C(NC(C)C)(C)C.[CH2:8]([Li])[CH2:9][CH2:10][CH3:11].[C:13]([C:15]1[C:16](=[O:22])[NH:17][C:18](C)=[CH:19][CH:20]=1)#[N:14].BrCCC>C1COCC1>[CH2:8]([C:18]1[NH:17][C:16](=[O:22])[C:15]([C:13]#[N:14])=[CH:20][CH:19]=1)[CH2:9][CH2:10][CH3:11]
A solution of diisopropylamine (20.5 mL, 2 eq) in THF (200 mL) was cooled to −5° C. n-Butyllithium (53.5 mL, 2.9 M in hexanes, 2 eq) was added over 10 minutes. The solution was allowed to rise to 0° C., stirred for 0.5 hours, then cooled again to −30° C. 3-Cyano-6-methyl-2(1H)pyridinone (10 g, 75 mmol) was added portionwise, and the mixture was allowed to warm to room temperature and stirred for 2 hours. The solution was then cooled to −50° C., and 1-bromopropane (6.8 mL, 1 eq) was added. The solution was allowed to warm to room temperature, stirred for 1 hour, and then quenched with a saturated ammonium chloride solution. The THF was evaporated and the aqueous phase extracted with DCM (2×100 mL). The organics were washed with saturated aqueous NaCl, dried over Na2SO4, and evaporated to yield intermediate (24a) as an orange solid (10.8 g, 61 mmol), which was used without further purification. MS m/z: [M+H+] calcd for C10H12N20, 177.2; found 177.0. 1H-NMR (DMSO) 7.87 (1H, d), 6.05 (1H, d), 2.38 (2H, t), 1.41 (2H, m), 1.15 (2H, m), 0.93 (1H, d), 0.73 (3H, t).
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