1
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Salam HAAE, Mohamed GG, Zayed EM. Synthesis, spectroscopic characterization, biological application and molecular docking studies of some transition metal complexes of isophthalamide ligand. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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2
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Pineda-Castañeda H, Rivera-Monroy ZJ, Maldonado M. Copper(I)-Catalyzed Alkyne-Azide Cycloaddition (CuAAC) "Click" Reaction: A Powerful Tool for Functionalizing Polyhydroxylated Platforms. ACS OMEGA 2023; 8:3650-3666. [PMID: 36743057 PMCID: PMC9893463 DOI: 10.1021/acsomega.2c06269] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/23/2022] [Indexed: 05/13/2023]
Abstract
Click chemistry is currently one of the most used tools for the generation of complex organic molecules. The advantages of using click chemistry in organic synthesis are remarkable; in many cases, the reactions occur under mild conditions and are free of solvents, with high yields and short reaction times. This makes it an extraordinarily effective and viable alternative for obtaining complex/conjugated molecules. In this review, the use of click chemistry CuAAC is especially emphasized for polyhydroxylated platforms such as resorcinarenes or calixarenes, focusing mainly on aspects of synthesis, specifically conditions, reagents, and methodologies.
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Affiliation(s)
- Héctor
Manuel Pineda-Castañeda
- Chemistry
Department, Universidad Nacional de Colombia,
Bogotá, Carrera 45 No 26-85, Building 451, office 409, Bogotá 11321, Colombia
| | - Zuly Jenny Rivera-Monroy
- Chemistry
Department, Universidad Nacional de Colombia,
Bogotá, Carrera 45 No 26-85, Building 451, office 409, Bogotá 11321, Colombia
| | - Mauricio Maldonado
- Chemistry
Department, Universidad Nacional de Colombia,
Bogotá, Carrera 45 No 26-85, Building 451, office 409, Bogotá 11321, Colombia
- Email
for M.M.:
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3
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Pineda-Castañeda H, Maldonado M, Rivera-Monroy ZJ. Efficient Separation of C-Tetramethylcalix[4]resorcinarene Conformers by Means of Reversed-Phase Solid-Phase Extraction. ACS OMEGA 2023; 8:231-237. [PMID: 36643487 PMCID: PMC9835186 DOI: 10.1021/acsomega.2c03218] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 08/11/2022] [Indexed: 05/13/2023]
Abstract
A reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed to study the conformer formation generated during the reaction for obtaining C-tetramethylcalix[4]resorcinarene. The chromatographic method was used to design a strategy for purifying the reaction products, using solid-phase extraction columns (RP-SPE) and gradient elution. The chromatographic profiles of the cyclocondensation reaction between resorcinol and acetaldehyde show the presence of three products under the different reaction and precipitation conditions studied. Using RP-SPE, it was possible to enrich the products, which were later characterized by means of RP-HPLC and 1H nuclear magnetic resonance (NMR). This investigation explored and established a new method for RP-HPLC analysis and RP-SPE separation of conformational isomers obtained in the formation reaction of C-tetramethylcalix[4]resorcinarene.
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4
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Casas-Hinestroza JL, Pérez-Redondo A, Maldonado M. Inclusion complexation between neurotransmitters with polyacetylated calix[4]pyrogallolarenes: 1H-NMR and crystallographic analysis. RESEARCH ON CHEMICAL INTERMEDIATES 2022. [DOI: 10.1007/s11164-022-04735-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Karle A, Twum K, Sabbagh N, Haddad A, Taimoory SM, Szczęśniak MM, Trivedi E, Trant JF, Beyeh NK. Naphthalene-functionalized resorcinarene as selective, fluorescent self-quenching sensor for kynurenic acid. Analyst 2022; 147:2264-2271. [DOI: 10.1039/d1an02224e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Naphthalene-functionalized resorcinarene selectively binds kynurenic acid in the presence of excess tryptophan in aqueous media, highlighting the potential of functionalized resorcinarenes as sensory recognition elements for biomolecular analytes.
