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Yiyuan Peng - One of the best experts on this subject based on the ideXlab platform.
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generation of diverse 2 Pyrones via palladium catalyzed site selective suzuki miyaura couplings of 3 bromo 4 tosyloxy 2 Pyrone
ChemInform, 2012Co-Authors: Xiaoli Lei, Qiuping Ding, Liang Gao, Yiyuan PengAbstract:The title method is based on the different reactivity of the halide and pseudohalide substituents at Pyrone (I).
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rapid access to 4 substituted Pyrones and 2 5h furanones via a palladium catalyzed c oh bond activation
Tetrahedron, 2011Co-Authors: Qiuping Ding, Yiyuan PengAbstract:An efficient palladium-catalyzed cross-coupling reaction of 4-hydroxy-Pyrone or 4-hydroxy-2(5H)-furanone with arylboronic acid is described, which affords the 4-substituted-Pyrones and 2(5H)-furanones in good yields. This transformation proceeds through a C–OH bond activation under mild conditions.
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generation of diverse 2 Pyrones via palladium catalyzed site selective suzuki miyaura couplings of 3 bromo 4 tosyloxy 2 Pyrone
Organic and Biomolecular Chemistry, 2011Co-Authors: Xiaoli Lei, Qiuping Ding, Liang Gao, Yiyuan PengAbstract:Based on different reactivity of the (pseudo)halide substituents in the 2-Pyrone (3-Br and 4-OTs), palladium-catalyzed sequential site-selective Suzuki–Miyaura cross-coupling reactions of 3-bromo-6-methyl-4-tosyloxy-2-Pyrone are described, which afford the diverse 2-Pyrones in good yields.
Moacir Geraldo Pizzolatti - One of the best experts on this subject based on the ideXlab platform.
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dihydrostyryl 2 Pyrone as a chemical marker of three non xanthone producing polygala species polygalaceae
Biochemical Systematics and Ecology, 2020Co-Authors: Tiago Tizziani, Dalila Venzke, Ana Paula Ruani, Gustavo Amadeu Micke, Moacir Geraldo Pizzolatti, Ines Maria Costa BrighenteAbstract:Abstract The phytochemical investigation of the ethyl acetate fraction of Polygala longicaulis Kunth resulted in the isolation and identification of two dihydrostyryl-2-Pyrones (1–2). This is the third species of the Polygala L. genus, along with Polygala altomontana Ludtke, Boldrini & Miotto and Polygala sabulosa A.W. Benn., to present the accumulation of dihydrostyryl-2-Pyrones. The data reported herein make an important contribution to the chemotaxonomy of this genus. This is the first report of dihydrostyryl-2-Pyrone (1) and dihydrometisticin (2) in P. longicaulis and the first report of dihydrometisticin in the genus Polygala. Furthermore, this is the first grouping of non-xanthone-producing Polygala species.
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phytochemical and chemotaxonomic study of polygala altomontana polygalaceae
Biochemical Systematics and Ecology, 2018Co-Authors: Tiago Tizziani, Dalila Venzke, Ana Paula Ruani, Marcos Pereira, Gustavo Amadeu Micke, Moacir Geraldo Pizzolatti, Ines Maria Costa BrighenteAbstract:Abstract In this study, 7 compounds were isolated from a hydroalcoholic extract of Polygala altomontana: aurapten (1), α-spinasterol (2) dihydrostyryl-2-Pyrone (3) and styryl-2-Pyrones (4–7). The styryl-2-Pyrone (5) is new in the literature and although the others are known compounds this is the first time they have been isolated from the species P. altomontana. This is the second species of the genus Polygala to present the accumulation of dihydrostyryl-2-Pyrones and styryl-2-Pyrones. The chemotaxonomic significance of this data for the Polygala genus was summarized.
