Synthesis
To a solution of (R)-methylpiperazine (400 mg) in dichloromethane (20 mL) at 0 ℃ was added di-tert-butyl dicarbonate (871 mg). The reaction was stirred at room temperature for 4 h and then quenched with water (20 mL), followed by extraction into dichloromethane (2 x 40 mL). The combined organics were washed with saturated aqueous brine solution (40 mL), dried (MgSO4), and concentrated to give (R)-1-Boc-3-methylpiperazine as a white solid (669 mg, 84%).
References
[1] Patent: WO2008/70740, 2008, A1. Location in patent: Page/Page column 191
[2] Patent: US2010/216812, 2010, A1. Location in patent: Page/Page column 45
[3] Patent: US2011/201622, 2011, A1. Location in patent: Page/Page column 14
[4] Bioorganic and Medicinal Chemistry Letters, 2008, vol. 18, # 11, p. 3282 - 3285
[5] Patent: US2005/70549, 2005, A1