Step B: Synthesis of 5-isopropylpyridin-2-amine as an intermediate; [0209] A mixture of 2-nitro-5-(prop-1-en-2-yl)pyridine (0.104 g, 0.63 mmol) with 10% palladium-carbon catalyst (0.011 g, 10 wt%) in ethanol (10 mL) was subjected to a hydrogen atmosphere and stirred at atmospheric pressure for overnight reaction. Upon completion of the reaction, the catalyst was removed by diatomaceous earth filtration and the filtrate was concentrated under reduced pressure to give 5-isopropylpyridin-2-amine (0.120 g, 139% yield) as an oily product. Its structure was confirmed by 1H NMR (500 MHz, CDCl3): δ 7.68 (d, J = 8.1 Hz, 1H), 7.51 (s, 1H), 7.48 (s, 2H), 7.14 (d, J = 9.1 Hz, 1H), 3.45-3.42 (m, 1H), 1.38 (d, J = 8.6 Hz, 6H); ESI MS m/z 137 [M + H]+.
