Diisopropyl diazene-1,2-dicarboxylate → methyl (S)-3-chloro-4-(2-amino-1-propoxy)benzoate

Participants

Reaction Steps

To a cooled (0° C.) solution of (S)-2-(N-tert-butoxycarbonylamino)-1-propanol (1.05 g, 5.99 mmol), methyl 3-chloro-4-hydroxybenzoate (1.12 g, 6.00 mmol), and PhP (2.36 g, 9.00 mmol) in THF (20 mL) was added diisopropyl azodicarboxylate (DIAD) (1.77 mL, 8.99 mmol), and the resulting mixture was heated under reflux for 2 days. The solution was evaporated off and the residue was dissolved in CH2Cl2 (20 mL) and TFA (10 mL). The resulting mixture was stirred at room temp for 1.5 hr. The solution was concentrated in vacuo, and the residue was dissolved in CHCl3. The mixture was extracted with H2O, and the aqueous layer was made basic by the addition of sat. NaHCO3. This basic aqueous layer was extracted with CHCl3. The extract was washed with brine, dried over Na2SO4 and evaporated to give 660 mg (2 steps, 32%) methyl (S)-3-chloro-4-(2-amino-1-propoxy)benzoate as a colorless oil. 1H-NMR (CDCl3) δ1.21 (d, 3 H, J=6.4 Hz), 3.41-3.48 (m, 1 H), 3.77-3.81 (m, 1 H), 3.89 (s, 3 H), 3.98-4.01 (m, 1 H), 6.91-6.94 (m, 1 H), 7.90-7.93 (m, 1 H), 8.05-8.06 (m, 1 H).

Provenance & Evidence