| 摘要 |
1. A cyclic pentapeptide of the formula: cyclo (-X1-X2-X3-X4-X5-)~ (I) wherein X n (n = 1-5) represent amino acid residues, respectively, and X1 is DPhe, DTyr, DTha, DTza, DNal, DBta, DTrp, DTrp(O), DTrp(CHO) or DTrp((CH2)m COR1) (wherein m is from 0 to 6, and R1 is a hydroxyl group, a C1-C6 alkoxy group, an amino group or a C1-C6 monoalkylamino group, provided that when m = 0, R1 is not a hydroxyl group), X2 is DAsp, DGlu or DCys(O3H), X3 is Pro, Hyp, Pip, Thz, .beta.Ala, Or Gly, Ala, .alpha.Aba, Aib, Val, Nva, Leu, Ile, aIle, Nle, Met, Met(O), Met(O2), Phe, Tza, Tha, Tyr, Trp, His, Arg, Lys, Lys(CHO), Orn, Orn(CHO), Asn, Gln, Asp, Glu, Cys(O3H), Cys, Ser or Thr wherein a hydrogen atom on the .alpha.-amino group may be substituted by a C1-C6 alkyl or C3-C7 cycloalkyl group which may have an optional group selected from the group consisting of an imidazolyl group, a carboxyl group, a sulfo group and a hydroxyl group, X4 is DAla, DThr, D.alpha.Aba, DVal, DNva, DLeu, DIle, DaIle, DNle, DtertLeu, DCpg, DChg, DDpg, DPen, Aib, Ac3c, Ac4c, Ac5C, Ac6c, Ac7c, or DPhg, DThg, DFug, DTzg or DItg wherein a hydrogen atom at the .alpha.- position may be substituted by a C1-C3 alkyl group, X5 is Pro, Pip, Thz, or His, Ala, aAba, Val, Nva, Leu, Ile, aIle, Nle, Met, C3al,Coal, C5a1 or C6al wherein a hydrogen atom on the .alpha.-amino group may be substituted by a C1-C6 alkyl group; or a pharmaceutically acceptable salt thereof.
|
