Boron tribromide → HCID 68688831, compound

HRID 1159032Notes

Reaction equation

HRID 1159032 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH2:23][CH2:22][N:11]2[C:12](=[O:21])[C:13]3[C:18]([CH:10]2[CH2:9]1)=[CH:17][CH:16]=[CH:15][C:14]=3[O:19]C)=[O:7])([CH3:4])([CH3:3])[CH3:2].B(Br)(Br)Br.C(OC(OC(C)(C)C)=O)(OC(C)(C)C)=O>ClCCl.C(OCC)(=O)C>[C:1]([O:5][C:6]([N:8]1[CH2:23][CH2:22][N:11]2[C:12](=[O:21])[C:13]3[C:18]([CH:10]2[CH2:9]1)=[CH:17][CH:16]=[CH:15][C:14]=3[OH:19])=[O:7])([CH3:4])([CH3:2])[CH3:3]

Participants

6

Reactant 3

HCID 25134Boron tribromide2×HCID 90495Di-tert-butyl dicarbonateHCID 16115260HCID 16115260, compound

Product 1

HCID 68688831HCID 68688831, compoundYield 91.2%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
0 °C

Procedure

To a solution of N-(t-butoxycarbonyl)-(±)-1,3,4,10b-tetrahydro-7-methoxy-pyrazino[2,1-a]isoindol-6(2H)-one (100 mg, 0.31 mmol) in dichloromethane (3 mL) at −78° C. was added dropwise boron tribromide (0.79 mL, 0.79 mmol; 1.0M in CH2Cl2). After 5 min, the reaction was warmed to 0° C. and an additional 0.2 mL of boron tribromide (1.0 M in CH2Cl2) was added. After 2 h, the yellow mixture was recooled to −78° C. and quenched with water. The reaction was warmed to room temperature and stirred for 14 h. The mixture was then concentrated, quenched again with aqueous hydrogen chloride (3M), and the resulting yellow solution was concentrated to dryness. The residue was diluted with tetrahydrofuran (10 mL) and saturated aqueous sodium bicarbonate (1 mL). Di-tert-butyl dicarbonate (69 mg, 0.31 mmol) was added, and the mixture was stirred for 1 h. The reaction was then diluted with ethyl acetate and the layers were separated. The organic layer was then dried over sodium sulfate, filtered, and concentrated. The resulting residue was purified by radial chromatography (20% ethyl acetate in hexanes) to give the desired product as an off-white solid (86 mg, 90%). MS (ESI) 305.3 (M+H).

Workup

  1. waitAfter 2 h
  2. customwas recooled to −78° C.
  3. customquenched with water
  4. temperatureThe reaction was warmed to room temperature
  5. concentrationThe mixture was then concentrated
  6. customquenched again with aqueous hydrogen chloride (3M)
  7. concentrationthe resulting yellow solution was concentrated to dryness
  8. additionThe residue was diluted with tetrahydrofuran (10 mL) and saturated aqueous sodium bicarbonate (1 mL)
  9. stirringthe mixture was stirred for 1 h
  10. customthe layers were separated
  11. dry with materialThe organic layer was then dried over sodium sulfate
  12. filtrationfiltered
  13. concentrationconcentrated
  14. customThe resulting residue was purified by radial chromatography (20% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-78706acee7514764b1c166927fe776df
Source dataset
uspto-grants-2010_10
Patent number
US07812024B2

Reaction notes

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