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Heck-Matsuda Arylation as a Strategy to Access Kavalactones Isolated from Polygala sabulosa, Piper methysticum, and Analogues
Alemanha, 2015Co-Authors: Soldi C, Moacir Geraldo Pizzolatti, Av Moro, Correia CrdAbstract:Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Herein, we describe the total syntheses of three bioactive Pyrones isolated from Polygala sabulosa (i.e., 1, 4, and 7) and eight isolated from Piper methysticum (i.e., 810, 13, 15, and 1820) using the HeckMatsuda arylation as the key strategy. The evaluation of this methodology by employing different arenediazonium tetrafluoroborates revealed that the Heck arylation was more efficient when the olefin undergoing arylation possessed the vinyl-2-Pyrone structural unit instead of the vinyl dihydro-2-Pyrone moiety. The HeckMatsuda arylation of many of the examined olefins proceeded in a practical manner with total regio- and stereocontrol.1936073616Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
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heck matsuda arylation as a strategy to access kavalactones isolated from polygala sabulosa piper methysticum and analogues
European Journal of Organic Chemistry, 2012Co-Authors: Moacir Geraldo Pizzolatti, Cristian Soldi, Angelica Venturini Moro, Carlos Roque D CorreiaAbstract:Herein, we describe the total syntheses of three bioactive Pyrones isolated from Polygala sabulosa (i.e., 1, 4, and 7) and eight isolated from Piper methysticum (i.e., 8–10, 13, 15, and 18–20) using the Heck–Matsuda arylation as the key strategy. The evaluation of this methodology by employing different arenediazonium tetrafluoroborates revealed that the Heck arylation was more efficient when the olefin undergoing arylation possessed the vinyl-2-Pyrone structural unit instead of the vinyl dihydro-2-Pyrone moiety. The Heck–Matsuda arylation of many of the examined olefins proceeded in a practical manner with total regio- and stereocontrol.
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trypanocidal activity of coumarins and styryl 2 Pyrones from polygala sabulosa a w bennett polygalaceae
Revista Brasileira De Farmacognosia-brazilian Journal of Pharmacognosy, 2008Co-Authors: Moacir Geraldo Pizzolatti, Beatriz G Mendes, Anildo Cunha, Cristian Soldi, Adolfo H Koga, Iriane Eger, Edmundo C Grisard, Mario SteindelAbstract:Bioactivity of fractions and compounds obtained from Polygala sabulosa against Trypanosoma cruzi epimastigote, blood trypomastigote and amastigote forms were evaluated in vitro. Dichloromethane and ethyl acetate fractions showed a strong trypanocidal activity on epimastigotes (IC50 < 10.4 µg/mL). Chromatographic analysis by TLC of these fractions confirmed the presence of previously described compounds (dihydrostyryl-2-Pyrones, styryl-2-Pyrones and 6-methoxy-7-prenyloxycoumarin). The dichloromethane fraction was fractioned by silica gel column chromatography to afford the compound α-spinasterol and the ethyl acetate fraction yielded apigenin, quercetin and a quercetin-3-O-glucoside, being the first description for the Polygala genus. 4-Methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-Pyrone, 4-methoxy-6-(11,12-dimethoxystyryl)-2-Pyrone, 6-methoxy-7-prenyloxycoumarin and quercetin-3-O-glucoside showed a weak activity against blood trypomastigotes (IC50 < 1008.6 µg/mL). The prenylated coumarin was the most active compound against both epimastigote and trypomastigote forms, IC50 10.5 and 88.2 µg/mL, respectively. The hemolytic activity and cell toxicity of each active compound was also assessed. Furthermore, 4-methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-Pyrone and 6-methoxy-7-prenyloxycoumarin reduced 4 times the T. cruzi infection rate for Vero cells at 100 and 50 µg/mL, respectively. These results show for the first time active compounds against T. cruzi in P. sabulosa.
Cristian Soldi - One of the best experts on this subject based on the ideXlab platform.
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heck matsuda arylation as a strategy to access kavalactones isolated from polygala sabulosa piper methysticum and analogues
European Journal of Organic Chemistry, 2012Co-Authors: Moacir Geraldo Pizzolatti, Cristian Soldi, Angelica Venturini Moro, Carlos Roque D CorreiaAbstract:Herein, we describe the total syntheses of three bioactive Pyrones isolated from Polygala sabulosa (i.e., 1, 4, and 7) and eight isolated from Piper methysticum (i.e., 8–10, 13, 15, and 18–20) using the Heck–Matsuda arylation as the key strategy. The evaluation of this methodology by employing different arenediazonium tetrafluoroborates revealed that the Heck arylation was more efficient when the olefin undergoing arylation possessed the vinyl-2-Pyrone structural unit instead of the vinyl dihydro-2-Pyrone moiety. The Heck–Matsuda arylation of many of the examined olefins proceeded in a practical manner with total regio- and stereocontrol.
