Lithium diisopropylamide → 8-bromo-4-nitro-10-oxo-10H-chromeno[3,2-b]pyridine 1-oxide

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-(4-bromo-2-(methoxycarbonyl)phenoxy)-4-nitropyridine 1-oxide (369 mg, 1.000 mmol) in 20 mL of dry THF at −78° C. was added dropwise lithium diisopropylamide (2M, 1.99 mL, 1.999 mmol) and the reaction was stirred at −78° C. for 3 h. The reaction was quenched at this temperature with 15 mL of 1 M HCl in ether and the whole was allowed to warm up to rt. The reaction was extracted with ethyl acetate (3×100 mL). The combined organics were dried over sodium sulfate, filtered and evaporated to dryness. Purification of the crude residue by column chromatography (hexane to H/CH2Cl2=1:1 to CH2Cl2) gave 8-bromo-4-nitro-10-oxo-10H-chromeno[3,2-b]pyridine 1-oxide (20 mg, 0.059 mmol, 5.94% yield) as an offwhite solid and 8-bromo-4-nitro-10H-chromeno[3,2-b]pyridin-10-one as an light yellow solid.

Provenance & Evidence