33176-11-3

Basic information

• Product Name: 2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione
• CAS NO: 33176-11-3
• Molecular Formula: C₁₀H₈O₄
• Molecular Weight: 192.1681
• Mol File: 33176-11-3.mol
• Article Data: 4

Chemical Properties

• Boiling Point: 403.6°C at 760 mmHg
• Flash Point: 185.2°C
• Density: 1.34g/cm³
• Vapor Pressure: 1E-06mmHg at 25°C
• Refractive Index: 1.569
• CAS DataBase Reference: 2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione(CAS DataBase Reference)
• NIST Chemistry Reference: 2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione(33176-11-3)
• EPA Substance Registry System: 2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione(33176-11-3)

Safety Data

• Hazardous Substances Data: 33176-11-3(Hazardous Substances Data)

Upstream product

• 16807-48-0 3‐acetyl‐2‐hydroxy‐6‐methyl‐4H‐pyran‐4‐one 
• 141-97-9 ethyl acetoacetate 
• 66505-40-6 dimethyl-γ-pyrone 
• 675-10-5 4-hydroxy-6-methyl-2-pyron 
• 18735-96-1 2,3-Dihydro-2,7-dimethyl-4H,5H-pyrano-<4,3-b>-pyran-4,5-dion 

Downstream Products

• 703-29-7 1-(2,4-dihydroxy-6-methylphenyl)ethanone 
• 185851-74-5 5-Benzyl-4-hydroxy-6-oxo-2-(2-oxo-propyl)-6H-pyran-3-carboxylic acid ethyl ester 
• 4860-88-2 4-hydroxy-7-methyl-2H,5H-pyrano[4,3-b]pyran-2,5-dione 
• 185851-66-5 3-Benzyl-4-hydroxy-7-methyl-2,5-dioxo-2H,5H-pyrano<4,3-b>pyran 
• 56364-25-1 4-hydroxy-6-methyl-3-[(2E)-3-phenylprop-2-enoyl]-2H-pyran-2-one 
• 771-03-9 3-acetyl-4-hydroxy-6-methyl-2H-pyran-2-one 
• 675-10-5 4-hydroxy-6-methyl-2-pyron 
• 1004-36-0 2,6-dimethylpyrone 
• 57439-16-4 methyl 2-hydroxy-6-methoxy-4-methylbenzoate 
• 15482-99-2 Methyl 2,6-dihydroxy-3-acetyl-4-methylbenzoate 
• 29736-80-9 3,5-dioxohexanoic acid methyl ester 

Relevant articles and documents

Synthesis and structural characterization of a fused bispyrone and preparation of the first metal bispyrylium complexes

Dehydroacetic acid reacts with acetic anhydride in the presence of perchloric acid to give a salt which upon careful neutralization affords a fused bis-γ-pyrone. The bis-γ-pyrone forms stable metal complexes with Li, Mg, Cu(ii), Ni(ii), Zn, Fe(ii), Co(ii) and Ba perchlorates whose crystal structures reveal that the ligand possesses significant bispyrylium character while the metal is coordinated at the negatively charged edge of the structure.

Reactions of fused and unfused α-pyrones with magnesium alkoxide, sodium alkoxide and water as the nucleophile: effects of chelation

The reactions between a series of α-pyrones (two mono- and three fused) and the non-chelating base sodium alkoxide, the chelating base magnesium alkoxide and water as the nucleophile, have been studied.Aromatic and other products formed reflect the points of attack on the pyrone systems and when sodium methoxide is used the ensuing cyclisation is preferentially by aldol mechanisms.The employment of excess magnesium methoxide or ethoxide gives magnesium-chelated precursors and the nature of products now depends on these intermediates, and the protection afforded by such magnesium chelation to the reaction products.In the case of structures containing chelated β-keto ester features the chelates are screened from attack as aldol acceptors, but are effective Claisen acceptors.In such chelates an adjacent methylene is activated by further magnesium alkoxide to act as an aldol or Claisen donor.These contrasting aldol/Claisen reactivities, as between a non-chelating and a chelating base, are illustrated in the ensuing chemistry of the pyrones.Treatment with water releases the main carbon chain with decarboxylation, from which new products may form.