Hydrochloric Acid → HCID 131714732, compound

Participants

Reaction Steps

1.27 g of Z-Arg-OH are dissolved in 20 ml of DMF and 240 μl of a 5N solution of HCl in dioxan while heating gently. After the addition of 1.9 g of H-Arg-Pro-Phe-His-OMe (in the form of the dihydrochloride) and 0.45 g of HOBt×H2O, the whole is cooled to 0° and then 0.85 g of DCCI in solid form is added. After the latter has dissolved, the whole is left to stand for 8 hours in an ice bath and for 1 day at room temperature and the precipitated DCH is filtered off. The filtrate is concentrated to approximately 5 ml and, from this, the peptide is precipitated by the addition of 50 ml of diisopropyl ether and dried. It is dissolved in 45 ml of methanol/glacial acetic acid/H2O (94:3:3), heated for 1 hour at 60°, again concentrated to approximately 5 ml and precipitated with diisopropyl ether and dried. The crude product is purified by chromatography over 120 g of silica gel (60, Merck, 230-400 mesh) using as eluant chloroform/methanol/H2O/glacial acetic acid (140:80:20:1). The pure fractions are combined, concentrated almost to dryness, dissolved in H2O and lyophilised, yielding Z-Arg-Arg-Pro-Phe-His-OMe in the form of the dihydrochloride-monoacetate; Rf (C)=0.4; Rf (E)=0.3.

Provenance & Evidence