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

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Reaction Steps

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.

Provenance & Evidence