p-Toluenesulfonic acid → 8-Bromo-3-(di-n-propylamino)chromane

HRID 1464691Notes

Reaction equation

HRID 1464691 reaction equation
[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[O:10][CH2:9][CH:8](O)[CH2:7]2.[CH2:13]([NH:16][CH2:17][CH2:18][CH3:19])[CH2:14][CH3:15].C1(C)C=CC(S(O)(=O)=O)=CC=1>C1C=CC=CC=1>[Br:1][C:2]1[CH:3]=[CH:4][CH:5]=[C:6]2[C:11]=1[O:10][CH2:9][CH:8]([N:16]([CH2:17][CH2:18][CH3:19])[CH2:13][CH2:14][CH3:15])[CH2:7]2

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 8902DipropylamineHCID 190871458-Bromochroman-3-ol

Product 1

HCID 190871478-Bromo-3-(di-n-propylamino)chromane

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

8-Bromo-3-chromanol (80% according to GC, 0.8×0.69 g, 0.8×3.0=2.4 mmol) was dissolved in dry benzene and di-n-propylamine (2 ml) and p-toluenesulfonic acid (60 mg) was added. The reaction mixture was refluxed under N2 and water separation in a Dean-Stark apparatus. The solvents were removed under reduced pressure and the residue was dissolved in MeOH (50 ml) and NaBH3CN (2.0 g) was added and the mixture was stirred overnight. Water (50 ml) and 15% NaOH (5 ml) was added and the product was extracted to CH2Cl2. The organic layer was washed with water, dried (Na2SO4), filtered and the solvents were removed under reduced pressure, leaving 700 mg of the raw product, which was chromatographed (SiO2, 100 g) using petroleum ether:ether (9:1) as the eluant. The fractions containing pure product were pooled and the solvent was evaporated. The residual oil was converted into the hydrochloride with HCl-saturated EtOH. Crystals (248 mg) melting at 135° C. were obtained from EtOAc/ether. GC/MS showed M+ /M+2 at m/e=311.05(7.7%)/313.05(8.7%) and the base peak pair at m/e=281.95(98%)/283.95(100%).

Workup

  1. temperatureThe reaction mixture was refluxed under N2
  2. customwater separation in a Dean-Stark apparatus
  3. customThe solvents were removed under reduced pressure
  4. dissolutionthe residue was dissolved in MeOH (50 ml)
  5. additionNaBH3CN (2.0 g) was added
  6. additionWater (50 ml) and 15% NaOH (5 ml) was added
  7. extractionthe product was extracted to CH2Cl2
  8. washThe organic layer was washed with water
  9. dry with materialdried (Na2SO4)
  10. filtrationfiltered
  11. customthe solvents were removed under reduced pressure
  12. customleaving 700 mg of the raw product, which
  13. customwas chromatographed (SiO2, 100 g)
  14. additionThe fractions containing pure product
  15. customthe solvent was evaporated

Sources & evidence

ORD record
ord-96b78ffe0f3e47c6bddb0eff55a97317
Source dataset
uspto-grants-1994_04
Patent number
US05306830

Reaction notes

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