Methylparaben → Methyl 4-(2-aminoethoxy)benzoate

Beteiligte Stoffe

Reaktionsschritte

To a cooled (0° C.) solution of 2-(N-tert-butoxycarbonylamino)ethanol (3.20 g, 19.9 mmol), methyl 4-hydroxybenzoate (3.02 g, 19.9 mmol) and Ph3P (6.25 g, 23.8 mmol) in THF (50 ml) was added dropwise DIAD (4.69 ml, 23.8 mmol) over for 5 min. The reaction mixture was heated under reflux for 3 hr. The mixture was evaporated and the residue was dissolved in CH2Cl2 (30 ml) and TFA (30 ml). The reaction mixture was stirred at room temperature overnight. The mixture was concentrated in vacuo and the residue was dissolved in CHCl3 and H2O. The solution was made basic by sat. NaHCO3 and extracted with CHCl3. The extract was washed with brine, dried over Na2SO4 and evaporated. The residue was purified by column chromatography on silica-gel with CHCl3-MeOH (30:1, v/v) as eluent to give methyl 4-(2-aminoethoxy)benzoate (1.03 g, 34% for 2 steps) as a colorless oil. 1H-NMR (CDCl3) δ 3.10–3.13 (m, 2 H), 3.89 (s, 3 H), 4.03–4.06 (m, 2 H), 6.92–6.94 (m, 2 H), 7.98–8.00 (m, 2 H).

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