Methylxanthone

An improved product is reported to be obtained in higher yield if the cyclization of dihydroxybenzophenones is carried out at 210 °C in glycerol containing a trace of potassium hydroxide 3-hydroxy-4-methylxanthone was obtained in 50% overall yield from salicylic acid and 2-methylresorcinol, for example (75CJC2054). 

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,... 

The new 3,6-dihydroxy-l,7-dimethoxyxanthone was identified in this plant together with the 5-chloro-l,6-dihydroxy-3-methoxy-8-methylxanthone, 1), 2), Fig.(15), which is the first chloroxanthone isolated from higher plants. 

The methyl homologue, 1-hydroxy-3-methylxanthone, has been synthesised in 3 % yield from equimolar proportions of salicyloylurea and orcinol in the presence of orthophosphoric acid, phosphorus oxychloride and anhydrous zinc chloride by heating at 150 C for 5 hours (ref. 125). 

Bromination of alkyl heterocycles with NBS can often give rise to substitution in the side-chain or the nucleus or both. When the reaction was applied to 1,7-dimethoxy-3-methylxanthone, the site of attack depended on the concentration of radical initiator the tendency to side-chain bromination increased with molar ratio of benzoyl peroxide. Reaction of manganese(III) acetate with... 

In 1998, Fujimoto and co-workers reported the isolation of a novel nidulalin derivative, the l,9a-dihydro derivative of nidulalin A (888) (Fig. 13.8), along with the known compounds, emodin (791), and l,7-dihydroxy-3-methylxanthone, from the ascomycete Amxiella micropertusa (629). These authors also reported the isolation of this same compound in 2006, denoting it as GS-4 (888) (Fig. 13.8),... 

Me ether [155214-57-6]. 2,4,7-Trichloro-3,6,8-trihydroxy-5-methoxy- 1-methylxanthone. Demethylchodatin C15H9CI3O6 M 391.591 Constit. of the lichens Lecanora pachysoma and Lecidella chodati. Yellow cryst. (EtOAc). Mp 284-286°. Di-Me ether Chodatin Ci HiiCl30g M 405.617... 

Dechloro-8-0-methylthiomelin, 1 -Hydroxy-2-chloro-5,8-dimethoxy-6-methylxanthone... 

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