Bromine → 3-Oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazine-6-carbaldehyde

HRID 1518016Notes

Reaction equation

HRID 1518016 reaction equation
Br[C:2]1[N:7]=[C:6]([N+:8]([O-])=O)[C:5]([OH:11])=[CH:4][CH:3]=1.[OH:12][C:13]1[C:14]([N+]([O-])=O)=NC=CC=1.[O:22]([CH3:24])[Na].BrBr>CO>[O:12]=[C:13]1[CH2:14][O:11][C:5]2[CH:4]=[CH:3][C:2]([CH:24]=[O:22])=[N:7][C:6]=2[NH:8]1

Participants

6

Reactant 4

HCID 24408BromineHCID 270573-Hydroxy-2-nitropyridineHCID 218738086-Bromo-2-nitropyridin-3-olHCID 178418582HCID 178418582, compound

Product 1

HCID 218737373-Oxo-3,4-dihydro-2H-pyrido[3,2-b][1,4]oxazine-6-carbaldehyde

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent2×

Procedure

6-Bromo-2-nitro-pyridin-3-ol. To a solution of 3-hydroxy-2-nitropyridine (20 g, 140 mmol) in CH3OH (400 mL) was added a solution of 25% NaOCH3 in CH3OH (33.0 mL, 153 mmol). After stirring at RT for 30 min, the reaction mixture was cooled to 0° C. and Br2 (7.2 mL, 140 mmol) added slowly. The mixture was stirred for 30 min, and then was quenched with glacial acetic acid (2.5 mL). The solvent was removed under reduced pressure. A portion of the crude material was purified on SiO2 (50% EtOAc/hexanes) to provide the title compound as a white solid. MS (ESI): exact mass calculated for C5H3BrN2O3, 217.93; m/z not found. 1H NMR (400 MHz, CDCl3): 10.24 (s, 1H), 7.74 (d, J=8.6, 1H), 7.54 (d, J=8.6, 1H).

Workup

  1. temperaturethe reaction mixture was cooled to 0° C.
  2. stirringThe mixture was stirred for 30 min
  3. customwas quenched with glacial acetic acid (2.5 mL)
  4. customThe solvent was removed under reduced pressure
  5. customA portion of the crude material was purified on SiO2 (50% EtOAc/hexanes)

Sources & evidence

ORD record
ord-16804d396ec844af8f11d61f9c96d6d6
Source dataset
uspto-grants-2012_07
Patent number
US08232391B2

Reaction notes

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