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

HRID 335859Notes

Reaction equation

[Br:1][C:2]1[CH:18]=[CH:17][C:5]([O:6][C:7]2[CH:8]=[N+:9]([O-:16])[CH:10]=[CH:11][C:12]=2[N+:13]([O-:15])=[O:14])=[C:4]([C:19]([O:21]C)=O)[CH:3]=1.C([N-]C(C)C)(C)C.[Li+].BrC1C=CC2OC3C(=NC=CC=3[N+]([O-])=O)C(=O)C=2C=1>C1COCC1>[Br:1][C:2]1[CH:18]=[CH:17][C:5]2[O:6][C:7]3[C:8](=[N+:9]([O-:16])[CH:10]=[CH:11][C:12]=3[N+:13]([O-:15])=[O:14])[C:19](=[O:21])[C:4]=2[CH:3]=1

Participants

Conditions

Temperature: -78 °C

Procedure

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.

Workup

customThe reaction was quenched at this temperature with 15 mL of 1 M HCl in ether
temperatureto warm up to rt
extractionThe reaction was extracted with ethyl acetate (3×100 mL)
dry with materialThe combined organics were dried over sodium sulfate
filtrationfiltered
customevaporated to dryness
customPurification of the crude residue by column chromatography (hexane to H/CH2Cl2=1:1 to CH2Cl2)

Sources & evidence

ORD record: ord-27174d44caf94429920213f519a8033f
Source dataset: uspto-grants-2014_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08883782B2

Reaction notes

Loading…