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Affiliation(s)
- Anna Karle
- Oakland University, 146 Library Drive, Rochester, Michigan, 48309-4479, USA
| | - Kwaku Twum
- Oakland University, 146 Library Drive, Rochester, Michigan, 48309-4479, USA
| | - Noorhan Sabbagh
- Oakland University, 146 Library Drive, Rochester, Michigan, 48309-4479, USA
| | - Alise Haddad
- Oakland University, 146 Library Drive, Rochester, Michigan, 48309-4479, USA
| | - S. Maryamdokht Taimoory
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
- Department of Chemistry, University of Michigan, 930 N. University Ave, 2811 Ann Arbor, MI 48019, USA
| | | | - Evan Trivedi
- Oakland University, 146 Library Drive, Rochester, Michigan, 48309-4479, USA
| | - John F. Trant
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - Ngong Kodiah Beyeh
- Oakland University, 146 Library Drive, Rochester, Michigan, 48309-4479, USA
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6
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Maldonado M, Sanabria E, Velasquez-Silva A, Casas-Hinestroza JL, Esteso MA. Comparative study of the volumetric properties of three regioisomers of diazoted C-tetra(propyl)resorcin[4]arene in DMSO at various temperatures. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.115252] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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7
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Castillo-Aguirre A, Esteso MA, Maldonado M. Resorcin[4]arenes: Generalities and Their Role in the Modification and Detection of Amino Acids. CURR ORG CHEM 2020. [DOI: 10.2174/1385272824999200510232141] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The characteristics and properties that enable resorcin[4]arenes to self-assemble
in order to form derivatives with amino acids with a high potential for application in various
fields are reviewed. In particular, resorcin[4]arene synthesis, their characteristics, the
variety in the size of cavity, their functional groups, and their applications associated with
molecular interactions are described in this study. Also, the types of amino acids that can
be recognized by resorcin[4]arenes, their interactions, the techniques that allow the determination
of the association constants, and the evaluation of the stoichiometry of the complex
formed, are reviewed.
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Affiliation(s)
- Alver Castillo-Aguirre
- Department of Chemistry, Faculty of Science, National University of Colombia-Bogota Headquarters, 30 No. 45-03 Carrera, Colombia
| | - Miguel Angel Esteso
- Universidad Catolica Santa Teresa de Jesus de Avila. Calle los Canteros s/n. 05005 Avila, Spain
| | - Mauricio Maldonado
- Department of Chemistry, Faculty of Science, National University of Colombia-Bogota Headquarters, 30 No. 45-03 Carrera, Colombia
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8
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Facile synthesis, X-ray diffraction studies, photophysical properties and DFT-D based conformational analysis of octa and dodecacyanomethoxycalix[4]resorcinarenes. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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9
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Gajjar JA, Vekariya RH, Parekh HM. Recent advances in upper rim functionalization of resorcin[4]arene derivatives: Synthesis and applications. SYNTHETIC COMMUN 2020. [DOI: 10.1080/00397911.2020.1766080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jinal A. Gajjar
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
| | - Rajesh H. Vekariya
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
| | - Hitesh M. Parekh
- Department of Chemistry, School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
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Pamuła M, Nissinen M, Helttunen K. Correlating Solution- and Solid-State Structures of Conformationally Flexible Resorcinarenes: Significance of a Sulfonyl Group in Intramolecular Self-Inclusion. Chemistry 2020; 26:7374-7383. [PMID: 32083359 PMCID: PMC7317440 DOI: 10.1002/chem.201905211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/14/2020] [Indexed: 01/13/2023]
Abstract
The synthesis of tetramethoxyresorcinarene podands bearing p-toluene arms connected by -SO3 - (1) and -CH2 O- (2) linkers is presented herein. In the solid state, the resorcinarene podand 1 forms an intramolecular self-inclusion complex with the pendant p-toluene group of a podand arm, whereas the resorcinarene podand 2 does not show self-inclusion. The conformations of the flexible resorcinarene podands in solution were investigated by variable-temperature experiments using 1D and 2D NMR spectroscopic techniques as well as by computational methods, including a conformational search and subsequent DFT optimisation of representative structures. The 1 H NMR spectra of 1 and 2 at room temperature show a single set of proton signals that are in agreement with C4v symmetry. At low temperatures, the molecules exist as a mixture of boat conformations featuring slow exchange on the NMR timescale. Energy barriers (ΔG≠ 298 ) of 55.5 and 52.0 kJ mol-1 were calculated for the boat-to-boat exchange of 1 and 2, respectively. The results of the ROESY experiments performed at 193 K and computational modelling suggest that in solution the resorcinarene podand 1 adopts a similar conformation to that present in its crystal structure, whereas podand 2 populates a more versatile range of conformations in solution.
