[CH2:1]([O:4][C:5]([N:7]1[CH2:11][C@H:10]([OH:12])[CH2:9][C@H:8]1[C:13]([OH:15])=[O:14])=[O:6])[CH:2]=[CH2:3].S(=O)(=O)(O)O.[CH2:21](N(CC)CC)C>CO>[CH2:1]([O:4][C:5]([N:7]1[CH2:11][C@H:10]([OH:12])[CH2:9][C@H:8]1[C:13]([O:15][CH3:21])=[O:14])=[O:6])[CH:2]=[CH2:3]To a solution of (2S,4R)-1-allyloxycarbonyl-2-carboxy-4-hydroxypyrrolidine (426 g) in methanol (3 l) was added 36N sulfuric acid (45 ml) at 10° C., and the mixture was allowed to heat to reflux for 2 hours. After cooling to ambient temperature, to this mixture was added triethylamine (430 ml) and the mixture was evaporated in vacuo. The residue was dissolved in ethyl acetate (3 l) and the solution was washed with brine, dried over magnesium sulfate and evaporated to give (2S,4R)-1-allyloxycarbonyl-2-methoxycarbonyl-4-hydroxypyrrolidine (385.6 g).
Wird geladen…
