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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Transforma??es qu?micas, caracteriza??es e estudo de modelagem molecular do clerodano bioativo trans-desidrocrotonina

Soares, Breno Almeida 15 September 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-03T20:32:41Z No. of bitstreams: 1 BrenoAlmeidaSoares_TESE.pdf: 5447488 bytes, checksum: 8e0fcaa75efcdf3b24876215c0ef7081 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-04T00:03:56Z (GMT) No. of bitstreams: 1 BrenoAlmeidaSoares_TESE.pdf: 5447488 bytes, checksum: 8e0fcaa75efcdf3b24876215c0ef7081 (MD5) / Made available in DSpace on 2016-02-04T00:03:56Z (GMT). No. of bitstreams: 1 BrenoAlmeidaSoares_TESE.pdf: 5447488 bytes, checksum: 8e0fcaa75efcdf3b24876215c0ef7081 (MD5) Previous issue date: 2014-09-15 / Neste trabalho foram desenvolvidos estudos sint?ticos e te?ricos para clerodanos bioativos obtidos de uma das plantas medicinais mais representativas da regi?o Amaz?nica do Brasil, Croton cajucara Benth. Especificamente, utilizou-se como mol?cula alvo o biocomposto majorit?rio isolado das cascas do caule deste Croton, o diterpen?ide 19-nor-clerodano trans-desidrocrotonina (t-DCTN). Derivados semisint?ticos foram obtidos de t-DCTN utilizando-se os seguintes procedimentos sint?ticos: 1) redu??o catal?tica com H2, 2) redu??o com NaBH4 e 3) redu??o estereosseletiva com NaBH4/CeCl3). Os derivados semi-sint?ticos do tipo 19-nor-furano-clerodanos alco?licos foram denominados de t-CTN, t-CTN-??OL, t-CTN-??OL, t-DCTN-??OL e t-DCTN-??OL, tendo sido caracterizados por RMN. Os ?lcoois clerodanos derivados t-CTN-??OL e t-CTN-??OL foram obtidos a partir do derivado semi-sint?tico t-CTN, que tamb?m pode ser isolado das cascas do caule de C. cajucara. Uma metodologia te?rica (DFT/B3LYP) envolvendo a previs?o de propriedades geom?tricas e magn?ticas como ?ngulos e dist?ncias de liga??es bem como deslocamento qu?mico e constante de acoplamento, foi desenvolvida para a mol?cula alvo t-DCTN em que foram correlacionados dados te?ricos de RMN e estruturais, tendo sido obtidas correla??o satisfat?rias com dados experimentais de RMN (com coeficientes de correla??o variando entre 0,97 e 0,99) e de difra??o de Raios-X. Esta metodologia te?rica foi validada para todos os derivados semi-sint?ticos apresentados neste trabalho. Em adi??o, informa??es topol?gicas obtidas com o aux?lio da Teoria Qu?ntica de ?tomos em Mol?culas (QTAIM) evidenciaram a presen?a de intera??es estabilizantes intramoleculares do tipo H-H e (C)O--H(C) em t-DCTN e t-CTN, contribuindo para o entendimento da diferente reatividade destes clerodanos na presen?a de NaBH4. / In this work it were developed synthetic and theoretical studies for clerodane-type diterpenes obtained from Croton cajucara Benth which represents one of the most important medicinal plant of the Brazil amazon region. Specifically, the majoritary biocompound 19-nor-clerodane trans-dehydrocrotonin (t-DCTN) isolated from the bark of this Croton, was used as target molecule. Semi-synthetic derivatives were obtained from t-DCTN by using the followed synthetic procedures: 1) catalytic reduction with H2, 2) reduction using NaBH4 and 3) reduction using NaBH4/CeCl3. The semi-synthetic 19-nor-furan-clerodane alcohol-type derivatives were denominated such as t-CTN, tCTN-??OL, t-CTN-??OL, t-DCTN-??OL, t-DCTN-??OL, being all of them characterized by NMR. The furan-clerodane alcohol derivatives t-CTN-??OL and tCTN-??OL were obtained form the semi-synthetic t-CTN, which can be isolated from the bark of C. cajucara. A theoretical protocol (DFT/B3LYP) involving the prevision of geometric and magnetic properties such as bond length and angles, as well as chemical shifts and coupling constants, were developed for the target t-DCTN in which was correlated NMR theoretical data with structural data, with satisfactory correlation with NMR experimental data (coefficients ranging from 0.97 and 0.99) and X-ray diffraction data. This theoretical methodology was also validated for all semi-synthetic derivatives described in this work. In addition, topological data from the Quantum Theory of Atoms in Molecules (QTAIM) showed the presence of H-H and (C)O--H(C) intramolecular stabilized interactions types for t-DCTN e t-CTN, contributing to the understanding of the different reactivity of this clerodanes in the presence of NaBH4.

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