Auramines

Diphenylmethane Dyes. The diphenyhnethane dyes aie usually classed with the tiiaiyhnethane dyes. The dyes of this subclass are ketoimine derivatives, and only three such dyes are registered in the Colour Index. They ate Auramine O [2465-27-2J Cl Basic Yellow 2 (Cl 41000) (21, R = CHg), Auramine G [2151 -60-2] Cl Basic Yellow 3 (Cl 41005) (22), and Cl Basic Yellow 37 [6358-36-7] (Cl 41001) (21, R = C2H5). These dyes are still used extensively for the coloration of paper and in the preparation of pigment lakes. 

Auramine O (4,4 -bis-dimethylaminobenzophenone imine hydrochloride) [2465-27-2] M 321.9, pK 10,71 (free base), 9.78 (carbinolamine). Crystd from EtOH as hydrochloride, very slightly soluble in CHCI3, UV 434 (370) nm. The free base has m 136 after crystn from benzene. [J Chem Soc 1724 1949 Biochemistry 9 1540 1970]. 

Amido-azo-benzene Amido-azo-toluene Aniline black Auramine Bismarck brown Brilliant indigo, 4 G. 

Microscopic examination ( smear ) detects about 8 to 10 X 1CF organisms/L of specimen using the older AFB (acid-fast bacillus) stain, with the newer auramine-rhodamine fluorsecent... 

The practical route for oxidizing leuco diphenylmethanes 15 demands inital conversion to an imine salt 16. The imine salt is obtained by heating a mixture of diphenylmethane, sulfur, ammonium chloride, and sodium chloride at 175°C in a current of ammonia or by heating a mixture of diphenylmethane, urea, sulfamic acid, sulfur, and ammonia at 175°C (Scheme 3). Dyes 16 can be represented as the quinonoid resonance structure 17. Dyes of this class, known as auramines, are all yellow, with the only commercial representative being auramine O 16a. Due to its poor lightfastness and instability to hot acids and bases, its use has been restricted to dyeing and printing cotton, paper, silk, leather, and jute. 

Like most dyes, substituents on di- and triphenylmethane dyes have a significant effect on the absorption spectra. Acetylation of the imino nitrogen of auramine O (32) results in shift to longer wavelength (Eq. 3). A... 

Leuco diarylmethane compounds which have received a good deal of attention are the leuco auramines. Reaction of Michler s hydrol with a... 

Historically, bladder tumors have been associated with exposures in the aniline dye industry. However, conclusive evidence for any one particular exposure could not be obtained in these studies since the workers were exposed to many chemicals within the same work area. For example, Case et al. (1954) investigated the incidence of bladder tumors among British workers in the chemical dye industry. In addition to aniline, the workers were exposed to other aromatic amines, including a- and P-naphthylamine, benzidine, and auramine. Although exposures could not be quantified, there was insufficient evidence to suggest that aniline was a cause of bladder cancers. More recent studies indicate that P-naphthylamine, 4-aminodiphenyl, 4-nitrodiphenyl, 4,4-diaminodiphenyl, or o-toluidine may be involved in increased cancers in the dye industry (Ward et al. 1991 Benya and Cornish 1994). 

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