SOMATOSTATINE PEPTIDES Russian patent published in 2000 - IPC

FIELD: organic synthesis. SUBSTANCE: invention provides novel hexapeptide of formula II: [A-Zz_a-(D/L)Trp-Lys-X₁-X₂] (II), in which X₁ is radical of formula a: (a) or b: (b), wherein R₁ optionally substituted phenyl and R₂ is group -Z₁-CH₂-R₁, -CH₂-CO-O-CH₂-R₁, or c: (c) or d: (d), wherein Z₁ is oxygen or sulfur atom; X₂ is alpha-amino acid substituted by aromatic radical on its side C_α chain or X₂ is amino acid motif Dab; A is bivalent residue selected from: Pro, (R₃-NH-COO)Pro, H₂N-Pro, HO-Pro, R₃-NH-CO-O- R₆-CH(NR₄)-CO-, , where R₃ is NR₈R₉-(C₂-C₆)-alkylene or guanidine-C₂-C₆-alkylene; R₄ is hydrogen or methyl; R₁₁ benzyl optionally substituted in its ring, -(CH₂)_1-3-OH or -(CH₂)_1-5-NH₂; R_b is -(CH₂)_1-3; each of R_8/ and R₉, independently from each other, are hydrogen, (C₁-C₄)-alkyl, acyl, or CH₂OH-(CHOH)_c-CH₂-, where c = 0, 1, 2, 3 or 4, or R₈ and R₉ form with nitrogen atom, to which they are linked, heterocyclic group, which can contain additional heteroatom (examples: pyridyl or morpholino groups); and Zz_a is natural or synthetic alpha-amino acid unit selected from: Ala, Val, Thr, Ser, Leu, Nle, Ile, His, Trp, Arg, Tyr, Phe, and NH₂-Phe in free base form or in the form of salt or complex compound. Compounds of invention have affinity for somatostatin receptors. EFFECT: extended choice of biologically-active polypeptides. 7 cl