Showing papers on "Xanthone published in 1993"
TL;DR: In an effort to develop increasingly potent and specific leukotriene B4 (LTB4) receptor antagonists, several xanthone dicarboxylic acids were synthesized and evaluated and compound 32 (LY210073) appears to be one of the strongest inhibitors of LTB4 receptor binding reported so far.
Abstract: In an effort to develop increasingly potent and specific leukotriene B4 (LTB4) receptor antagonists, several xanthone dicarboxylic acids were synthesized and evaluated. Two separate synthetic routes were used to construct a xanthone nucleus containing a regiospecific orientation of each carboxylic acid pharmacophore. These compounds represent the major conformationally-restricted analogues of benzophenone dicarboxylic acids previously shown to antagonize the activation of human neutrophils by LTB4. The most potent agent was compound 32, which inhibited the specific binding of [3H]LTB4 to receptors on intact human neutrophils (IC50, 6.2 +/- 0.1 nM), LTB4-induced luminol-dependent chemiluminescence (IC50, 55 +/- 11 nM), aggregation (IC50, 133 +/- 42 nM), and chemotaxis (IC50, 899 +/- 176 nM). The compound was a poor antagonist of N-formyl-L-methionyl-L-leucyl-L-phenylalanine-induced chemiluminescence (IC50, 1599 +/- 317 nM) and aggregation (IC50, 2166 +/- 432 nM), indicating specificity in the inhibition of LTB4-stimulated events. Compound 32 (LY210073), which was completely devoid of agonist activity, appears to be one of the strongest inhibitors of LTB4 receptor binding reported so far.
64 citations
TL;DR: The structure of garcinone E was elucidated as 1, 3, 6, 7-tetrahydroxy-2, 5, 8-tri-(3-methyl-2-buteny)xanthone by spectroscopic methods, including the application of a number of two dimensional (2D)NMR techniques.
Abstract: As part of a survey of anti-tumorpromotive chemicals, garcinone E (1) and nine known xanthones, 8-deoxygartanin, gartanin, xanthone I, β-mangostin, garcinone B, 6-deoxy-γ-mangostin, 1, 5, 8-trihydroxy-3-methoxy-2-(3-methyl-2-butenyl)xanthone, γ-mangostin and α-mangostin, together with egonol, were isolated from the fruit hulls of Garcinia mangostana L. collected in Thailand. The structure of garcinone E was elucidated as 1, 3, 6, 7-tetrahydroxy-2, 5, 8-tri-(3-methyl-2-buteny)xanthone by spectroscopic methods, including the application of a number of two dimensional (2D)NMR techniques (1H-1H, 13C-1H correlation spectroscopy (COSY), nuclear Overhauser effect spectroscopy (NOESY) and correlation via long-range coupling (COLOC).
48 citations
TL;DR: A new xanthone named paxanthone, 9,11-dihydroxy-5-methoxy-3,3-dimethylpyrano[3,2-a]xanthen-12(3H)-one, has been isolated from the callus tissues of Hypericum paturum together with toxyloxanthone B and γ-mangostin.
45 citations
TL;DR: In this paper, the photoreduction of xanthone with p-aminothiophenol in a sodium dodecylsulfate solution was investigated with the aid of a nanosecond laser flash photolysis technique at magnetic fields of 0-10 T.
20 citations
TL;DR: The xanthone as mentioned in this paper was derived from the base catalysed self-condensation of the chromone and showed that it can be obtained by refluxing with NaOMe in MeOH.
19 citations
TL;DR: The structure of the anticoccidial antibiotic xanthoquinodin A1(1), isolated from Humicola sp.
16 citations
TL;DR: The structure of Cercospora beticola toxin (CBT) was elucidated on the basis of mass, 1H NMR, 13C NMR and 2D NMR spectra and from biosynthetic evidence obtained from incorporation of [1-13C]acetate and [1,2-13c] acetate as discussed by the authors.
Abstract: The structure of Cercospora beticola toxin (CBT)1, a phytotoxic metabolite, was elucidated on the basis of mass, 1H NMR, 13C NMR and 2D NMR (13C, 13C COSY and 1H, 1H ROESY) spectra and from biosynthetic evidence obtained from incorporation of [1-13C]acetate and [1,2-13C] acetate. The product is a 2:2 complex with Mg of a compound derived from the coupling of two octaketide-derived reduced anthraquinone and xanthone moieties.
15 citations
Journal Article•
TL;DR: Compounds 2a and 2b are more active in inhibiting the proliferation of F10 metastatic murine melanoma cells, and 2a is 13 times more active at microM concentration after 48 h exposure.
Abstract: Chromone, flavone and xanthone analogues of geiparvarin (1) are described. Compounds 2a and 2b are more active in inhibiting the proliferation of F10 metastatic murine melanoma cells. In particular, 2a is 13 times more active at microM concentration after 48 h exposure.
