Hydrochloric Acid → 10'-Methylvinblastine

Participants

Reaction Conditions

Reaction Steps

A mixture of iron(III) oxalate hexahydrate (45.0 mg, 0.093 mmol) in H2O (37 mL) was cooled to 0° C. and air was bubbled through the mixture for 10 minutes. A solution of 10′-methylanhydrovinblastine (21a, 7.5 mg, 0.0093 mmol, 1 equiv) in H2O (0.5 mL), aqueous 0.1 N HCl (0.5 mL), and CF3CH2OH (0.1 mL) was transferred by pipette to the mixture and NaBH4 (14.6 mg, 0.39 mmol, 1 equiv) in H2O (1 mL) was added to the mixture at 0° C. The resulting mixture was stirred for 30 minutes before being quenched by addition of 28-30% aqueous NH4OH (10 mL). The mixture was extracted with 10% MeOH in CH2Cl2 and the organic layer was dried over Na2SO4 and concentrated under reduced pressure. PTLC (SiO2, Et3N:MeOH:EtOAc=3:3:97) provided 10′-methylvinblastine (21b, 3.1 mg, 0.0038 mmol, 40%) as a white solid and 10′-methylleurosidine (1.5 mg, 0.0018 mmol, 19%).

Provenance & Evidence