Coumarin → 7-benzoyloxy-4-methyl-coumarin

Participants

Reaction Steps

The route shown in Scheme 1 exemplifies synthesis of the coumarin compounds of the present invention. Triethylamine is added to a solution of 7-hydroxy-4-methyl-chromen-2-one (i) and a benzoyl chloride (ii) in THF at room temperature. The reaction mixture is stirred at room temperature overnight and filtered. The filtrate is concentrated to afford a 7-benzoyloxy-4-methyl-coumarin (iii). A mixture of compound (iii) and finely powdered aluminum chloride is heated at 170° C. for 2 hours to afford an 8-benzoyl-7-hydroxy-4-methyl-chromen-2-one (iv). A mixture of compound (iv), 2-bromoacetophenone (v), and K2CO3 in CH3CN is refluxed overnight. The reaction mixture is filtered and the filtrate is concentrated. The residue is purified by column chromatography to afford a pure 8-benzoyl-4-methyl-9-phenyl-furo[2,3-h]chromen-2-one (vi).

Provenance & Evidence