370 mg of Z-Sta-OH, 225 mg of H-β-Ala-His-NH2, 153 mg of HOBt×H2O and 247 mg of DCCI are suspended in 4.5 ml of DMF and stirred at room temperature. After approximately 10 minutes a clear solution has formed and afrer approximately 20 minutes DCH begins to crystallize out. The mixture is left to stand overnight, then stirred for 30 minutes at 0°, DCH is filtered off und the filtrate is concentrated to an oil. This is heated for 1 hour at 60° in 14 ml of methanol/glacial acetic acid/H2O (94:3:3), the solution is concentrated to 3 ml and the crude product is precipitated by 30 ml of diisopropyl ether and dried. To remove the acetic acid, the residue is dissolved in n-butanol, washed in succession with 5% strength NaHCO3 solution and with water, and the butanol phase is again concentrated to dryness. After purification by chromatography over 30 g of silica gel (Merck No. 60, 230-400 mesh) using as eluant chloroform/methanol (75:25), Z-Sta-β-Ala-His-NH3 is obtained; Rf (G)=0.28.
