Nitronium tetrafluoroborate → trans-3,4-Dihydro-2,2-dimethyl-4-(1-oxoisoindolin-2-yl)-6-trifluoromethylsulfonyl-2H-1-benzopyran-3-yl nitrate

116 mg of nitronium tetrafluoroborate were added to a solution of 300 mg of trans-3,4-dihydro-2,2-dimethyl-4-(1-oxoisoindolin-2-yl)-6-trifluoromethylsulfonyl-2H-1-benzopyran-3-ol (prepared as described in Preparation 13) in 5 ml of methylene chloride, and the resulting mixture was stirred at room temperature for 1.5 hours. At the end of this time, the reaction mixture was diluted with 20 ml of water and extracted with 15 ml of methylene chloride. The extract was washed with water and with a saturated aqueous solution of sodium chloride, in that order, after which it was dried over anhydrous magnesium sulfate. The solvent was then removed by distillation under reduced pressure, and the resulting residue was purified by column chromatography through silica gel, using a 1:4 by volume mixture of ethyl acetate and cyclohexane as the eluent, to afford 88 mg of the title compound as crystals, melting at 189.5°-190° C.

1. extractionextracted with 15 ml of methylene chloride
2. washThe extract was washed with water and with a saturated aqueous solution of sodium chloride, in that order
3. dry with materialafter which it was dried over anhydrous magnesium sulfate
4. customThe solvent was then removed by distillation under reduced pressure
5. customthe resulting residue was purified by column chromatography through silica gel
6. additionby volume mixture of ethyl acetate and cyclohexane as the eluent

ORD record

ord-7c14f7ec756c4d5e977b765c36ee4f43

Source dataset

uspto-grants-1993_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05254578