3301-79-9

Basic information

• Product Name: 6-Carboxyfluorescein
• Synonyms: 3-Oxo-3',6'-dihydroxy-1,3-dihydrospiro[isobenzofuran-1,9'-[9H]xanthene]-6-carboxylic acid;Carboxyfluorescein;3',6'-dihydroxy-1-keto-spiro[isobenzofuran-3,9'-xanthene]-5-carboxylic acid;3',6'-dihydroxy-1-oxo-spiro[2-benzofuran-3,9'-xanthene]-5-carboxylic acid;3',6'-dihydroxy-1-oxospiro[2-benzofuran-3,9'-xanthene]-5-carboxylic acid;6-Carboxyfluorescein,6-FAM, FLUOS;6-Carboxyfluorescein Hydrate;6-FAM, 6-CF
• CAS NO: 3301-79-9
• Molecular Formula: C₂₁H₁₂O₇
• Molecular Weight: 376.32
• EINECS: 276-331-1
• Product Categories: marker;Electronic Chemicals;Fluorescent Labels and Indicators;Fluorescent Labels & Indicators;Fluorescent;Xanthene
• Mol File: 3301-79-9.mol

Chemical Properties

• Melting Point: >300 °C(lit.)
• Boiling Point: 736.4 °C at 760 mmHg
• Flash Point: 271 °C
• Appearance: Yellow to orange/Solid
• Density: 1.73 g/cm³
• Vapor Pressure: 9.09E-23mmHg at 25°C
• Refractive Index: 1.816
• Storage Temp.: 2-8°C
• Solubility: DMSO: soluble
• PKA: 3.3, 4.6, 6.4, 7.0(at 25℃)
• BRN: 54341
• CAS DataBase Reference: 6-Carboxyfluorescein(CAS DataBase Reference)
• NIST Chemistry Reference: 6-Carboxyfluorescein(3301-79-9)
• EPA Substance Registry System: 6-Carboxyfluorescein(3301-79-9)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 26-36/37
• WGK Germany: 3
• F: 10-21
• Hazardous Substances Data: 3301-79-9(Hazardous Substances Data)

Usage

Uses

Used in Biomedical Research:
6-Carboxyfluorescein is used as a fluorescent labeling agent for biomolecules due to its relatively high absorptivity, excellent fluorescence quantum yield, and good water solubility. Its excitation maximum closely matches the 488 nm spectral line of the argon-ion laser, making it suitable for fluorescence-based assays and imaging techniques.
Used in Sperm Cell Analysis:
6-Carboxyfluorescein is employed as a reagent to check the plasma membrane integrity in sperm cells. This application helps in assessing the viability and functionality of sperm cells, which is crucial for fertility studies and assisted reproductive technologies.
Used in the Preparation of Fluorescent Conjugates:
6-Carboxyfluorescein is a useful reagent for the preparation of hydrolytically stable fluorescent conjugates. It serves as a starting material for the synthesis of other fluorescein-derived reagents, which find applications in various fields, including biochemistry, molecular biology, and diagnostics.
Used in Drug Synthesis:
As a derivative of fluorescein, 6-carboxyfluorescein can be utilized in the synthesis of other fluorescein-derived compounds with potential pharmaceutical applications. These compounds can be developed for targeted drug delivery, imaging, or therapeutic purposes in the medical and pharmaceutical industries.

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.

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.

InChI:InChI=1/C21H12O7/c22-11-2-5-14-17(8-11)27-18-9-12(23)3-6-15(18)21(14)16-7-10(19(24)25)1-4-13(16)20(26)28-21/h1-9,22-23H,(H,24,25)

Upstream product

• 108-46-3 recorcinol 
• 552-30-7 trimellitic Anhydride 
• 100-44-7 benzyl chloride 

Downstream Products

• 92557-81-8 6-carboxyfluorescein N-hydroxysuccinimide ester 
• 192374-17-7 3',6'-bis(2,2-dimethyl-1-oxopropoxy)-3-oxo-spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-6-carboxylic acid 
• 1004751-28-3 C₂₇H₁₆INO₆ 
• 1386385-76-7 N-(3-azidoprop-1-yl)fluoresceinyl-6-carboxamide 
• 1431933-70-8 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Cit-NH2 
• 1609495-15-9 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Lys-NH2 
• 1431933-69-5 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Cit-Arg-NH2 
• 1609495-14-8 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Lys-Arg-NH2 
• 1431933-68-4 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Cit-Arg-Arg-NH2 
• 1609495-13-7 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Lys-Arg-Arg-NH2 
• 1609495-09-1 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Cit-Gln-Arg-Arg-Arg-NH2 
• 1609495-12-6 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Arg-Lys-Gln-Arg-Arg-Arg-NH2 
• 1431933-66-2 Flu-βAla-Tyr-Gly-Arg-Lys-Lys-Cit-Arg-Gln-Arg-Arg-Arg-NH2 

Relevant articles and documents

Site-specific, reversible and fluorescent immobilization of proteins on CrAsH-modified surfaces for microarray analytics

