Synthesis
(b) Preparation of the intermediate compound 5-chloro-4-methyl-2-nitroaniline: Sodium ethoxide (8.27 g, 45.9 mmol) was dissolved in ethanol (10 mL) to prepare a sodium ethoxide solution. The solution was slowly added to a solution of ethanol (10 mL) containing N-(2-nitro-4-methyl-5-chlorophenyl)acetamide (7.0 g, 30.6 mmol) with stirring at room temperature. After 1 hour of reaction, the reaction mixture was poured into water (100 mL) and precipitate was precipitated. The precipitate was collected by filtration and washed with a mixture of isopropanol and n-hexane (1:3, 10 mL) followed by n-hexane (10 mL) to give 5.71 g (85% yield) of 5-chloro-4-methyl-2-nitroaniline. Mass spectrometry (MS) showed a m/z of 187.0 (M + 1).
References
[1] Patent: WO2010/19208, 2010, A1. Location in patent: Page/Page column 167-168
[2] Journal of Medicinal Chemistry, 1992, vol. 35, # 23, p. 4455 - 4463
[3] Journal of Heterocyclic Chemistry, 1981, vol. 18, p. 1635 - 1636
[4] Patent: WO2011/23812, 2011, A1. Location in patent: Page/Page column 164
