Dicaffeoylquinic acid (DCQA) is a natural polyphenolic compound widely distributed in plants such as coffee beans, which possesses a range of pharmacological activities. Herein, is reported studies undertaken towards the first total synthesis of 3,5-DCQA conjugates. Two synthetic routes were investigated. The first route involves a seven step sequence beginning from quinic acid. The overall yield via this synthetic approach was 30%. The key steps involved in the sequence were a regioselective benzylation of the C-3-hydroxyl group followed by silyl protection of the C-1 and C-4 hydroxyl groups. Deprotection of the benzyl group by hydrogenolysis and opening of the lactone afforded the 3,5-diol. Esterification of the 3,5-diol with 3,4-tert-butyldimethylsilyl caffeoyl chloride afforded the di-ester. Removal of the protecting groups afforded 3,5-DCQA. The second route involved selective protection of the C-3-hydroxyl group with silyl followed by benzylation of the C-1 and C-3 hydroxyl groups. Saponification of the lactone ring followed by benzylation of the carboxylic acid gave the benzyl ester. Silyl deprotection afforded the 3,5-diol. The 3,5-diol was subsequently esterified by refluxing in toluene with commercially available Meldrum’s acid. In the final step, the synthesis of 3,5-DCQA was achieved by a Knoevenagel condensation of 3,4-dihydroxybenzaldehyde and a malonate ester of quinic acid. An efficient method for the synthesis of possible metabolites of quinic acid conjugates was also described. This protocol employs N-(4-methoxyphenyl)-trifluoroacetimidate glucuronyl as the donor. The key reaction in this sequence was the coupling of N-(4-methoxyphenyl)-trifluoroacetimidate glucuronyl with 4-hydroxy-3-methoxy-benzaldehyde.

Made available in DSpace on 2017-07-24T19:38:03Z (GMT). No. of bitstreams: 1 Vanessa Cristina Godoy Jasinski.pdf: 3849900 bytes, checksum: f8ecb7e08b0fac6fae8e4aec5fe4c1e3 (MD5) Previous issue date: 2010-03-12 / This study aimed to: develop methodological sequences for the collection and analysis of essential oils and phenolic compounds of B. uncinella, applicable to the study of other species of the genus Baccharis; determined by techniques of gas chromatography-mass spectrometry, the chemical composition of essential oils from the leaves of male and female specimens of B. uncinella from different populations of the plant growing in nature; isolate and determine the chemical structure of phenolic compounds present in leaves using mainly chromatographic and spectroscopic methods. In the Campos Gerais of Paraná, it was observed the occurrence of two supposed varieties of B. uncinella, Bu1 and Bu2, with markedly different sizes and quite different flowering times. For the first time the leaves were collected from male and female specimens of two populations of B. uncinella, proceed to the extraction and analysis of essential oils by GC-MS techniques. The essential oils of four samples had very similar compositions, as opposed to frequently published data indicating no difference between the compositions of oils of male and female specimens of the same species of Baccharis. The results obtained in this study are due to the care in collections of male and female specimens (in the same place and time), in the preparation of material (careful separation of the leaves), using the same conditions in the hydrodestillation and analysis by CG-EM . All four samples had low levels of monoterpenes and the following sesquiterpenes as the main components: caryophyllene (Bu1 10.03% and Bu1 7.64%; Bu2 6.06% and Bu2 7.96%); spathulenol (Bu1 28.99% and Bu1 29.68%; Bu2 24.30% and Bu2 16.94%), caryophyllene oxide (Bu1 12.98% and Bu2 14.24%; Bu2 9.75% and Bu2 23.52%). These results also confirmed the botanical identifications that were made based on the morphology of flowers, indicating the inexistence of the supposed sub-species. The water remaining after the hydrodestillation was extracted with CHCl3 and then with AcOEt, yielding four extracts containing mainly 3.5-dicaffeoylquinic and 3.4-dicaffeoylquinic acids, as demonstrated by analysis of their 1H and 13C NMR spectra. The leaves were also extracted in Sohxlet using three solvents in sequence: CHCl3, AcOEt and MeOH. Part of the methanol extract was purified by dissolving it in water, removing the precipitates formed by a