Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis
Direct <i>O</i>-alkylation of <i>p-tert</i>-butyldihomooxacalix[4]arene (<b>1</b>) with <i>N</i>-(bromopropyl)- or <i>N</i>-(bromoethyl)phthalimides and K<sub>2</sub>CO<sub>3</sub> in acetonitrile was conducted under...
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MDPI AG
2021-03-01
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| Online Access: | https://www.mdpi.com/1420-3049/26/6/1503 |
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| author | Alexandre S. Miranda Paula M. Marcos José R. Ascenso M. Paula Robalo Vasco D. B. Bonifácio Mário N. Berberan-Santos Neal Hickey Silvano Geremia |
| author_facet | Alexandre S. Miranda Paula M. Marcos José R. Ascenso M. Paula Robalo Vasco D. B. Bonifácio Mário N. Berberan-Santos Neal Hickey Silvano Geremia |
| author_sort | Alexandre S. Miranda |
| collection | DOAJ |
| description | Direct <i>O</i>-alkylation of <i>p-tert</i>-butyldihomooxacalix[4]arene (<b>1</b>) with <i>N</i>-(bromopropyl)- or <i>N</i>-(bromoethyl)phthalimides and K<sub>2</sub>CO<sub>3</sub> in acetonitrile was conducted under conventional heating (reflux) and using microwave irradiation and ball milling methodologies. The reactions afforded mono- and mainly distal di-substituted derivatives in the cone conformation, in a total of eight compounds. They were isolated by column chromatography, and their conformations and the substitution patterns were established by NMR spectroscopy (<sup>1</sup>H, <sup>13</sup>C, COSY and NOESY experiments). The X-ray structures of four dihomooxacalix[4]arene phthalimide derivatives (<b>2a</b>, <b>3a</b>, <b>3b</b> and <b>5a</b>) are reported, as well as their photophysical properties. The microwave (MW)-assisted alkylations drastically reduced the reaction times (from days to less than 45 min) and produced higher yields of both 1,3-di-substituted phthalimides (<b>3a</b> and <b>6a)</b> with higher selectivity. Ball milling did not reveal to be a good method for this kind of reaction. |
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| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T13:23:25Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-a08dfaf4c250446981896f9f6e03c46e2023-11-21T09:52:47ZengMDPI AGMolecules1420-30492021-03-01266150310.3390/molecules26061503Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical AnalysisAlexandre S. Miranda0Paula M. Marcos1José R. Ascenso2M. Paula Robalo3Vasco D. B. Bonifácio4Mário N. Berberan-Santos5Neal Hickey6Silvano Geremia7Centro de Química Estrutural, Faculdade de Ciências da Universidade de Lisboa, Edifício C8, 1749-016 Lisboa, PortugalCentro de Química Estrutural, Faculdade de Ciências da Universidade de Lisboa, Edifício C8, 1749-016 Lisboa, PortugalCentro de Química Estrutural, Instituto Superior Técnico, Complexo I, Av. Rovisco Pais, 1049-001 Lisboa, PortugalCentro de Química Estrutural, Instituto Superior Técnico, Complexo I, Av. Rovisco Pais, 1049-001 Lisboa, PortugalIBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, PortugalIBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, PortugalCentre of Excellence in Biocrystallography, Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri 1, 34127 Trieste, ItalyCentre of Excellence in Biocrystallography, Department of Chemical and Pharmaceutical Sciences, University of Trieste, via L. Giorgieri 1, 34127 Trieste, ItalyDirect <i>O</i>-alkylation of <i>p-tert</i>-butyldihomooxacalix[4]arene (<b>1</b>) with <i>N</i>-(bromopropyl)- or <i>N</i>-(bromoethyl)phthalimides and K<sub>2</sub>CO<sub>3</sub> in acetonitrile was conducted under conventional heating (reflux) and using microwave irradiation and ball milling methodologies. The reactions afforded mono- and mainly distal di-substituted derivatives in the cone conformation, in a total of eight compounds. They were isolated by column chromatography, and their conformations and the substitution patterns were established by NMR spectroscopy (<sup>1</sup>H, <sup>13</sup>C, COSY and NOESY experiments). The X-ray structures of four dihomooxacalix[4]arene phthalimide derivatives (<b>2a</b>, <b>3a</b>, <b>3b</b> and <b>5a</b>) are reported, as well as their photophysical properties. The microwave (MW)-assisted alkylations drastically reduced the reaction times (from days to less than 45 min) and produced higher yields of both 1,3-di-substituted phthalimides (<b>3a</b> and <b>6a)</b> with higher selectivity. Ball milling did not reveal to be a good method for this kind of reaction.https://www.mdpi.com/1420-3049/26/6/1503dihomooxacalix[4]arenesphthalimide derivativesconventional synthesismicrowave irradiationball millingNMR spectroscopy |
| spellingShingle | Alexandre S. Miranda Paula M. Marcos José R. Ascenso M. Paula Robalo Vasco D. B. Bonifácio Mário N. Berberan-Santos Neal Hickey Silvano Geremia Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis Molecules dihomooxacalix[4]arenes phthalimide derivatives conventional synthesis microwave irradiation ball milling NMR spectroscopy |
| title | Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis |
| title_full | Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis |
| title_fullStr | Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis |
| title_full_unstemmed | Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis |
| title_short | Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis |
| title_sort | conventional vs microwave or mechanically assisted synthesis of dihomooxacalix 4 arene phthalimides nmr x ray and photophysical analysis |
| topic | dihomooxacalix[4]arenes phthalimide derivatives conventional synthesis microwave irradiation ball milling NMR spectroscopy |
| url | https://www.mdpi.com/1420-3049/26/6/1503 |
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