Pentafluoropyridine → 2-(4-Fluorophenyl)-3-(pyridin-4-yl)-4-(2,3,5,6-tetrafluoropyridin-4-yl)-1H-pyrrole

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Reaction Steps

1.8 ml (2.75 mmol) of 1.54 N solution of t-butyllithium in pentane were added to a solution of 650 mg (1.37 mmol) of 4-bromo-2-(4-fluorophenyl)-3-(pyridin-4-yl)-1-triisopropylsilyl-1H-pyrrole [prepared as described in step 7(iii) above] in 15 ml of tetrahydrofuran at −78° C. and the mixture was stirred for 10 minutes. At the end of this time, 165 μl (1.51 mmol) of pentafluoropyridine were added to the reaction mixture. The cooling bath was then removed and the mixture was stirred for 30 minutes. At the end of this time, 70 ml of water and 50 ml of a saturated aqueous solution of sodium hydrogencarbonate were added to the reaction mixture, and then this was extracted with ethyl acetate. The organic extract was washed with water and then concentrated by evaporation under reduced pressure. The residue thus obtained was purified by chromatography on a silica gel column using a 4:1 by volume mixture of hexane and ethyl acetate as the eluant to give 346 mg (yield 65%) of the title compound as a pale yellow powder.

Provenance & Evidence