Yellow, Acid Acridine

The pH indicator shows the acid or basic properties of sample molecnles. Commonly used for acid indicating are solutions of bromocresol green (20 mg dissolved in 10 ml of ethanol combined with 1 ml of 0.1-molar aqueous NaOH) or bromophenol blue (20 mg dissolved in 10 ml of ethanol, pH-adjusted with 0.1-molar NaOH or 0.2% aqneous citric acid). In the presence of acids, 2,6-dichloroindophenol (40 mg dissolved in 100 ml of ethanol) changes the color from blue to red. The fluorescent dye acridine orange (20 mg dissolved in 100 ml of ethanol) changes pH-dependently the color of its flnorescence from yellow-green to yellow. 

The simplest case for complete enforcement of the convergent conformation was provided by meta xylidine diamine 10. Condensation of two triacids with this amine in the melt gave excellent yields of the dicarboxylic acid 11 (Eq. (2)). The architectural cliche is easily repeated in the naphthalene series to provide 12 and in the acridine series to provide 13. The latter is derived from the commercially available acridine yellow at very low cost. 

To a solution of oxalic chloride (5 g) in dichloromethane, a solution of diphenyl amine (5 g) in dichloromethane was added dropwise and refluxed for 30 min. The solution was concentrated (50%) and aluminum trichloride (8 g) added in portions. The mixture was refluxed for 45 min and the solvent evaporated. To this residue hydrochloric acid in ice water (1 M) was added and the red-colored precipitate filtered. The precipitate was dissolved in potassium hydroxide (10% in water), refluxed overnight, and poured into hydrochloric acid in ice water (5 M). The yellow acridine-9-carboxylic acid was filtered, washed with water, and dried. 

In order to obtain the base in a state of absolute purity Koenigs 8 dissolves 10 g. in 50 cc. of alcohol and adds a solution of 10 g of tartaric acid in 100 cc. of alcohol. The tartrate which separates is washed with alcohol, dissolved in water, and converted into the base with ammonia. The acridine should then form greenish yellow needles which melt at 117-8°. 

Yellow crystals. Acid reaction. Forms a water-sol sodium salt. Can be pptd as a water -insol salt by acridine derivs such as acriflavlne, by sulfa drugs such as homosulfanil-amide, by basic antibiotics such as streptomycin base, by enzymes such as papain and lysozyme, by dyes such as methylene blue, and by metallic salts such as CaCl2. LDW j.p. in mice 0-05 mg/ 10-12 g mouse (Hosoya). 

Cyanine dyes are avidly accumulated by mitochondria in vivo (7) with a resultant quenching of their fluorescence when assessed in cell suspension (8) however, in the fluorescence microscope the mitochondria appear as brightly fluorescent, filamentous structures (7). Similarly acridine orange and 9-aminoacridine are accumulated by acidic endosomes with a quenching of their blue fluorescence in the fluorescence microscope the vesicles appear as yellow or orange vesicles, this being the characteristic emission of very concentrated solutions of these dyes (1). 

Related to the xanthene dyes are the acridines, azines, oxazines, and thiazines. Acridine Yellow results from the fusion of toluene-2,4-diamine with glycerin and oxalic acid, followed by oxidation with ferric chloride. Basic Orange 15 (Phosphine) is a by-product of the manufacture of Basic Violet 14 (Fuchsine) and is an acridine dye. 

Acridine yellow, in D-00079 Astrafloxine G Chloride, in A-00450 Astrazon blue B Chloride, in A-00452 Benzenecarbothioic acid 2-hydroxy(di-2-... 

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