[CH3:1][O:2][C:3]1[CH:8]=[CH:7][C:6]([O:9][CH2:10][O:11][CH3:12])=[CH:5][N:4]=1.C[Li].CN([CH:18]=[O:19])C>C1COCC1.C(NC(C)C)(C)C>[CH3:1][O:2][C:3]1[CH:8]=[C:7]([C:6]([O:9][CH2:10][O:11][CH3:12])=[CH:5][N:4]=1)[CH:18]=[O:19]
To a mixture of 2-methoxy-5-(methoxymethoxy)pyridine (30 g, 0.178 mol) and diisopropylamine (507 uL, 3.6 mmol) in THF (500 mL) was added methyl lithium (1.6 M/THF, 200 mL, 0.32 mol) at −40° C. Upon the completion of addition, the mixture was warmed to 0° C. and continued to stir at 0° C. for 3 h. The reaction mixture was then cooled back down to −40° C. followed by addition of DMF (24.7 mL, 0.32 mol) slowly. The mixture was then stirred at −40° C. for 1 h and quenched with a mixture of HCl (12 N, 120 mL) and THF (280 mL). Water (200 mL) was added and the pH of the mixture was adjusted to pH 8-9 with solid K2CO3. The mixture was extracted with EtOAc (300 mL) twice. The organic layer was combined, dried over Na2SO4, and concentrated to give 2-methoxy-5-(methoxymethoxy)isonicotinaldehyde (33.5 g, 95.7%) as a brown solid, which was used for next step without further purification. 1H NMR (400 MHz; CD3OD) 7.90 (s, 1H), 6.92 (s, 1H), 5.64 (s, 1H), 5.20 (s, 2H), 3.84 (s, 3H), 3.48 (s, 3H); MS (ESI) m/z 198.1 [M+H]+.
Wird geladen…
