Methanol → Boc-Ser(Bzl)-Glu(OBzl)-OH

Beteiligte Stoffe

Reaktionsschritte

H-Glu(OBzl)-OH (39.4 g, 166 mmol) was stirred with Boc-Ser(Bzl)-OSu (65.0 g, 166 mmol) in 900 ml DMF overnight in the presence of Et3N (2.3 ml, 165 mmol). More Et3N was added during this time in order to maintain the reaction slightly basic. The clear solution was evaporated to dryness and the oily residue partitioned between EtOAc (1.5 liters) and 5% HOAc (2 liters). The organic layer was washed with H2O (2 times), dried over Na2SO4, and concentrated to a clear oil (90.0 g) which was taken up in 3 liters of ether and treated with 25 ml of cyclohexylamine The solid formed was recrystallized from MeOH and ether: yield, 76.2 g (74.8%); mp 154°-156.5°; [α]D25 =+6.32° (c l, MeOH).

Herkunft & Nachweise