[Synthesis]
Step 2. N-(3-cyanopyridin-2-yl)-N-methylmethanesulfonamide (10 g, 47.3 mmol) was dissolved in ethanol and transferred to a Parr reactor. 300 mL of ethanol solution of 2 M ammonia and 5% Pd/C catalyst (1.2 g) were added to the reactor. The reactor was sealed and hydrogenated for 3 hours at 37°C and then continued at 30°C for 20 hours under 60 Psi hydrogen pressure. Upon completion of the reaction, the reaction mixture was filtered through a Celite pad to remove the catalyst. The filtrate was concentrated under reduced pressure and the resulting residue was treated with ethyl acetate, cooled to 20 °C and glacial acetic acid (10 mL) was added. The mixture was stirred for 10 minutes and concentrated again. The residue was dissolved in 150 mL of ethyl acetate in a glass flask. The inside of the flask was scraped to induce crystallization and a white solid precipitated. The solid was collected, washed sequentially with ethyl acetate and petroleum ether, and dried to give N-(3-(aminomethyl)pyridin-2-yl)-N-methylmethanesulfonamide acetic acid (B5). Yield: 11 g, 85% yield.1H NMR (CDCl3) δ: 8.3-8.5 (m, 1H), 8.04 (d, 1H), 7.4-7.55 (m, 1H), 6.02-7.15 (br, 3H), 3.85 (s, 2H), 3.14 (d, 6H), 1.9 (s, 3H). MS: (M+1) 216, calculated value C9H13N3O2S. |