34187-25-2

Upstream product

• 213991-17-4 2',6'-dihydroxy-6,6-dimethylpyrano[2,3:4',3']chalcone 
• 31525-67-4 dimethylacetal of 3-methyl-3-hydroxybutyraldehyde 
• 480-40-0 5,7-dihydroxy-2-phenyl-chromen-4-one 

Downstream Products

• 89482-13-3 5-acetoxy-6'',6''-dimethylpyrano<2'',3'':7,8>flavone 
• 64125-33-3 5-methoxy-8,8-dimethyl-2-phenyl-4H,8H-benzo[1,2-b:3,4-b’]dipyran-4-one 

Relevant academic research and scientific papers

Synthesis of isopongaflavone

The synthesis of isopongaflavone1 9, a constituent of the seeds of Tephrosia bracteolata, is described. Phloroacetophenone 1 on treatment with chlorobutyne affords 2,6-dihydroxy-6′,6′-dimethyIpyrano[2′,3′: 4,3]acetophenone 2 which on methoxymethylation yields 2,6-di(methoxymethoxy)-6′, 6′-dimethylpyrano[2′,3′: 4,3]acetophenone 5. Alkaline condensation of 5 and benzaldehyde gives 2′, 6′-di(methoxymethoxy)-6″,6″-dimethylpyrano[2″, 3″ : 4′, 3′] chalcone 6. DDQ treatment of 2′, 6′-dihydroxy-6″,6″-dimethylpyrano[2″, 3″ : 4′, 3′] chalcone 7, obtained by the demethoxymethylation of 6, furnishes 5-hydroxy-6″,6″-dimethylpyrano[2″, 3″ : 4, 3]flavone 8 which on O-methylation gives 5-methoxy-6″,6″-dimethylpyrano[2″, 3″ : 4, 3]flavone 9.