[CH2:1]([C:3]1[C:4]([C:15]2[CH:16]=[CH:17][C:18]3[N:19]([CH:21]=[C:22]([CH:24]=O)[N:23]=3)[CH:20]=2)=[N:5][C:6]([O:13][CH3:14])=[C:7]([CH:12]=1)[C:8]([O:10][CH3:11])=[O:9])[CH3:2].[CH3:26][NH:27][CH3:28].CC(O)=O.[BH-](OC(C)=O)(OC(C)=O)OC(C)=O.[Na+]>ClC(Cl)C.C(Cl)Cl>[CH3:26][N:27]([CH2:24][C:22]1[N:23]=[C:18]2[CH:17]=[CH:16][C:15]([C:4]3[C:3]([CH2:1][CH3:2])=[CH:12][C:7]([C:8]([O:10][CH3:11])=[O:9])=[C:6]([O:13][CH3:14])[N:5]=3)=[CH:20][N:19]2[CH:21]=1)[CH3:28]To a solution of methyl 5-ethyl-6-(2-formylimidazo[1,2-a]pyridin-6-yl)-2-methoxynicotinate (90 mg, 0.27 mmol) in dichloroethane (1.5 mL) was added solution of dimethylamine (2M THF, 0.20 mL, 0.40 mmol) followed by AcOH (25 μL, 0.42 mmol). After stirring at room temperature for 5 min NaBH(OAc)3 (90 mg, 0.42 mmol) was added. Reaction was stirred at room temperature ˜1.5 h and monitored by LC/MS until starting aldehyde was completely consumed. Reaction was diluted with DCM (5 mL) and then quenched with NaHCO3 (aqueous saturated, 5 mL). Product was extracted with DCM (3×5 mL). Organic phase was washed with NaCl (aqueous saturated, 10 mL) and dried over Na2SO4. Removal of the solvent afforded methyl 6-(2-((dimethylamino)methyl)imidazo[1,2-a]pyridin-6-yl)-5-ethyl-2-methoxynicotinate (100.6 mg) which was used directly in the next step. LC-MS 369.3 [M+H]+, RT 0.83 min.
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