| Abstract: | In order to study the influence of substituents of the aromatic ring of D-phenyl-alanine on the inhibiting capacity of luliberian
analogs, we have synthesized two new analogs:
 and
 luliberin. The synthesis was performed by the fragmentary condensation method using 2+(3+5) and 2+(5+3) schemes. A new and
convenient method of obtaining the amide of the C-terminal tetrapeptide of the luliberin sequence has been developed. In the
condensation of the fragments, both the azide and the carbodimide method of synthesis with the addition of l-hydroxybenzotriazole
were used. The guanidino group of arginine was protected by nitration, while the hydroxy groups of serine and of tyrosine
were not protected. The complete elimination of the protective groups from the decapeptides was performed by catalytic hydrogenation
over Pd on carbon and by anhydrous HF with the addition of anisole at 0°C. The protected octa- and decapeptides were purified
by gel filtration on Sephadex LH-20 in ethanol or by preparative thin-layer chromatography on silica gel plates. The final
peptides were purified by ion-ex-exchange chromatography on Sephadex CM-25.
A. A. Zhdanov Leningrad State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 706–714, September–October,
1980. |
