Dimethylamine, hydrochloride → 2-Dimethylamino-8-bromo-1,2,3,4-tetrahydronaphthalene

HRID 256567Notes

Reaction equation

HRID 256567 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[CH2:10][C:9](=O)[CH2:8][CH2:7]2.C([O-])(=O)C.[Na+].C([BH3-])#N.[Na+].Cl.[CH3:23][NH:24][CH3:25]>C(#N)C>[CH3:23][N:24]([CH3:25])[CH:9]1[CH2:8][CH2:7][C:6]2[C:11](=[C:2]([Br:1])[CH:3]=[CH:4][CH:5]=2)[CH2:10]1

Participants

6

Reactant 4

HCID 10473Dimethylamine, hydrochlorideHCID 517045Sodium AcetateHCID 41361878-Bromo-1,2,3,4-tetrahydronaphthalen-2-oneHCID 5003444Sodium cyanoborohydride

Product 1

HCID 183141992-Dimethylamino-8-bromo-1,2,3,4-tetrahydronaphthaleneYield 30%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

To a solution of 8-bromo-2-tetralone (4.5 gm, 20 mMol) in acetonitrile (100 mL) were added sodium acetate (9.9 gm, 120 mMol), sodium cyanoborohydride (880 mg, 120 mMol), dimethylamine hydrochloride (9.8 gm, mMol) and 4A sieves (2.0 gm). The mixture was stirred at room temperature for 3 days. The reaction mixture was then filtered through a bed of celite, and the filtrate was poured into a slurry of ice and water. The solution was made acidic (HCl) and extracted well with diethyl ether. The remaining aqueous was made basic (NH4OH) and extracted well with dichloromethane. These organic phases were combined, dried (Na2SO4), and concentrated in vacuo to give a dark oil. Purification by flash chromatography (5% methanol in dichloromethane+tr. NH4OH) gave the title compound as a yellow oil (1.5 gm, 30%).

Workup

  1. filtrationThe reaction mixture was then filtered through a bed of celite
  2. additionthe filtrate was poured into a slurry of ice and water
  3. extractionextracted well with diethyl ether
  4. extractionextracted well with dichloromethane
  5. dry with materialdried (Na2SO4)
  6. concentrationconcentrated in vacuo
  7. customto give a dark oil
  8. customPurification by flash chromatography (5% methanol in dichloromethane+tr. NH4OH)

Sources & evidence

ORD record
ord-5afd577dae7d43c9aec5e8e4eafc8dbb
Source dataset
uspto-grants-1993_11
Patent number
US05258379

Reaction notes

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