Identificação de componentes de óleos voláteis: Análise espectroscópica de misturas de sesquiterpenos

This paper describes a chromatographic method to fractionate volatile oils and to identify their sesquiterpenic constituents. The fractionation process includes flash chromatography over silica gel and chromatography over silica gel/AgNO3, utilising pentane, CH2Cl2 and/or acetone as eluents. GC chromatograms were obtained in order to get the relative percentage of each constituent in the volatile oils, to get the retention time value of them as well as to analyse and combine the fractions eluted from the columns. Such procedure afford mixtures of sesquiterpenes which are analysed by GC/MS, 13C and ¹H NMR.

Sesquiterpenos das algas marinhas Laurencia Lamouroux (Ceramiales, Rhodophyta) 1: Significado ecológico

The present work is a revision on the ecological significance of the production of sesquiterpenes by the marine algae of the genus Laurencia (Ceramiales, Rhodophyta).

Benzoquinonas, hidroquinonas e sesquiterpenos de Auxemma glazioviana

Two new compounds, 5 and 8, and an epimeric mixture 4a/4b were isolated from hardwood of Auxemma glazioviana. Their structures and relative configurations were determined by modern spectroscopic analysis to be rel-10alpha,11alpha-epoxy-11beta-ethoxy-8alpha- hydroxy-2-methoxy -8abeta-methyl-5,6,7,8,8a,9,10,10abeta-octahydro-1,4-anthracenedione (or rel-2R,2aR,5R,5aS ,10bS,10cS-2-ethoxy-5-hydroxy-8-methoxy-5a-methyl- 2a,3,4,5,5a,6,10b,10c-octahydro-2H-anthra[9,1-bc]furan-7,10-dione, 4a), rel-10alpha,11alpha- epoxy-11alpha-ethoxy-8alpha-hydroxy-2-methoxy-8abeta-methyl-5,6,7,8,8a,9,10,10abeta-octahydro- 1,4-anthracenedione (or rel-2S,2aR,5R,5aS ,10bS,10cS-2-ethoxy-5-hydroxy-8-methoxy- 5a-methyl-2a,3,4,5,5a,6,10b10c-octahydro-2H-anthra[9,1-bc]furan-7,10-dione, 4b), rel-10alpha,11alpha-epoxy-8alpha,11-dihydroxy-2-methoxy-8abeta-methyl-5,6,7,8,8a,9,10,10abeta- octahydro-1,4-anthracenedione (or rel-2S,2aR,5R,5aS ,10bS,10cS-2,5-dihydroxy-8- methoxy-5a-methyl-2a,3,4,5,5a,6,10b,10c-octahydro-2H-anthra[9,1-bc]furan-7,10 -dione, 5) and rel-10,11-epoxy-8abeta-methyl-1,4,5alpha,9alpha-tetrahydroxy-5,6,7,8,8a,9,10,10a- octahydro-8-anthracenone (or rel-2aS,5aS,6R,10bR ,10c5-2a,6,7,10-tetrahydroxy-5a-methyl-2a,3,4,5,5a,6,10b,10c-octahydro-2H-anthra [9,1-bc]-furan-5-one, 8). In addition, known compounds were also isolated.

Sesquiterpenos do caule de Pilocarpus riedelianus e atividades sobre microorganismos

Pilocarpus riedelianus was studied in order to obtain compounds with activity against fungi and bacteria. The dichloromethane extract, the most active one, was chromatographed yielding hexane and dichloromethane fractions. Six known sesquiterpenes, alpha-calacorene, beta-calacorene, gamma-calacorene, cadalene, sesquichamaenol and 1-hydroxy-1,3,5-bisabolatrien-10-one were identified in the hexane fractions. The identification of these compound was done by NMR and GC/MS analyses. The hexane fraction from the dichloromethane extract showed activity against several fungi and bacteria.

