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Sigma-Aldrich

3,4-Dihydroxy-3-cyclobutene-1,2-dione

≥99.0% (HPLC)

Synonym(s):

Squaric acid

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About This Item

Linear Formula:
(HO)2C4(=O)2
CAS Number:
2892-51-5
Molecular Weight:
114.06
Beilstein/REAXYS Number:
774275
EC Number:
220-761-4
MDL number:
MFCD00001334
UNSPSC Code:
12352103
PubChem Substance ID:
24847567
NACRES:
NA.23

Quality Level

200

assay

≥99.0% (HPLC)

form

solid

mp

>300 °C (lit.)

SMILES string

OC1=C(O)C(=O)C1=O

InChI

1S/C4H2O4/c5-1-2(6)4(8)3(1)7/h5-6H

InChI key

PWEBUXCTKOWPCW-UHFFFAOYSA-N

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General description

3,4-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.

Application

3,4-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.

pictograms

Corrosion
GHS05

signalword

Danger

hcodes

H314

Hazard Classifications

Eye Dam. 1 - Skin Corr. 1B

Storage Class

8A - Combustible corrosive hazardous materials

wgk_germany

WGK 3

flash_point_f

374.0 °F

flash_point_c

190 °C

ppe

dust mask type N95 (US), Eyeshields, Faceshields, Gloves

Certificates of Analysis (COA)

Search for Certificates of Analysis (COA) by entering the products Lot/Batch Number. Lot and Batch Numbers can be found on a product’s label following the words ‘Lot’ or ‘Batch’.

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Synthesis, spectral properties, and detection limits of reactive squaraine dyes, a new class of diode laser compatible fluorescent protein labels
Oswald et al.
Bioconjugate chemistry, 11(3), 438-438 (2000-05-23)
Jian Xie et al.
Organic letters, 6(1), 83-86 (2004-01-03)
[structure: see text] Protein tyrosine phosphatases (PTPases) are important targets in medicinal chemistry. These enzymes play a role in a number of human diseases, including type II diabetes and infection by Yersinia pestis, the causative agent of bubonic plague. Derivatives
Heterocycles, 35, 1149-1149 (1993)
Igor Bensemann et al.
Organic & biomolecular chemistry, 1(8), 1425-1434 (2003-08-22)
The preparation and crystal structures of fourteen complexes of N,N'-bis(2-pyridyl)aryldiamines with dicarboxylic acids and two complexes with squaric acid are reported. The recognition between the carboxylic acids and the 2-aminopyridine units occurs through the formation of the cyclic R(2)2 (8)
Construction of a 3D array of cadmium (ii) using squarate as a building block.
Maji, Tapas Kumar, et al.
CrystEngComm, 155-158 (2001)
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