Trifluoroacetic acid → 9-Bromo-1,2,3,4,10,10a-hexahydro-pyrazino[1,2-a]indole

HRID 853043Notes

Reaction equation

HRID 853043 reaction equation
[Br:1][C:2]1[C:3]2[CH:4]=[C:5]3[CH2:14][NH:13][CH2:12][CH2:11][N:6]3[C:7]=2[CH:8]=[CH:9][CH:10]=1.FC(F)(F)C(O)=O.[BH4-].[Na+].[OH-].[Na+]>C1COCC1>[Br:1][C:2]1[C:3]2[CH2:4][CH:5]3[CH2:14][NH:13][CH2:12][CH2:11][N:6]3[C:7]=2[CH:8]=[CH:9][CH:10]=1

Participants

6

Reactant 4

HCID 6422Trifluoroacetic acidHCID 14798Sodium HydroxideHCID 4311764Sodium borohydrideHCID 22338185HCID 22338185, compound

Product 1

HCID 223380779-Bromo-1,2,3,4,10,10a-hexahydro-pyrazino[1,2-a]indoleYield 68.2%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

9-Bromo-1,2,3,4-tetrahydro-pyrazino[1,2-a]indole (3.5 g, 13.9 mmol) was dissolved in THF (15 mL) and trifluoroacetic acid (30 mL) and cooled to 0° C. Sodium borohydride (1 g, 27.9 mmol) was added in portions, the mixture was stirred for 90 min at room temperature and added to an ice/water mixture (150 mL). After addition of sodium hydroxide solution (28%, 35 mL) to render the mixture basic it was extracted with dichloromethane. Organic phases were pooled, washed with brine, dried with MgSO4 and the solvent was evaporated. Chromatography on silica gel (dichloromethane/methanol/ammonia 180:10:1) yielded 9-bromo-1,2,3,4,10,10a-hexahydro-pyrazino[1,2-a]indole (2.4 g, 68%) as a yellowish solid, MS: m/e=252.0 (M+).

Workup

  1. extractionwas extracted with dichloromethane
  2. washwashed with brine
  3. dry with materialdried with MgSO4
  4. customthe solvent was evaporated

Sources & evidence

ORD record
ord-bdc12adb43964d8b87d129c672335b9e
Source dataset
uspto-grants-2007_08
Patent number
US07253281B2

Reaction notes

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