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ABSTRACT: Five new flavonoids, 5,8-dihydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone (1), 7-hydroxy-3,5-dimethoxy-3',4'-methylenedioxyflavone (2), 7-(2,3-dihydroxy-3-methylbutoxy)-3,5-dimethoxy-3',4'-methylenedioxyflavone (3), 7-(2,3-dihydroxy-3-methylbutoxy)-3,3',4',5-tetramethoxyflavone (4), and 7-(2,3-dihydroxy-3-methylbutoxy)-3,3',4',5,8-pentamethoxyflavone (5), were isolated from the leaves of Melicope triphylla. In addition, six known flavonoids were detected: 3,4',5-trihydroxy-3',7,8-trimethoxyflavone (6), 5,7-dihydroxy-3-methoxy-3',4'-methylenedioxyflavone (7), 4',5,7-trihydroxy-3,3'-dimethoxyflavone (8), 4',7-dihydroxy-3,3',5,8-tetramethoxyflavone (9), 4',7-dihydroxy-3,3',5-trimethoxyflavone (10), and 4',5,7-trihydroxy-3,3',8-trimethoxyflavone (11). The new compound structures were determined by spectroscopic methods. Compounds 1-5 did not exhibit any ichthyotoxic activity against Japanese killifish (medaka in Japanese) (Oryzias latipes var.) at 10 ppm.
Chemical & pharmaceutical bulletin 01/2013; 61(4):384-9. · 1.70 Impact Factor
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ABSTRACT: AbstractA polymer-supported terpyridine Pd(II) complex was prepared and found to promote the Suzuki–Miyaura coupling reaction in water.
Thus, terpyridine ligand was prepared from p-hydroxybenzaldehyde, propane sultone, and 2-acetylpyridine according to the reported procedures. Immobilization of terpyridine
ligand onto a polystyrene–poly(ethylene glycol) (PS–PEG) resin through ionic bonds to sulfonate group took place and the complexation
of PS–PEG–terpyridine ligand with Pd(II) underwent to give PS–PEG–terpyridine-Pd(II) complex. This polymeric catalyst showed
high catalytic activity and high reusability for the Suzuki–Miyaura coupling reaction.
Graphical Abstract
KeywordsSuzuki–Miyaura coupling reaction-Cross-coupling-Terpyridine-Polymer-supported catalyst-Palladium
Catalysis Letters 04/2012; 139(3):85-89. · 2.24 Impact Factor
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ABSTRACT: Six new flavonoids-5-hydroxy-3,8-dimethoxy-3',4':6,7-bismethylenedioxyflavone (1), 3,3',4',5-tetramethoxy-7-(3-methylbut-2-enyloxy)flavone (2), 7-(2-hydroxy-3-methylbut-3-enyloxy)-3,3',4',5-tetramethoxyflavone (3), 7-(2-hydroxy-3-methylbut-3-enyloxy)-3,5-dimethoxy-3',4'-methylenedioxyflavone (4), 7-(2-hydroxy-3-methylbut-3-enyloxy)-3,3',4',5,8-pentamethoxyflavone (5), and 7-(2-hydroxy-3-methylbut-3-enyloxy)-3,5,8-trimethoxy-3',4'-methylenedioxyflavone (6)-were isolated from the leaves of Melicope triphylla. In addition, six already known flavonoids were also detected: 5-hydroxy-3,6,7-trimethoxy-3',4'-methylenedioxyflavone (7), 5,7-dihydroxy-3,3',4',8-tetramethoxyflavone (8), 4',5-dihydroxy-3,3',7,8-tetramethoxyflavone (9), 3,5,6,7,8-pentamethoxy-3',4'-methylenedioxyflavone (10), 3,5,6,7-tetramethoxy-3',4'-methylenedioxyflavone (11), and 3,3',4',5,6,7,8-heptamethoxyflavone (12). The structures of the new compounds were established by spectroscopic methods. Compound 2 displayed ichthyotoxic activity against Japanese killifish (medaka in Japanese) (Oryzias latipes var.) at 10 ppm.
