Triterpenos pentacíclicos e esteróides da casca do uchi (Sacoglottis uchi, Humiriaceae)

The ethanol extract from stem bark of Sacoglottis uchi Huber (popularly known as \x93uchi\x94 in the Amazon Region) was submitted to chromatographic fractionation. The dichloromethane fractions provided the pentacyclic triterpene 3-oxo-friedelin (1). The dichloromethane:methanol fractions provided the pentacyclic triterpenes pseudotaraxasterol (2), lupeol (3), a-amyrin (4), betulin (5), and methyl 2ß,3ß-dihydroxy-urs-12-en-28-oate (6) and a mixture of the steroids sitosterol (7) and stigmasterol (8). Their chemical structures were determined by NMR spectroscopy and comparison with spectroscopic data from the literature. All compounds are described for the first time in this species.O extrato etanólico da casca do caule de Sacoglottis uchi Huber (conhecida popularmente como \x93uchi\x94 na Amazônia) foi submetido a fracionamento cromatográfico. As frações eluídas com diclorometano forneceram o triterpeno pentacíclico 3-oxo-friedelina (1). As frações em diclorometano:metanol forneceram os triterpenos pentacíclicos pseudotaraxasterol (2), lupeol (3), a-amirina (4), betulina (5) e 2ß,3ß-di-hidroxi-urs-12-en-28-oato de metila (6), além de uma mistura dos esteróides sitosterol (7) e estigmasterol (8). Suas estruturas químicas foram determinadas por espectroscopia de RMN e comparação com os dados espectroscópicos descritos na literatura. Todas as substâncias isoladas são descritas pela primeira vez nesta espécie

