Boron trifluoride etherate → 3,4-Dihydro4-(2-dimethylaminoethyl)-6-nitro-2H-1,4-benzoxazine

HRID 1740743Notes

Reaction equation

HRID 1740743 reaction equation
B(F)(F)F.CCOCC.[BH4-].[Na+].[CH3:12][N:13]([CH3:30])[CH2:14][CH2:15][N:16]1[C:21]2[CH:22]=[C:23]([N+:26]([O-:28])=[O:27])[CH:24]=[CH:25][C:20]=2[O:19][CH2:18][C:17]1=O.C([O-])(O)=O.[Na+]>C1COCC1>[CH3:12][N:13]([CH3:30])[CH2:14][CH2:15][N:16]1[C:21]2[CH:22]=[C:23]([N+:26]([O-:28])=[O:27])[CH:24]=[CH:25][C:20]=2[O:19][CH2:18][CH2:17]1

Participants

6

Reactant 4

HCID 8000Boron trifluoride etherateHCID 516892Sodium BicarbonateHCID 4311764Sodium borohydrideHCID 105158064-(2-Dimethylaminoethyl)-6-nitro-2H-1,4-benzoxazin-3(4H)-one

Product 1

HCID 107771353,4-Dihydro4-(2-dimethylaminoethyl)-6-nitro-2H-1,4-benzoxazineYield 93.5%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

Boron trifluoride etherate (2 ml, 16.2 mmol) was added dropwise to a suspension of sodium borohydride (0.46 g, 12 mmol) in dry THF (30 ml) at 0° C., under argon. After 1 hr, a solution of 4-(2- dimethylaminoethyl)-6-nitro-2H-1,4-benzoxazine-3(4H )-one (D1, 1.08 g, 4 mmol) in dry THF (20 ml) was added. The reaction mixture was heated under reflux for 2 hr, then cooled in ice. Aqueous NaHCO3 was added dropwise until effervescence ceased, then the solvent was removed under reduced pressure and the residue dissolved in a mixture of EtOH (10 ml) and 5N HCl (10 ml) and heated under reflux for 45 minutes. After cooling, the solvent was removed under reduced pressure. The residue was treated with satturated K2CO3 solution to pH 8, then extracted with EtOAc. The combined extracts were dried (Na2SO4) and evaporated under reduced pressure to give the title compound (0.94 g, 92%).

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureunder reflux for 2 hr
  3. temperaturecooled in ice
  4. customthe solvent was removed under reduced pressure
  5. dissolutionthe residue dissolved in a mixture of EtOH (10 ml) and 5N HCl (10 ml)
  6. temperatureheated
  7. temperatureunder reflux for 45 minutes
  8. temperatureAfter cooling
  9. customthe solvent was removed under reduced pressure
  10. additionThe residue was treated with satturated K2CO3 solution to pH 8
  11. extractionextracted with EtOAc
  12. dry with materialThe combined extracts were dried (Na2SO4)
  13. customevaporated under reduced pressure

Sources & evidence

ORD record
ord-f5f77ce68a894850a7e393c12b9b5722
Source dataset
uspto-grants-1999_10
Patent number
US05972935

Reaction notes

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