Chemical & pharmaceutical bulletin 01/2012; 60(9):1112-7. · 1.70 Impact Factor
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ABSTRACT: Four new flavonoids, 3,5-dihydroxy-7,8-dimethoxy-3',4'-methylenedioxyflavone (1), 3,5-dihydroxy-7-methoxy-3',4'-methylenedioxyflavone (2), 3,5-dihydroxy-7-isopentenyloxy-8-methoxy-3',4'-methylenedioxyflavone (3) and 5-hydroxy-3-isopentenyloxy-7-methoxy-3',4'-methylenedioxyflavone (4), were isolated from the leaves of Melicope triphylla. In addition, two known flavonoids were detected including 5-hydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone (5) and 5-hydroxy-7-isopentenyloxy-3,8-dimethoxy-3',4'-methylenedioxyflavone (6). The structures of the new compounds were established by spectroscopic methods.
Chemical & pharmaceutical bulletin 01/2010; 58(10):1339-42. · 1.70 Impact Factor
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Heterocycles 01/2010; 81(3). · 1.00 Impact Factor
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Synthesis-stuttgart. 01/2008; 2008(12):1960-1964.
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ABSTRACT: Nitromethane was safely applied as a C1 nucleophile for palladium-catalyzed pi-allylic substitution in water with amphiphilic PS-PEG resin-supported phosphine-palladium complexes. Catalytic asymmetric nitromethylation of cycloalkenyl esters was achieved in water as a single reaction medium under heterogeneous conditions using 5 mol % palladium of a PS-PEG resin-supported palladium-imidazoindolephosphine complex to give optically active (cycloalkenyl)nitromethanes with up to 98% ee.
The Journal of Organic Chemistry 11/2006; 71(22):8644-6. · 4.45 Impact Factor
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ABSTRACT: [reaction: see text] Rhodium-catalyzed asymmetric allylic alkylation of 1-substituted 2-propenyl acetates with dimethyl malonate proceeded with high enantioselectivity in the presence of cesium carbonate as a base and a rhodium catalyst generated from Rh(dpm)(C(2)H(4))(2) (dpm = dipivaloylmethanato) and a chiral phosphino-oxazoline whose basic skeleton is axially chiral binaphthyl to give branch alkylation products in greater than 90% ee.
Organic Letters 06/2003; 5(10):1713-5. · 5.86 Impact Factor
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ABSTRACT: Enantioselective addition of aryllithiums 2a-d (Ar = Ph (a), 2-MeC(6)H(4) (b), 2-MeOC(6)H(4) (c), 1-naphthyl (d)) to 6-(dimethylamino)fulvene (1) in the presence of (-)-sparteine in toluene at -78 degrees C generated chiral cyclopentadienyllithiums (4) substituted with an N,N-dimethylamino(aryl)methyl group, where the enantioselectivities are 51, 91, 90, and 83% for 4a, 4b, 4c, and 4d, respectively. Treatment of the chiral cyclopentadienides 4 with FeCl(2) or Fe(acac)(2) gave ferrocenes, which contain an N,N-dimethylamino(aryl)methyl side chain on both of the cyclopentadienyl rings. The enantiomeric purity of the chiral ferrocenes 7 thus obtained is 99% ee or higher for those containing a 2-MeC(6)H(4) (7b) or a 2-MeOC(6)H(4) (7c) group.
The Journal of Organic Chemistry 06/2002; 67(10):3355-9. · 4.45 Impact Factor
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ABSTRACT: The palladium-catalyzed coupling reaction of aryl halides with terminal alkynes, the Sonogashira coupling, took place in water under copper-free conditions by use of an amphiphilic polystyrene-poly(ethylene glycol) (PS–PEG) resin-supported palladium–phosphine complex to give the corresponding aryl-substituted alkynes in high yields. The PS–PEG resin-supported palladium catalyst was recovered by simple filtration and reused four times without any loss of catalytic activity.Graphical abstract
Tetrahedron. 66(5):1064-1069.