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Affiliation(s)
- Małgorzata Pamuła
- Department of ChemistryNanoscience CenterUniversity of JyvaskylaP.O. Box 3540014JyvaskylaFinland
| | - Maija Nissinen
- Department of ChemistryNanoscience CenterUniversity of JyvaskylaP.O. Box 3540014JyvaskylaFinland
| | - Kaisa Helttunen
- Department of ChemistryNanoscience CenterUniversity of JyvaskylaP.O. Box 3540014JyvaskylaFinland
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11
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Casas-Hinestroza JL, Cifuentes A, Ibáñez E, Maldonado M. Effect of the formation of capsules of tetra(propyl) pyrogallol[4]arene on the host-guest interaction with neurotransmitters. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Experimental Comparative Study of Dynamic Behavior in Solution Phase of C-Tetra(phenyl)resorcin[4]arene and C-Tetra(phenyl)pyrogallol[4]arene. Molecules 2020; 25:molecules25102275. [PMID: 32408559 PMCID: PMC7287697 DOI: 10.3390/molecules25102275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/25/2020] [Accepted: 05/08/2020] [Indexed: 11/24/2022] Open
Abstract
The synthesis of phenyl-resorcinarenes and pyrogallolarenes is known to produce a conformational mixture of cone and chair isomers. Depending on the synthesis conditions the composition of the conformational mixture is variable; however, the cone conformer is the greatest proportion of phenyl-resorcin[4]arenes and chair conformer of pyrogallol[4]arenes. The experimental evidence suggests that phenyl-substituted resorcinarene and pyrogallolarene exist as a dynamic boat in solution.
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Castillo-Aguirre AA, Pérez-Redondo A, Maldonado M. Influence of the hydrogen bond on the iteroselective O-alkylation of calix[4]resorcinarenes. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Velásquez-Silva A, Forero RS, Sanabria E, Pérez-Redondo A, Maldonado M. Host-guest inclusion systems of tetra(alkyl)resorcin [4]arenes with choline in DMSO: Dynamic NMR studies and X-ray structural characterization of the 1:1 inclusion complex. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.07.093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Shimoyama D, Haino T. Conformational Characteristics of Feet-to-Feet-Connected Biscavitands. J Org Chem 2019; 84:13483-13489. [PMID: 31456400 DOI: 10.1021/acs.joc.9b01730] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
X-ray crystallography of an acetoxy-protected bisresorcinarene and biscavitands possessing phosphonate and dialkylsilyl bridges revealed that the bisresorcinarene and the biscavitands adopt helical forms in the solid state. Helical conformations were also found in solution. The helix-helix interconversions of the biscavitands occurred with high activation barriers of more than 50 kJ mol-1. The activation parameters of the helix-helix interconversions were determined using exchange spectroscopy (EXSY). The positive activation enthalpies and the negative activation entropies suggest that the transition states of the helix-helix interconversion process are most likely more strained and symmetric than the ground states. The compensatory enthalpy-entropy correlation is found in the series of activation parameters, giving rise to a compensation temperature of 254 K.
