Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic Stability
This work reports the functionalization of pyranoflavyliums pigment using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride coupling chemistry. Four cinnamic acids were used to establish an ester bond with the hydroxyl group of the pyranoflavylium, namely 4-dimethylamino-, 4-amino-, 4-brom...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-10-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/21/7351 |
| _version_ | 1797467131344846848 |
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| author | Ana Rita Pereira Victor de Freitas Nuno Mateus Joana Oliveira |
| author_facet | Ana Rita Pereira Victor de Freitas Nuno Mateus Joana Oliveira |
| author_sort | Ana Rita Pereira |
| collection | DOAJ |
| description | This work reports the functionalization of pyranoflavyliums pigment using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride coupling chemistry. Four cinnamic acids were used to establish an ester bond with the hydroxyl group of the pyranoflavylium, namely 4-dimethylamino-, 4-amino-, 4-bromo-, and trans-cinnamic acids. The experimental condition, namely the molar ratios, solvent, and reaction time, were adjusted to obtain higher reaction yields in a reduced period. Excellent reaction yields of 68%, 85%, 94%, and 99% were achieved for 4-amino, trans-, 4-bromo, and 4-dimethylamino pyranoflavylium cinnamates, respectively. The structure of the functionalized pigments was fully clarified using one-dimensional (1H) and two-dimensional (COSY, HSQC, and HMBC) NMR experiments and HRSM analysis. Regardless of the type of functionalization, the UV-Visible spectrum showed a bathochromic shift (red region) on the maximum absorption wavelength and the absence of acid-base reactions throughout a broad pH range in comparison to the pyranoflavylium precursor. This work offers a valuable environmentally friendly, quick, and straightforward alternative to flavylium compounds’ challenging and labor-intensive functionalization, resulting in novel dyes with higher stability and dissimilar chromatic features. |
| first_indexed | 2024-03-09T18:48:19Z |
| format | Article |
| id | doaj.art-ca0dc00ec00c49ef874f099d80cd84e7 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T18:48:19Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-ca0dc00ec00c49ef874f099d80cd84e72023-11-24T06:02:48ZengMDPI AGMolecules1420-30492022-10-012721735110.3390/molecules27217351Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic StabilityAna Rita Pereira0Victor de Freitas1Nuno Mateus2Joana Oliveira3Laboratório Associado para a Química Verde—REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, PortugalLaboratório Associado para a Química Verde—REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, PortugalLaboratório Associado para a Química Verde—REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, PortugalLaboratório Associado para a Química Verde—REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, PortugalThis work reports the functionalization of pyranoflavyliums pigment using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride coupling chemistry. Four cinnamic acids were used to establish an ester bond with the hydroxyl group of the pyranoflavylium, namely 4-dimethylamino-, 4-amino-, 4-bromo-, and trans-cinnamic acids. The experimental condition, namely the molar ratios, solvent, and reaction time, were adjusted to obtain higher reaction yields in a reduced period. Excellent reaction yields of 68%, 85%, 94%, and 99% were achieved for 4-amino, trans-, 4-bromo, and 4-dimethylamino pyranoflavylium cinnamates, respectively. The structure of the functionalized pigments was fully clarified using one-dimensional (1H) and two-dimensional (COSY, HSQC, and HMBC) NMR experiments and HRSM analysis. Regardless of the type of functionalization, the UV-Visible spectrum showed a bathochromic shift (red region) on the maximum absorption wavelength and the absence of acid-base reactions throughout a broad pH range in comparison to the pyranoflavylium precursor. This work offers a valuable environmentally friendly, quick, and straightforward alternative to flavylium compounds’ challenging and labor-intensive functionalization, resulting in novel dyes with higher stability and dissimilar chromatic features.https://www.mdpi.com/1420-3049/27/21/73517-hydroxy-pyranoflavylium1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochlorideester bondcoupling chemistrycinnamic acids |
| spellingShingle | Ana Rita Pereira Victor de Freitas Nuno Mateus Joana Oliveira Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic Stability Molecules 7-hydroxy-pyranoflavylium 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride ester bond coupling chemistry cinnamic acids |
| title | Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic Stability |
| title_full | Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic Stability |
| title_fullStr | Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic Stability |
| title_full_unstemmed | Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic Stability |
| title_short | Functionalization of 7-Hydroxy-pyranoflavylium: Synthesis of New Dyes with Extended Chromatic Stability |
| title_sort | functionalization of 7 hydroxy pyranoflavylium synthesis of new dyes with extended chromatic stability |
| topic | 7-hydroxy-pyranoflavylium 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride ester bond coupling chemistry cinnamic acids |
| url | https://www.mdpi.com/1420-3049/27/21/7351 |
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