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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:
774275
EC Number:
220-761-4
MDL number:
MFCD00001334
UNSPSC Code:
12352103
PubChem Substance ID:
24847567
NACRES:
NA.23
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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.[1] These derivatives are also used as dyes for fluorescence detection of small biological molecules.[2]

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.[2]
  • To form diffraction quality crystals.[3]
  • 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.[4]

Pictograms

Corrosion
GHS05

Signal Word

Danger

Hazard Statements

H314

Hazard Classifications

Eye Dam. 1 - Skin Corr. 1B

Storage Class Code

8A - Combustible corrosive hazardous materials

WGK

WGK 3

Flash Point(F)

374.0 °F

Flash Point(C)

190 °C

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Certificates of Analysis (COA)

Lot/Batch Number
BCCM1861
BCCL4127
BCCJ3245
BCCH1576
BCCD5797

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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)
Heterocycles, 35, 1149-1149 (1993)
Construction of a 3D array of cadmium (ii) using squarate as a building block.
Maji, Tapas Kumar, et al.
CrystEngComm, 155-158 (2001)
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)
Tetrahedron Letters, 48, 3595-3595 (2007)
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Questions

1–3 of 3 Questions  

  1. How is shipping temperature determined? And how is it related to the product storage temperature?

    1 answer

    1. Products may be shipped at a different temperature than the recommended long-term storage temperature. If the product quality is sensitive to short-term exposure to conditions other than the recommended long-term storage, it will be shipped on wet or dry-ice. If the product quality is NOT affected by short-term exposure to conditions other than the recommended long-term storage, it will be shipped at ambient temperature. As shipping routes are configured for minimum transit times, shipping at ambient temperature helps control shipping costs for our customers. For more information, please refer to the Storage and Transport Conditions document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/316/622/storage-transport-conditions-mk.pdf

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  2. How can I determine the shelf life / expiration / retest date of this product?

    1 answer

    1. If this product has an expiration or retest date, it will be shown on the Certificate of Analysis (COA, CofA). If there is no retest or expiration date listed on the product's COA, we do not have suitable stability data to determine a shelf life. For these products, the only date on the COA will be the release date; a retest, expiration, or use-by-date will not be displayed.
      For all products, we recommend handling per defined conditions as printed in our product literature and website product descriptions. We recommend that products should be routinely inspected by customers to ensure they perform as expected.
      For products without retest or expiration dates, our standard warranty of 1 year from the date of shipment is applicable.
      For more information, please refer to the Product Dating Information document: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/marketing/global/documents/449/386/product-dating-information-mk.pdf

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  3. What is a good way to derivatize squaric acid

    1 answer

    1. The derivatization of squaric acid has not been investigated. It would be up to the end-user to research this application. It may be helpful to review the following publication:
      https://pubs.acs.org/doi/10.1021/ja00959a040

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