Hydrochloric Acid → 7-bromo-1H,2H,3H-pyrido[2,3-b][1,4]oxazin-2-one

HRID 1644510Notes

Reaction equation

HRID 1644510 reaction equation
C([O:3][C:4](=O)[CH2:5][O:6][C:7]1[C:12]([N+:13]([O-])=O)=[CH:11][C:10]([Br:16])=[CH:9][N:8]=1)C.Cl.[Sn](Cl)(Cl)(Cl)Cl.CO.C(Cl)(Cl)Cl>C1COCC1>[Br:16][C:10]1[CH:9]=[N:8][C:7]2[O:6][CH2:5][C:4](=[O:3])[NH:13][C:12]=2[CH:11]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 24287Tin tetrachlorideHCID 4647502Ethyl 2-((5-bromo-3-nitropyridin-2-yl)oxy)acetate2×HCID 21584188Chloroform methanol

Product 1

HCID 45901417-bromo-1H,2H,3H-pyrido[2,3-b][1,4]oxazin-2-oneYield 37.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
65 °C

Procedure

Ethyl[(5-bromo-3-nitropyridin-2-yl)oxy]acetate (intermediate 212) (4.3 g, 14.1 mmol) was dissolved in anhydrous THF (10 mL) and concentrated HCl (10 mL) was added at 0° C. Tin chloride (5.0 g, 26.4 mmol) was added in small portions. The reaction was stirred for 1 hr and heated at 65° C. overnight. The reaction mixture was concentrated under reduced pressure, extracted with chloroform, dried over magnesium sulfate and concentrated. Chromatography on silica gel with methanol/chloroform gave the product as a light pink solid (1.2 g, 37% yield).

Workup

  1. concentrationThe reaction mixture was concentrated under reduced pressure
  2. extractionextracted with chloroform
  3. dry with materialdried over magnesium sulfate
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-2e436141dac24d59bbf38d683b399fc3
Source dataset
uspto-grants-2012_02
Patent number
US08124602B2

Reaction notes

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