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A18186 3,4-Dimethoxy-3-cyclobutene-1,2-dione, 98%

CAS Number
Dimethyl squarate
Squaric acid dimethyl ester

Stock No. Size Price ($) Quantity Availability
A18186-03 1g 47.60
A18186-06 5g 160.00
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3,4-Dimethoxy-3-cyclobutene-1,2-dione, 98%


Chemical Properties

Formula Weight
Melting point
Storage & Sensitivity
Keep Cold.
Very soluble in water.


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.


Store away from oxidizing agents. Keep the container tightly closed and place it in a cool, dry and well ventilated condition.

Literature References

Yong Qian.; Gaoyuan Ma.; Aifeng Lv.; Hai-Liang Zhu.; Jing Zhao.; Viresh H Rawal. Squaramide-catalyzed enantioselective Friedel-Crafts reaction of indoles with imines.Chem Commun (Camb).2010,46(17), 3004-3006.

M Burak Onaran.; Anthony B Comeau.; Christopher T Seto. Squaric acid-based peptidic inhibitors of matrix metalloprotease-1.J Org Chem.2005,70(26), 10792-10802.

GHS Hazard and Precautionary Statements

Hazard Statements: H315-H317-H319-H334-H335

Causes skin irritation. May cause an allergic skin reaction. Causes serious eye irritation. May cause allergy or asthma symptoms or breathing difficulties if inhaled. May cause respiratory irritation.

Precautionary Statements: P261-P264b-P271-P272-P280-P285-P302+P352-P304+P340-P305+P351+P338-P333+P313-P337+P313-P342+P311-P362-P501c

Avoid breathing dust/fume/gas/mist/vapours/spray. Wash face, hands and any exposed skin thoroughly after handling Use only outdoors or in a well-ventilated area. Contaminated work clothing should not be allowed out of the workplace. Wear protective gloves/protective clothing/eye protection/face protection. In case of inadequate ventilation wear respiratory protection. IF ON SKIN: Wash with plenty of soap and water. IF INHALED: Remove to fresh air and keep at rest in a position comfortable for breathing. IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing. If skin irritation or rash occurs: Get medical advice/attention. If eye irritation persists: If experiencing respiratory symptoms: Call a POISON CENTER or doctor/physician. Take off contaminated clothing and wash before reuse. Dispose of contents/ container to an approved waste disposal plant

Other References

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