6-Carboxyfluorescein Property

Melting point:

>300 °C(lit.)

Boiling point:

736.4±60.0 °C(Predicted)

Density 

1.73±0.1 g/cm3(Predicted)

storage temp. 

Sealed in dry,2-8°C

solubility 

DMSO: soluble

form 

Solid

pka

3.3, 4.6, 6.4, 7.0(at 25℃)

color 

Yellow to orange

PH Range

Weak green ' uorescence (6.0) to strong green ' uourescence (7.2)

λmax

492nm

BRN 

54341

Major Application

Diagnosis of hematologic cancer, nongastric diseases, detection of genetically modified wheat, chromosomes, gene expression, nucleic acid, hepatitis A virus, avian influenza virus subtype H5 and H5N1, SARS virus, herpex simplex virus

Biological Applications

Diagnosing bladder cancer; evaluating corneal endothelial barrier function; as a substrate for measuring protein kinase activity, methyltransferase activity, phospholipase activity, rhodanese activity,sulfotransferase activity;use in ophthalmology

CAS DataBase Reference

3301-79-9(CAS DataBase Reference)

EPA Substance Registry System

Spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-6-carboxylic acid, 3',6'-dihydroxy-3-oxo- (3301-79-9)

Safety

Hazard Codes 

Xi

Risk Statements 

36/37/38

Safety Statements 

26-36/37

WGK Germany 

3

F 

10-21

HS Code 

3204 90 00

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

Precautionary statements

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P280Wear protective gloves/protective clothing/eye protection/face protection.

6-Carboxyfluorescein Chemical Properties,Usage,Production

Chemical Properties

Orange Solid

Uses

6-Carboxyfluorescein (6-FAM) is derivative of fluorescein giving stable derivative upon conjugation with biopolymers.It has been used to check the plasma membrane integrity in sperm cells. The single isomer, 6-FAM, contains a carboxylic acid that can be used to react with primary amines via carbodiimide activation of the carboxylic acid. Commercially available FAM is a mixture of two isomers, 5-FAM and 6-FAM, and the correct name is 5(6)-carboxyfluorescein.

Preparation

1,2,4-Benzenetricarboxylic anhydride (also called 4- carboxyphthalic anhydride, 25.0 g, 0.13 mol) was added to a solution of 1,3-dihydroxybenzene (also called resorcinol, 28.6 g, 0.26 mol) in methane sulfonic acid (1M). An air condenser was attached to the flask and the reaction was heated at 85 oC in an open vessel for 24 h. After cooling to room temperature, the reaction mixture was poured into 7 volumes of ice/water. An orange-yellow precipitate formed; this was collected by filtration and dried in an oven at 200 oC. This residue was recrystallized two times from methanol/hexane to give 1.0 g of 6- carboxyfluorescein methanesulfonic acid adduct preferentially crystallizes from MeOH/hexanes. The mother liquors from this procedure were collected, the solvent was removed in vacuo, and the residues were recrystallized two times from ethanol/hexanes to give 3.2 g of 5-carboxyfluorescein methanesulfonic acid adduct preferentially crystallizes from EtOH/hexanes. Finally, the mother liquors from this experiment were combined, evaporated to dryness, and recrystallized two times from methanol/hexanes to give another 3.0 g of 6-carboxyfluorescein methanesulfonic acid adduct preferentially crystallizes from MeOH/hexanes, making a total yield of 4.0 g, 40 %. Careful dropwise addition of conc. HCl(aq) to solutions of these methanesulfonic esters preferentially crystallizes from EtOH/hexanes and preferentially crystallizes from MeOH/hexanes in 4M sodium hydroxide gave 5-carboxyfluorescein and 6-carboxyfluorescein, respectively in near quantitative yield.

Definition

ChEBI: 6-carboxyfluorescein is a monocarboxylic acid. It derives from a fluorescein (lactone form).

Application

6-Carboxyfluorescein is a useful reagent for the preparation of hydrolytically stable fluorescent conjugates and is a useful starting material for the synthesis of other fluorescein-derives reagent. Fluorescein is the most common fluorescent derivatization reagent for labeling biomolecules. In addition to its relatively high absorptivity, excellent fluorescence quantum yield, and good water solubility, fluorescein has an excitation maximum that closely matches the 488 nm spectral line of the argon-ion laser.

Biochem/physiol Actions

6-Carboxyfluorescein diacetate is a membrane permeable compound. It can be hydrolysed by intracellular esterases to form a membrane impermeable bright green fluorescent molecule, 6-carboxyfluorescein.