertheless pronounced polyelectrochromism with highly intense absorptions in the Vis (2+/4+ states) and the NIR (2+ states) with extinction coefficients of up to >100,000 M−1·cm−1. The strong absorptivity enhancement with respect to the individual divinylphenylene diruthenium building blocks is attributed to conformational restrictions imposed by the macrocycle backbone. Moreover, the di- and tetracations of these macrocycles are paramagnetic as revealed by EPR spectroscopy.

APA, Harvard, Vancouver, ISO, and other styles

36

Xu, Rong-Yao, Xiu Liu, Guang Sun, Zhi-Yuan Zhang, Ming Dong, Liya Zhao, Si-Miao Zhang, et al. "Efficient macrocyclization facilitated by skeleton preorganization." RSC Advances 13, no. 43 (2023): 30269–72. http://dx.doi.org/10.1039/d3ra05671f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Thapa, Rajesh, and Stefan M. Kilyanek. "Synthesis and structural characterization of iridium(I) complexes of 20-membered macrocyclic rings bearing chelating bis(N-heterocyclic carbene) ligands." Acta Crystallographica Section C Structural Chemistry 75, no. 12 (November 25, 2019): 1652–57. http://dx.doi.org/10.1107/s2053229619015006.

Full text

Abstract:

The reactivities of two 20-membered macrocyclic ligands, each containing two N-heterocyclic carbene (NHC) and two amine groups, towards [IrCl(COD)]2 (COD is cycloocta-1,5-diene) were investigated. Macrocycles containing imidazolin-2-ylidene groups formed the monometallic complex [(1,2,5,6-η)-cycloocta-1,5-diene](5,16-dibenzyl-1,5,9,12,16,20-hexaazatricyclo[18.2.1.19,12]tetracosa-10,21-dien-21,22-diylidene)iridium(I) bromide dichloromethane monosolvate, [Ir(C8H12)(C32H42N6)]Br·CH2Cl2, 2a. The structure of iridium complex 2a at 100 K has triclinic P\overline{1} symmetry. The ligand in 2a coordinates to the Ir center through the NHC moieties in a cis fashion. Additionally, the ligand adopts an umbrella-like structure that appears to envelope the Ir center. The structure displays C—H...Br interactions. Macrocycles containing benzimidazolin-2-ylidene groups formed the bimetallic complex [μ-5,20-dibenzyl-1,5,9,16,20,24-hexaazapentacyclo[22.6.1.19,16.010,15.025,30]dotriaconta-10(15),11,13,25(30),26,28-hexaene-31,32-diylidene]bis{bromido[(1,2,5,6-η)-cycloocta-1,5-diene]iridium(I)}, [Ir2Br2(C8H12)2(C40H46N6)], 2b. The structure of complex 2b at 100 K has orthorhombic Pbca symmetry. Each NHC moiety in 2b coordinates in a monodentate fashion to an Ir(COD) fragment. The structure exhibits disorder of the main molecule. This disorder is found in the portion of the macrocycle containing an amine group. This structure also displays C—H...Br interactions. Finally, the structure of the hexafluorophosphate salt of the imidazolin-2-ylidene-containing macrocycle, namely 5,16-dibenzyl-1λ5,5,9,12λ5,16,20-hexaazatricyclo[18.2.1.19,12]tetracosa-1(23),10,12(24),21-tetraene-1,12-diium bis(hexafluorophosphate), C32H44N6 2+·2PF6 −, 1c, was determined. The structure of macrocycle 1c at 100 K has triclinic P\overline{1} symmetry and was found to contain C—H...F interactions.

APA, Harvard, Vancouver, ISO, and other styles

38

Robert, Antoine, Pierre Dechambenoit, Elisabeth A. Hillard, Harald Bock, and Fabien Durola. "Non-planar oligoarylene macrocycles from biphenyl." Chem. Commun. 53, no. 84 (2017): 11540–43. http://dx.doi.org/10.1039/c7cc06798d.

