128216-91-1

Upstream product

• 1322775-81-4 C₁₆H₁₄O₃ 
• 536-74-3 phenylacetylene 
• 1466-76-8 2-6-dimethoxybenzoic acid 

Downstream Products

• 491-78-1 5-Hydroxyflavone 
• 42079-78-7 5-methoxyflavone 
• 57060-62-5 (Z)-2-benzylidene-4-methoxybenzofuran-3(2H)-one 
• 57060-62-5 C₁₆H₁₂O₃ 

Relevant academic research and scientific papers

Metal-free methodology for the preparation of sterically hindered alkynoylphenols and its application to the synthesis of flavones and aurones

A metal-free synthesis for the preparation of sterically demanding ortho-demethylated ynones from mixed anhydrides and potassium alkynyltrifluoroborate salts has been developed. The one-pot reaction proceeds rapidly in the presence of a Lewis acid without the exclusion of air and moisture. This method is advantageous in that it is operationally simple, proceeds under mild conditions, and has a broad substrate scope. 2,6-Dimethoxy substituted anhydrides afford the corresponding mono-demethylated ynone products in good yields. In particular, 2-hydroxy substituted ynone products are valuable synthetic intermediates because their conversion to biologically active natural product scaffolds is straightforward. Flavones were obtained via 6-endo cyclization of the o-alkynyoylphenol intermediates under acidic conditions. Cesium carbonate was found to promote rapid 5-exo cyclization to furnish aurone products.

Synthesis of γ-benzopyranone by TfOH-promoted regioselective cyclization of o-alkynoylphenols

Regioselective cyclization of o-alkynoylphenols forming γ-benzopyranones has been demonstrated. Trifluoromethanesulfonic acid (TfOH) induced 6-endo cyclization of o-alkynoylphenols without forming 5-exo cyclized benzofuranone derivatives to provide the corresponding γ-benzopyranones in high yields.

Regioselective synthesis of flavone derivatives via DMAP-catalyzed cyclization of o-alkynoylphenols

A catalytic amount of DMAP promoted cyclization of o-alkynoylphenols via a 6-endo cyclization mode leading to flavone derivatives in high yields without forming 5-exo cyclized aurone derivatives. Utilizing this method, methoxy substituted flavone and alkyl substituted γ-benzopyranone derivatives were synthesized.