A síntese dos sesquiterpenos baquenolidas

The bakkenolide group of sesquiterpenes has been a focal point of synthetic efforts amongst several research laboratories all linked to our common origins at the Chemistry Institute at the State University in São Paulo. In this review we would like to present a historical perspective of this research, with unpublished background information, and a definitive retrosynthetic analysis of these molecules. This chemistry spans the time period from 1972 to 2006, and traces the initial steps with Prof. Dr. Helena Ferraz to the present day.

Sesquiterpenos de sementes de Guarea guidonia (Meliaceae)

Two new sesquiterpenes 6α-ethoxyeudesm-4(15)-en-1β-ol (1) and (7R*)-5-epi-opposit-4(15)-ene-1β,7-diol (7) were isolated from the seeds of a specimen of Guarea guidonia (Meliaceae). Five other known sesquiterpenes, eudesm-4(15)-ene-1β,6α-diol (2), 5-epi-eudesm-4(15)-ene-1β,6β-diol (3), eudesm-4(15)-ene-1β,5α-diol (4), eudesm-4(15),7-dien-1β-ol (5) and (7R*)-opposit-4(15)-ene-1β,7-diol (6), were also isolated in this work. Their structures were determined on the basis of spectral data (MS, IR, and NMR-1D and 2D) and subsequent comparisons with the literature. The substances 3, 4 and 6 are reported for the first time in Meliaceae and 5 for the first time in the genus Guarea.

Flavonoides e sesquiterpenos de Croton pedicellatus Kunth

The chemical investigation of the ethanolic extract from leaves of Croton pedicellatus yielded the bis-nor-sesquiterpenes blumenol A and blumenol A glucoside, along with the flavonoids: tiliroside, 6"-O-p-coumaroyl-β-galactopyranosyl- kaempferol, 6"-O-p-coumaroyl-β-glucopyranosyl-3"-methoxy- kaempferol, kaempferol, 3-glucopyranosyl-quercetin and alpinumisoflavone, as well as 4-hydroxy-3,5-dimethoxybenzoic acid. The identification of all isolated compounds was performed by spectrometric methods, including HR-ESI-MS, 1D and 2D NMR experiments, and by comparison with previously-described physical and spectral data.

Sesquiterpenos produzidos pelo fungo endofítico Phomopsis cassiae com atividade antifúngica e inibidora de acetilcolinesterase

SESQUITERPENES PRODUCED BY ENDOPHYTIC FUNGUS Phomopsis cassiae WITH ANTIFUNGAL AND ACETYLCHOLINESTERASE INHIBITION ACTIVITIES. Two new diastereoisomeric cadinanes sesquiterpenes 3,9-dihydroxycalamenene (1-2), along with the known 3-hydroxycalamen-8-one (3) and aristelegone-A (4), were isolated from ethyl acetate extract of Phomopsis cassiae, an endophytic fungus in Cassia spectabilis. Their structures, including relative stereochemistry, were determined on the basis of detailed interpretation of 2D NMR spectra and comparison with related known compounds. Compounds 1-4 displayed antifungal activity against the phytopathogenic fungi Cladosporium cladosporioides and C. sphaerospermum, as well as inhibition of acetylcholinesterase.

Sesquiterpenos de Ocotea lancifolia (Lauraceae)

Six new eremophilane sesquiterpenes, (rel)-4β,5β,7β-eremophil-9-en-12-oic acid (1), (rel)-4β,5β,7β-eremophil-1(10)-en-12-oic acid (2), (rel)-4β,5β,7β-eremophil-1(10)-en-2-oxo-12-oic acid (3), (rel)-4β,5β,7β-eremophil-9-en-12,8α-olide (4), (rel)-4β,5β,7β-eremophil-9-en-12,8β-olide (5) and (rel)-4β,5β,7β-eremophil-9α,10α-epoxy-12-oic acid (6), were isolated from the leaves of a specimen of Ocotea lancifolia (Lauraceae). Two other known sesquiterpenes, 4β,5β,7β-eremophil-11-en- 10α-ol (7) reported for the first time in the genus Ocotea, and the aromadendrene sesquiterpene, spathulenol (8), were also isolated. Their structures were determined on the basis of spectral data (MS, IR, UV and NMR-1D and 2D) and subsequent comparisons with the literature.