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trypanocidal activity of coumarins and styryl 2 Pyrones from polygala sabulosa a w bennett polygalaceae
Revista Brasileira De Farmacognosia-brazilian Journal of Pharmacognosy, 2008Co-Authors: Moacir Geraldo Pizzolatti, Beatriz G Mendes, Anildo Cunha, Cristian Soldi, Adolfo H Koga, Iriane Eger, Edmundo C Grisard, Mario SteindelAbstract:Bioactivity of fractions and compounds obtained from Polygala sabulosa against Trypanosoma cruzi epimastigote, blood trypomastigote and amastigote forms were evaluated in vitro. Dichloromethane and ethyl acetate fractions showed a strong trypanocidal activity on epimastigotes (IC50 < 10.4 µg/mL). Chromatographic analysis by TLC of these fractions confirmed the presence of previously described compounds (dihydrostyryl-2-Pyrones, styryl-2-Pyrones and 6-methoxy-7-prenyloxycoumarin). The dichloromethane fraction was fractioned by silica gel column chromatography to afford the compound α-spinasterol and the ethyl acetate fraction yielded apigenin, quercetin and a quercetin-3-O-glucoside, being the first description for the Polygala genus. 4-Methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-Pyrone, 4-methoxy-6-(11,12-dimethoxystyryl)-2-Pyrone, 6-methoxy-7-prenyloxycoumarin and quercetin-3-O-glucoside showed a weak activity against blood trypomastigotes (IC50 < 1008.6 µg/mL). The prenylated coumarin was the most active compound against both epimastigote and trypomastigote forms, IC50 10.5 and 88.2 µg/mL, respectively. The hemolytic activity and cell toxicity of each active compound was also assessed. Furthermore, 4-methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-Pyrone and 6-methoxy-7-prenyloxycoumarin reduced 4 times the T. cruzi infection rate for Vero cells at 100 and 50 µg/mL, respectively. These results show for the first time active compounds against T. cruzi in P. sabulosa.
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antinociceptive properties of coumarins steroid and dihydrostyryl 2 Pyrones from polygala sabulosa polygalaceae in mice
Journal of Pharmacy and Pharmacology, 2006Co-Authors: Juliana V Ardenghi, Moacir Geraldo Pizzolatti, Anildo Cunha, Cristian Soldi, Juliana B Pretto, Marcia Maria De Souza, Flavia Carla Meotti, Janaina Davila Moura, Adair R S SantosAbstract:We have investigated the possible antinociceptive action of the extract, fractions and pure compounds obtained from the whole plant Polygala sabulosa A. W. Bennett (Polygalaceae) in acetic acid-induced visceral pain in mice. Intraperitoneal injection of animals with the hydroalcoholic extract and fractions (CH2Cl2, EtOAc, n-BuOH, aqueous fraction) (1–100 mg kg−1) caused a dose-related and significant inhibition of the acetic acid-induced visceral nociceptive response. The CH2Cl2, EtOAc and n-BuOH fractions were more potent than the hydroalcoholic extract and aqueous fraction. The isolated compounds dihydrostyryl-2-Pyrones (1, 2, 3), styryl-2-Pyrone (7), α-spinasterol (9), scopoletin (10) and two esters of the coumarin (scopoletin) obtained semisynthetically, acetylscopoletin (10a) and benzoylscopoletin (10b) (0.001–10 mg kg−1), exhibited significant and dose-related antinociceptive effects against acetic acid-induced visceral pain. The results distinguished, for the first time, the extract, fractions and pure compounds obtained from P. sabulosa that produced marked antinociception against the acetic acid-induced visceral nociceptive response, supporting the ethnomedical use of P. sabulosa.
Thies Peters - One of the best experts on this subject based on the ideXlab platform.
