Example 170: Synthesis of 5-methyl-3-nitropyridin-2-amine; Sulfuric acid (97%, 100 mL) was placed in a cooling bath at -10°C. When the internal temperature reached 5°C, 2-amino-5-methylpyridine (25 g, 231.2 mmol) was added in batches with stirring (1 hour elapsed time). The suspension was stirred at room temperature until the remaining solid was completely dissolved. The resulting solution was heated to 55 °C and kept 70% conical. Nitric acid (15.6 mL) was added dropwise while maintaining an internal temperature between 55-60 °C. After addition, the mixture was continued to be stirred for 30 minutes and then poured into crushed ice (800 g). The mixture was stirred until completely dissolved and subsequently adjusted to pH 9 with 40% aqueous sodium hydroxide at 0 °C. The reaction mixture was extracted with chloroform (3 x 250 mL). The organic layers were combined, washed with brine (2 x 200 mL), dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give 5-methyl-3-nitropyridin-2-amine (9.49 g) as a yellow solid in 27% yield. esms m/z (relative strength): 154 (M + H)+ (100).
[1] Patent: WO2006/76644, 2006, A2. Location in patent: Page/Page column 204
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