cold rest and extracting it with AcOEt. The extract thus obtained with ethyl acetate was subjected to several vacuum chromatography steps leading to the isolation and identification of 3,5- dicaffeoylquinic acid by the analysis of its 1H and 13C NMR spectra. This route to the phenolic compounds was improved by obtaining extracts with ethyl acetate from aqueous solution at pH 8 and pH 3. The extract made in slightly alkaline conditions contained mainly flavonoids, while the one obtained at pH 3 contained derivatives of quinic acid. The AcOEt extract at pH 8 was fractionated on silica gel column under pressure leading to the isolation of three flavonoids identified by their UV, 1H and 13C NMR spectra (quercetin, luteolin and apigenin). The AcOEt extract at pH 4 was fractionated on a silica gel column leading to the isolation and identification of 3,4-dicaffeoylquinic acid by the 1H and 13C NMR spectra. / Este estudo teve como objetivos: desenvolver seqüências metodológicas para a obtenção e análise de óleos essenciais e compostos fenólicos de B. uncinella, aplicáveis ao estudo de outras espécies do gênero Baccharis; determinar por técnicas de cromatografia gasosa acoplada à espectrometria de massas, a composição química dos óleos essenciais das folhas de espécimes masculinos e femininos de B. uncinella procedentes de diferentes populações da planta crescendo in natura; isolar e determinar a estrutura química de compostos fenólicos presentes nas folhas utilizando, principalmente, métodos cromatográficos e espectrométricos. Nos Campos Gerais do Paraná, foi observada a ocorrência de duas supostas variedades de B. uncinella, Bu1 e Bu2, com portes acentuadamente diferentes e épocas de floração bem distintas. Pela primeira vez foram coletadas as folhas de espécimes masculinos e femininos de duas populações de B. uncinella, procedendo-se à extração e análise de seus óleos essenciais por técnicas de CG-EM. Os óleos essenciais das quatro amostras apresentaram composições muito semelhantes, em contraposição a dados frequentemente publicados, que indicam haver diferenças entre as composições de óleos de espécimes masculinos e femininos da mesma espécie de Baccharis. O resultado obtido na presente pesquisa se deve aos cuidados tomados nas coletas dos espécimes masculinos e femininos (mesmo local e horário), na preparação do material (separação minuciosa das folhas), no uso das mesmas condições nas hidrodestilações e nas análises por CG-EM. Todas as quatro amostras apresentaram baixos teores de monoterpenos e os seguintes sesquiterpenos como principais componentes: cariofileno (Bu1 10,03% e Bu1 7,64%; Bu2 6,06% e Bu2 7,96%); espatulenol (Bu1 28,99% e Bu1 29,68%; Bu2 24,30 %e Bu2 16,94%); cariofileno óxido (Bu1 12,98% e Bu2 14,24%; Bu2 9,75% e Bu2 23,52%). Estes resultados também confirmaram as identificações botânicas feitas com base na morfologia das flores, indicando a inexistência da suposta variedade. As águas restantes após as hidrodestilações foram extraídas com CHCl3 e em seguida com AcOEt, obtendo-se quatro extratos contendo principalmente os ácidos 3,5- dicafeoilquínico e 3,4-dicafeoilquínico, como demonstrado por análises dos seus espectros de RMN de 1H e 13C. As folhas foram também extraídas em Sohxlet por solventes em sequência:CHCl3, AcOEt e MeOH. Parte do extrato metanólico foi purificado dissolvendo-se em água, eliminando os precipitados formados por repouso a frio e extraindo-se com AcOEt. O extrato obtido desta forma com acetato de etila foi submetido a diversas cromatografias a vácuo, sendo isolado e identificado o ácido 3,5-dicafeoilquínico pela análise dos espectros de RMN de 1H e 13C. Esta rota para os compostos fenólicos foi melhorada através da obtenção de extratos com acetato de etila a partir da solução aquosa em pH 8 e em pH 3. O extrato feito em meio levemente alcalino continha principalmente flavonóides, enquanto que o que foi obtido em pH 3 continha os derivados do ácido quínico. O extrato AcOEt em pH 8 foi fracionado em coluna de silica gel sob pressão, levando ao isolamento e identificação de três flavonóides, identificados pelos seus espectros de UV, RMN 1H e 13C (quercetina, luteolina e apigenina). O extrato AcOEt em pH 4 foi fracionado em coluna de sílica gel, isolando-se e identificando-se o ácido 3,4-dicafeoilquínico pelo seus espectros de RMN de 1H e de 13C.