Synthesis and Phytotoxicity of new substituted p- benzoquinones

Objetivou-se neste trabalho sintetizar e avaliar a atividade herbicida de compostos análogos à sorgoleona, quinona encontrada em exsudatos de raízes de sorgo. A 2,5-diidroxibenzo-1,4-quinona foi submetida à reação de metoxilação. O produto desejado, a 2,5-dimetoxibenzo-1,4-quinona [5] foi identificado em uma mistura, não sendo possível, entretanto fazer o seu isolamento. Partiu-se, então, para uma nova tentativa em que o 2,4,6-trimetoxibenzaldeído foi submetido à oxidação de Baeyer-Villiger. Porém, o produto esperado, 2- formiloxi-1,3,5-trimetoxibenzeno [12] não foi obtido, a reação resultou apenas na recuperação do material de partida. Em uma terceira tentativa, o 1,3,5- trimetoxibenzeno foi alquilado, resultando no composto 2-(dodec-1-il)-1,3,5- trimetoxibenzeno [7] em 31 % de rendimento. O éter [7] foi submetido à reação de oxidação com CAN e AMCPB, sendo apenas recuperado o material de partida (92% e 96%, respectivamente). A oxidação do éter [7] com CrO3 em presença de ácido acético glacial resultou em um composto não identificado, com 25% de rendimento. Finalmente, a oxidação do éter [7] com ácido peracético resultou na 3,5-dimetoxi-2-(dodec-1-il)benzo-1,4-quinona [8] em 33% de rendimento. A próxima etapa foi a tentativa de hidrólise da metoxila mais impedida da quinona [8]. Utilizou-se algumas gotas de HClO4 70%, mas o que se obteve foi uma mistura de substâncias e o produto desejado não foi detectado. Uma outra metodologia foi usada, onde a hidroquinona foi submetida à metoxilação. Essa reação resultou no 1,4-dimetoxibenzeno [13], em 88% de rendimento, que foi utilizado como material de partida para a síntese dos éteres 1,4-dimetoxi-2-(pent-1-il)-benzeno [15a] (64 % de rendimento); 1,4-dimetoxi-2- (hex-1-il)-benzeno [15b] (82 % de rendimento); 1,4-dimetoxi-2-(hept-1-il)- benzeno [15c] (67 % de rendimento); 1,4-dimetoxi-2-(oct-1-il)-benzeno [15d] (57 % de rendimento); 1,4-dimetoxi-2-(non-1-il)-benzeno [15e] (62 % de rendimento); 1,4-dimetoxi-2-(dodec-1-il)-benzeno [15f] (64 % de rendimento); 1,4-dimetoxi-2-(tetradec-1-il)-benzeno [15g] (52 % de rendimento); 1,4- dimetoxi-2-(hexadec-1-il)-benzeno [15h] (82 % de rendimento) e 1,4-dimetoxi-2- (octadec-1-il)-benzeno [15i] (46 % de rendimento). Esses éteres foram submetidos à reações de oxidação com CAN, resultando na obtenção das quinonas 5-pentil-2-(4-pentil-2,5-dimetoxifenil) benzo-1,4-quinona [16a] (37 % de rendimento); 5-hexil-2-(4-hexil-2,5-dimetoxifenil)benzo-1,4-quinona [16b] (24 % de rendimento); 5-heptil-2-(4-heptil-2,5-dimetoxifenil)benzo-1,4-quinona [16c] (45 % de rendimento); 5-octil-2-(4-octil-2,5-dimetoxifenil)benzo-1,4- quinona [16d] (21 % de rendimento); 5-nonil-2-(4-nonil-2,5- dimetoxifenil)benzo-1,4-quinona [16e] (37 % de rendimento); 5-dodecil-2-(4- dodecil-2,5-dimetoxifenil)benzo-1,4-quinona [16f] (39 % de rendimento); 5- tetradecil-2-(4-tetradecil-2,5-dimetoxifenil)benzo-1,4-quinona [16g] (42 % de rendimento); 5-hexadecil-2-(4-hexadecil-2,5-dimetoxifenil)benzo-1,4-quinona [16h] % (42 de rendimento) e 5-octadecil-2-(4-octadecil-2,5- dimetoxifenil)benzo-1,4-quinona [16i] (45 % de rendimento), como produtos majoritários, além das quinonas 2-pentil-1,4-benzoquinona [17a] (5 % de rendimento), 2-hexil-1,4-benzoquinona [17b] (5 % de rendimento), 2-heptil-1,4- benzoquinona [17c] (5 % de rendimento), 2-octil-1,4-benzoquinona [17d] (5 % de rendimento), 2-nonil-1,4-benzoquinona [17e] (5 % de rendimento), 2-dodecil- 1,4-benzoquinona [17f] (15 % de rendimento), 2-tetradecil-1,4-benzoquinona [17g] (3 % de rendimento), 2-hexadecil-1,4-benzoquinona [17h] ( 11 % de rendimento), 2-octadecil-1,4-benzoquinona [17i] (7 % de rendimento) resultantes da desmetilação oxidativa, como produtos secundários. O éter [15h] também foi submetido à oxidação com CrO3 em ácido acético glacial resultando na obtenção da 5-hexadecil-2-(4-hexadecil-2,5-dimetoxifenil)benzo-1,4-quinona [16h], em 6,8% de rendimento e da 2-hexadecil-1,4-benzoquinona [17h] em 3,8% de rendimento. A atividade fitotóxica das quinonas [8], [16a] - [16i], [17h] e [17i] foram avaliadas por meio de ensaios biológicos utilizando-se as plantas-teste Cucumis sativus, Sorghum bicolor, Euphorbia heterophylla e Ipomoea grandifolia. A quinona [16c] causou inibição de 47% em relação ao acúmulo de biomassa seca do sistema radicular do Sorghum bicolor L. e 29% e 35% em relação ao acúmulo de biomassa seca das partes aéreas de Cucumis sativus e Sorghum bicolor, respectivamente. As quinonas [17i] e [8] causaram 34,04 e 36,17 % de inibição em relação ao acúmulo de biomassa seca do sistema radicular e a quinona [17i] inibiu em 31,51 % a parte aérea de plantas de Euphorbia heterophylla. As inibições apresentadas pelos compostos sintetizados e testados sobre