Bromine → 6-bromospiro[3,1-benzoxazine-4,1'-cyclobutan]-2(1H)-one

HRID 458555Notes

Reaction equation

HRID 458555 reaction equation
[C:1]12([C:9]3[CH:10]=[CH:11][CH:12]=[CH:13][C:8]=3[NH:7][C:6](=[O:14])[O:5]1)[CH2:4][CH2:3][CH2:2]2.C([O-])(=O)C.[K+].[Br:20]Br>C(O)(=O)C>[Br:20][C:11]1[CH:12]=[CH:13][C:8]2[NH:7][C:6](=[O:14])[O:5][C:1]3([CH2:4][CH2:3][CH2:2]3)[C:9]=2[CH:10]=1

Participants

5

Reactant 3

HCID 24408BromineHCID 517044Potassium AcetateHCID 18442664Spiro[3,1-benzoxazine-4,1'-cyclobutan]-2(1H)-one

Product 1

HCID 112426146-bromospiro[3,1-benzoxazine-4,1'-cyclobutan]-2(1H)-oneYield 53%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent2×

Procedure

To a solution of spiro[3,1-benzoxazine-4,1′-cyclobutan]-2(1H)-one (0.36 g, 1.9 mmol) and potassium acetate (0.56 g, 5.7 mmol) in acetic acid was added a solution of bromine (0.09 mL, 1.95 mmol) in acetic acid (2 mL) at room temperature. Upon completion by TLC of the reaction, the acetic acid was removed. The residue was treated with saturated sodium bicarbonate (100 mL) and the product extracted with ethyl acetate (50 mL). The organics were dried over magnesium sulfate and concentrated. Trituration of residue with ether gave 6-bromospiro[3,1-benzoxazine-4,1′-cyclobutan]-2(1H)-one (0.27 g, 52%) as a white solid. 1H NMR (DMSO-d6): δ 10.37 (s, 1H), 7.65 (d, 1H, J=2.1 Hz), 7.47 (dd, 1H, J=8.5, 2.2 Hz), 6.86 (d, 1H, J=8.5 Hz), 2.52–2.47 (m, 2H), 2.04–1.98 (m, 2H), 1.87–1.80 (m, 2H). MS (ESI) m/z 268/270 ([M+H]+); MS (ESI) m/z 266/268 ([M−H]−).

Workup

  1. customUpon completion by TLC of the reaction
  2. customthe acetic acid was removed
  3. additionThe residue was treated with saturated sodium bicarbonate (100 mL)
  4. extractionthe product extracted with ethyl acetate (50 mL)
  5. dry with materialThe organics were dried over magnesium sulfate
  6. concentrationconcentrated

Sources & evidence

ORD record
ord-9be73ecf89dc42daa02f1e1a56f270de
Source dataset
uspto-grants-2007_03
Patent number
US07192956B2

Reaction notes

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