Xanthone

About: Xanthone is a research topic. Over the lifetime, 1639 publications have been published within this topic receiving 25870 citations. The topic is also known as: 9-oxo-xanthene & Diphenyline ketone oxide.

Decoding the Cytochrome P450 Catalytic Activity in Divergence of Benzophenone and Xanthone Biosynthetic Pathways

Abstract: Plant benzophenones and xanthones have an impressive spectrum of biological activities. Here, we characterized three cytochrome P450 (CYP) enzymes from the Garcinia xanthochymus tree that convey 2,4,6-trihydroxybenzophenone (2,4,6-triHB) toward the diversification between the biosynthesis of benzophenones and xanthones. The CYP3 catalyzes the transformation of 2,4,6-triHB to 2,3′,4,4′,6-pentahydroxybenzophenone (2,3′,4,4′,6-pentaHB) through two consecutive hydroxylations, while the paralog CYP1 catalyzes the synthesis of 1,3,7-trihydroxyxanthone (1,3,7-triHX). To understand the product diversity, we performed homology modeling and active site-directed reciprocal mutations on CYP3. The mutant enzyme assays revealed the key role of the V375 residue. Although the V375A mutation favors the 1,3,7-triHX formation, the V375L enhances further the yield of 2,3′,4,4′,6-pentaHB. The engineered triple mutant CYP3-V375L/S479A/K480H demonstrated an improved product specificity and catalytic transformation toward 2,3′,4,4′,6-pentaHB. Our results represent an advance in the metabolism of benzophenones and xanthones, laying the foundation for discovery of downstream genes and even the production of new derivatives. The engineering of CYP enzymes that stand in divergence of biosynthetic pathways for benzophenones and xanthones provides the basis for designing new drugs and facilitates future synthetic biology applications.

N-(3-Hydroxy-9H-xanthenyl-O-(9H-fluoren-9-yl)methylcarbamic Acid

Abstract: [114587-60-9] C28H21NO4 (MW 435.47) InChI = 1S/C28H21NO4/c30-17-13-14-23-26(15-17)33-25-12-6-5-11-22(25)27(23)29-28(31)32-16-24-20-9-3-1-7-18(20)19-8-2-4-10-21(19)24/h1-15,24,27,30H,16H2,(H,29,31) InChIKey = ABGQOXIZMUEHIU-UHFFFAOYSA-N (handle for solid-phase peptide synthesis (SPPS) with Fmoc chemistry) Form Supplied in: not commercially available. Analysis of Reagent Purity: NMR and elemental analysis are available for different linkers on 3-hydroxy position. Preparative Methods: depending on the linker attached to the 3-hydroxy position, there are two main methods to prepare this SPPS handle. The first method1 started from 3-hydroxy xanthone which was reacted with (chloromethyl)polystyrene to introduce the polymeric support. The resulting polymer supported xanthone derivative was then reduced with LiBH4 followed by treatment of the resulting alcohol with Fmoc-NH2 in the presence of a catalytic amount of acid to provide the desired title SPPS handle (eq 1). (1) In the second method,2 3-hydroxy xanthone was reacted with different alkyl halides to introduce a series of 3-hydoxy substituted alkyl esters, which were then saponified to the corresponding acids. With an improved set of reduction conditions, the xanthone derivatives were then converted to the alcohols followed by the introduction of the Fmoc amine to give the title reagent with alkanoic acids of different chain lengths attached to the 3-hydoxy position. These handles were then introduced onto polystyrene (PS) resins or polyethylene glycolpolystyrene (PEG-PS) graft supports with peptide coupling reagents (eq 2). (2)

2‐(3,7‐Dimethyl­octa‐2,6‐dien­yl)‐1,3,5,8‐tetra­hydroxyxanthone

Abstract: The title compound, C23H24O6, a xanthone derivative, was isolated from Garcinia polyantha Oliver. The orientation of the 3,7-dimethyl­octa-2,6-dienyl substituent with respect to the xanthone ring system is (+)synclinal. The crystal packing is stabilized by O—H⋯O and C—H⋯O inter­molecular hydrogen bonds and π–π inter­actions.

Antimicrobial and Cytotoxic Agents from Calophyllum inophyllum

Abstract: The study of the chemical constituents of the root bark and the nut of Calophyllum inophyllum has resulted in the isolation and characterization of a xanthone derivative, named inoxanthone, 3, together with 12 known compounds: caloxanthones A, 4 and B, 5, macluraxanthone, 6, 1,5-dihydroxyxanthone, 7, calophynic acid, 8, brasiliensic acid, 9 inophylloidic acid, 10, friedelan-3-one, 11, calaustralin, 12, calophyllolide, 13, inophyllums C, 14 and E, 15. Their structures were established on the basis of spectral evidence. Their in vitro cytotoxicity against the KB cell line and their antibacterial activity and potency against a wide range of micro organisms were evaluated.

Synthesis of Toxyloxanthone B.

Abstract: A synthesis of the naturally occurring xanthone toxyloxanthone B is described, in which the key step is the regioselective addition of a methyl salicylate to a substituted benzyne followed by cyclization of the intermediate aryl anion to form the xanthone, the regiochemistry of the aryne addition being confirmed by X-ray crystallography Subsequent introduction of the pyran ring by [3,3]-rearrangement and deprotection completed the synthesis