plantas de Ipomoea grandifolia variaram de 0 a 17,92 % para a parte aérea e de 3,51 a 29,82 % para o sistema radicular dessas plantas.This work reports on an attempt to synthesize and evaluate the herbicidal activity of analogue compounds of sorgoleona, quinone found in sorgum root exudates. A 2,5-dihydroxybenzo-1,4-quinone was submitted to methoxylation. The required product, 2,5-dimethoxybenze-1,4-quinone [5] was identified in a mixture. However, its isolation was not possible. In a second attempt, 2,4,6- trimethoxybenzaldehyde was submitted to Baeyer-Villiger oxidation. Nevertheless, the required product, 2-formiloxi-1,3,5-trimethoxybenzene [12] was not obtained, and the reaction resulted only in the recovery of the start material. In a third attempt, 1,3,5-trimethoxybenzene was alkylated to result in the compound 2-(dodec-1-yl)-1,3,5-trimethoxybenzene [7] with 31 % yield. Ether [7] was submitted to oxidative reaction with CAN and AMCPB. However, only the start material was recovered (92% and 96%, respectively). The oxidation of ether [7] with CrO3 in the presence of glacial acetic acid resulted in a compound not yet identified, with 25% yield. Finally, the oxidation of ether [7] with peracetic acid resulted in 3,5-dimethoxy-2-(dodec-1-yl)benzo-1,4-quinone [8] with 33% yield. In the next step, it was attempted to hydrolyze the most hindered methoxyl of quinone [8]. A few drops of HClO4 70% were used, but it just lead to a mixture of substances and the required product was not detected. In another methodology, hydroquinone was submitted to methoxylation. This reaction resulted in 1,4-dimethoxybenzene [13], with 88% yield, which was used as a start material in the synthesis of the ethers 1,4-dimethoxy-2-(pent-1-yl)- benzene [15a] (64 % yield); 1,4-dimethoxy-2-(hex-1-yl)-benzene [15b] (82 % yield); 1,4-dimethoxy-2-(hept-1-yl)-benzene [15c] (67 % yield); 1,4-dimethoxy- 2-(oct-1-yl)-benzene [15d] (57 % yield); 1,4-dimethoxy-2-(non-1-il)-benzene [15e] (62 % yield); 1,4-dimethoxy-2-(dodec-1-yl)-benzene [15f] (64 % yield); 1,4-dimethoxy-2-(tetradec-1-yl)-benzene [15g] (52 % yield); 1,4-dimethoxy-2- (hexadec-1-yl)-benzene [15h] (82 % yield) and 1,4-dimethoxy-2-(octadec-1-yl)- benzene [15i] (46 % yield). These ethers were submitted to oxidative reaction with CAN, leading to quinones 5-pentyl-2-(4-pentyl-2,5-dimethoxyphenyl) benzo-1,4-quinone [16a] (37 % yield); 5-hexyl-2-(4-hexyl-2,5- dimethoxyphenyl)benzo-1,4-quinone [16b] (24 % yield); 5-heptyl-2-(4-heptyl- 2,5-dimethoxyphenyl)benzo-1,4-quinone [16c] (45 % yield); 5-octyl-2-(4-octyl- 2,5-dimethoxyphenyl)benzo-1,4-quinone [16d] (21 % yield); 5-nonyl-2-(4- nonyl-2,5-dimethoxyphenyl)benzo-1,4-quinone [16e] (37 % yield); 5-dodecyl-2- (4-dodecyl-2,5-dimethoxyphenyl)benzo-1,4-quinone [16f] (39 % yield); 5- tetradecyl-2-(4-tetradecyl-2,5-dimethoxyphenyl)benzo-1,4-quinone [16g] (42 % yield); 5-hexadecyl-2-(4-hexadecyl-2,5-dimethoxyphenyl)benzo-1,4-quinone [16h] (42 % yield) and 5-octadecyl-2-(4-octadecyl-2,5-dimethoxyphenyl)benzo- 1,4-quinone [16i] (45 % yield), as major products, in addition to the quinones 2- pentyl-1,4-benzoquinone [17a] (5 % yield), 2-hexyl-1,4-benzoquinone [17b] (5 % yield), 2-heptyl-1,4-benzoquinone [17c] (5 % yield), 2-octyl-1,4- benzoquinone [17d] (5 % yield), 2-nonyl-1,4-benzoquinone [17e] (5 % yield), 2-dodecyil-1,4-benzoquinone [17f] (15 % yield), 2-tetradecyl-1,4-benzoquinone [17g] (3 % yield), 2-hexadecyl-1,4-benzoquinone octadecyl-1,4-benzoquinone [17h] ( 11 % yield), 2- [17i] (7 % yield) resulting from oxidative demethylation, as secondary products. Ether [15h] was also submitted to oxidation with CrO3 in glacial acetic acid to produce 5-hexadecyl-2-(4- hexadecyl-2,5-dimethoxyphenyl)benzo-1,4-quinone [16h], with 6,8% yield, and 2-hexadecyl-1,4-benzoquinone [17h] with 3,8% yield. The phytotoxic activity of the quinones [8], [16a] - [16i], [17h] and [17i] was evaluated by biological assays using Cucumis sativus, Sorghum bicolor, Euphorbia heterophylla and Ipomoea grandifolia as test-plants. Quinone [16c] caused inhibition 47% in relation to the accumulation of dry biomass of the radicular system of Sorghum bicolor and 29% and 35% in relation to the accumulation of aerial parts of Cucumis sativus and Sorghum bicolor, respectively. Quinones [17i] and [8] caused 34,04% and 36,17 % inhibition in relation to the accumulation of radicular system dry biomass, and [17i] inhibited by 31,51 % the aerial parts of Euphorbia heterophylla. The inhibitions presented by the compounds synthesized and tested on Ipomoea grandifolia varied from 0 to 17,92 % for the aerial part, and from 3,51 to 29,82 % for the radicular parts of this plant.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Triterpene esters isolated from leaves of Maytenus salicifolia Reissek.

