反应详情

11 ml of methylene chloride, followed by 452 mg of N-(4-nitrobenzyloxycarbonyl)acetamidine, were added to a solution of 1.1 g of (2S,4S)-4-(4-methoxybenzylthio)-2-(1-piperazinylcarbonyl)-1-(4-nitrobenzyloxycarbonyl)-pyrrolidine hydrochloride [prepared as described in step (ii) above] in 22 ml of methanol, whilst heating the solution under reflux. The resulting mixture was then heated under reflux for a further 4hours. At the end of this time, the reaction mixture was freed from the solvent by distillation under reduced pressure, and the resulting residue was purified by column chromatography through silica gel, using a 20:1 by volume mixture of ethyl acetate and methanol as the eluent to give 466 mg of the title compound, as a powder.

1. temperaturewhilst heating the solution
2. temperatureunder reflux
3. temperatureThe resulting mixture was then heated
4. temperatureunder reflux for a further 4hours
5. distillationAt the end of this time, the reaction mixture was freed from the solvent by distillation under reduced pressure
6. customthe resulting residue was purified by column chromatography through silica gel
7. additionby volume mixture of ethyl acetate and methanol as the eluent