9-Phenyl-2,3,7-trihydroxy-6-fluorone

Test with 9-phenyl-2,3 7-trihydroxy-6-fluorone (phenyl fiuorone) ... 

A pink precipitate or coloration is produced by the action of acid solutions of alkali germanates with the yellow alcohol solution of 9-phenyl-2,3,7-trihydroxy-6-fluorone (I). The composition of the reaction product is not known. In view of the phenolic nature of the dyestuff serving here as reagent, the possibility of ester formation as indicated by (II) is not excluded. Consideration must also be given to the production of an adsorption compound (color lake)2 between GeOa aq and (I). 

Reagent 0.06 % solution of 9-phenyl-2,3,7-trihydroxy-6-fluorone in 95 % alcohol, acidified with one drop oi % N hydrochloric acid. The solution is stable. 

Phenyl-3-fluorone (2,6,7-trihydroxy-9-phenylxanthen-3-one) [975-17-7] M 320.3, m >300 (dec), 350°, Xmax462nm (e 4.06 x 10, in IM HCl aqueous EtOH). RecrystalUse it from warm, acidified EtOH by addition of ammonia. The crude material (Ig) can be extracted with EtOH (50mL) in a Soxhlet apparams for lOhours to remove impmities. Impurities can be detected by paper electrophoresis. The triacetate forms yellow needles from EtOH (m 230-233°). [Petrova et al. Anal Lett 5 695 1972, Beilstein 18 H 199, 18 1404,18 III/IV 2824.]... 

Turchini and Gosselin de Beaumont" reported the use of 9-phenyl-(or 9-methyl-) 2,6,7-trihydroxy-3-fluorone for the differential staining of ribo- and desoxyribo-nucleic acids. The former gives rise to a yellow-pink color and the latter to a bluish-violet tint. It is necessary to hydrolyze the nucleic acid since it is the pentoses thereby liberated which yield the color, indicating that the reagent differentiates between ribose and its 2-desoxy analogue. 

Phenylfluorones are a variety of chelating xanthene molecules which form sparingly soluble coloured complexes with certain inorganic species. Phenyl-fluorone (2,6,7-Trihydroxy-9-phenyl-3H-xanthen-3-one) itself, for example, forms a reddish suspension with Ge(/V0, Ga(//7), Sn(iy), SB(//7) and other species. The coloured suspensions can be stabilized with a protective polymer such as poly(vinyl alcohol) for spectrophotometric measurement. 

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