Sulfuric Acid → HCID 68599622, compound

HRID 2384983Notes

Reaction equation

HRID 2384983 reaction equation
N[C:2]1[CH:13]=[CH:12][C:5]2[N:6]([CH3:11])[C:7](=[O:10])[CH2:8][O:9][C:4]=2[CH:3]=1.S(=O)(=O)(O)[OH:15].N([O-])=O.[Na+]>O>[OH:15][C:2]1[CH:13]=[CH:12][C:5]2[N:6]([CH3:11])[C:7](=[O:10])[CH2:8][O:9][C:4]=2[CH:3]=1

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 27644607-amino-4-methyl-3,4-dihydro-2H-1,4-benzoxazin-3-oneHCID 23668193Sodium Nitrite

Product 1

HCID 68599622HCID 68599622, compoundYield 32%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent3×

Conditions

Temperature
0 °C

Procedure

To a cooled (0° C.) solution of 7-amino-4-methyl-2H-1,4-benzoxazin-3(4H)-one (10.0 g, 56 mmol) in water (80 mL) was added concentrated sulfuric acid (17 mL). After stirring at 0° C. for 10 min, a solution of sodium nitrite (4.1 g, 59 mmol) in water (10 mL) was added dropwise. After stirring for 0.5 h, the reaction mixture was added dropwise to a solution of cupric sulfate (50 g) in water (300 mL) at reflux. Once the addition was complete, the reaction mixture was allowed to cool to ambient temperature and was extracted with ethyl acetate (5×200 mL). The combined organic solution was dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was purified by trituration with ice-cold ethyl acetate (25 mL) and the solid was collected by vacuum filtration, air-dried and dried under high vacuum to afford 7-hydroxy-4-methyl-2H-1,4-benzoxazin-3(4H)-one (3.22 g, 32%) as a tan solid: 1H NMR (300 MHz, DMSO-d6) δ9.40 (s, 1H), 6.95 (d, J=8.7 Hz, 1H), 6.45 (dd, J=8.7, 2.6 Hz, 1H), 6.40 (d, J=2.6 Hz, 1H), 4.56 (s, 2H), 3.21 (s, 3H); MS (ES+) m/z 180.1 (M+1).

Workup

  1. stirringAfter stirring for 0.5 h
  2. temperatureat reflux
  3. additionOnce the addition
  4. temperatureto cool to ambient temperature
  5. extractionwas extracted with ethyl acetate (5×200 mL)
  6. dry with materialThe combined organic solution was dried over anhydrous sodium sulfate
  7. filtrationfiltered
  8. concentrationconcentrated in vacuo
  9. customThe residue was purified by trituration with ice-cold ethyl acetate (25 mL)
  10. filtrationthe solid was collected by vacuum filtration
  11. customair-dried
  12. customdried under high vacuum

Sources & evidence

ORD record
ord-5ea096a59e1545789eadb6de4ca53300
Source dataset
uspto-grants-2012_09
Patent number
US08263606B2

Reaction notes

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