tert-butyl (2-hydroxy-5-nitrophenyl)carbamate synthesis

Yield:1141925-05-4 79%

Reaction Conditions:

with 4-dimethylaminopyridine;triethylamine in dichloromethane at 0; for 1 h;Inert atmosphere;

Steps:

1 tert-Butyl (2-hydroxy-5-nitrophenyl)carbamate (1):

tert-Butyl (2-hydroxy-5-nitrophenyl)carbamate (1): To a solution of 2-amino-4- nitrophenol (10 g, 65.0 mmol) in DCM (200 mL) were added triethylamine (13.8 mL, 97.3 mmol) and boc-anhydride (15.6 g, 71.4 mmol) at 0 °C and stirred for 10 minutes. Then DMAP (3.96 g, 32.4 mmol) was added portion wise and stirred for 1 h. The reaction mixture was diluted with water (50 mL) neutralized with citric acid (200 mL) and extracted with DCM (2 x 100 mL). The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain 1 (13 g, 79%) as a yellow solid. 1H NMR (400 MHz, DMSO-d₆): δ 1.48 (s, 9H), 6.97 (d, J = 8.8 Hz, 1H), 7.86 (m, 1H), 8.21 (s, 1H), 8.64 (d, J = 2.4 Hz, 1H), 11.56 (s, 1H). MS m/z (M-H): 253.2

References:

WO2014/149164,2014,A1 Location in patent:Paragraph 001193