Safranin

Safranin
Solid safranin	Safranin in aqueous solution
Names
	Preferred IUPAC name 3,7-Diamino-2,8-dimethyl-5-phenylphenazin-5-ium chloride
Identifiers
CAS Number	477-73-6 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:197447 ;
ChemSpider	2005991 ;
ECHA InfoCard	100.006.836
PubChem CID	2723800;
UNII	XTX0YXU2HV ;
CompTox Dashboard (EPA)	DTXSID60874047 ;
	InChI InChI=1S/C20H18N4.ClH/c1-12-8-17-19(10-15(12)21)24(14-6-4-3-5-7-14)20-11-16(22)13(2)9-18(20)23-17;/h3-11H,1-2H3,(H3,21,22);1H Key: OARRHUQTFTUEOS-UHFFFAOYSA-N ; InChI=1/C20H18N4.ClH/c1-12-8-17-19(10-15(12)21)24(14-6-4-3-5-7-14)20-11-16(22)13(2)9-18(20)23-17;/h3-11H,1-2H3,(H3,21,22);1H Key: OARRHUQTFTUEOS-UHFFFAOYAR; InChI=1/C20H18N4/c1-12-8-17-19(10-15(12)21)24(14-6-4-3-5-7-14)20-11-16(22)13(2)9-18(20)23-17/h3-11H,1-2H3,(H3,21,22)/p+1;
	SMILES [Cl-].n1c4c([n+](c2c1cc(c(N)c2)C)c3ccccc3)cc(c(c4)C)N;
Properties
Chemical formula	C20H19ClN4
Molar mass	350.85 g·mol−1
Solubility in water	Soluble
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H315, H318
Precautionary statements	P264, P280, P302+P352, P305+P351+P338, P310, P332+P313, P362
NFPA 704 (fire diamond)	2 0 0
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Safranin (Safranin O or basic red 2) is a biological stain used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring cell nuclei red. This is the classic counterstain in both Gram stains and endospore staining. It can also be used for the detection of cartilage,^[2] mucin and mast cell granules.

Safranin typically has the chemical structure shown at right (sometimes described as dimethyl safranin). There is also trimethyl safranin, which has an added methyl group in the ortho- position (see Arene substitution pattern) of the lower ring. Both compounds behave essentially identically in biological staining applications, and most manufacturers of safranin do not distinguish between the two. Commercial safranin preparations often contain a blend of both types.

Safranin is also used as redox indicator in analytical chemistry.

^ ^a ^b ^c ^d "Safety Data Sheet: Safranin O" (PDF). LabChem. Retrieved 10 March 2016.
^ Rosenberg L (1971). "Chemical Basis for the Histological Use of Safranin O in the Study of Articular Cartilage". J Bone Joint Surg Am. 53 (1): 69–82. doi:10.2106/00004623-197153010-00007. PMID 4250366. Archived from the original (abstract) on 2008-04-17.

[labchem-1] "Safety Data Sheet: Safranin O" (PDF). LabChem. Retrieved 10 March 2016.

[2] Rosenberg L (1971). "Chemical Basis for the Histological Use of Safranin O in the Study of Articular Cartilage". J Bone Joint Surg Am. 53 (1): 69–82. doi:10.2106/00004623-197153010-00007. PMID 4250366. Archived from the original (abstract) on 2008-04-17.

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