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Matamoros E, Light ME, Cintas P, Palacios JC. Schiff Bases and Stereocontrolled Formation of Fused 1,3-Oxazolidines from 1-Amino-2-Indanol: A Systematic Study on Structure and Mechanism. Molecules 2023; 28:1670. [PMID: 36838659 PMCID: PMC9961571 DOI: 10.3390/molecules28041670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/13/2023] [Accepted: 01/31/2023] [Indexed: 02/12/2023] Open
Abstract
This paper thoroughly explores the formation of Schiff bases derived from salicylaldehydes and a conformationally restricted amino alcohol (1-amino-2-indanol), as well as the generation of 1,3-oxazolidines, a key heterocyclic core present in numerous bioactive compounds. We provide enough evidences, both experimental-including crystallographic analyses and DFT-based calculations on imine/enamine tautomerism in the solid state and solution. In the course of imine formation, a pentacyclic oxazolidine-oxazine structure could be isolated with complete stereocontrol, whose configuration has been determined by merging theory and experiment. Mechanistic studies reveal that, although oxazolidines can be obtained under kinetic conditions, the prevalence of imines obeys to thermodynamic control as they are the most stable structures. The stereochemical outcome of imine cyclization under acylating conditions leads to formation of 2,4-trans-oxazolidines.
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Affiliation(s)
- Esther Matamoros
- Department of Organic and Inorganic Chemistry, Faculty of Sciences and IACYS-Green Chemistry and Sustainable Development Unit, University of Extremadura, 06006 Badajoz, Spain
| | - Mark E. Light
- Department of Chemistry, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Pedro Cintas
- Department of Organic and Inorganic Chemistry, Faculty of Sciences and IACYS-Green Chemistry and Sustainable Development Unit, University of Extremadura, 06006 Badajoz, Spain
| | - Juan C. Palacios
- Department of Organic and Inorganic Chemistry, Faculty of Sciences and IACYS-Green Chemistry and Sustainable Development Unit, University of Extremadura, 06006 Badajoz, Spain
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Martínez RF, Matamoros E, Cintas P, Palacios JC. Imine or Enamine? Insights and Predictive Guidelines from the Electronic Effect of Substituents in H-Bonded Salicylimines. J Org Chem 2020; 85:5838-5862. [PMID: 32259438 DOI: 10.1021/acs.joc.0c00130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Imine and enamine bonds decorate the skeleton of numerous reagents, catalysts, and organic materials. However, it is difficult to isolate at will a single tautomer, as dynamic equilibria occur easily, even in the solid state, and are sensitive to electronic and steric effect, including π-conjugation and H-bonding. Here, using as model Schiff bases generated from salicylaldehydes and TRIS in a set of linear free energy relationships (LFER), we disclose how the formation of either imines or enamines can be controlled and provide a comprehensive framework that captures the structural underpinning of this prediction. This work highlights the potentiality of tailor-made designs en route to compounds with desirable functionality.
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Affiliation(s)
- R Fernando Martínez
- Departamento de Quı́mica Orgánica e Inorgánica, Facultad de Ciencias and IACYS-Unidad de Quı́mica Verde y Desarrollo Sostenible, Universidad de Extremadura, E-06006 Badajoz, Spain
| | - Esther Matamoros
- Departamento de Quı́mica Orgánica e Inorgánica, Facultad de Ciencias and IACYS-Unidad de Quı́mica Verde y Desarrollo Sostenible, Universidad de Extremadura, E-06006 Badajoz, Spain
| | - Pedro Cintas
- Departamento de Quı́mica Orgánica e Inorgánica, Facultad de Ciencias and IACYS-Unidad de Quı́mica Verde y Desarrollo Sostenible, Universidad de Extremadura, E-06006 Badajoz, Spain
| | - Juan C Palacios
- Departamento de Quı́mica Orgánica e Inorgánica, Facultad de Ciencias and IACYS-Unidad de Quı́mica Verde y Desarrollo Sostenible, Universidad de Extremadura, E-06006 Badajoz, Spain
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Matamoros E, Cintas P, Light ME, Palacios JC. Electronic effects in tautomeric equilibria: the case of chiral imines from d-glucamine and 2-hydroxyacetophenones. Org Biomol Chem 2019; 17:10209-10222. [PMID: 31774417 DOI: 10.1039/c9ob02147g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A one-pot procedure for preparing a series of chiral imines by direct condensation of d-glucamine with 2-hydroxyacetophenones is described. Under conventional acetylation an unexpected mixture of two different peracetylated molecules is obtained, one with an open enamine structure, and the other incorporating an N-acetyl-1,3-oxazolidine into the acyclic skeleton. Surprisingly, both molecules coexist within the crystal's unit cell, as inferred from single-crystal X-ray analysis of a 5-bromo-substituted aryl derivative. Moreover, the 1,3-oxazolidine ring exists as rotational conformers (E,Z) owing to the restricted rotation around the N-acetyl bond. The equilibrium involving imine and enamine structures has been assessed in detail, providing in addition linear free-energy relationships between the tautomerization constants (KT) and the electronic effect of the substituents.
