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Dulcie A Mulholland - One of the best experts on this subject based on the ideXlab platform.
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cox 2 inhibitory activity of homoisoflavanones and xanthones from the bulbs of the southern african ledebouria socialis and ledebouria ovatifolia hyacinthaceae hyacinthoideae
Phytochemistry, 2013Co-Authors: Catherine Waller, Moses K. Langat, Alfred E Thumser, Neil R Crouch, Dulcie A MulhollandAbstract:The bulbs of Ledebouria socialis (Hyacinthaceae) yielded the benzocyclobutene homoisoflavonoid, (R)-2',5-dihydroxy-3',4',7-trimethoxyspiro{2H-1-benzopyran-3-(4H)-9-bicyclo[4.2.0]octa[1,3,5]triene}-4-one, socialinone (1). Ledebouria ovatifolia yielded (2e,3R)-2,5-dihydroxy-7-methoxyspiro[2H-1-benzopyran-3(4H), 5'(6'H)-cyclobuta[f][1,3]benzodioxol]-4-one (2) and the homoisoflavanone, (E)-3-(3',4'-dihydroxybenzylidene)-5,7-dihydroxychroman-4-one, ovatifolionone (5), the dihydrochalcone, 4,4'-dihydroxy-2',6'-dimethoxydihydrochalcone (3), and xanthone, 1,6-dihydroxy-2,3,5-trimethoxy-8-methyl-9H-xanthen-9-one (4) along with 21 known compounds. Structures were determined using spectroscopic techniques. The anti-inflammatory activities of the homoisoflavonoids and xanthones isolated were evaluated against cyclooxygenase-1 and -2 isoenzymes. (R)-3-(3',4'-Dihydroxybenzyl)-7-hydroxy-5-methoxychroman-4-one (7), (E)-3-(3',4'-dihydroxybenzylidene)-7-hydroxy-5-methoxychroman-4-one (10), 1,3,6-trihydroxy-2-methoxy-8-methylxanthen-9-one (6) and ovatifolionone acetate (5Ac) exhibited significant activity against cyclooxygenase-2 at <10μM.
Ren-jie Song - One of the best experts on this subject based on the ideXlab platform.
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Intermolecular Anodic Oxidative Cross-Dehydrogenative C(sp3)-N Bond-Coupling Reactions of Xanthenes with Azoles.
Organic letters, 2019Co-Authors: Yong-zheng Yang, Ren-jie SongAbstract:A new anode strategy for accessing xanthen-9-azoles via an electrochemical C(sp3)-H/N-H cross-coupling of Xanthenes with azoles is described. This reaction proceeds efficiently with a broad scope of both Xanthenes and N-H-free azoles under metal- and additional oxidant-free conditions and represents a new access to direct incorporation of important N-heterocycle units into the resulting Xanthenes.
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Intermolecular Anodic Oxidative Cross-Dehydrogenative C(sp3)–N Bond-Coupling Reactions of Xanthenes with Azoles
2019Co-Authors: Yong-zheng Yang, Ren-jie SongAbstract:A new anode strategy for accessing xanthen-9-azoles via an electrochemical C(sp3)–H/N–H cross-coupling of Xanthenes with azoles is described. This reaction proceeds efficiently with a broad scope of both Xanthenes and N–H-free azoles under metal- and additional oxidant-free conditions and represents a new access to direct incorporation of important N-heterocycle units into the resulting Xanthenes
Moses K. Langat - One of the best experts on this subject based on the ideXlab platform.
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bioactive constituents from manilkara obovata sabine g don j h hemsl
Natural Product Research, 2020Co-Authors: Emmanuel Akosung, Sidonie Beactrice Kenmogne, Jules Lobe Songue, Jean Pierre Longue Ekon, Mehreen Lateef, Emmanuel Ngeufa Happi, Moses K. Langat, Georges Bellier Tabekoueng, Flavien A. A. TozeAbstract:The phytochemical investigation of the methanolic extracts of roots, stem bark, leaves and twigs of Manilkara obovata has led to the isolation of one new friedelane triterpene, lacefriedelic acid or 3β,23-dihydroxy D:A-friedooleanan-28-oic acid (1) and one new prenylated xanthone, lacexanthone or 4,7-dihydroxy-2,3,3,9,9-pentamethyl-2,2-dihydrofurano[2,3-a]pyrano[2,3-i]xanthen-13(9H)-one (2) alongside twenty-four known compounds. Compounds 1-11 are reported here for the first time from the genus Manilkara. The structures of all compounds were determined by spectroscopic analyses and X-ray crystallography. The methanolic extracts of twigs and leaves showed anti-oxidant activity of 93.2 and 91.1%, respectively, at 100 µg/mL when measured by DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), while the twig extract displayed 86.3% at 100 µg/mL against the urease inhibition assay. Some isolated compounds (1-4, 15 and 20) showed significant to moderate anti-oxidant activity and urease inhibition assay. It is estimated that significantly active anti-oxidants and urease inhibitors metabolized by the plant may find future application in food industry.