The triterpene ester (3b)-olean-18-en-3-yl stearate (1), together with (3b)-urs-12-en-3-yl stearate (2), and (3b)-lup-20(29)-en-3-yl stearate (3) were isolated from leaves of Maytenus salicifolia Reissek (Celastraceae). The structure of 1, a new compound, including its configuration, was established by 1H, 13C, and DEPT-135 NMR data, including 2D experiments( HSQC, HMBC, COSY, and NOESY). The molecular mass (692 Da) was confirmed by gas chromatography coupled with mass spectrometry (CG/ MS)

Stereochemistry of 16α-hydroxyfriedelin and 3-oxo-16-methylfriedel-16-ene established by 2D NMR spectroscopy.

Friedelin (1), 3β-friedelinol (2), 28-hydroxyfriedelin (3), 16α-hydroxyfriedelin (4), 30-hydroxyfriedelin (5) and 16α,28-dihydroxyfriedelin (6) were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl3 solution, 16α-hydroxyfriedelin (4) reacted turning into 3-oxo-16- methylfriedel-16-ene (7). This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl3 solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY) spectroscopy and mass spectrometry (GC-MS). It is also the first time that all the 13C-NMR and 2D NMR spectral data are reported for compounds 4 and 7

Structural determination of 3beta-stearyloxy-urs-12-ene from Maytenus salicifolia by 1D and 2D NMR and quantitative 13C NMR spectroscopy.

Six pentacyclic triterpenoids, 3b-stearyloxy-urs-12-ene (1), friedelin (2), 3b-friedelinol (3), a-amyrin (4), b-amyrin (5), and lupeol (6), have been isolated from the hexane extract of Maytenus salicifolia Reissek (Celastraceae) leaves. The molecular and structural formula as well as the stereochemistry of a new pentacyclic triterpene (1) were determined using data obtained from 1H and 13C NMR spectra, DEPT135 and by 2D HSQC, HMBC, COSY and NOESY experiments. The molecular formula C48H84O2 was established using quantitative 13C NMR, and the molecular weight (692 Da) was confirmed by elemental analysis and mass spectrometry (GC-MS)

Microwave-assisted synthesis of borneol esters and their antimicrobial activity

<p>Seventeen borneol esters (<b>1</b>–<b>17</b>) were synthesised by conventional and microwave-assisted methodology using DIC/DMAP, and seven are described for the first time (<b>8</b>, <b>9</b>, <b>10</b>, <b>12</b>, <b>13</b>, <b>16</b> and <b>17</b>). The microwave-assisted methodology was carried out without use of solvents, displayed short reaction times, and showed equal or higher yields for all the long-chain esters and three aromatic compounds (<b>11</b>, <b>12</b> and <b>14)</b> when compared to the conventional approach. All the borneol esters were evaluated against the bacteria <i>Streptococcus sanguinis</i>, <i>Staphylococcus aureus</i>, <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i> and the fungus <i>Candida albicans</i>. Compounds <b>12</b>, <b>13</b> and <b>14</b> displayed promising antibacterial activity with a MIC equal to ampicilin (62.5 mg mL⁻¹) for some microorganisms. In fact, bornyl 3′,4′-dimethoxybenzoate (<b>13</b>) was active against all tested bacteria and fungus.</p

Salacia crassifolia (Celastraceae) : chemical constituents and antimicrobial activity.

The phytochemical study of hexane extract from leaves of Salacia crassifolia resulted in the isolation of 3β-palmitoxy-urs-12-ene, 3-oxofriedelane, 3β-hydroxyfriedelane, 3-oxo-28-hydroxyfriedelane, 3-oxo-29-hydroxyfriedelane, 28,29-dihydroxyfriedelan-3-one, 3,4-seco-friedelan-3-oic acid, 3β-hydroxy-olean-9(11):12-diene and the mixture of α-amirin and β-amirin. β-sitosterol, the polymer gutta-percha, squalene and eicosanoic acid were also isolated. The chemical structures of these constituents were established by IR, 1H and 13C NMR spectral data. Crude extracts and the triterpenes were tested against Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis and no activity was observed under the in vitro assay conditions. The hexane, chloroform, ethyl acetate and ethanol crude extracts, and the constituent 3,4-seco-friedelan-3-oic acid and 28,29-dihydroxyfriedelan-3-one showed in vitro antimicrobial activity against Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Streptococcus sanguinis and Candida albicans