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The aim of the present study was the synthesis and the biological screening of new analogs of Ac-RYYRWK-NH2, modified at the N-terminal with 1-[(methoxyphosphono)methylamino]cycloalkanecarboxylic acids. The four newly synthesized ligands for the nociceptin/orphanin FQ (N/OFQ) receptor (NOP) have been prepared by solid-phase peptide synthesis--Fmoc-strategy.… (More)
Aiming to develop more potent analgesic substances a new series of hexapeptides containing β2-tryptophan analogues was synthesized. The Trp in position 4 and 5, respectively in Ac-Arg-Phe-Met-Trp-Met-Lys-NH2 (opioid receptor antagonist) and Ac-Arg-Tyr-Tyr-Arg-Trp-Lys-NH2 (highly potent and selective NOP-receptor agonist) was substituted by the… (More)
The asymmetric Friedel-Crafts alkylation of various indoles with a chiral nitroacrylate provides optically active β-tryptophan analogues after reduction of the nitro group and removal of the chiral auxiliary. This reaction generally occurs in good yield and high diastereoselectivity (up to 90:10).
We report the synthesis and the biological activity of new analogues of Ac-RFMWMK-NH2 and Ac-RYYRWK-NH2, modified in position 4 and 5, respectively, with incorporation of newly synthesized β(2)-tryptophan analogues. Trp was substituted by the (S)-2-(1-methyl-1H-indol-3-yl)propionic residue or by (S)-2-(5-methoxy-1H-indol-3-yl)propionic residue. The… (More)
The cytotoxic effects of novel racemic and optically active constrained N-phosphonoalkyl bicyclic β-amino acids were tested against a panel of human tumor cell lines. All of the compounds investigated exhibited different concentration-dependent antiproliferative effects against the HT-29, MDA-MB-231, HepG2 and HeLa cell lines after 24 h treatment. The most… (More)
Following the discovery of the N/OFQ/NOP system and its modulatory role in physiological and pathophysiological processes, intensive study has started to find selective NOP ligands with hypothetic therapeutic potential. Among the agonists, a hexapeptide Ac-RYYRWK-NH2 has been identified. It expresses high NOP receptor affinity and selectivity. Its molecule… (More)
New series of N-modified analogues of the N/OFQ(1–13)NH2 with aminophosphonate moiety have been synthesized and investigated for biological activity. These peptides were prepared by solid-phase peptide synthesis—Fmoc-strategy. The N/OFQ(1–13)NH2 analogues were tested for agonistic activity in vitro on electrically stimulated rat vas deferens smooth-muscle… (More)