C([O:3][C:4](=O)[CH2:5][CH2:6][CH2:7][C:8]1[CH:13]=[N:12][CH:11]=[CH:10][N:9]=1)C>[Pd].CCO>[CH2:13]1[NH:12][CH2:11][CH2:10][N:9]2[C:4](=[O:3])[CH2:5][CH2:6][CH2:7][CH:8]124-Pyrazin-2-yl-butyric acid ethyl ester (1 g, 5.14 mmol) was dissolved in abs. EtOH (50 ml) and hydrogenated over 10% Pd/C (200 mg) at 50 psi for 20 hours. After filtration, the solvent was removed under vacuum and the residue was purified by flash chromatography (DCM/MeOH/32% NH4OH from 95/5/0.5 to 90/10/1 respectively) to afford the title compound (454 mg, 57% yield).
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