To a solution of 4-[5-amino-6-(5-phenyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl]cyclohex-3-en-1-one (15 mg, 0.045 mmol) in DCE (500 μL) was added a solution of ethaneamine (34 μL, of 2 M, 0.07 mmol) in THF and the reaction mixture was stirred for 5 min. Thereafter Na(OAc)3BH (15 mg, 0.07 mmol) was added followed by addition of AcOH (3 mg, 3 μL, 0.05 mmol) and the reaction mixture was stirred for 2 h at room temperature. The crude material was dissolved in DMSO and purified via reverse phase HPLC using 1-99 MeOH/H2O (0.05% HCl modifier) to obtain 5-[4-(ethylamino)cyclohexen-1-yl]-3-(5-phenyl-1,3,4-oxadiazol-2-yl)pyrazin-2-amine (2 mg, 9%) as yellow solid. 1H NMR (400 MHz, DMSO-d6) δ 8.84 (s, 1H), 8.56 (s, 1H), 8.12 (d, J=7.9 Hz, 2H), 7.68 (d, J=7.0 Hz, 3H), 7.60 (s, 1H), 6.58 (s, 1H), 3.05 (dd, J=13.2, 6.6 Hz, 2H), 2.76 (m, 3H), 2.38 (m, 1H), 2.27 (d, J=10.9 Hz, 1H), 1.78 (m, 1H), 1.26 (t, J=7.2 Hz, 3H). LC/MS m/z 363.05 [M+H]+.
