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basic red 2

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basic red 2

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Also known as Safranin

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, mucin and mast cell granules.

Chemical data

Formula
C20H19ClN4
Molecular weight
350.8 g/mol
IUPAC name
3,7-dimethyl-10-phenylphenazin-10-ium-2,8-diamine chloride
SMILES
CC1=CC2=C(C=C1N)[N+](=C3C=C(C(=CC3=N2)C)N)C4=CC=CC=C4.[Cl-]
InChIKey
OARRHUQTFTUEOS-UHFFFAOYSA-N
Polar surface area
68.8 Ų
H-bond donors
2
H-bond acceptors
4
Formal charge
0

via PubChem

Wikidata facts

Mass
350.13
Image
Sample of Safranin O.jpg
Show 3 more facts
chemical formula
C₂₀H₁₉ClN₄
canonical SMILES
CC1=CC2=C(C=C1N)[N+](=C3C=C(C(=CC3=N2)C)N)C4=CC=CC=C4.[Cl-]
Commons category
Safranin
Sources (2)

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Article

2 sections
Contents
  • Safranines
  • 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, 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.

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