86978-00-9

Upstream product

• 31273-58-2 1-(7-hydroxy-2,2-dimethylchroman-6-yl)ethanone 
• 94-30-4 ethyl 4-methoxybenzoate 
• 86977-99-3 1-(7-Hydroxy-2,2-dimethyl-chroman-6-yl)-3-(4-methoxy-phenyl)-propane-1,3-dione 
• 86977-98-2 4-Methoxy-benzoic acid 6-acetyl-2,2-dimethyl-chroman-7-yl ester 

Downstream Products

• 143725-43-3 2-(4-Methoxy-phenyl)-8,8-dimethyl-8H-pyrano[3,2-g]chromen-4-one 

Relevant academic research and scientific papers

Synthesis of 3,4-dihydro-2,2-dimethyl-2Hpyranoflavones

Treatment of 2-benzylidene derivatives 1a-k with potassium cyanide in ethanol furnish 3,4-dihydro-2,2-dimethyl-2H-pyranoflavones 2a-k in quantitative yield. The structures of the final products have been elucidated on the basis of spectral studies.

A Facile Synthesis of Isopongaflavone, Atalantoflavone Dimethylether, Racemoflavone Dimethylether and their Analogues

A convenient route to pyranoflavones (natural and synthetic) from acetyl hydroxy chroman via the corresponding analogues by the use of Claisen condensation in the key step is reported.Keywords: 2-Aryl-8,8-dimethyl-6,7-dihydro-4H,8H-benzodipy

Baker-Venkataraman Rearrangement of o-Aroyloxyacetyldihydrobenzopyrans - Synthesis of 3,4-Dihydro-2,2-dimethyl-2H-pyranoflavones

Reactions of 6-acetyl-7-hydroxy-3,4-dihydro-2,2-dimethyl-2H-benzopyran (I) and 8-acetyl-7-hydroxy-5-methoxy-3,4-dihydro-2,2-dimethyl-2H-benzopyran (II) with 4-methoxybenzoyl chloride and 3,4-methylenedioxybenzoyl chloride give the respective o-aroyloxyacetyldihydrobenzopyrans (III, VI, IX and XII).These on Baker-Venkataraman rearrangement in the presence of pyridine and KOH afford the diaroylmethanes (IV, VII, X and XIII), which undergo cyclisation in the presence of glacial acetic acid and fused sodium acetate to the corresponding dihydropyranoflavones (V, VIII, XI and XIV).