Full text

Abstract:

Saddle- and propeller-shaped, partially condensed conjugated macrocycles are synthesized by fourfold Perkin condensation plus fourfold photocyclizations. Their macrocyclic loops are pronouncedly non-planar.

APA, Harvard, Vancouver, ISO, and other styles

39

Desmond, Richard T., Anniefer N. Magpusao, Chris Lorenc, Jeremy B. Alverson, Nigel Priestley, and Mark W. Peczuh. "De novo macrolide–glycolipid macrolactone hybrids: Synthesis, structure and antibiotic activity of carbohydrate-fused macrocycles." Beilstein Journal of Organic Chemistry 10 (September 17, 2014): 2215–21. http://dx.doi.org/10.3762/bjoc.10.229.

Full text

Abstract:

Natural product-like macrocycles were designed as potential antibacterial compounds. The macrocycles featured a D-glucose unit fused into a 12- or 13-member macrolactone. The rings are connected via the C6’ and anomeric (C1’) positions of the monosaccharide. The new macrocycles/macrolides were characterized by X-ray crystallography. Their structures showed that, in addition to the ester and alkene units, the dihedral angle about the glycosidic linkage (exo-anomeric effect) influenced the overall shape of the molecules. Glycosylation of an available hydroxy group on the macrocycle gave a hybrid macrolide with features common to erythromycin and sophorlipid macrolactone. Weak antibiotic activity (MICs <100 μg/mL) was observed for several of the compounds.

APA, Harvard, Vancouver, ISO, and other styles

40

Inokuma, Yasuhide. "Calix[3]Pyrrole and Related Macrocycles: Synthesis and Properties." ECS Meeting Abstracts MA2023-01, no. 15 (August 28, 2023): 1409. http://dx.doi.org/10.1149/ma2023-01151409mtgabs.

Full text

Abstract:

Calix[4]pyrrole is a porphyrinogen-like macrocycle in which four pyrrole units are linked by four sp3-hybridized carbon atoms at the α-positions. While such tetrapyrrolic macrocycles are readily synthesized by acid-catalyzed condensation reactions of pyrrole monomer and carbonyl compound, analogous macrocycles composed of three pyrrole units are always not observed. Calix[3]pyrrole is a ring-contracted analogue of calix[4]pyrrole, and has been missing in porphyrin-related chemistry. In this presentation, the first synthesis of calix[3]pyrrole and its furan-embedded analogues is reported, and their unique reactivity derived from their macrocyclic ring strain will be discussed. Synthesis of calix[3]pyrrole started with a linear trimer of 3,3-dimethylpentane-2,5-dione. Intramolecular cyclization of the linear hexaketone was accomplished in 5 steps to give a cyclic hexaketone precursor. Paal–Knorr type pyrrole formation reaction of cyclic hexaketone gave calix[3]pyrrole in 41% yield (Scheme 1). Using similar strategies, analogous calix[3]-type macrocycles, namely, calix[1]furan[2]pyrrole, calix[2]furan[1]pyrrole, and calix[3]furan, were successfully synthesized. Single crystal X-ray diffraction analysis of calix[3]pyrrole revealed its strained structure, and the theoretical calculations showed the strain energy of calix[3]pyrrole is 22.1 kcal/mol per unit higher than that of calix[4]pyrrole. Such strain energy tends to decrease as the number of pyrrole unit decreased. Calix[3]pyrrole exhibited unique reactivity derived from macrocyclic ring strain under acidic (Rothemund–Lindsey) conditions that are frequently used for porphyrin synthesis. When calix[3]pyrrole was dissolved in 10 mM solution of trifluoroacetic acid in dichloromethane, calix[6]pyrrole was quantitatively formed within 30 seconds (Scheme 1). Similar strain-induced ring expansion was observed for calix[1]furan[2]pyrrole, but full conversion took approximately 5 minutes. On the other hand, calix[2]furan[1]pyrrole and calix[3]furan did not show ring expansion. Detailed mechanistic analysis revealed that protonation at a pyrrole unit in calix[3]pyrrole triggers irreversible ring-cleavage to give a linear tripyrrane moiety which undergoes cyclodimerization under acidic conditions. The strain-induced ring expansion reaction of calix[3]pyrrole solved a long-standing question in porphyrin-related chemistry. Tripyrrolic macrocycles such as calix[3]pyrrole are, even formed, not isolable from pyrrole condensation reaction using acid, because the strain-induced conversion to calix[6]pyrrole is too fast. Besides, this reaction provided a novel approach to ring-expanded calix-type macrocycles. Figure 1

