反应详情

(3S-cis)-3-t-Butoxycarbonylamino-4-methyl-2-oxo-1-azetidinesulfonic acid, tetrabutyl ammonium salt (10.76 g) is dissolved in 50 ml of 95-97% formic acid and stirred for 4 hours under nitrogen. A small amount of product from a previous reaction is added as seed and the mixture is stirred for one more hour. The mixture is stored in the freezer for about 16 hours and the frozen mixture is warmed to room temperature and stirred for an additional hour. The solid formed is filtered and washed with methylene chloride to yield 982 mg of the title compound. The filtrate is diluted with 1 liter of methylene chloride and kept at -20° C. for 4 hours. The precipitate that forms is recrystallized from water-methanol-acetone to give an additional 167 mg of title compound.

1. customA small amount of product from a previous reaction
2. additionis added as seed
3. stirringthe mixture is stirred for one more hour
4. waitThe mixture is stored in the freezer for about 16 hours
5. stirringstirred for an additional hour
6. customThe solid formed
7. filtrationis filtered
8. washwashed with methylene chloride