Nile red
IUPAC name	7-diethylamino-3,4-benzophenoxazine-2-one
Other names	Nile red, Nile blue oxazone
Identifiers
CAS number	7385-67-3
PubChem	65182
SMILES	CCN(CC)C1=CC2=C(C=C1)N= C3C4=CC=CC=C4C(=O)C=C3O2
Properties
Molecular formula	C20H18N2O2
Molar mass	318.369 g/mol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Nile red (also known as Nile blue oxazone) is a lipophilic stain. It is produced by boiling a solution of Nile blue with sulfuric acid.^[1] As can be seen from the structural formulae, this process replaces an amino group with a carbonyl group. Nile red stains intracellular lipid droplets red. Nile red is also intensely fluorescent, with a strong yellow-gold emission when in a lipid-rich environment. It excites at 485 nm, and emits at 525 nm.

Since the reaction to generate Nile red does not usually completely exhaust the supply of Nile blue, additional separation steps are required if pure Nile red is needed.

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