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General procedure for the synthesis of 5-cyclopropylpyridin-3-amine from 5-bromo-3-aminopyridine and cyclopropylboronic acid: To a solution of 5-bromopyridin-3-amine (4.75 g, 27.45 mmol) in dioxane (45 mL) was added cyclopropylboronic acid (4.75 g, 55.30 mmol), cesium carbonate (Cs2CO3, 28 g, 85.67 mmol) in sequence , tetrakis(triphenylphosphine)palladium (1.66 g, 1.44 mmol), and water (5 mL), and mixed with stirring at room temperature. The reaction mixture was heated to 100 °C with continuous stirring for 15 hours. After the reaction was completed, it was cooled to room temperature and the reaction mixture was diluted with water (200 mL). The mixture was extracted with ethyl acetate (500 mL x 3) and the organic phases were combined. The organic phase was washed with saturated brine and dried over anhydrous sodium sulfate (Na2SO4). The solvent was removed by concentration under reduced pressure and the residue was purified by fast column chromatography using hexane/ethyl acetate (0% to 100% gradient) as eluent to afford 5-cyclopropylpyridin-3-amine as a light brown oil (2.08 g, 56% yield). Mass spectrum (MS): m/z = 135.0 [M + H]+.

[1] Patent: WO2017/106607, 2017, A1. Location in patent: Paragraph 00477
[2] Patent: EP2762476, 2014, A1. Location in patent: Paragraph 0174
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