Dicyclohexylcarbodiimide → Z-Ser(tBu)-Asn-Leu-OMe

Participants

Reaction Conditions

Reaction Steps

8.90 g of H-Asn-Leu-OMe and 11.0 g of Z-Ser(tBu)-OH are dissolved in 100 ml of freshly distilled dimethylformamide. The solution is cooled to 0°C and 3.90 g of N-hydroxysuccinimide followed by 8.70 g of dicyclohexylcarbodiimide are added. After 30 minutes standing at 0°C and 18 hours at 25°C the precipitated dicyclohexylurea is filtered off and the filtrate is poured into 800 ml of ice water. The crystalline precipitate which hereupon separates out is dried in vacuo at 40°C and then recrystallised from methanol-water. The Z-Ser(tBu)-Asn-Leu-OMe which is hereupon obtained in an analytically pure form melts at melting point 202° - 205°C; [α]D20 =-18° (c = 1.05 in glacial acetic acid).

Provenance & Evidence