反应详情

温度

0 °C

A suspension of 5 g (21.05 mmol) of 3-chloro-2,4-difluoro-5-nitro-benzoic acid (known from WO 03/077914) in 50 mL of H2O is cooled to a temperature of 0° C. Then 5.86 ml (42.10 mmol) of triethylamine were added dropwise followed by the dropwise addition of 1.82 ml (21.05 mmol) of methylamine (40% in H2O). After 30 min of stirring at 0° C., 0.18 ml (2.11 mmol) of methylamine (40% in H2O) is added and the mixture is stirred again during 30 min at a temperature of 0° C. The pH of the mixture is adjusted to 1-0.5 by the addition of concentrated HCl at a temperature of 0° C. The product is extracted with tert-butyl methyl ether (2 times) and the organic phase is washed once with brine, dried on Na2SO4, filtrated and the solvent is evaporated. 5.35 g (21.52 mmol, 102%) of a crude yellow solid were obtained and used directly in the next step without purification. LC/MS: 247/249 (M−1)−.

1. stirringthe mixture is stirred again during 30 min at a temperature of 0° C
2. extractionThe product is extracted with tert-butyl methyl ether (2 times)
3. washthe organic phase is washed once with brine
4. customdried on Na2SO4
5. filtrationfiltrated
6. customthe solvent is evaporated