Basic information
- CAS
2892-51-5- Standard SMILES
O=c1c(O)c(O)c1=O- InChIKey
PWEBUXCTKOWPCW-UHFFFAOYSA-N- Molecular formula
- C4H2O4
- Average molar mass
- 114.06 g/mol
- Monoisotopic mass
- 113.99530854
Names & identifiers
- Preferred name
- Squaric acid
- IUPAC
- 3,4-dihydroxycyclobut-3-ene-1,2-dione
- English name
- Squaric acid
- Molecular formula
- C4H2O4
- Molecular weight
- 114.06
Names & synonyms
Squaric acid2892-51-5Quadratic acid3,4-dihydroxycyclobut-3-ene-1,2-dioneQuadratsaeure1,2-Diketo-3,4-dihydroxycyclobuteneDihydroxycyclobutenedioneDTXSID9049409SVR9D0VODWNSC-125692DTXCID8029369CHEBI:52141
Show more names
Squaric2-dioneNSC 624671squaricaciSQUARC ACIDobutene-1,2-dione
RefChem:185166220-761-43,4-Dihydroxy-3-cyclobutene-1,2-dione3-Cyclobutene-1,2-dione, 3,4-dihydroxy-dihydroxycyclobut-3-ene-1,2-dioneCyclobutenedione, dihydroxy-1,2-Dihydroxycyclobutene-3,4-dioneMFCD00001334
Database identifiers
- CAS
2892-51-5、31150-56-8- PubChem CID
- 17913
- DTXSID
DTXSID9049409- ChEBI
CHEBI:52141- UNII
- SVR9D0VODW
- EC Number
- 220-761-4、693-144-4
- Nikkaji
- J13.719G
Properties
Computed structural properties
- XLogP
- -0.7
- Topological polar surface area
- 74.6 Ų
- Hydrogen bond donors
- 2
- Hydrogen bond acceptors
- 4
- Rotatable bonds
- 0
- Heavy atoms
- 8
- Formal charge
- 0
- Complexity
- 178
Experimental & physicochemical properties
Physical DescriptionSolid; [Merck Index] Gray crystalline solid; [Sigma-Aldrich MSDS]
Physicochemical properties
- Melting point
- 300 °C · >300 °C(lit.)
- Boiling point
- 250.96 °C · 250.96°C
- Density
- 1.82 g/cm3 · 1.82 g/cm3
- refractive index
- 1.58 · 1.5800 (estimate)
- Flash point
- 190 °C · 190 °C
- storage temp.
- Inert atmosphere,Room Temperature
- solubility
- 20 g/l · 20g/l
- form
- Crystalline Powder
- pka
- 1.5 · 1.5(at 25℃)
- color
- White to beige
- PH
- 1 · 1 (1g/l, H2O, 20℃)
- Water Solubility
- 20 g/L · 20 g/L (30 ºC)
- Merck
- 14 · 14,8769
Safety & regulation
Safety information is for reference only and does not replace the supplier’s Safety Data Sheet (SDS), applicable regulations, or professional assessment.
GHS classification
GHS Classification
Warning
H315 (72.1%): Causes skin irritation [Warning Skin corrosion/irritation]；H317 (86.9%): May cause an allergic skin reaction [Warning Sensitization, Skin]；H319 (72.1%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]；H335 (70.5%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]
P261, P264, P264+P265, P271, P272, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P333+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)
Aggregated GHS information provided per 61 reports by companies from 9 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.；Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.
Hazard information
Regulatory Information1,2-Dihydroxy-3,4-cyclobutenedione: Does not have an individual approval but may be used under an appropriate group standard
Hazards SummaryA skin and strong eye irritant; May cause skin sensitization; [Sigma-Aldrich MSDS] Search for (2892-51-5[EC/RN Number]) AND (dermatitis OR allergic OR sensitizer OR sensitization): no reports of skin sensitization; [PubMed]
Hazard Classes and Categories
Skin Irrit. 2 (72.1%)；Skin Sens. 1 (86.9%)；Eye Irrit. 2 (72.1%)；STOT SE 3 (70.5%)
Skin Irrit. 2 (100%)；Skin Sens. 1 (100%)；Eye Irrit. 2 (100%)；STOT SE 3 (100%)
Regulatory information
Chemistry & industry
Uses & manufacturing
UsesUsed to make pharmaceutical intermediates, squarylium dyes, and photoconducting squaraines; The dibutylester is used as a contact sensitizer in the treatment of alopecia and warts; [Merck Index]
General Manufacturing Information3-Cyclobutene-1,2-dione, 3,4-dihydroxy-: ACTIVE
Applications
UsesSquaric acid used as intermediate for squaraine dyes and heterocycles. Squaric acid is an immunotherapy used to treat common warts. This treatment is non-toxic, and easy to use. The treatment activated your immune system to combat the warts and therefore it may cause an allergic reaction , similar to poison oak. This reaction can be managed with a topical cortisone cream. Blistering and lightening of the skin may occur, but rarely.Squaric acid derivatives – synthetic targets for ring expansion reactions
Uses3,4-Dihydroxy-3-cyclobutene-1,2-dione is used to produce diethoxy-cyclobutenedione by heating, pharmaceutical intermediates, squarylium dyes, and photoconducting squaraines; The dibutylester is used as a contact sensitizer in the treatment of alopecia and warts.
Uses3,4-Dihydroxy-3-cyclobutene-1,2-dione can be used:In fluorescence detection in immunoassays, hybridization assays, enzymatic reactions, and other analytical procedures.To form diffraction quality crystals. To synthesize a squarate dianion, which is used as a building block to create uncharged polymeric networks. These ordered structures are used in catalysis, nonlinear optics, electrical conductivity, molecular recognition, and molecular sieves.
General Description3,4-dihydroxy-3-cyclobutene-1,2 dione, commonly known as squaric acid, is widely used in bioorganic and medicinal chemistry. It is an inhibitor of glyoxylase, semiqauric acid, pyruvate dehrogenase, and transketolase. It is used as a replacement for phosphate in a peptide-based ligand for an SH2 domain. Its derivatives are high-affinity ligands for excitatory amino acid receptors. These derivatives are also used as dyes for fluorescence detection of small biological molecules.
Related reactions
27 records
Compound notes
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