Ethyl orthoformate → Allyl 3-(methylamino)benzoate

HRID 341893Notes

Reaction equation

HRID 341893 reaction equation
[NH2:1][C:2]1[CH:3]=[C:4]([CH:11]=[CH:12][CH:13]=1)[C:5]([O:7][CH2:8][CH:9]=[CH2:10])=[O:6].[CH:14](OCC)(OCC)OCC>FC(F)(F)C(O)=O>[CH3:14][NH:1][C:2]1[CH:3]=[C:4]([CH:11]=[CH:12][CH:13]=1)[C:5]([O:7][CH2:8][CH:9]=[CH2:10])=[O:6]

Participants

4

Reactant 2

HCID 31214Ethyl orthoformateHCID 18930599Allyl 3-aminobenzoate

Product 1

HCID 22168609Allyl 3-(methylamino)benzoateYield 17%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidCatalyst

Procedure

Allyl 3-aminobenzoate (5 g, 28.2 mM) was dissolved in triethyl orthoformate (50 ml) and trifluoroacetic acid (5 drops) was added. The solution was stirred and refluxed up through 3 å molecular sieves for 5 hours. Solvent was removed, and the residue dissolved in ethanol (50 ml), followed by the addition of acetic acid (8.08 ml) and sodium cyanoborohydride (6.85 g, 0.108M) in several portions. The mixture was stirred at ambient temperature for 16 hours, and solvent removed. The residue was dissolved in diethyl ether, washed with water, brine, and dried over MgSO4. Crude product was purified by chromatography on silica, eluting with a gradient from dichloromethane to dichloromethane/ethyl acetate (95:5), to give allyl 3-methylaminobenzoate (0.93 g, 17%). Nmr (CDCl3): δ 2.88 (s, 3H); 4.81 (dt, 2H); 5.23-5.45 (m, 2H); 5.94-6.13 (m, 1H); 6.83 (dd, 1H); 7.25 (dd, 1H); 7.33 (t, 1H); 7.43 (dm, 1H).

Workup

  1. temperaturerefluxed up through 3 å molecular sieves for 5 hours
  2. customSolvent was removed
  3. dissolutionthe residue dissolved in ethanol (50 ml)
  4. additionfollowed by the addition of acetic acid (8.08 ml) and sodium cyanoborohydride (6.85 g, 0.108M) in several portions
  5. stirringThe mixture was stirred at ambient temperature for 16 hours
  6. customsolvent removed
  7. dissolutionThe residue was dissolved in diethyl ether
  8. washwashed with water, brine
  9. dry with materialdried over MgSO4
  10. customCrude product was purified by chromatography on silica
  11. washeluting with a gradient from dichloromethane to dichloromethane/ethyl acetate (95:5)

Sources & evidence

ORD record
ord-774ed228af6844a0a6e734c41b228f86
Source dataset
uspto-grants-1999_01
Patent number
US05856321

Reaction notes

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