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relaxation of evoked contractile activity of isolated guinea pig ileum by kavain
Planta Medica, 1997Co-Authors: Ulrike Seitz, Johannes Gleitz, Angela Ameri, Helmut Pelzer, Thies PetersAbstract:: Kava Pyrones are the pharmacologically active compounds of Piper methysticum Forst. In the present study, the effect of the synthetic kava Pyrone (+/-)-kavain was investigated on evoked contractile activity of isolated guinea-pig ileum. (+/-)-Kavain (1 microM-1 mM) dose-dependently reduced contractions of ileum evoked by carbachol (10 microM), by BAY K 8644 (0.3 microM), or by substance P (0.05 microM). (+/-)-Kavain also inhibited the contractile responses induced by raising the extracellular K+ concentration from 4 to 20 mM and by blocking the K+ channel by barium chloride (1 mM) or 4-aminopyridine (0.3 mM). After pre-incubation with 1 microM nifedipine, carbachol (1 microM) evoked 18.2 +/- 14.3% of contraction at control (i.e. prior pre-incubation with nifedipine). This remaining response was completely abolished by high concentrations of (+/-)-kavain (400 microM). After treatment of the longitudinal ileum strips with pertussis toxin (PTX), carbachol (1 microM) evoked 27.0 +/- 6.2% of the control response in untreated ileum. These contractions were also blocked by (+/-)-kavain (400 microM). However, (+/-)-kavain had no effect on the caffeine-induced (20 mM) contractions of ileum strips, which were permeabilized with digitonin or beta-escin. Moreover, it failed to affect Ca(2+)-evoked contractions of skinned muscles. These results suggest that the kava Pyrone (+/-)-kavain may act in a non-specific musculotropic way on the smooth muscle membrane.
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kavain inhibits non stereospecifically veratridine activated na channels
Planta Medica, 1996Co-Authors: Johannes Gleitz, Angela Ameri, Norbert Gottner, Thies PetersAbstract:: The action of the natural kava Pyrone, (+)-kavain, and its synthetic racemate, (+/-)-kavain, on voltage-dependent Na+ channels was investigated, while considering their stereospecific properties, on veratridine-induced increases in cytosolic free Na+ and Ca2+ ([Na+]i, [Ca2+]i) and the release of endogenous glutamate from cerebrocortical synaptosomes. Both compounds dose-dependently suppressed the veratridine-induced increase in [Na+]i, [Ca2+]i and glutamate release with IC50 values (+/- S.D.) of 71 +/- 22, 72 +/- 7, 120 +/- 37 micromol/l (+)-kavain and 77 +/- 21, 90 +/- 14, 92 +/- 23 micromol/l (+/-)-kavain, respectively. As judged from the dose-dependency, IC50 values, velocity and time course of action, both kava Pyrones were equally effective suggesting a non-stereospecific inhibition of veratridine-activated Na+ channels.
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kavain inhibits veratridine activated voltage dependent na channels in synaptosomes prepared from rat cerebral cortex
Neuropharmacology, 1995Co-Authors: Johannes Gleitz, A. Beile, Thies PetersAbstract:Abstract Kava Pyrones are pharmacologically active compounds extracted from Piper methysticum Forst. Because kava Pyrones were characterized by their anticonvulsive, analgesic and centrally muscle relaxing action, we investigated the influence of (±)-kavain, a synthetic kava Pyrone, on veratridine-stimulated increase in intrasynaptosomal Na + concentration ([Na + ] i ) of rat cerebrocortical synaptosomes. [Na + ] i was measured spectrofluorometrically employing SBFI as Na + sensitive fluorescence dye. Veratridine (5 μmol/l) enhanced basal [Na + ] i 6.6-fold from 11.3 to 74.1mmol/l Na + . Incubation of synaptosomes for 100 sec with (±)-kavain was sufficient to reduce dose dependently the stimulated increase of [Na + ] i with an IC 50 value of 86.0 μmol/l, and almost complete inhibition of Na + -channels was attained with 400 μmol/l (±)-kavain. The reference compounds, procain (400 μmol/l) and tetrodotoxin (TTX, 10 μmol/l) reduced veratridine-elevated [Na + ] i to 30.4% and 7.9% of control whereas the centrally acting muscle relaxant mephenesin (400 μmol/l) was without any effect. Postapplication of 400 μmol/l (±)-kavain or 10 μmol/l TTX immediately diminished veratridine-elevated [Na + ] i to nearly basal levels with a half life time of 69.7 and 41.8 sec, respectively. To study the influence of (±)-kavain on non stimulated synaptosomes, an increase in [Na + ] i was induced by 200 μmol/l ouabain, which enhanced [Na + ] i hyperbolically with an initial rate of 18.4 mmol Na + /l min. Preincubation of synaptosomes with 400 μmol/l (±)-kavain or 10 μmol/l TTX partly prevented Na + -influx for both compounds to the same extent of about 57% of control. The presented data indicate a fast and specific inhibition of voltage-dependent Na + -channels by (±)-kavain.