Sesquiterpenos e outros constituintes das folhas de Pterodon pubescens Benth (Leguminosae)

In addition to β-sitosterol, stigmasterol, phaeophitin A, luteolin, kaempferol, quercetin, (+)-catechin, quercetin-3-O-α-L-rhamnopyranoside, rutin, and p-hydroxy-benzoic acid, six known sesquiterpenes, namely (rel)-2β,6β-epoxy-5β-hydroxy-isodaucane, oplopanone, 1β,6α-dihydroxy-4(15)-eudesmene, caryophyllene oxide, α-cadinol, and spathulenol, were isolated from the leaves of Pterodon pubescens (Leguminosae) growing in the Cerrado of Mato Grosso do Sul, Brazil. The (rel)-2β,6β-epoxy-5β-hydroxy-isodaucane corresponds to the correct structure of homalomenol D. The sesquiterpene oplopanone, which bears a modified cadinane skeleton, is being reported for the first time in this genus. The structures of the compounds were determined on the basis of spectral data (MS, IR, and NMR-1D and 2D) and subsequent comparison with data reported in the literature.

Sesquiterpenos do caule de Pilocarpus riedelianus e atividades sobre microorganismos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sesquiterpenos produzidos pelo fungo endofítico Phomopsis cassiae com atividade antifúngica e inibidora de acetilcolinesterase

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sesquiterpenos e lignanas de Holostylis reniformis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudos visando à síntese de sesquiterpenos bacanos

Nesta tese, efetuamos estudos visando à síntese de sesquiterpenos bacanos, cuja etapa chave consistiu na construção do sistema cis-hidrindânico, através de reação de contração de anel de cis-octalinas e 2-octalonas mediada por trinitrato de tálio (TTN). Apenas as cis-octalinas como, por exemplo, o cis-4a-metil-l,2,3,4,4a,5,8,8a-octahidronaftaleno e o cis-4a, 7-dimetil-l,2,3,4,4a,5,8,8a-octa-hidronaftaleno, foram passíveis de reação de contração de anel em rendimentos satisfatórios; já a cis-5,10-dimetil-l(9)-octal-2-ona levou ao produto de contração em baixo rendimento. Tentamos utilizar a reação de cis-4a-metil-l,2,3,4,4a,5,8,8a-octa-hidronaftaleno com TTN na síntese da nor-baquenolida-A, porém não conseguimos completar a síntese desta, pois não foi possível efetuar a última etapa sintética, nas várias abordagens testadas. Grandes esforços também foram empregados na preparação diastereosseletiva da cis-5,10-dimetil-l(9)-octal-2-ona através de três abordagens diferentes que foram investigadas, sendo duas delas com êxito. Contudo, o baixo rendimento (38%) da etapa de contração de anel da cis-5,10-dimetil-l(9)-octal-2-ona não permitiu a continuação da rota sintética proposta para a baquenolida-A. Também realizamos a resolução cinética de três diferentes cis-octalóis que foram preparados através da reação de Diels-Alder seguida de redução diastereosseletiva - com a lipase Novozym 435, e os produtos resolvidos foram obtidos em excelentes rendimentos isolados (≥ 40% para cada enantiômero) e excelentes excessos enantioméricos (≥ 98%).

Neolignans and sesquiterpenes from leaves and embryogenic cultures of Ocotea Catharinensis (Lauraceae)

The extracts from leaves of Ocotea catharinensis Mez (Lauraceae) were found to contain fourteen neolignans and two sesquiterpenes: nine benzofuran types (including three new compounds 1e, 2f and 4b), one new seco-benzofuran type (3b), two bicyclo[3.2.1]octane types (including the new compound 5c), two new dimers of bicyclo[3.2.1]octane type (7a and 7b) and two sesquiterpenes (including a new humulanol 9). In addition, seven neolignans were also showed to occur in somatic embryos of O. catharinensis including one new bicyclo[3.2.1]octane type (4a).