反应详情

500 ml of trifluoroacetic acid were added dropwise, whilst ice-cooling, 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 (e) above] in 700 ml of methylene chloride, and the resulting mixture was stirred at room temperature for 4 hours. At the end of this time, the reaction mixture was freed from the methylene chloride solvent and the trifluoroacetic acid by distillation under reduced pressure, and a mixture of benzene and a small amount of ethyl acetate was added to the residue. The crystals which precipitated were collected by filtration and were recrystallized from a mixture of methanol and ethyl acetate, to give the title compound as crystals, melting at 162°166° C. [α]D23 -13.0° (c=0.885, methanol)

1. distillationthe trifluoroacetic acid by distillation under reduced pressure
2. additiona mixture of benzene
3. additiona small amount of ethyl acetate was added to the residue
4. customThe crystals which precipitated
5. filtrationwere collected by filtration
6. customwere recrystallized from a mixture of methanol and ethyl acetate