APA, Harvard, Vancouver, ISO, and other styles

41

Jiang, Zhiwei, Ruijiao Dong, Austin M. Evans, Niklas Biere, Mahmood A. Ebrahim, Siyao Li, Dario Anselmetti, William R. Dichtel, and Andrew G. Livingston. "Aligned macrocycle pores in ultrathin films for accurate molecular sieving." Nature 609, no. 7925 (August 31, 2022): 58–64. http://dx.doi.org/10.1038/s41586-022-05032-1.

Full text

Abstract:

AbstractPolymer membranes are widely used in separation processes including desalination1, organic solvent nanofiltration2,3 and crude oil fractionation4,5. Nevertheless, direct evidence of subnanometre pores and a feasible method of manipulating their size is still challenging because of the molecular fluctuations of poorly defined voids in polymers6. Macrocycles with intrinsic cavities could potentially tackle this challenge. However, unfunctionalized macrocycles with indistinguishable reactivities tend towards disordered packing in films hundreds of nanometres thick7–9, hindering cavity interconnection and formation of through-pores. Here, we synthesized selectively functionalized macrocycles with differentiated reactivities that preferentially aligned to create well-defined pores across an ultrathin nanofilm. The ordered structure was enhanced by reducing the nanofilm thickness down to several nanometres. This orientated architecture enabled direct visualization of subnanometre macrocycle pores in the nanofilm surfaces, with the size tailored to ångström precision by varying the macrocycle identity. Aligned macrocycle membranes provided twice the methanol permeance and higher selectivity compared to disordered counterparts. Used in high-value separations, exemplified here by enriching cannabidiol oil, they achieved one order of magnitude faster ethanol transport and threefold higher enrichment than commercial state-of-the-art membranes. This approach offers a feasible strategy for creating subnanometre channels in polymer membranes, and demonstrates their potential for accurate molecular separations.

APA, Harvard, Vancouver, ISO, and other styles

42

Perez-Martinez, Jesus de Maria, Fatima Morales, Alberto Martinez-Cuezva, Mateo Alajarin, and Jose Berna. "Synthesis of an Adamantane-Based Tetralactam and Its Association with Dicarboxamides." Proceedings 41, no. 1 (November 14, 2019): 65. http://dx.doi.org/10.3390/ecsoc-23-06511.

Full text

Abstract:

Tetralactam macrocycles are suitable candidates to be employed as synthetic receptors for charged or neutral guests. In the sensing of neutral molecules, nonpolar solvents such as chloroform or dichloromethane are usually employed so the hydrogen-bonded interactions can be established. Thus, one of the main limitations of the studied macrocycles is their low solubility in those solvents. Herein, we describe the synthesis of an adamantane-based tetralactam macrocycle that is soluble in chlorinated solvents. For this purpose, by following a clipping methodology, we firstly synthesized a kinetically stable pseudorotaxane, constituted by a removable tetraalkylfumaramide thread and the desired macrocycle. A subsequent thermal dethreading straightforwardly yielded the adamantane-based macrocycle. Afterwards, the affinity of this receptor for a series of fumaramide and succinamide guests was studied, calculating the association constants when the corresponding [2]pseudorotaxanes are assembled.

