| 摘要 |
Compounds of the general formula <FORM:1113267/C2/1> in which A, B, C and D are L-alpha-amino acyl residues linked in peptide fashion, R1 is H, NH2 substd. with a protective group, or an L-alpha-amino acyl residue or a peptide acyl residue of 2-6 L-alpha-amino acyl residues or a residue of an L-alpha-amino acid substd. with a protective group on its alpha-amino or side chain functional group or both, and R2 is OH or NH2 or either of these carrying a protective group, or N-forming the terminal atom of an amino acyl residue or peptide chain with or without protective groups on its functional groups and wherein X is CH2S, CH2CH2, CH2NH, CH2O, NHNH or CONH are prepared by ring closure of a linear peptide of the formula <FORM:1113267/C2/2> where P is OH, A-OX, AB-OH, A-B-C-OH, or A-B-C-D-OH and Q correspondingly is H-A-B-C-D, H-B-C-D, H-C-D, H-D or H, the free amino groups in P and/or Q being protected, with a peptide bond forming agent, e.g. dicyclohexylcarbodiimide, sec. butyl chloroformate or N-ethyl-5-phenyl-isoxazolium-31-sulphonate. H - Tyr - Ileu - Glu(NH2) - Asp(NH2) - S-(3 - carboxypropyl) - Cys - Pro - Leu - Gly(NH2) is prepd. from Z-Tyr-Ileu-Glu(NH2)-Asp(NH2)-S-(Bz) -Cys-Pro-Leu-Gly(NH2) and t-butyl ester of g -iodo-butyric acid, the octapeptide being prepared from Z-Tyr N3 and the heptapeptide and the iodo ester from the free iodo acid and ti-butyl acetate. The t-butyl ester of a -tosylamino-g -iodobutyric acid is prepd. from the free acid and t-butyl acetate to form a -tosylamino butyro lactone and the chloro ester which is reacted with NaI. |
