Borane;tetrahydrofuran → 7-Nitro-3,4-dihydro-2H-1,4-benzoxazine

HRID 601506Notes

Reaction equation

HRID 601506 reaction equation
[N+:1]([C:4]1[CH:14]=[CH:13][C:7]2[NH:8][C:9](=O)[CH2:10][O:11][C:6]=2[CH:5]=1)([O-:3])=[O:2].B.C1COCC1>C1COCC1>[N+:1]([C:4]1[CH:14]=[CH:13][C:7]2[NH:8][CH2:9][CH2:10][O:11][C:6]=2[CH:5]=1)([O-:3])=[O:2]

Participants

4

Reactant 2

HCID 2723981Borane;tetrahydrofuranHCID 27638307-nitro-3,4-dihydro-2H-1,4-benzoxazin-3-one

Product 1

HCID 184161517-Nitro-3,4-dihydro-2H-1,4-benzoxazineYield 89.5%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
0 °C

Procedure

Mix 7-nitro-4H-benzo[1,4]oxazin-3-one (2.00 g, 10.3 mmol) in THF (10 mL) and treat with BH3.THF (1.0M in THF, 35 mL). Heat the solution to reflux for 30 min, then cool to 0° C. and quench with 1N HCl (20 mL). Stir the solution for 30 min, then concentrate to ½ volume. Collect the orange solid, wash with water, and dry under vacuum to give the title compound (1.66 g, 89%). MS (ES+) 181.1 (M+1)+, MS (ES−) 179.2 (M−1)−. 1H NMR (400 MHz, DMSO-d6): δ 7.68 (dd, 1H, J=8.8, 2.6 Hz), 7.53 (s, 1H), 7.47 (d, 1H, J=2.6 Hz), 6.63 (d, 1H, J=9.2 Hz), 4.15 (t, 2H, J=4.4 Hz), 3.44-3.40 (m, 2H),

Workup

  1. temperatureHeat the solution
  2. temperatureto reflux for 30 min
  3. customquench with 1N HCl (20 mL)
  4. concentrationconcentrate
  5. customCollect the orange solid
  6. washwash with water
  7. customdry under vacuum

Sources & evidence

ORD record
ord-32c2f40d694546a085d996d5bf56b54a
Source dataset
uspto-grants-2011_03
Patent number
US07902356B2

Reaction notes

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