Borane → 2-amino-N,N-dimethyl-alpha-(3-methyl-2-thienyl)benzeneethanamine

HRID 486672Notes

Reaction equation

HRID 486672 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[CH2:8][CH:9]([C:14]1[S:15][CH:16]=[CH:17][C:18]=1[CH3:19])[N:10]([CH:12]=O)[CH3:11].B>O1CCCC1>[NH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[CH2:8][CH:9]([C:14]1[S:15][CH:16]=[CH:17][C:18]=1[CH3:19])[N:10]([CH3:11])[CH3:12]

Participants

4

Reactant 2

HCID 6331BoraneHCID 104234922-amino-N-formyl-N-methyl-alpha-(3-methyl-2-thienyl)benzeneethanamine

Product 1

HCID 100611792-amino-N,N-dimethyl-alpha-(3-methyl-2-thienyl)benzeneethanamineYield 67.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

A stirred solution of 5.79 g of 2-amino-N-formyl-N-methyl-α-(3-methyl-2-thienyl)benzeneethanamine in 400 ml of tetrahydrofuran was treated dropwise under nitrogen with 90 ml of a 1M solution of borane in tetrahydrofuran. The solution was stirred overnight at room temperature and then quenched with 60 ml of a 10% sodium hydroxide solution. The aqueous mixture was extracted with dichloromethane (2×100 ml), dried over anhydrous sodium sulfate, filtered and concentrated. The concentrate was treated with 15 ml of glacial acetic acid and 35 ml of concentrated hydrochloric acid. After stirring at room temperature overnight, the solution was decanted over 200 g of ice, basified with 20 ml of 50% aqueous sodium hydroxide, and extracted with dichloromethane (3×100 ml). The organic phase was dried over anhydrous sodium sulfate, filtered and concentrated. Purification was accomplished by means of HPLC (Water's Associates Prep LC/System 500, silica gel, elution with methanol). Concentration of the appropriate fraction afforded a solid which was recrystallized from diethyl ether to afford 3.7 g of 2-amino-N,N-dimethyl-α-(3-methyl-2-thienyl)benzenethanamine, mp 75°-77° C.

Workup

  1. customquenched with 60 ml of a 10% sodium hydroxide solution
  2. extractionThe aqueous mixture was extracted with dichloromethane (2×100 ml)
  3. dry with materialdried over anhydrous sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated
  6. additionThe concentrate was treated with 15 ml of glacial acetic acid and 35 ml of concentrated hydrochloric acid
  7. stirringAfter stirring at room temperature overnight
  8. customthe solution was decanted over 200 g of ice
  9. extractionextracted with dichloromethane (3×100 ml)
  10. dry with materialThe organic phase was dried over anhydrous sodium sulfate
  11. filtrationfiltered
  12. concentrationconcentrated
  13. customPurification
  14. washwas accomplished by means of HPLC (Water's Associates Prep LC/System 500, silica gel, elution with methanol)
  15. customConcentration of the appropriate fraction afforded a solid which
  16. customwas recrystallized from diethyl ether

Sources & evidence

ORD record
ord-af542f42606e40c2817a57d292068050
Source dataset
uspto-grants-1994_03
Patent number
US05292760

Reaction notes

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