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Affiliation(s)
- Daisuke Shimoyama
- Department of Chemistry, Graduate School of Science , Hiroshima University , 1-3-1 Kagamiyama , Higashi-Hiroshima 739-8526 , Japan
| | - Takeharu Haino
- Department of Chemistry, Graduate School of Science , Hiroshima University , 1-3-1 Kagamiyama , Higashi-Hiroshima 739-8526 , Japan
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16
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Velásquez-Silva BA, Castillo-Aguirre A, Rivera-Monroy ZJ, Maldonado M. Aminomethylated Calix[4]resorcinarenes as Modifying Agents for Glycidyl Methacrylate (GMA) Rigid Copolymers Surface. Polymers (Basel) 2019; 11:polym11071147. [PMID: 31277429 PMCID: PMC6680909 DOI: 10.3390/polym11071147] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 06/28/2019] [Accepted: 07/02/2019] [Indexed: 01/16/2023] Open
Abstract
Functionalization of tetrapropylcalix[4]resorcinarene, tetrapentylcalix[4]resorcinarene, tetranonylcalix[4]resorcinarene, and tetra-(4-hydroxyphenyl)calix[4]resorcinarene by means of aminomethylation reactions with the amino acids β-alanine and l-proline in the presence of aqueous formaldehyde was carried out. When β-alanine was used, the reaction products were tetrabenzoxazines. The reaction with tetra-(4-hydroxyphenyl)calix[4]resorcinarene did not proceed under the experimental conditions; therefore, l-proline was used, and the corresponding tetra-Mannich base was regio- and diasteroselectively formed. The products were characterized via FT-IR, 1H NMR, 13C NMR, and elemental analysis. With these aminomethylated-calix[4]resorcinarenes, the chemical surface modification of the copolymers poly(GMA-co-EDMA) and poly(BMA-co-EDMA-co-MMA) in a basic medium was studied. The results were quite satisfactory, obtaining the corresponding copolymers functionalized by nucleophilic substitution reaction and ring-opening between the carboxyl group of the upper rim of aliphatic calix[4]resorcinarenes and the hydroxyl group of the lower rim in the aromatic calix[4]resorcinarene and the epoxy group of the glycidyl methacrylate residue of each copolymer. The modified copolymers were characterized via FT-IR, scanning electron microscopy imaging, and elemental analysis. Finally, the modified copolymer surfaces exhibited interaction with peptides, showing their potential application in chromatographic separation techniques such as high-performance liquid chromatography.
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Affiliation(s)
- Betty Astrid Velásquez-Silva
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-Sede Bogotá, Carrera 30 No. 45-03, 7122 Carrera, Colombia
| | - Alver Castillo-Aguirre
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-Sede Bogotá, Carrera 30 No. 45-03, 7122 Carrera, Colombia
| | - Zuly Jenny Rivera-Monroy
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-Sede Bogotá, Carrera 30 No. 45-03, 7122 Carrera, Colombia
| | - Mauricio Maldonado
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-Sede Bogotá, Carrera 30 No. 45-03, 7122 Carrera, Colombia.
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Calixarenes: Generalities and Their Role in Improving the Solubility, Biocompatibility, Stability, Bioavailability, Detection, and Transport of Biomolecules. Biomolecules 2019; 9:biom9030090. [PMID: 30841659 PMCID: PMC6468619 DOI: 10.3390/biom9030090] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/24/2019] [Accepted: 02/28/2019] [Indexed: 12/11/2022] Open
Abstract
The properties and characteristics of calix[n]arenes are described, as well as their capacity to form amphiphilic assemblies by means of the design of synthetic macrocycles with a hydrophilic head and a hydrophobic tail. Their interaction with various substances of interest in pharmacy, engineering, and medicine is also described. In particular, the role of the calix[n]arenes in the detection of dopamine, the design of vesicles and liposomes employed in the manufacture of systems of controlled release drugs used in the treatment of cancer, and their role in improving the solubility of testosterone and anthelmintic drugs and the biocompatibility of biomaterials useful for the manufacture of synthetic organs is emphasized. The versatility of these macrocycles, able to vary in size, shape, functional groups, and hydrophobicity and to recognize various biomolecules and molecules with biological activity without causing cytotoxicity is highlighted.
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Abstract
This article is based on a review of the literature and our own experience with toxicological molecules. We explain the nature of calix[n]arenes and as their recognized properties are used to detect compounds of toxicological interest, mainly the most important pesticide families such as organophosphorated, organochlorine compounds, pyrethroid insecticides, carbamate fungicides, and herbicides, using different techniques. In addition, we show the role of the macrocycle and its interactions, and the advantage of using this type of compound for improving conventional techniques, where the phenomenon of recognition is very important, such as chromatography, solid-phased extraction, and the development of specific sensors, among others and Even we also show the use of this macrocycle for detoxication procedures in vivo. In this way, we display as the multiple possibilities of functionalization of the calix[n]arenes makes these versatile molecules in the phenomena of specific recognition. Finally, This review highlights the main analytical methods reported in the literature for determination of plaguicides by host-guest interaction with calixarenes. In this way, among the available analytical tools, chromatographic, and electrochemical-based methods are the most used techniques for the detection and to quantify plaguicides using calixarenes.
