79339-21-2

Upstream product

• 2657-28-5 2,4,6-trihydroxy-3-methyl-acetophenon 
• 3535-37-3 3,4-dimethoxybenzoic acid chloride 

Downstream Products

• 68349-74-6 desmodol trimethyl ether 
• 68349-72-4 desmodol dimethyl ether 
• 68349-71-3 desmodol 
• 79339-18-7 6-methyl-3',4',5,7-tetrahydroxyflavone 
• 79339-20-1 5,7-Dihydroxy-2-(3,4-dimethoxyphenyl)-6-methyl-4H-1-benzopyran-4-one 
• 79339-19-8 8-C-methyl-5,7-dihydroxy-3',4'-dimethoxyflavone 

Relevant academic research and scientific papers

Synthesis of novel C-methylflavones

If the Baker-Venkataraman rearrangement of C-methylphloracetophenone triaroyl esters is carried out in DMSO with powdered NaOH, the result greatly depends on the substitution pattern both of the phloracetophenone moiety possessing either one or two C-methyl groups and of the aroyl parts bearing a conjugated methoxy group (or not such a group) with respect to the carbonyl group. With benzoyl, 4-methoxybenzoyl or 3,4-dimethoxybenzoyl as aroyl group the 3,5-dimethylphloracetophenone triaroyl esters 10a-c directly yield the corresponding unsubstituted ring B or 4′-methoxy- and 3′,4′-dimethoxy-substituted 5,7-dihydroxy-6,8-dimethylflavones 11a-c. In contrast, the 3-methylphloracetophenone triaroyl esters 3a-c react quite differently, depending on the aroyl substitution pattern. Thus, the triester 3a containing benzoyl groups gives the hemiketal Wessely-Moser isomers 5a, 5a′ whereas the triesters 3b and 3c containing 4-methoxy- or 3,4-dimethoxybenzoyl groups are converted into compounds existing as two equilibria of two β-diketo and two β-keto enol tautomers. Finally, dehydration of each mixture furnishes solely the corresponding unsubstituted ring B or 4′-methoxy- and 3′,4′-dimethoxy-substituted 5,7-dihydroxy-6-methylflavones 8a-c. Methylation of 11c affords 7-O-methyl and 5,7-di-O-methyl derivatives 12a and b. VCH Verlagsgesellschaft mbH, 1996.

Synthesis of Desmodol, a Naturally Occurring Pyranoflavone

Desmodol (VI) isolated from the roots and stems of Desmodium caudatum DC has been synthesised. 3-Methylphloroacetophenone on veratroylation affords 2,4,6-triveratroyl-3-methylpholoroacetophenone (II) which is converted in two steps into flavones (III) and (IV).III on demethylation followed by treatment with 2-chloro-2-methyl-but-3-yne affords desmodol (VI), identical with the natural sample.