Xanthone derivatives

Nakatani K, Norimichi N, Tsutomu A, Hideyuki Y, Yasushi O. Inhibition of cyclooxygenase and prostaglandin E2 synthesis by -y-mangostin, a xanthone derivative in man-gosteen, in C6 rat glioma cells. Biochem Pharmacol 2002 63 73-79. 

Recanatini, M., Bisi, A., Cavalli, A., et al. (2001) A new class of nonsteroidal aro-matase inhibitors design and synthesis of chromone and xanthone derivatives and inhibition of the P450 enzymes aromatase and 17 alpha-hydroxylase/C 17,20-lyase. ./. Med. Chem. 44, 672-680. 

While treatment in HBr + AcOH by the Tarbell method424 leads directly from allylphenols 168 to compounds 169, other methods involve the formation of the brominated derivative obtained by adding HBr (in the presence of diphenylamine) to the allylphenol.432 Ring closure is effected by sodium ethoxide. Thus, the ll//-furo[3,2-a]xanthone derivative (177) can be obtained either directly from the allyl derivative (175) or via the bromo derivative (176).432 433 Similarly, 179 has been obtained from the chromone 178.434... 

In general, the Garcinia species contains xanthones and phenolic compounds. Xanthones and xanthone derivatives have been isolated from the various species of Garcinia (Rama Rao et al., 1980 Minami et al., 1994). However, the isolation of (-)-hydroxycitric acid [(-)-HCA] from a few species of Garcinia and its biological properties has attracted the attention of biochemists and health practitioners. (-)-HCA is found in the fruit rinds of G. cambogia, G. indica and G. atroviridis (Lewis and Neelakantan, 1965 Lewis, 1969), which are abundant in the Indian subcontinent and western Sri Lanka (CSIR, 1956 Watt, 1972). 

Xanthone derivatives can be obtained by oxidation of the hydroxyxanthanes prepared by the Paquette method or by employing the same method on derivatives of salicylic acid207 or / -ketoesters208. With the latter procedure compounds 349 and 350, respectively, were prepared. 

Canedo (3) identified polycyclic xanthone derivatives, (HI), a novel class of antitumor compounds isolated from a new marine microbe strain PO13-046 belonging to the genus Actinomadura sp., which has activity against several cancel cell lines. 

Gentiana (gentian) root is mutagenic in bacteria, which is due to the xanthone derivatives, gentisin and isogentisin. In experimental animals Gentiana olivieri is... 

Swertia species (felwort) are mutagenic in bacteria, because of the several xanthone derivatives that it contains. The clinical relevance of this remains to be established. They also have hypoglycemic effects in animals (5). 

A marine fungal isolate, identified as Wardomyces anomalus, was cultivated and found to produce two new xanthone derivatives, 2, 3, 6, 8-tetrahydroxy-l-methylxanthone 333 and 2, 3, 4, 6,... 

Main components The bitter principles, gentiopicrin (up to 3%) and amarogentin (in G. lutea amaropanin and amaroswerin in the other species), which is only present in small amounts, but possesses a far stronger bitter taste, as well as xanthone derivatives (gentisin and others), tannins, mucilage, considerable amounts of fermentable sugar... 

Interesting transformations occur in systems where the cyclohexa-2,5-dienone fragment is in a spiro connection with heterocycles. Thus, treatment of griseofulvin derivative 317 with magnesium iodide results in the xanthone derivative 318 via a dienone-phenol rearrangement (equation 152). 

Numerous xanthone derivatives have undergone clinical Investigation. AH-7725 (21) was comparable to DSCG In clinical trials, dille xanoxlc acid (22) was reported to be effective In exercise-Induced asthma. 

The general methods for the synthesis of xanthones were shown as Fig. 7 by Pedro et al. [50]. The other well-known methods for synthesizing xanthone derivatives have also been mentioned below. 

The NMR spectra of a great number of naturally occnrring xanthones have been reported and all chemical shifts assigned [102-104]. The carbonyl carbon shift is very important for identifying the oxygenation pattern of xanthone derivatives. The general observation is a decrease in electron density at the carbonyl carbon due to chelation ... 

S. Gobbi, A. Rampa et al. (2001). A new class of nonsteroidal aromatase inhibitors Design and 1293. synthesis of chromone and xanthone derivatives... 

Tetrahydro-l//-xanthene-l,9-diones, synthesised from cyclohexa-l,3-diones and 2-fluorobenzoyl chlorides, are efficient Michael acceptors, offering a route to 4a-substituted xanthone derivatives similar to the secalonic acid half unit (Scheme 12) <97JCS(P1)1819>. 

Methylchromone-3-carbaldehyde M -dunetbylhydrazone gives the endb-adduct with -phenylmaleimide from which xanthone derivatives result on treatment with palladis charcoal (94T4905). 

Bromoaryloxy)propanonitriles yield chroman-4-ones through a Parham cycloacylation and in a similar manner diphenyl ethers afford xanthone derivatives (94JCR(S)82). 

Matsushima, T., A. Araki, O. Yagame, et al. 1985. Mutagenicities of xanthone derivatives in Salmonella typhimurium TAIOO, TA98, TA97, and TA2637. Mutat. Res. 150(1-2) 141-146. 

Wrigley SK, Latif MA, Gibson, TM, Chicarelli-Robinson MI, Williams DH (1994) Structure Elucidation of Xanthone Derivatives with CD4-binding Activity from Penicillium gtabrum (Wehmer) Westling. Pure Appl Chem 66 2383... 

Rezanaka T, Rezanaka P, Sigler K (2008) A Biaryl Xanthone Derivative Having Axial Chirahty from Penicillium vinaceum. J Nat Prod 71 820... 

Tajixanthone was isolated from cultures of Aspergillus stellatus in 1970, and it was proposed the structure 153 [178]. Subsequently, the structure was revised to the correct one, 154 [179]. The same xanthone derivative was also isolated from Aspergillus variecolor, and the structure 154 was confirmed with the 5-configuration assigned for C-15 and C-20 and R-configuration for C-25 (Figure 3.51) [180]. 

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