12 citations
Patent•
26 May 1993
TL;DR: In this article, a polyarylene ether that contains xanthone units and has a very high heat resistance can be prepared from inexpensive, readily accessible monomers by polycondensation in a basic medium under essentially anhydrous conditions in the presence or absence of an aromatic solvent at temperatures of from 150° to 400° C.
Abstract: Polyarylene ethers that contain xanthone units and have a very high heat resistance can be prepared from inexpensive, readily accessible monomers by polycondensation in a basic medium under essentially anhydrous conditions in the presence or absence of an aromatic solvent at temperatures of from 150° to 400° C. Xanthone monomers and also hydroxyhalogen-substituted benzophenone compounds may be used as starting materials.
11 citations
TL;DR: The results on the pharmacological studies of xanthone glycoside and lanceoside suggested that they have a CNS depressant effect.
Abstract: 1-Hydroxy-3,4,7,8-tetramethoxyxanthone, β-sitosterol, uvaol-3-palmitate, and sweroside have been isolated from the fresh whole plant of Tripterospermum lanceolatum (Hayata) Haraex Satake (Gentianaceae). Our results on the pharmacological studies of xanthone glycoside and lanceoside suggested that they have a CNS depressant effect.
4 citations
TL;DR: In this paper, the 2,2′-diiodoketone is oxidized to the corresponding ketones by refluxing with Cu powder in N,N-dimethylformamide (DMF).
Journal Article•
TL;DR: A series of 2-substituted 1,4-dihydropyridines with a xanthone backbone was prepared and the compounds were evaluated for inotropic, chronotropic and calcium antagonist properties.
Abstract: A series of 2-substituted 1,4-dihydropyridines with a xanthone backbone was prepared. The compounds were evaluated for inotropic, chronotropic and calcium antagonist properties.
TL;DR: In this article, the xanthone was obtained from the base catalysed self-condensation of the chromone by refluxing with NaOMe in MeOH, and the pyran was derived from the reaction of ω-acetyl-2-hydroxyacetophenone with HC(OEt) 3 -Ac 2 O.
Abstract: The xanthone 8 results from the base catalysed self-condensation of the chromone 1 . The chromone 2 gives the xanthones 9 and 11 with sodium and DMF-POCl 3 respectively, phenol 14 with NaOMe, and the pyran 22 with 2-thiomethylchromone 6 . The enamine 16 on Vilsmeier-Haak reaction affords the chloroxanthone 12 . The pyran 15 , isolated as a byproduct from the reaction of ω-acetyl-2-hydroxyacetophenone with HC(OEt) 3 -Ac 2 O, affords the xanthone 13 by refluxing with NaOMe in MeOH.
TL;DR: The structure of Cercospora beticola toxin (CBT) was elucidated on the basis of mass, 1H NMR, 13C NMR and 2D NMR spectra and from biosynthetic evidence obtained from incorporation of [1-13C]acetate and [1,2-13c] acetate as discussed by the authors.
Abstract: The structure of Cercospora beticola toxin (CBT)1, a phytotoxic metabolite, was elucidated on the basis of mass, 1H NMR, 13C NMR and 2D NMR (13C, 13C COSY and 1H, 1H ROESY) spectra and from biosynthetic evidence obtained from incorporation of [1-13C]acetate and [1,2-13C] acetate. The product is a 2:2 complex with Mg of a compound derived from the coupling of two octaketide-derived reduced anthraquinone and xanthone moieties.
TL;DR: Pyranojacareubin; 1,5-dihydroxy-6',6'-dimethyl-2H-pyran(2',3':6,7) -6",6"-dim-ethyI- 2H,4H-Pyran (2",3":2,3)xanthone and a new xanthone l,6-dioxioxioxoxy-5methoxy-6,6'dim-ethyl-1.7-(3,3-dimethylprop-2-enyl)
Abstract: Pyranojacareubin; 1,5-dihydroxy-6',6'-dimethyl-2H-pyran(2',3':6,7) -6",6"-dim-ethyI-2H,4H-pyran(2",3":2,3)xanthone and a new xanthone l,6-dihydroxy-5-methoxy-6',6'-dim-ethyl-2H-pyran(2',3':3,2)-7-(3,3-dimethylprop-2-enyl)xanthone were isolated from the ether extract of the root bark of Rheedia acuminata together with friedelin and friedelanol.
Patent•
18 May 1993
TL;DR: In this article, a polyarylene ether is prepared from inexpensive, readily accessible monomers by polycondensation in basic medium under essentially anhydrous conditions in the presence or absence of an aromatic solvent at temperatures of from 150 to 400 DEG C.
Abstract: Polyarylene ethers which contain xanthone units and have very high heat resistance can be prepared from inexpensive, readily accessible monomers by polycondensation in basic medium under essentially anhydrous conditions in the presence or absence of an aromatic solvent at temperatures of from 150 to 400 DEG C. The starting materials in this process can be either xanthone monomers or hydroxyhalogen-substituted benzophenone compounds.