[OH:1][CH2:2][C:3]1[N:4]2[C:8]([C:9]([C:12]([O:14][CH3:15])=[O:13])=[CH:10][CH:11]=1)=[CH:7][CH:6]=[CH:5]2>C(Cl)Cl.O=[Mn]=O>[CH:2]([C:3]1[N:4]2[C:8]([C:9]([C:12]([O:14][CH3:15])=[O:13])=[CH:10][CH:11]=1)=[CH:7][CH:6]=[CH:5]2)=[O:1]To a solution of methyl 5-(hydroxymethyl)indolizine-8-carboxylate (13 g, 63.41 mmol) in DCM (300 mL) was added MnO2 (55 g, 0.634 mol) at 0° C. The reaction mixture was stirred at rt overnight. After the completion, the reaction was filtered and concentrated. The crude product was purified by column (PE:EtOAc=300:1) to give the desired product methyl 5-formylindolizine-8-carboxylate (5.8 g, yield 45%). 1H NMR (400 MHz, DMSO): δ 10.01 (s, 1H), 8.90-8.91 (m, 1H), 7.31-7.35 (d, 1H, J=7.6 Hz), 7.68-7.70 (d, 1H, J=1 Hz), 7.29-7.31 (m, 1H), 7.14-7.16 (m, 1H), 3.97 (s, 3H) ppm.
Wird geladen…