Carbamic acid, N-(5-chloro-2-nitrophenyl)-N-methyl-, 1,1-dimethylethyl ester synthesis
- Product Name:Carbamic acid, N-(5-chloro-2-nitrophenyl)-N-methyl-, 1,1-dimethylethyl ester
- CAS Number:299176-17-3
- Molecular formula:C12H15ClN2O4
- Molecular Weight:286.71
Yield:299176-17-3 73.1%
Reaction Conditions:
with dmap;triethylamine in tetrahydrofuran at 20; for 16 h;
Steps:
b Step fb) Preparation of tert-butyl (5-chloro-2-nitrophenyl carbamate (compound A5.3)
To a solution of 5-chloro-N-methyl-2-nitroaniline (40.2 g, 0.216 mol, compound A5.2) in dry THF (2.0 L) was added Boc20 (141.5 g, 0.648 mol), DMAP (13.4 g, 0.11 mmol) and Et3N (25.9 g, 1.08 mmol). The resulting reaction mixture was stirred at 20 °C for 16 h before it was poured into 1 L of ice-water carefully and extracted with EtOAc (2 L) twice. The combined organic phase was dried over anhy. Na2S04, filtered, and concentrated in vacuo to give a crude product, which was purified by silica gel flash chromatography (petroleum ether: EtOAc = 100: 1 ~ 20: 1) to give tert-butyl (5-chloro-2-nitrophenyl)(methyl)carbamate (45.2 g, 73.1% yield) as a yellow solid. NMR (400 MHz, CDCb) ppm: 1.24 - 1.43 (m, 9 H) 3.23 (s, 3 H) 7.26 - 7.28 (m, 2 H) 7.80 - 7.82 (m, 1 H).
References:
WO2019/228940,2019,A1 Location in patent:Page/Page column 34-35
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