Preparation of soluble peptide tachykinin antagonists

Glycosated cyclopeptides I [X1 = D- or L-Cys(Y), D- or L-SeCys(Y); Z1 = Asp, Z2 = Dap; Z1 = Dap, Z2 = Asp; X2, X3, X4 = natural or synthetic hydrophobic amino acids, having Z1, Z2, X2, X3, and X4 the same D- or L-configuration; Y = glycosidic group selected from the aldo and keto hexoses in the furanose or pyranose form bound to the Cys residue with an a- or b- thioacetal bond or a cyclitol or a polyvinyl alc. or PEG group contg. 5-10 monomers, bound to the Cys with a thioether bond; SeCys = selenocysteine; Dap = 2,3-diaminopropanoic acid], are endowed of high soly. and of potent tachykinin-antagonistic activity. Thus, galactocysteine cyclopeptide II, prepared by standard solid-phase methods, inhibited neurokinin A response to an agonist with pA2 = 8.4 and had a solubility. of 1.8 mg/mL.