234108-58-8

Step 2: A mixture of tert-butyl 4-(cyanomethyl)-3-oxopiperazine-1-carboxylate (3.0 g, 12.5 mmol) with PtO2 (300 mg, 1.32 mmol) in ethanol (20 mL) was stirred at 20 °C and reacted overnight in a hydrogen (50 psi) atmosphere. Upon completion of the reaction, the PtO2 catalyst was removed by filtration and the filtrate was concentrated under reduced pressure to afford tert-butyl 4-(2-aminoethyl)-3-oxopiperazine-1-carboxylate (2.8 g, 93% yield), the product being a yellow solid.LC-MS (ESI) analysis showed: m/z = 244.2 [M + H]+ .

[1] Patent: US2015/31674, 2015, A1. Location in patent: Paragraph 0303; 0305; 0729
[2] Patent: US2004/102450, 2004, A1. Location in patent: Page/Page column 90-91