17014-70-9

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By heating the HCl salt of acronycine (1), the new acridone derivatives (6, 9, 13 and 15) were obtained together with noracronycine (2), dihydronoracronycine (3), 1,3-dihydroxy-10-methylacridone (4) and (5). Compound (5), one of the main products of this reaction, is a linear type dihydro derivative of 2, compound (9) is a furanoacridone derivative with a geminal methyl group and compound (15) is a derivative of 5 with an additional C5 unit.

Sixteen acridone alkaloids were isolated from Glycosmis citrifolia (Willd.) Lindl. (Rutaceae) collected in Taiwan.Seven of them are novel and are reported for the first time, and can be divided into four groups: the linear pyranoacridones glucofoline (1a) and pyranofoline (2a), the furanoacridone furofoline-II (3b), the hexa-oxygenated acridone (4a), and the prenylated acridones glycocitrine-I (5a), -II (5c), and 3-O-methylglycocitrine-II (5d).The structures were elucidated from spectral data and chemical transformations.N.O.e. experiments on the methoxymethyl derivatives of phenolic acridones were successfully applied to the determination of the position of the hydroxy group on the acridone nucleus.The location of the phenyl group of (5c) was established by correlation with compound (8), employing cyclization of (5c) with benzeneselenenyl chloride.Formic acid-catalysed cyclization of (5c) induced undesirable rearrangement of the prenyl group to form the products (9) and (10).

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