Pyridine → (3-Amino-4-tert-butyl-phenyl)-carbamic acid benzyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 4-tert-butylbenzene-1,3-diamine (D-9) (657 mg, 4 mmol) and pyridine (0.39 mL, 4.8 mmol) in CH2Cl2/MeOH (12/1, 8 mL) was cooled to 0° C., and a solution of benzyl chloroformate (0.51 mL, 3.6 mmol) in CH2Cl2 (8 mL) was added dropwise over 10 min. The mixture was stirred at 0° C. for 15 min, then warmed to room temperature. After 1 h, the mixture was washed with 1M citric acid (2×20 mL), saturated aqueous sodium bicarbonate (20 mL), dried (Na2SO4), filtered and concentrated in vacuo to afford the crude (3-amino-4-tert-butyl-phenyl)-carbamic acid benzyl ester as a brown viscous gum (0.97 g), which was used without further purification. 1H NMR (400 MHz, CDCl3) δ 7.41-7.32 (m, 6H), 7.12 (d, J=8.5 Hz, 1H), 6.89 (br s, 1H), 6.57 (dd, J=2.3, 8.5 Hz, 1H), 5.17 (s, 2H), 3.85 (br s, 2H), 1.38 (s, 9H); 13C NMR (100 MHz, CDCl3, rotameric) δ 153.3 (br), 145.3, 136.56, 136.18, 129.2, 128.73, 128.59, 128.29, 128.25, 127.14, 108.63 (br), 107.61 (br), 66.86, 33.9, 29.7; ESI-MS 299.1 m/z (MH+).

Provenance & Evidence