Chloroform → cyclo-L-Ala-L-Glu(OBzl)

Participants

Reaction Conditions

Reaction Steps

Boc-L-Ala-L-Glu(OBzl)-ONp (56.0 g, 0.1 mol) was dissolved and cooled to −15° C. TFA was added and the mixture was stirred for 1 hour and gradually warmed to room temperature. Completion of the reaction was monitored by TLC using the system CHCl3:Et-OAc:MeOH=6:3:1. After completion of the reaction, the mixture was evaporated in vacuum, then twice evaporated with iso-propanol and dissolved in 500 ml of EtOAc. N-methylmorpholine was added until the mixture reached a pH level of 9 to 9.5. After 12 hours, the cyclo-L-Ala-L-Glu(OBzl) precipitated. The precipitate was filtered off, washed with EtOAc, ether and hexane. The yield was 21.0 g (70%). Rf=0.55 (CHCl3:EtOAc:MeOH:AcOH=6:3:1:0.1); HPLC data: retention time 15.9 min.

Provenance & Evidence