A novel technique for protein immobilization onto CrAsH-modified surfaces is presented. This approach enables an efficient, reversible and fluorogenic immobilization of proteins. Moreover, expressed proteins can also be directly immobilized from cellular lysates without prior purification. The immobilized proteins are suitable for protein-protein interaction studies and the fluorescence enhancement upon immobilization can be employed for the direct detection of the immobilized protein without the need for secondary detection methods. This journal is

Physicochemical characterization of bisphosphonic carboxyfluorescein for osteotropic drug delivery

Disodium (fluorescein-6-carbonyloxy)acetoaminomethylene bisphosphonate (CF-BP), a prodrug of 6-carboxyfluorescein, is efficiently absorbed by the skeleton where it hydrolyses to carboxyfluorescein. An osteotropic drug-delivery system based on this bisphosphonic prodrug has been developed as a novel method for site-specific and controlled delivery of drugs to the bone. In this study the physicochemical properties of the prodrug have been characterized by investigating the affinity of CF-BP for hydroxyapatite and the hydrolysis of the compound to carboxyfluorescein. In the binding study, CF-BP bound very rapidly to hydroxyapatite without degradation and carboxyfluorescein was subsequently gradually released by hydrolysis of bound CF-BP. Hydrolysis of CF-BP in buffer solutions followed pseudo-first-order kinetics, and quantitative regeneration of carboxyfluorescein was observed. In addition, regeneration of carboxyfluorescein from CF-BP was accelerated in the presence of fresh rat plasma. These results suggest that CF-BP has the physicochemical properties required for site-specific and controlled delivery of carboxyfluorescein to bones.

Synthesis and fluorescence properties of six fluorescein-nitroxide radical hybrid-compounds

Six fluorescein-nitroxide radical hybrid-compounds (2ab, 3ab, 4, and 5) were synthesized by the condensation of 5- or 6-carboxy-fluorescein and 4-amino-TEMPO (2ab), 5- or 6-aminofluorescein and 4-carboxy-TEMPO (3ab), and fluorescein and 4-carboxy-TEMPO (4), or by reaction of the 3-hydroxyl group of fluorescein with DPROXYL-3-ylmethyl methanesulfonate (5). Fluorescence intensities (around 520 nm) after reduction of the radical increased to 1.43-, 1.38-, and 1.61-folds for 2a, 2b and 3b respectively; 3a alone exhibited a decrease in intensity on reduction. Since 4 was readily solvolyzed in PBS or even methanol to afford fluorescein and 4-carboxy-TEMPO, its fluorescence change could not be measured. Hybrid compound 5 containing an ether-linkage between the fluorescein phenol and 3-hydroxymethyl-DPROXYL hydroxyl centers, was stable and on reduction, showed a maximum increase (3.21-fold) in relative fluorescence intensity in PBS (pH 5.0), despite its remarkably low absolute fluorescence intensity.

Benzoylphosphonate-based photoactive phosphopeptide mimetics for modulation of protein tyrosine phosphatases and highly specific labeling of SH2 domains

A light switch for phosphotyrosine- recognizing proteins: Irradiation of the bioisosteric benzoylphosphonate suffices to "turn off" the activity of target proteins and to label them covalently (see scheme). Photoactive bioisosters may find applications in functional cell biology, bioanalytics, and proteome research.

Design, synthesis, and characterization of fluorescent cobalamin analogues with high quantum efficiencies

Cobalamin tethered to fluorescein or Rhodamine 6G has been synthesized and characterized. The fluorophore is conjugated to the ribose-5-OH of cobalamin through a rigid linker to prevent the fluorophore from folding back through space and interacting with

Method for locating hidden microorganism contaminated surfaces in industrial water systems

A method for locating hidden microorganism contaminated surfaces in industrial water systems is described and claimed. The method works by applying a solution or dispersion of a fluorogenic reagent in water to the hidden water contact surfaces of said industrial water system and allowing said fluorogenic reagent to react with any hidden microorganisms present, wherein said fluorogenic reagent is selected from the group of fluorogenic reagents that are known to react with microorganisms such that a fluorescent signal of said fluorogenic reagent is detectable in such a way as to make the detection of the fluorescent signal indicate that there are hidden microorganisms present on the water contact surfaces of the equipment and piping.

MICROWAVE ACTIVATION OF HETEROCYCLIZATIONS INVOLVING CARBOXYLIC ACIDS

In the microvawe activation mode the duration of the synthesis of 2-phenylbenzimidazole, 2-phenylbenzoxazole, and also a number of xanthene dyes was reduced to several minutes.

Liposome composition and its production

The liposome compositions entrapping a drug are prepared by constituting the liposomal membrane with a saturated phospholipid and a glycolipid having sulfo group. Thus obtained compositions circulate stably in blood for a long time after intravenous administration.

Liposome composition and production thereof

The liposome compositions entrapping a drug are prepared by constituting the liposomal membrane with a saturated phospholipid and a glycolipid having sialic acid group. Thus obtained compositions circulate stably in blood for a long time after intravenous administration.

Liposome composition and its production

The liposome compositions entrapping a drug are prepared by constituting the liposomal membrane with saturated phospholipids and anionic surfactants of high Krafft point at concentrations above their critical micelle concentrations. Thus obtained compositions circulate stably in blood for a long time after intravenous administration.