Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight Structure
(<i>E</i>)-1-(1<i>H</i>-Benzo[<i>d</i>]imidazol-2-yl)-3-(dimethylamino)prop-2-en-1-one <b>2</b> was synthesized by one-pot synthesis protocol of 2-acetyl benzo[<i>d</i>]imidazole with dimethylformamide dimethylacetal (DMF-DMA) in xylene at...
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| Format: | Article |
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MDPI AG
2020-10-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/10/10/955 |
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| author | Saeed Alshahrani Saied M. Soliman Abdullah Saleh Alamary Abdullah Mohammed Al-Majid Matti Haukka Sammer Yousuf Assem Barakat |
| author_facet | Saeed Alshahrani Saied M. Soliman Abdullah Saleh Alamary Abdullah Mohammed Al-Majid Matti Haukka Sammer Yousuf Assem Barakat |
| author_sort | Saeed Alshahrani |
| collection | DOAJ |
| description | (<i>E</i>)-1-(1<i>H</i>-Benzo[<i>d</i>]imidazol-2-yl)-3-(dimethylamino)prop-2-en-1-one <b>2</b> was synthesized by one-pot synthesis protocol of 2-acetyl benzo[<i>d</i>]imidazole with dimethylformamide dimethylacetal (DMF-DMA) in xylene at 140 °C for 8 h. Reaction of enaminone derivative <b>1</b> with acetylacetone in the presence of AcOH/NH<sub>4</sub>OAc under reflux afforded the cyclized pyridino-benzo[<i>d</i>]imidazole derivative <b>3</b>. The latter compound was converted into the corresponding <i>β</i>-enaminone <b>4</b> with DMF-DMA. The single crystal X-ray diffraction technique eventually confirmed the assigned chemical structure of the <i>N</i>-alkyl-<i>β</i>-enaminone <b>2</b> and pyridino-benzo[<i>d</i>]imidazole derivative <b>3</b>. <i>N</i>-alkyl-<i>β</i>-enaminone <b>2</b> crystallized in the monoclinic space group P2<sub>1</sub>/n with unit cell parameters of <b>a</b> = 9.8953(3) Å, <b>b</b> = 5.7545(2) Å, <b>c</b> = 21.7891(7) Å, and β =100.627(2)°, and with one molecule per asymmetric unit. On the other hand, compound <b>3</b> crystallized in the orthorhombic crystal system and space group P2<b><sub>1</sub></b>2<b><sub>1</sub></b>2<b><sub>1</sub></b> with unit cell parameters of <b>a</b> = 6.82950(10) Å, <b>b</b> = 8.00540(10) Å, <b>c</b> = 22.4779(2) Å, and also with one molecule per asymmetric unit. Based on Hirshfeld analysis, the H...H (51.3%), O...H (10.0%), N...H (10.3%), and C...H (27.6%) contacts in <b>2</b> and the H...H (46.8%), O...H (9.9%), N...H (13.0%), and C...H (21.6%) in addition to the C…C (6.7%) interactions in <b>3</b> are the most important towards crystal stability via molecular packing. The main difference is the presence of π–π interaction among the molecular units of <b>3</b> but not in <b>2</b>. The calculated <sup>1</sup>H and <sup>13</sup>C NMR chemical shifts showed good agreements with experimental data. Electronic properties and reactivity parameters of both compounds are also calculated and compared. |
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| language | English |
| last_indexed | 2024-03-10T15:26:35Z |
| publishDate | 2020-10-01 |
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| series | Crystals |
| spelling | doaj.art-6c53dc0d88794bb9858f4f22309ff2ac2023-11-20T18:01:01ZengMDPI AGCrystals2073-43522020-10-01101095510.3390/cryst10100955Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight StructureSaeed Alshahrani0Saied M. Soliman1Abdullah Saleh Alamary2Abdullah Mohammed Al-Majid3Matti Haukka4Sammer Yousuf5Assem Barakat6Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi ArabiaDepartment of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321, EgyptDepartment of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi ArabiaDepartment of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi ArabiaDepartment of Chemistry, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, FinlandH.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi-75270, PakistanDepartment of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia(<i>E</i>)-1-(1<i>H</i>-Benzo[<i>d</i>]imidazol-2-yl)-3-(dimethylamino)prop-2-en-1-one <b>2</b> was synthesized by one-pot synthesis protocol of 2-acetyl benzo[<i>d</i>]imidazole with dimethylformamide dimethylacetal (DMF-DMA) in xylene at 140 °C for 8 h. Reaction of enaminone derivative <b>1</b> with acetylacetone in the presence of AcOH/NH<sub>4</sub>OAc under reflux afforded the cyclized pyridino-benzo[<i>d</i>]imidazole derivative <b>3</b>. The latter compound was converted into the corresponding <i>β</i>-enaminone <b>4</b> with DMF-DMA. The single crystal X-ray diffraction technique eventually confirmed the assigned chemical structure of the <i>N</i>-alkyl-<i>β</i>-enaminone <b>2</b> and pyridino-benzo[<i>d</i>]imidazole derivative <b>3</b>. <i>N</i>-alkyl-<i>β</i>-enaminone <b>2</b> crystallized in the monoclinic space group P2<sub>1</sub>/n with unit cell parameters of <b>a</b> = 9.8953(3) Å, <b>b</b> = 5.7545(2) Å, <b>c</b> = 21.7891(7) Å, and β =100.627(2)°, and with one molecule per asymmetric unit. On the other hand, compound <b>3</b> crystallized in the orthorhombic crystal system and space group P2<b><sub>1</sub></b>2<b><sub>1</sub></b>2<b><sub>1</sub></b> with unit cell parameters of <b>a</b> = 6.82950(10) Å, <b>b</b> = 8.00540(10) Å, <b>c</b> = 22.4779(2) Å, and also with one molecule per asymmetric unit. Based on Hirshfeld analysis, the H...H (51.3%), O...H (10.0%), N...H (10.3%), and C...H (27.6%) contacts in <b>2</b> and the H...H (46.8%), O...H (9.9%), N...H (13.0%), and C...H (21.6%) in addition to the C…C (6.7%) interactions in <b>3</b> are the most important towards crystal stability via molecular packing. The main difference is the presence of π–π interaction among the molecular units of <b>3</b> but not in <b>2</b>. The calculated <sup>1</sup>H and <sup>13</sup>C NMR chemical shifts showed good agreements with experimental data. Electronic properties and reactivity parameters of both compounds are also calculated and compared.https://www.mdpi.com/2073-4352/10/10/955benzo[<i>d</i>]imidazole<i>β</i>-enaminoneDMF-DMAHirshfeld analysisDFT |
| spellingShingle | Saeed Alshahrani Saied M. Soliman Abdullah Saleh Alamary Abdullah Mohammed Al-Majid Matti Haukka Sammer Yousuf Assem Barakat Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight Structure Crystals benzo[<i>d</i>]imidazole <i>β</i>-enaminone DMF-DMA Hirshfeld analysis DFT |
| title | Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight Structure |
| title_full | Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight Structure |
| title_fullStr | Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight Structure |
| title_full_unstemmed | Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight Structure |
| title_short | Synthesis of Enaminones-Based Benzo[<i>d</i>]imidazole Scaffold: Characterization and Molecular Insight Structure |
| title_sort | synthesis of enaminones based benzo i d i imidazole scaffold characterization and molecular insight structure |
| topic | benzo[<i>d</i>]imidazole <i>β</i>-enaminone DMF-DMA Hirshfeld analysis DFT |
| url | https://www.mdpi.com/2073-4352/10/10/955 |
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