Synthesis
The general procedure for the synthesis of 2,6-dimethyl-4-nitroaniline from N-(2,6-dimethyl-4-nitrophenyl)-4-methylbenzenesulfonamide is as follows: N-(2,6-dimethyl-4-nitrophenyl)-4-methylbenzenesulfonamide (3.2 g, 10.0 mmol) was dissolved in 32 mL of concentrated sulfuric acid and the reaction was heated for 1 hr at 50 °C. After completion of the reaction, the mixture was slowly poured into an ice-water mixture. The precipitate precipitated was collected by filtration and washed with cold water. The crude product was purified by recrystallization from ethyl acetate to give 2,6-dimethyl-4-nitroaniline (1.0 g, 53% yield) in yellow crystalline form. Thin layer chromatography (TLC) Rf value was 0.34 (unfolding agent: hexane/ethyl acetate, 5/1, v/v). Melting point: 164-165°C. 1H NMR (DMSO-d6, 400MHz) δ 7.79 (s, 2H), 6.16 (s, 2H), 2.16 (s, 6H). Mass spectrum (ESI) m/z: 166.8 [M+H]+, 188.8 [M+Na]+.
References
[1] Patent: EP3138833, 2017, A1. Location in patent: Paragraph 0040; 0043
[2] European Journal of Organic Chemistry, 2009, # 5, p. 739 - 748
[3] Journal of Medicinal Chemistry, 1983, vol. 26, # 11, p. 1625 - 1630
[4] Heterocycles, 2008, vol. 76, # 2, p. 1313 - 1328
[5] Patent: KR2018/69782, 2018, A. Location in patent: Paragraph 0422; 0424; 0431-0433
