[Synthesis of cyclic and cyclically branched tachykinin partial sequences. 1. Synthesis of the homodet-cyclic eledoisin(6-11)-hexapeptide].

Ala-Phe-Ile-Gly-Leu-Met has been disengaged by cyclization of H-Leu-Met-Ala-Phe-Ile-Gly-OH by means of dicyclohexylcarbodiimide/N-Hydroxysuccinimide or the adequate p-nitrophenylester. Acc. to various strategic variants, the design of the linear precursor has been performed by condensation of the segments of Boc-Leu-Met-OH and H-Ala-Phe-Ile-Gly-OH. The resulting cyclo-[Eledoisin(6-11)-Hexapeptide] has in a clearly separated range of dose dual agonistic and antagonistic effects at the guinea-pig ileum.