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

HRID 885675Notes

Reaction equation

HRID 885675 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-e576a2e667b04a6cad05fe3306c37d41
Source dataset
uspto-grants-2012_08
Patent number
US08242275B2

Reaction notes

Loading…