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Affiliation(s)
- Esther Matamoros
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencias, and IACYS-Unidad de Química Verde y Desarrollo Sostenible, Universidad de Extremadura, E-06006 Badajoz, Spain.
| | - Pedro Cintas
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencias, and IACYS-Unidad de Química Verde y Desarrollo Sostenible, Universidad de Extremadura, E-06006 Badajoz, Spain.
| | - Mark E Light
- Department of Chemistry, Faculty of Natural and Environmental Sciences, The University of Southampton, Southampton SO17 1BJ, UK
| | - Juan C Palacios
- Departamento de Química Orgánica e Inorgánica, Facultad de Ciencias, and IACYS-Unidad de Química Verde y Desarrollo Sostenible, Universidad de Extremadura, E-06006 Badajoz, Spain.
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Omelchenko IV, Shishkin OV, Dopieralski P, Latajka Z. About the Aromaticity of symm-Triaminotrinitrobenzene. J Phys Chem A 2019; 123:2244-2251. [DOI: 10.1021/acs.jpca.9b00433] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Iryna V. Omelchenko
- Department of X-ray Diffraction Study and Quantum Chemistry, SSI “Institute for Single Crystals” NAS of Ukraine, 60 Nauky ave., Kharkiv 61072, Ukraine
- Faculty of Chemistry, V. N. Karazin Kharkiv National University, 4 Svobody sq., Kharkiv 61077, Ukraine
| | - Oleg V. Shishkin
- Department of X-ray Diffraction Study and Quantum Chemistry, SSI “Institute for Single Crystals” NAS of Ukraine, 60 Nauky ave., Kharkiv 61072, Ukraine
- Faculty of Chemistry, V. N. Karazin Kharkiv National University, 4 Svobody sq., Kharkiv 61077, Ukraine
| | | | - Zdzislaw Latajka
- Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383 Wroclaw, Poland
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Matamoros E, Cintas P, Palacios JC. Tautomerism and stereodynamics in Schiff bases from gossypol and hemigossypol with N-aminoheterocycles. Org Biomol Chem 2019; 17:6229-6250. [DOI: 10.1039/c9ob01011d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gossypol, a natural male contraceptive, can be functionalized via dynamic imine linkages, whose tautomerism has been explored in detail.
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Affiliation(s)
- Esther Matamoros
- Departamento de Química Orgánica e Inorgánica
- Facultad de Ciencias
- and IACYS-Unidad de Química Verde y Desarrollo Sostenible
- Universidad de Extremadura
- 06006 Badajoz
| | - Pedro Cintas
- Departamento de Química Orgánica e Inorgánica
- Facultad de Ciencias
- and IACYS-Unidad de Química Verde y Desarrollo Sostenible
- Universidad de Extremadura
- 06006 Badajoz
| | - Juan Carlos Palacios
- Departamento de Química Orgánica e Inorgánica
- Facultad de Ciencias
- and IACYS-Unidad de Química Verde y Desarrollo Sostenible
- Universidad de Extremadura
- 06006 Badajoz
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Tiekink ER. Supramolecular assembly based on “emerging” intermolecular interactions of particular interest to coordination chemists. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.01.009] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Mahmudov KT, Pombeiro AJL. Resonance-Assisted Hydrogen Bonding as a Driving Force in Synthesis and a Synthon in the Design of Materials. Chemistry 2016; 22:16356-16398. [PMID: 27492126 DOI: 10.1002/chem.201601766] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Indexed: 11/08/2022]
Abstract
Resonance-assisted hydrogen bonding (RAHB), a concept introduced by Gilli and co-workers in 1989, concerns a kind of intramolecular H-bonding strengthened by a conjugated π-system, usually in 6-, 8-, or 10-membered rings. This Review highlights the involvement of RAHB as a driving force in the synthesis of organic, coordination, and organometallic compounds, as a handy tool in the activation of covalent bonds, and in starting moieties for synthetic transformations. The unique roles of RAHB in molecular recognition and switches, E/Z isomeric resolution, racemization and epimerization of amino acids and chiral amino alcohols, solvatochromism, liquid-crystalline compounds, and in synthons for crystal engineering and polymer materials are also discussed. The Review can provide practical guidance for synthetic chemists that are interested in exploring and further developing RAHB-assisted synthesis and design of materials.
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Affiliation(s)
- Kamran T Mahmudov
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal. .,Department of Chemistry, Baku State University, Z. Xalilov Str. 23, Az 1148, Baku, Azerbaijan.
| | - Armando J L Pombeiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.
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Romero-Fernández MP, Ávalos M, Babiano R, Cintas P, Jiménez JL, Palacios JC. A further look at π-delocalization and hydrogen bonding in 2-arylmalondialdehydes. Tetrahedron 2016. [DOI: 10.1016/j.tet.2015.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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