Acetic Acid → 5-bromo-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-1-amine

HRID 373826Notes

Reaction equation

HRID 373826 reaction equation
[Br:1][C:2]1[CH:11]=[CH:10][CH:9]=[C:8]2[C:3]=1[CH2:4][CH2:5][CH2:6][C:7]2=O.[CH3:13]N.C(O)(=O)C.[C:19]([BH3-])#[N:20].[Na+]>C(O)C>[Br:1][C:2]1[CH:11]=[CH:10][CH:9]=[C:8]2[C:3]=1[CH2:4][CH2:5][CH2:6][CH:7]2[N:20]([CH3:19])[CH3:13]

Participants

6

Reactant 4

HCID 176Acetic AcidHCID 6329MethylamineHCID 5003444Sodium cyanoborohydrideHCID 108895725-Bromo-1,2,3,4-tetrahydronaphthalen-1-one

Product 1

HCID 198085905-bromo-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-1-amine

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

8.5 of 5-bromotetralone are dissolved in 100 ml of ethanol, and 25 ml of a 33% solution of methylamine in ethanol are added. The mixture is cooled to 5° and the pH is adjusted to 6-7 with acetic acid. Then 2.5 g of sodium cyanoborohydride are added in portions. The reaction mixture is then stirred at room temperature during 36 hours. The solvent is evaporated and the residue is added to 1N NaOH. The aqueous phase is extracted 3× with ether and the combined organic extracts are dried on Na2SO4 and evaporated. The remaining oil (8.7 g) is dissolved in 100 ml of methanol and 6 ml of a 33% aqueous solution of formaldehyde are added. The mixture is cooled to 5° and 2.8 g of sodium borohydride are added. After stirring at room temperature for 24 hours, the reaction mixture is concentrated and the residue is added to 1N HCl. The aqueous phase is washed 2× with ether. The pH is then adjusted to 10 with 30% NaOH and extraction follows 3× with ether. The organic extracts are dried on Na2SO4 and concentrated. The 5-bromo-N,N-dimethyl-1,2,3,4-tetrahydro-1-naphthalenylamine is obtained.

Workup

  1. temperatureThe mixture is cooled to 5°
  2. customThe solvent is evaporated
  3. additionthe residue is added to 1N NaOH
  4. extractionThe aqueous phase is extracted 3× with ether
  5. customthe combined organic extracts are dried on Na2SO4
  6. customevaporated
  7. dissolutionThe remaining oil (8.7 g) is dissolved in 100 ml of methanol
  8. addition6 ml of a 33% aqueous solution of formaldehyde are added
  9. temperatureThe mixture is cooled to 5°
  10. addition2.8 g of sodium borohydride are added
  11. stirringAfter stirring at room temperature for 24 hours
  12. concentrationthe reaction mixture is concentrated
  13. additionthe residue is added to 1N HCl
  14. washThe aqueous phase is washed 2× with ether
  15. extractionThe pH is then adjusted to 10 with 30% NaOH and extraction
  16. customThe organic extracts are dried on Na2SO4
  17. concentrationconcentrated

Sources & evidence

ORD record
ord-aa1b43559ea244178ced9d4149b33d13
Source dataset
uspto-grants-1992_11
Patent number
US05166181

Reaction notes

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