Pararosaniline

 ( Triarylmethane Dyes ) 

Pararosaniline, pararosaniline free base, Basic Red 9, or C.I. 42500 is an organic compound with the chemical formula . It is the free base form of pararosaniline hydrochloride, , a magenta solid with a variety of uses as a dye.Thomas Gessner and Udo Mayer "Triarylmethane and Diarylmethane Dyes" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. It is one of the four components of basic fuchsine.Horobin RW, Kiernan JA (2002) Conn's Biological Stains, 10th ed. Oxford: BIOS. It is structurally related to other triarylmethane dyes called (e.g. crystal violet) which feature methyl groups on nitrogen.

It is prepared by the condensation of aniline and . Alternatively, it arises from the oxidation of 4,4'-bis(aminophenyl)methane in the presence of aniline.

• It is used to dye polyacrylonitrile fibers.
• It is used to detect sulfur dioxide.
• Pararosaniline is used as a colorimetric test for aldehydes, in the Schiff test. It is the only basic fuchsine component suitable for making the aldehyde-fuchsine stain for pancreatic islet beta cells.
• It has use as an antischistosomal.

• 4,4'-Thiodianiline
• 4,4'-Methylenedianiline
• 4,4'-Oxydianiline
• Dapsone

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