98153-26-5

Upstream product

• 150-19-6 O-methylresorcine 
• 637-44-5 phenylpropyolic acid 
• 31356-10-2 (E)-2-benzylidene-6-methoxybenzofuran-3(2H)-one 
• 673-22-3 2-Hydroxy-4-methoxybenzaldehyde 
• 4440-01-1 lithium phenylacetylide 
• 1322775-64-3 C₁₆H₁₄O₃ 
• 536-74-3 phenylacetylene 

Downstream Products

• 22395-22-8 7-methoxoyflavone 
• 127839-71-8 3-benzoyl-7-methoxy-2-phenyl-4H-1-benzopyran-4-one 
• 31356-11-3 (Z)-6-methoxyaurone 
• 1415384-96-1 5-methoxy-2-(3-phenylprop-2-ynoyl)phenyl benzoate 
• 42079-78-7 5-methoxyflavone 
• 525-82-6 FLAVONE 

Relevant academic research and scientific papers

One Pot Synthesis of γ-Benzopyranones via Iron-Catalyzed Aerobic Oxidation and Subsequent 4-Dimethylaminopyridine Catalyzed 6-endo Cyclization

One-pot synthesis of γ-benzopyranones was realized in decent yields and excellent regioselectivities via iron-catalyzed aerobic oxidation and 4-dimethylaminopyridine-catalyzed cyclization of related propargylic alcohols. Derivatizations to aromatic substituted γ-benzopyranones and synthesis of naturally occurring 3′,4′-dimethoxyflavone have also been realized. (Figure presented.).

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.

Intramolecular Cyclisation Catalysed by Silver(I) Ion; a Convenient Synthesis of Aurones

Silver(I) ion catalysed intramolecular cyclisation of (1a-d) at room temperature gives corresponding aurone (2a-d) as the major product with a trace amount of the flavone; compounds (1a-d) could be prepared by the addition of the corresponding lithium acetylide (4a-b) to the substituted salicyl aldehyde (5a-c), followed by MnO2 oxidation.

Synthesis of Highly Functionalized Flavones and Chromones Using Cycloacylation Reactions and C-3 Functionalization. A Total Synthesis of Hormothamnione

The cycloacylations of hydroxy- and methoxy-substituted phenols with aryl- and alkylpropiolic acids using Eaton's reagent (10percent phosphorus pentoxide in methanesulfonic acid) gives highly substituted flavones and chromones in up to 63 percent yield.Styrylchromones were prepared from 2-methylchromones by condensation reactions of the 2-methyl group with various substituted benzaldehydes in sodium ethoxide and ethanol in almost quantitative yield.Methylation or hydroxylation at C-3 of these highly substituted flavones and styrylchromones was accomplished in a highly regioselective manner employing lithium diisopropylamide followed by quenching with an electrophile.Quenching of the initial anion with methyl triflate gave 3-methyl products while quenching of the initial anion with trimethylborate followed by oxidation gave 3-hydroxy products.A total synthesis of the naturally occurring styrylchromone hormothamnione, containing a 3-methyl substituent, is reported by use of these synthetic techniques.

Lithiation in Flavones, Chromones, Coumarins, and Benzofuran Derivatives

Flavones are lithiated at position 3 by lithium di-isopropylamide in tetrahydrofuran at -78 deg C and the products are stable at that temperature.Appropriate reagents replace the lithium by carboxy, ethoxycarbonyl, mercapto, methylthio, trimethylsilyl, hydroxy, and other groups, sometimes giving products not previously available.Benzofurans are preferentially lithiated at position 2 if this is free, and may not be attacked if it is blocked, but if there is an activating group (i.e., one able to co-ordinate with the lithium cation) at position 2, then lithiation occurs at position 3.In the benzofuran series ring-opening is easier and lithiation often leads directly to acetylenic phenols.Chromones can be lithiated at positions 2 and 3 depending upon the substitution pattern and whether the substituents are activating.Aurones are not easily deprotonated, and only the acetylenic phenol arising from ring opening was found in the one successful case.Coumarins tend to behave simply as esters and give amides with the lithiating reagent, but 4-methoxycoumarin is readily lithiated at position 3.It is suggested that 3-deprotonation in ethers occurs easily only when there is an ether link antiperiplanar to the proton removed, and that the lithiated species are really unstable intermediates in trans-eliminations leading to alkyne derivatives.