Nitric Acid → 6-Nitro-2H-pyrido[3,2-B][1,4]oxazin-3(4H)-one

HRID 1990658Notes

Reaction equation

HRID 1990658 reaction equation
[O:1]1[CH2:6][C:5](=[O:7])[NH:4][C:3]2[N:8]=[CH:9][CH:10]=[CH:11][C:2]1=2.[N+:12]([O-])([OH:14])=[O:13]>C(O)(=O)C.C(OC(=O)C)(=O)C>[N+:12]([C:9]1[CH:10]=[CH:11][C:2]2[O:1][CH2:6][C:5](=[O:7])[NH:4][C:3]=2[N:8]=1)([O-:14])=[O:13]

Participants

5

Reactant 2

HCID 944Nitric AcidHCID 884992H-pyrido(3,2-b)-1,4-oxazin-3(4H)-one

Product 1

HCID 220607326-Nitro-2H-pyrido[3,2-B][1,4]oxazin-3(4H)-one

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 7918Acetic AnhydrideSolvent

Procedure

2H-Pyrido[3,2-b]-1,4-oxazin-3 (4H)-one (2.5 g) was dissolved in acetic acid (6 mL) and acetic anhydride (30 mL). Fuming nitric acid (3 mL) was added dropwise to the reaction solution in ice-bath. The reaction solution was stirred in ice-bath overnight. Solution was poured into crashed ice. The light yellow precipitation was collected by filtration, washed with water and dried to give a mixture of nitrated products (regio-isomers). The mixture was crystallized from dichloromethane to give 6-nitro-2H-pyrido[3,2-b]-1,4-oxazin-3 (4H)-one (1 g) as a light yellow solid. 6-Nitro-2H-pyrido[3,2-b]-1,4-oxazin-3 (4H)-one (1 g) was reduced under hydrogenolysis conditions using 10% Pd—C in methanol (50 mL) and 1N HCl solution (10 mL) at 50 psi for 2 h. The catalyst was filtered off and washed with methanol and 1N HCl solution. The filtrate was evaporated to give 6-amino-2H-pyrido[3,2-b]-1,4-oxazin-3 (4H)-one.

Workup

  1. additionSolution was poured
  2. customThe light yellow precipitation
  3. filtrationwas collected by filtration
  4. washwashed with water
  5. customdried
  6. customto give
  7. additiona mixture of nitrated products (regio-isomers)
  8. customThe mixture was crystallized from dichloromethane

Sources & evidence

ORD record
ord-2fa638d4ca8c4d0cbe9314a9368e519a
Source dataset
uspto-grants-2010_01
Patent number
US07642351B2

Reaction notes

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