Hydrochloric Acid → 4-cyano-2,2-bisfluoromethyl-6-nitro-2H-1-benzopyran

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Reaction Steps

To a mixture of 4.05 g of 2,2-bisfluoromethyl-3,4-dihydro-6-nitro-2H-1-benzopyran-4-one and 10 ml of dry benzene were added 2.52 ml of trimethylsilyl cyanide and 0.82 g of zinc iodide with stirring under ice-cooling, and the mixture was stirred at room temperature for 12 hours. The mixture was further combined with 8 ml of pyridine and 4.41 ml of phosphorus oxychloride and heated to reflux for 6 hours. The reaction mixture was acidified with ice water and aqueous hydrochloric acid and extracted with methylene chloride. The organic layer was washed with water and dried, then concentrated under reduced pressure, and the resulting residue was subjected to silica gel column chromatography (eluent; methylene chloride:hexane=7:3) to give 0.99 g of 2,2-bisfluoromethyl-6-nitro-2H-1-benzopyran-4-carbonitrile; m.p. 136-137° C.;

Provenance & Evidence