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

Beteiligte Stoffe

Reaktionsschritte

A mixture of 1.09 g of sodium nitrite, 10 ml of methylene chloride and 10 ml of water was added to a mixture of 4.0 g of ethyl 6-amino-2,2-bisfluoromethyl-2H-1-benzopyran-4-carboxylate, 1.66 g of sulfuric acid and 40 ml of water under ice cooling, followed by stirring under ice cooling for 10 minutes. Further, a mixture of 2.85 g of potassium iodide and 5 ml of water was added to the reaction mixture, followed by stirring at room temperature for 1.5 hour. Water was added to the reaction mixture, and the mixture was extracted with methylene chloride. The organic layer was washed with a 20% aqueous solution of sodium sulfite and a brine and then dried over sodium sulfate. The residue obtained by concentration under reduced pressure was subjected to silica gel column chromatography (an eluting solvent, ethyl acetate:hexane=1:1) to obtain 3.67 g of ethyl 2,2-bisfluoromethyl-6-iodo-2H-1-benzopyran-4-carboxylate having a melting point of 89°-90° C.

Herkunft & Nachweise