反应详情

500 ml of trifluoroacetic acid were added dropwise to a solution of 85.5 g of 5-{4-[2(R)-t-butoxycarbonylaminopropoxy]benzyl}-3-triphenylmethylthiazolidine-2,4-dione, [prepared as described in step (a), above] in 700 ml of methylene chloride, whilst ice-cooling, and the mixture was stirred at room temperature for 4 hours. At the end of this time, the reaction mixture was freed from methylene chloride and trifluoroacetic acid by distillation under reduced pressure. The residue was then triturated with a mixture of benzene and a small amount of ethyl acetate, and the crystals which precipitated were collected by filtration. These crystals were recrystallized from a mixture of methanol and ethyl acetate to give 36.9 g of the title compound melting at between 162° C. and 166° C.

1. temperaturecooling
2. distillationAt the end of this time, the reaction mixture was freed from methylene chloride and trifluoroacetic acid by distillation under reduced pressure
3. customThe residue was then triturated with a mixture of benzene
4. customa small amount of ethyl acetate, and the crystals which precipitated
5. filtrationwere collected by filtration
6. customThese crystals were recrystallized from a mixture of methanol and ethyl acetate