52951-26-5

Basic information

• Product Name: 3-Cyclobutene-1,2-dione, 3-hydroxy-4-(phenylamino)-
• CAS NO: 52951-26-5
• Molecular Formula: C10H7NO3
• Molecular Weight: 189.17
• Mol File: 52951-26-5.mol
• Article Data: 3

Chemical Properties

• CAS DataBase Reference: 3-Cyclobutene-1,2-dione, 3-hydroxy-4-(phenylamino)-(CAS DataBase Reference)
• NIST Chemistry Reference: 3-Cyclobutene-1,2-dione, 3-hydroxy-4-(phenylamino)-(52951-26-5)
• EPA Substance Registry System: 3-Cyclobutene-1,2-dione, 3-hydroxy-4-(phenylamino)-(52951-26-5)

Safety Data

• Hazardous Substances Data: 52951-26-5(Hazardous Substances Data)

Upstream product

• 62-53-3 aniline 
• 2892-51-5 squaric acid 

Downstream Products

• 2892-51-5 squaric acid 

Relevant articles and documents

Kinetic Analysis and Mechanism of the Hydrolytic Degradation of Squaramides and Squaramic Acids

The hydrolytic degradation of squaramides and squaramic acids, the product of partial hydrolysis of squaramides, has been evaluated by UV spectroscopy at 37 °C in the pH range 3-10. Under these conditions, the compounds are kinetically stable over long time periods (>100 days). At pH >10, the hydrolysis of the squaramate anions shows first-order dependence on both squaramate and OH-. At the same temperature and [OH-], the hydrolysis of squaramides usually displays biphasic spectral changes (A → B → C kinetic model) with formation of squaramates as detectable reaction intermediates. The measured rates for the first step (k1 ≈ 10-4 M-1 s-1) are 2-3 orders of magnitude faster than those for the second step (k2 ≈ 10-6 M-1 s-1). Experiments at different temperatures provide activation parameters with values of ΔH? ≈ 9-18 kcal mol-1 and ΔS? ≈ -5 to -30 cal K-1 mol-1. DFT calculations show that the mechanism for the alkaline hydrolysis of squaramic acids is quite similar to that of amides.

Synthesis of Glutaconaldehydes from Pyridinium Betaines of Squaric Acid

The pyridinium ring of squaric acid betaines (2) is opened by hydroxide ions.Electronegative substituents (R = Cl, CN) at C-3 promote this reaction.The stereochemistry of the resulting 5-(2-hydroxy-3,4-dioxocyclobut-1-en-1-yl)aminopenta-2,4-dienales (3) is confirmed by NMR-spectroscopy.Treatment of 3 with sodium hydroxide results in further hydrolysis to the sodium salts of glutaconaldehydes (5) and 3-amino-4-hydroxycyclobut-3-ene-1,2-dione (6).These products are also directly obtained from the nicotinic acid derivates 2d (R = COOEt) and 2e (R = CONH2), in the latter case cyclisation of the glutaconic acid derivate to the known 3-formylpyrid-2-one (10) is observed.