Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.1/856
Título: Investigation of structural effects on the reactivity of heterocyclic bioactive compounds
Autor: Frija, L.
Orientador: Cristiano, Maria Lurdes Santos
Lourenço, Rui Fausto Martins Ribeiro da Silva
Palavras-chave: Teses
Química orgânica
Tetrazoles
Benzisotiazoles
Fotoquímica
Data de Defesa: 2008
Resumo: In the course of this investigation, structural effects on the reactivity of a series of heterocyclic compounds, in particular tetrazole and benzisothiazole derivatives, submitted to different chemical environments, were explored. The photochemistry of several representative tetrazoles was considered in solution and for the compounds trapped in a rigid matrix of solidified argon at cryogenic temperatures. UV-excitation resulted in photofragmentation of tetrazoles with a wide range of exit channels. Important mechanistic questions concerning the photodecomposition of allyl-tetrazolyl derivatives in different solvents were answered, and new synthetic methodologies for the preparation of heterocyclic compounds, such as pyrimidinones or oxazines, from allyl-tetrazoles, were developed. For the matrix-isolated compounds, since the obtained fragments in general stay in the matrix cage where they are formed, no subsequent cross-reactions involving species resulting from photolysis of different reactant molecules can occur. This fact introduced a useful simplification for the interpretation of the reaction mechanisms. FTIR spectroscopy provided experimental frequencies and intensities of characteristic absorptions of the matrix-isolated chemical species, both for reagents and photoproducts. The analysis of experimental data was assisted by their direct comparison with the vibrational spectra theoretically calculated for the single molecule in vacuum. Spectroscopic characterization of a number of relatively unusual or highly reactive molecules, formed from photolysis of matrix-isolated tetrazoles, is presented for the first time. Novel tetrazolyl and benzisothiazolyl naphthylmethylic ethers were synthesized and the development of experimental conditions for their palladium-catalysed hydrogenolysis, using a hydrogen donor or molecular hydrogen, was carried out successfully. Structural effects on the reactivity of the heteroaromatic ethers were investigated. Furthermore, new benzisothiazole-tetrazolyl derivatives differing on the spacer-group used for linkage of the two heterocyclic systems were designed, produced and tested as multidentate ligands in coordination reactions with transition-metal complexes.
Descrição: Tese de dout., Química, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2008
URI: http://hdl.handle.net/10400.1/856
Designação: Doutoramento em Química. Especialização em Química Orgânica
Aparece nas colecções:UA01-Teses

Ficheiros deste registo:
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13_Appendix D.pdf4,91 MBAdobe PDFVer/Abrir
12_Appendix C.pdf83,97 kBAdobe PDFVer/Abrir
11_Appendix B.pdf1,26 MBAdobe PDFVer/Abrir
10_Appendix A.pdf235,49 kBAdobe PDFVer/Abrir
9_CAPITULO 5.pdf140,29 kBAdobe PDFVer/Abrir
8_CAPITULO 4.pdf306,77 kBAdobe PDFVer/Abrir
7_CAPITULO 3_PARTE 3.pdf627,15 kBAdobe PDFVer/Abrir
6_CAPITULO 3_PARTE 2.pdf287,52 kBAdobe PDFVer/Abrir
5_CAPITULO 3_PARTE 1.pdf1,03 MBAdobe PDFVer/Abrir
4_CAPITULO 2.pdf536 kBAdobe PDFVer/Abrir
3_CAPITULO 1.pdf491,16 kBAdobe PDFVer/Abrir
2_INDICE_RESUMO.pdf173,86 kBAdobe PDFVer/Abrir
1_CAPA.pdf27,35 kBAdobe PDFVer/Abrir


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