Sulfuric Acid → ethyl 2,2-bisfluoromethyl-6-iodo-2H-1-benzopyran-4-carboxylate

Participants

Reaction Steps

To a mixture of 4.0 g of 6-amino-2,2-bis(fluoromethyl)-2H-1-benzopyran-4-carboxylic acid ethyl ester, 1.66 g of sulfuric acid and 40 ml of water was added a mixture of 1.09 g of sodium nitrite, 10 ml of methylene chloride and 10 ml of water under ice-cooling. The mixture was stirred under ice-cooling for 10 minutes. Further, to the reaction mixture was added a mixture of 2.85 g of potassium iodide and 5 ml of water, and the mixture was stirred at room temperature for 1.5 hours. To the reaction mixture solution was added water and the resultant solution was extracted with methylene chloride. An organic layer was washed with a 20% aqueous sodium sulfite solution and a saturated saline solution, dried over sodium sulfate and concentrated under reduced pressure. The obtained residue was subjected to silica gel column chromatography (developing solution, ethyl acetate:hexane=10:1) to obtain 3.67 g of 2,2-bis(fluoromethyl)-6-iodo-2H-1-benzopyran-4-carboxylic acid ethyl ester with a melting point of 89°-90° C.

Provenance & Evidence