Acetate-hydrochloric acid → HCID 131719313, compound

Participants

Reaction Steps

BocCys(Acm)ONp is prepared from BocCys(Acm)OH (Novabiochem, Laufalingen, CH) and p-nitrophenol by reaction with N,N'-dicyclohexylcarbodiimide (DCC) in ethyl acetate and used without purification for the preparation of Boc-Cys(Acm)-Pro-OH (XII) by reacting it with H-Pro-OH in DMF/etyl acetate/HCl at 0° C. while keeping pH neutral by addition of Et3N. Yield 81%. Purity>95% (TLC). Boc-Asn-Cys(Acm)-Pro-OH (XIII) is obtained by deblocking XII in HCl/HOAc at room temperature, dissolving the thus obtained raw H-Cys(Acm)-Pro-OH.HCl in DMF and neutralizing it with Et3N, and adding Boc-Asn-ONp (Novabiochem, Laufelingen, CH) at -5° C. while keeping pH neutral. XIII is isolated in 81% yield. [a]D20 =-77.1° (1 g/100 ml DMF). The tetrapeptide derivative X is prepared from XIII and Boc-Gln-ONp (Novabiochem, Laufelingen, CH) in a way corresponding to the preparation of XIII from XII and Boc-Asn-ONp. Yield 78.5%; [a]D20 =-89.7° (1 g/100 ml H2O).

Provenance & Evidence