APA, Harvard, Vancouver, ISO, and other styles

43

Whittaker, Jacob, Suresh Moorthy, Jonathan Cremers, Jason R. Price, John C. McMurtrie, and Jack K. Clegg. "Synthesis of Two 2,2′-Bipyridine Containing Macrocycles for the Preparation of Interlocked Architectures." Australian Journal of Chemistry 70, no. 5 (2017): 588. http://dx.doi.org/10.1071/ch16710.

Full text

Abstract:

The synthesis and characterisation of two 28-membered, 2,2′-bipyridine-containing macrocycles in high yield is reported. The first imine-containing macrocycle was formed via a Williamson ether synthesis and showed no evidence of higher oligomer formation. Reduction of the imines with sodium borohydride produced the second macrocycle quantitatively.

APA, Harvard, Vancouver, ISO, and other styles

44

Chai, Hongxin, Zhi-Sheng Pan, Liu-Pan Yang, Shan He, Fangfang Pan, Kari Rissanen, and Wei Jiang. "Probing the guest-binding preference of three structurally similar and conformationally adaptive macrocycles." Chemical Communications 55, no. 54 (2019): 7768–71. http://dx.doi.org/10.1039/c9cc03341f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Jurek, Paul, Joseph H. Reibenspies, and Garry E. Kiefer. "CB-TE2A+·Cl−·3H2O: a short intermolecular hydrogen bond between zwitterionic bicyclo[6.6.2]tetraamine macrocycles." Acta Crystallographica Section C Structural Chemistry 72, no. 2 (January 19, 2016): 139–42. http://dx.doi.org/10.1107/s2053229616000358.

Full text

Abstract:

1,4,8,11-Tetraazabicyclo[6.6.2]hexadecane-4,11-diacetic acid (CB-TE2A) is of much interest in nuclear medicine for its ability to form copper complexes that are kinetically inert, which is beneficialin vivoto minimize the loss of radioactive copper. The structural chemistry of the hydrated HCl salt of CB-TE2A, namely 11-carboxymethyl-1,8-tetraaza-4,11-diazoniabicyclo[6.6.2]hexadecane-4-acetate chloride trihydrate, C16H31N4O4+·Cl−·3H2O, is described. The compound crystallized as a positively charged zwitterion with a chloride counter-ion. Two of the amine groups in the macrocyclic ring are protonated. Formally, a single negative charge is shared between two of the carboxylic acid groups, while one chloride ion balances the charge. Two intramolecular hydrogen bonds are observed between adjacent pairs of N atoms of the macrocycle. Two intramolecular hydrogen bonds are also observed between the protonated amine groups and the pendant carboxylate groups. A short intermolecular hydrogen bond is observed between two partially negatively charged O atoms on adjacent macrocycles. The result is a one-dimensional polymeric zigzag chain that propagates parallel to the crystallographicadirection. A second intermolecular interaction is a hydrogen-bonding network in the crystallographicbdirection. The carbonyl group of one macrocycle is connected through the three water molecules of hydration to the carbonyl group of another macrocycle.

APA, Harvard, Vancouver, ISO, and other styles

46

Tominaga, Masahide, Kosuke Mizuno, Haruka Yamamoto, Tadashi Hyodo, and Kentaro Yamaguchi. "Co-Inclusion of cyclic ethers and chloroform by a macrocycle with benzophenone-3,3′,4,4′-tetracarboxylic diimide units." CrystEngComm 22, no. 17 (2020): 2964–69. http://dx.doi.org/10.1039/d0ce00221f.

Full text

Abstract:

Crystallization of a diimide-based macrocycle having adamantane parts and several cyclic ethers in chloroform provided inclusion crystals, where both guests were cooperatively accommodated within inner spaces between the macrocycles.

APA, Harvard, Vancouver, ISO, and other styles

47

Rondeau-Gagné, Simon, Jules Roméo Néabo, Maxime Daigle, Katy Cantin, and Jean-François Morin. "Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification." Beilstein Journal of Organic Chemistry 10 (July 15, 2014): 1613–19. http://dx.doi.org/10.3762/bjoc.10.167.