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kavain inhibits veratridine activated voltage dependent na channels in synaptosomes prepared from rat cerebral cortex
Neuropharmacology, 1995Co-Authors: Johannes Gleitz, A. Beile, Thies PetersAbstract:Kava Pyrones are pharmacologically active compounds extracted from Piper methysticum Forst. Because kava Pyrones were characterized by their anticonvulsive, analgesic and centrally muscle relaxing action, we investigated the influence of (+/-)-kavain, a synthetic kava Pyrone, on veratridine-stimulated increase in intrasynaptosomal Na+ concentration ([Na+]i) of rat cerebrocortical synaptosomes. [Na+]i was measured spectrofluorometrically employing SBFI as Na+ sensitive fluorescence dye. Veratridine (5 mumol/I) enhanced basal [Na+]i 6.6-fold from 11.3 to 74.1 mmol/l Na+. Incubation of synaptosomes for 100 sec with (+/-)-kavain was sufficient to reduce dose dependently the stimulated increase of [Na+]i with an IC50 value of 86.0 mumol/l, and almost complete inhibition of Na(+)-channels was attained with 400 mumol/l) reduced veratridine-elevated [Na+]i to 30.4% and 7.9% of control whereas the centrally acting muscle relaxant mephenesin (400 mumol/l) was without any effect. Postapplication of 400 mumol/l (+/-)-kavain or 10 mumol/l TTX immediately diminished veratridine-elevated [Na+]i to nearly basal levels with a half life time of 69.7 and 41.8 sec, respectively. To study the influence of (+/-)-kavain on non stimulated synaptosomes, an increase in [Na+]i was induced by 200 mumol/l ouabain, which enhanced [Na+]i hyperbolically with an initial rate of 18.4 mmol Na+/l min. Preincubation of synaptosomes with 400 mumol/l (+/-)-kavain or 10 mumol/l TTX partly prevented Na(+)-influx for both compounds to the same extent of about 57% of control. The presented data indicate a fast and specific inhibition of voltage-dependent Na(+)-channels by (+/-)-kavain.
Qiuping Ding - One of the best experts on this subject based on the ideXlab platform.
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generation of diverse 2 Pyrones via palladium catalyzed site selective suzuki miyaura couplings of 3 bromo 4 tosyloxy 2 Pyrone
ChemInform, 2012Co-Authors: Xiaoli Lei, Qiuping Ding, Liang Gao, Yiyuan PengAbstract:The title method is based on the different reactivity of the halide and pseudohalide substituents at Pyrone (I).
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rapid access to 4 substituted Pyrones and 2 5h furanones via a palladium catalyzed c oh bond activation
Tetrahedron, 2011Co-Authors: Qiuping Ding, Yiyuan PengAbstract:An efficient palladium-catalyzed cross-coupling reaction of 4-hydroxy-Pyrone or 4-hydroxy-2(5H)-furanone with arylboronic acid is described, which affords the 4-substituted-Pyrones and 2(5H)-furanones in good yields. This transformation proceeds through a C–OH bond activation under mild conditions.
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generation of diverse 2 Pyrones via palladium catalyzed site selective suzuki miyaura couplings of 3 bromo 4 tosyloxy 2 Pyrone
Organic and Biomolecular Chemistry, 2011Co-Authors: Xiaoli Lei, Qiuping Ding, Liang Gao, Yiyuan PengAbstract:Based on different reactivity of the (pseudo)halide substituents in the 2-Pyrone (3-Br and 4-OTs), palladium-catalyzed sequential site-selective Suzuki–Miyaura cross-coupling reactions of 3-bromo-6-methyl-4-tosyloxy-2-Pyrone are described, which afford the diverse 2-Pyrones in good yields.
