General procedure for the synthesis of 2-(piperidin-4-yl)pyrimidine hydrochloride from tert-butyl 4-(pyrimidin-2-yl)piperidine-1-carboxylate: tert-butyl 4-(pyrimidin-2-yl)piperidine-1-carboxylate prepared in step A (4.64 g, 17.6 mmol) was dissolved in dioxane solution (50 mL) of 4N HCl and stirred for 2.25 h at room temperature. Upon completion of the reaction, the reaction mixture was concentrated to afford 4.16 g of 2-(piperidin-4-yl)pyrimidine hydrochloride in 100% yield without further purification. The product was characterized by 1H NMR (500 MHz, CD3OD): δ 8.95 (d, J = 5.5 Hz, 2H), 7.60 (t, J = 5.0 Hz, 1H), 3.53 (dt, J = 13.0, 3.5 Hz, 2H), 3.35 (tt, J = 4.0, 11.0 Hz, 1H), 3.20 (br t, J = 13.8 Hz, 2H), 2.30 (br d, J = 14.0 Hz, 2H), 2.11-2.20 (m, 2H).ESI-MS analysis: calculated value C9H13N3 [M+H]+ 163, measured value 164 (M+H).
