Br[C:2]1[N:3]=[C:4]([O:13][CH2:14][CH:15]2[CH2:18][CH2:17][CH2:16]2)[C:5]([N:8]2[CH2:12][CH2:11][CH2:10][CH2:9]2)=[N:6][CH:7]=1.[C:19]([O:22][CH2:23]C)(=[O:21])C.C(N(CC)CC)C>CO>[CH3:23][O:22][C:19]([C:2]1[CH:7]=[N:6][C:5]([N:8]2[CH2:12][CH2:11][CH2:10][CH2:9]2)=[C:4]([O:13][CH2:14][CH:15]2[CH2:18][CH2:17][CH2:16]2)[N:3]=1)=[O:21]A 50 mL bomb with a glass liner was charged with the 5-bromo-3-cyclobutylmethoxy-2-pyrrolidin-1-yl-pyrazine (2.27 g, 7.3 mmol), ethyl acetate (6 mL, degassed), methanol (7 mL, degassed) and triethylamine (2.0 mL, 14.5 mmol). PdCl2dppfCH2Cl2 (0.29 g, 0.36 mmol) was charged to the bomb; the bomb was sealed and degassed under vacuum. The reaction was purged with carbon monoxide (×5) then pressurized to 5 bar and heated to 100° C. for 1 hour. The reaction mixture was filtered through celite and washed with methanol then ethyl acetate and the filtrate was concentrated in vacuo. The residue was dissolved in ethyl acetate (100 mL) and washed with water (100 mL) the organic layer was dried over MgSO4 and concentrated in vacuo to afford 6-cyclobutylmethoxy-5-pyrrolidin-1-yl-pyrazine-2-carboxylic acid methyl ester as an orange solid, 2.2 g (75% yield). LC@215 nm; Rt 2.39: 75%, m/z (ES+): 292 (M+H).
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