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cox 2 inhibitory activity of homoisoflavanones and xanthones from the bulbs of the southern african ledebouria socialis and ledebouria ovatifolia hyacinthaceae hyacinthoideae
Phytochemistry, 2013Co-Authors: Catherine Waller, Moses K. Langat, Alfred E Thumser, Neil R Crouch, Dulcie A MulhollandAbstract:The bulbs of Ledebouria socialis (Hyacinthaceae) yielded the benzocyclobutene homoisoflavonoid, (R)-2',5-dihydroxy-3',4',7-trimethoxyspiro{2H-1-benzopyran-3-(4H)-9-bicyclo[4.2.0]octa[1,3,5]triene}-4-one, socialinone (1). Ledebouria ovatifolia yielded (2e,3R)-2,5-dihydroxy-7-methoxyspiro[2H-1-benzopyran-3(4H), 5'(6'H)-cyclobuta[f][1,3]benzodioxol]-4-one (2) and the homoisoflavanone, (E)-3-(3',4'-dihydroxybenzylidene)-5,7-dihydroxychroman-4-one, ovatifolionone (5), the dihydrochalcone, 4,4'-dihydroxy-2',6'-dimethoxydihydrochalcone (3), and xanthone, 1,6-dihydroxy-2,3,5-trimethoxy-8-methyl-9H-xanthen-9-one (4) along with 21 known compounds. Structures were determined using spectroscopic techniques. The anti-inflammatory activities of the homoisoflavonoids and xanthones isolated were evaluated against cyclooxygenase-1 and -2 isoenzymes. (R)-3-(3',4'-Dihydroxybenzyl)-7-hydroxy-5-methoxychroman-4-one (7), (E)-3-(3',4'-dihydroxybenzylidene)-7-hydroxy-5-methoxychroman-4-one (10), 1,3,6-trihydroxy-2-methoxy-8-methylxanthen-9-one (6) and ovatifolionone acetate (5Ac) exhibited significant activity against cyclooxygenase-2 at <10μM.
Yong-zheng Yang - One of the best experts on this subject based on the ideXlab platform.
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Intermolecular Anodic Oxidative Cross-Dehydrogenative C(sp3)-N Bond-Coupling Reactions of Xanthenes with Azoles.
Organic letters, 2019Co-Authors: Yong-zheng Yang, Ren-jie SongAbstract:A new anode strategy for accessing xanthen-9-azoles via an electrochemical C(sp3)-H/N-H cross-coupling of Xanthenes with azoles is described. This reaction proceeds efficiently with a broad scope of both Xanthenes and N-H-free azoles under metal- and additional oxidant-free conditions and represents a new access to direct incorporation of important N-heterocycle units into the resulting Xanthenes.
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Intermolecular Anodic Oxidative Cross-Dehydrogenative C(sp3)–N Bond-Coupling Reactions of Xanthenes with Azoles
2019Co-Authors: Yong-zheng Yang, Ren-jie SongAbstract:A new anode strategy for accessing xanthen-9-azoles via an electrochemical C(sp3)–H/N–H cross-coupling of Xanthenes with azoles is described. This reaction proceeds efficiently with a broad scope of both Xanthenes and N–H-free azoles under metal- and additional oxidant-free conditions and represents a new access to direct incorporation of important N-heterocycle units into the resulting Xanthenes
Priyabrat Dash - One of the best experts on this subject based on the ideXlab platform.
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greener route for synthesis of aryl and alkyl 14h dibenzo a j Xanthenes using graphene oxide copper ferrite nanocomposite as a recyclable heterogeneous catalyst
Scientific Reports, 2017Co-Authors: Aniket Kumar, Lipeeka Rout, Lakkoji Satish Kumar Achary, R S Dhaka, Priyabrat DashAbstract:A facile, efficient and environmentally-friendly protocol for the synthesis of Xanthenes by graphene oxide based nanocomposite (GO-CuFe2O4) has been developed by one-pot condensation route. The nanocomposite was designed by decorating copper ferrite nanoparticles on graphene oxide (GO) surface via a solution combustion route without the use of template. The as-synthesized GO-CuFe2O4 composite was comprehensively characterized by XRD, FTIR, Raman, SEM, EDX, HRTEM with EDS mapping, XPS, N2 adsorption-desorption and ICP-OES techniques. This nanocomposite was then used in an operationally simple, cost effective, efficient and environmentally benign synthesis of 14H-dibenzo Xanthene under solvent free condition. The present approach offers several advantages such as short reaction times, high yields, easy purification, a cleaner reaction, ease of recovery and reusability of the catalyst by a magnetic field. Based upon various controlled reaction results, a possible mechanism for Xanthene synthesis over GO-CuFe2O4 catalyst was proposed. The superior catalytic activity of the GO-CuFe2O4 nanocomposite can be attributed to the synergistic interaction between GO and CuFe2O4 nanoparticles, high surface area and presence of small sized CuFe2O4 NPs. This versatile GO-CuFe2O4 nanocomposite synthesized via combustion method holds great promise for applications in wide range of industrially important catalytic reactions.