Full text

Abstract:

The synthesis and self-assembly of two new phenylacetylene macrocycle (PAM) organogelators were performed. Polar 2-hydroxyethoxy side chains were incorporated in the inner part of the macrocycles to modify the assembly mode in the gel state. With this modification, it was possible to increase the reactivity of the macrocycles in the xerogel state to form polydiacetylenes (PDAs), leading to a significant enhancement of the polymerization yields. The organogels and the PDAs were characterized using Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM).

APA, Harvard, Vancouver, ISO, and other styles

48

Allen, Joshua L., Elie Paillard, Paul D. Boyle, and Wesley A. Henderson. "Lithium bis(2-methyllactato)borate monohydrate." Acta Crystallographica Section E Structure Reports Online 68, no. 6 (May 12, 2012): m749. http://dx.doi.org/10.1107/s1600536812017540.

Full text

Abstract:

The title compound {systematic name: poly[[aqualithium]-μ-3,3,8,8-tetramethyl-1,4,6,9-tetraoxa-5λ4-borataspiro[4.4]nonane-2,7-dione]}, [Li(C8H12BO6)(H2O)] n (LiBMLB), forms a 12-membered macrocycle, which lies across a crystallographic inversion center. The lithium cations are pseudo-tetrahedrally coordinated by three methyllactate ligands and a water molecule. The asymmetric units couple across crystallographic inversion centers, forming the 12-membered macrocycles. These macrocycles, in turn, cross-link through the Li+ cations, forming an infinite polymeric structure in two dimensions parallel to (101).

APA, Harvard, Vancouver, ISO, and other styles

49

Moon, Dohyun, Yong Pyo Hong, and Jong-Ha Choi. "Spectroscopic characterization and molecular structure of 3,14-dimethyl-2,6,13,17-tetraazapentacyclo[16.4.0.12,17.16,13.07,12]tetracosane." Acta Crystallographica Section C Structural Chemistry 72, no. 9 (August 25, 2016): 701–4. http://dx.doi.org/10.1107/s2053229616013280.

Full text

Abstract:

Constrained cyclam derivatives have been found to exhibit anti-HIV effects. The strength of binding to the CXCR4 receptor correlates with anti-HIV activity. The conformation of the macrocyclic compound is very important for co-receptor recognition. Therefore, knowledge of the conformation and crystal packing of macrocycles has become important in developing new highly effective anti-HIV drugs. Structural modifications of N-functionalized polyaza macrocyclic compounds have been achieved using various methods. A new synthesis affording single crystals of the title tetraazapentacyclo[16.4.0.12,17.16,13.07,12]tetracosane macrocycle, C22H40N4, is reported. Formaldehyde reacts readily at room temperature with the tetraazatricyclo[16.4.0.02,17]docosane precursor to yield a macropolycycle containing two five-membered rings. Characterization by elemental, spectroscopic and single-crystal X-ray diffraction analyses shows that the asymmetric unit contains half of a centrosymmetric molecule. The molecular structure shows atransconformation for the two methylene bridges owing to molecular symmetry. The crystal structure is stabilized by intramolecular C—H...N hydrogen bonds. NMR and IR spectroscopic properties support the methylene-bridged macrocyclic structure.

APA, Harvard, Vancouver, ISO, and other styles

50

Yousaf, Muhammad, Ximena Zarate, Eduardo Schott, Alan J. Lough, and Bryan D. Koivisto. "Photophysical behaviour of BODIPY-phenylacetylene macrocyclic dyads for light-harvesting applications." RSC Advances 8, no. 50 (2018): 28533–37. http://dx.doi.org/10.1039/c8ra03384f.

Full text

Abstract:

The synthesis and study of a family of BODIPY-phenylacetylene macrocycles where donor groups have been added to the macrocycle in order to tune the physicochemical properties and absorption profile is reported.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Macrocycles'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles