3,4-Dimethoxy-3-cyclobutene-1,2-dione Chemical Properties

Melting point:

55-57 °C (lit.)

Boiling point:

219.65°C (rough estimate)

Density 

1.3863 (rough estimate)

refractive index 

1.5800 (estimate)

storage temp. 

2-8°C

solubility 

DMSO, Methanol (Slightly)

form 

Solid

color 

Off-White to Pale Brown

Water Solubility 

Very soluble in water.

InChIKey

SZBNZTGCAMLMJY-UHFFFAOYSA-N

CAS DataBase Reference

5222-73-1(CAS DataBase Reference)

NIST Chemistry Reference

3,4-Dimethoxy-3-cyclobutene-1,2-dione(5222-73-1)

Safety Information

Risk Statements 

42/43

Safety Statements 

22-24/25-26-36/37/39

WGK Germany 

3

HS Code 

29145090

MSDS

• Language:English Provider:SigmaAldrich
• Language:English Provider:ACROS
• Language:English Provider:ALFA

3,4-Dimethoxy-3-cyclobutene-1,2-dione Usage And Synthesis

Chemical Properties

white crystalline powder

Uses

3,4-Dimethoxy-3-cyclobutene-1,2-dione (Dimethyl squarate) finds it uses in the synthesis of chiral squaramides, highly enantioselective catalyst for the Friedel-Crafts reactions of indoles, 3-(hydroxyamino)-4-methoxy-3-cyclobutene-1,2-dione, squarate derivatives of the O-SP-core antigens, methyl squarate derivative of the Ogawa O-SP-core antigen, o-quinodimethanes, benzocyclobutenes, quinones. It is employed as a starting material in the preparation of o-quinodimethanes, benzocyclobutenes, and quinones.

General Description

3,4-Dimethoxy-3-cyclobutene-1,2-dione (Dimethyl squarate) is a cyclobutene derivative. It reacts with hydroxylamine derivatives to afford 3-hydroxyamino-4-methoxy-3-cyclobutene-1,2-diones.

Synthesis

3,4-Dimethoxy-3-cyclobutene-1,2-dione (compound 30) was synthesized using a modified Liu et al. method [7]. The procedure was as follows: 3,4-dihydroxy-3-cyclobutene-1,2-dione (squaric acid, 2.053 g, 18 mmol) was dissolved in anhydrous methanol (18 mL), followed by addition of trimethyl orthoformate (4 mL, 36.5 mmol) to the solution. The reaction mixture was refluxed at 56 °C for 24 hours. Upon completion of the reaction, the crude product was concentrated under reduced pressure. The resulting light yellow solid was dissolved in dichloromethane and purified by silica gel column chromatography (eluent ratio of ethyl acetate: hexane = 1:2) to afford 3,4-dimethoxycyclobut-3-ene-1,2-dione (2.29 g, 89.4% yield) as a final white solid. The melting point of the compound is 55-57 °C (literature value 56-58 °C) [7,8]. NMR hydrogen spectrum (300 MHz, CD2Cl2) δ 4.34 (6H, s, OCH3); NMR carbon spectrum (75 MHz, CD3OD) δ 189.35 (C2, C=O), 189.35 (C1, C=O), 184.35 (C3), 184.35 (C4), 60.29 (OCH3), 60.29 ( OCH3). Low resolution mass spectra (EI): m/z 142.03 (100%), 114.03 (18%), 99.01 (16%), 86.01 (54%), 67.99 (8%), 56.25 (7%).

References

[1] Bioorganic and Medicinal Chemistry Letters, 2017, vol. 27, # 2, p. 282 - 287
[2] Organic Syntheses, 1999, vol. 76, p. 189 - 189
[3] Chemistry - A European Journal, 2011, vol. 17, # 49, p. 13698 - 13705
[4] Chemistry - A European Journal, 2017, vol. 23, # 47, p. 11234 - 11238
[5] Chemical Communications, 2018, vol. 54, # 26, p. 3231 - 3234

3,4-Dimethoxy-3-cyclobutene-1,2-dione(5222-73-1)Related Product Information

• Dimethyl sulfoxide
• 1,1-Dimethoxyethane
• Diphenyldimethoxysilane
• Dimethyldimethoxysilane
• Dacthal
• (-)-Dimethyl D-tartrate
• Dimethyl malonate
• Dimethyl ether
• Dimethyl acetylenedicarboxylate
• Dimethyl fumarate
• 3-SULFOLENE
• Dimethyl sebacate
• N,N-Dimethylformamide
• Dimethyl malate
• DIMETHYL PHOSPHATE
• Dimethyl suberate
• Dimethyl sulfate
• Dimethyl carbonate