213991-16-3

Upstream product

• 480-66-0 2,4,6-trihydroxyacetophenone 
• 31380-13-9 2,6-dihydroxy-6',6'-dimethylpyrano[2',3': 4,3]acetophenone 
• 1111-97-3 3-chloro-3-methylbut-1-yne 
• 100-52-7 benzaldehyde 
• 67052-50-0 2,6-di(methoxymethoxy)-6',6'-dimethylpyrano[2',3': 4,3]acetophenone 

Downstream Products

• 213991-17-4 2',6'-dihydroxy-6,6-dimethylpyrano[2,3:4',3']chalcone 

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.