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Affiliation(s)
- Edilma Sanabria Español
- Grupo GICRIM, Programa de Investigación Criminal , Universidad Manuela Beltrán , Bogotá , Colombia
| | - Mauricio Maldonado
- Departamento de Química, Facultad de Ciencias , Universidad Nacional de Colombia , Bogotá , Colombia
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Casas-Hinestroza JL, Maldonado M. Conformational Aspects of the O-acetylation of C-tetra(phenyl)calixpyrogallol[4]arene. Molecules 2018; 23:molecules23051225. [PMID: 29783780 PMCID: PMC6100403 DOI: 10.3390/molecules23051225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 11/16/2022] Open
Abstract
Reaction between pyrogallol and benzaldehyde results in a conformational mixture of C-tetra(phenyl)pyrogallol[4]arene (crown and chair). The conformer mixture was separated using crystallization procedures and the structures were determined using FTIR, 1H-NMR, and 13C-NMR. O-acetylation of C-tetra(phenyl)pyrogallol[4]arene (chair) with acetic anhydride, in pyridine results in the formation of dodecaacetyl-tetra(phenyl)pyrogallol[4]arene. The structure was determined using 1H-NMR and 13C-NMR finding that the product maintains the conformation of the starting conformer. On the other hand, the O-acetylation reaction of C-tetra(phenyl)pirogallol[4]arene (crown) under same conditions proceeded efficiently, and its structure was determined using 1H-NMR and 13C-NMR. Dynamic 1H-NMR of acetylated pyrogallolarene was studied by means of variable temperature in DMSO-d6 solution, and it revealed that two conformers are formed in the solution. Boat conformations for acetylated pyrogallolarene showed a slow interconversion at room temperature.
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Affiliation(s)
- José Luis Casas-Hinestroza
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-sede Bogotá, Carrera 30 # 45-03, Bogotá 111321, Columbia.
| | - Mauricio Maldonado
- Departamento de Química, Facultad de Ciencias, Universidad Nacional de Colombia-sede Bogotá, Carrera 30 # 45-03, Bogotá 111321, Columbia.
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Sanabria E, Esteso MÁ, Vargas E, Maldonado M. Experimental comparative study of solvent effects on the structure of two sulfonated resorcinarenes. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.01.111] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Selective O-Alkylation of the Crown Conformer of Tetra(4-hydroxyphenyl)calix[4]resorcinarene to the Corresponding Tetraalkyl Ether. Molecules 2017; 22:molecules22101660. [PMID: 28976918 PMCID: PMC6151838 DOI: 10.3390/molecules22101660] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 09/29/2017] [Accepted: 09/30/2017] [Indexed: 11/17/2022] Open
Abstract
Reactions of glycidyl methacrylate with the crown and chair conformers of tetra(4-hydroxyphenyl)calix[4]resorcinarene were studied. The reactions were done over epoxide groups present in the ester, which can easily undergo an opening reaction with hydroxyl groups in the macrocyclic system. Initially, epoxidation reactions were carried out with pure conformers, and it was observed that the reaction between tetra(4-hydroxyphenyl)calix[4]resorcinarene fixed in the chair conformation does not occur, while for the molecule fixed in the crown conformation only one tetraalkylated derivative was obtained. The obtained product was characterized using IR, ¹H-NMR, 13C-NMR, COSY, HMQC and HMBC techniques. An exhaustive NMR study showed that the reaction is selective at the hydroxyl groups in the lower rim, without affecting the hydroxyl groups in the upper rim. In addition, the RP-HPLC analysis of the epoxidation reaction mixture, using both crown and chair conformers, showed that only the crown conformer reacted under tested conditions. Finally, a comparative study of the reactivity of tetranonylcalix[4]resorcinarene with glycidyl methacrylate showed that the reaction does not take place. Instead, the formation of the tetranonylcalix[4]resorcinarene tetrasodium salt was observed, which confirms that the hydroxyl groups in the upper rim are unreactive under these conditions.
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