RESUMEN
In previous work, we discovered a lead compound and conducted initial SAR studies on a novel series of dioxotriazines to identify the compound as one of the P2X3 receptor antagonists. This compound showed high P2X3 receptor selectivity and a strong analgesic effect. Although not selected for clinical development, the compound was evaluated from various aspects as a tool compound. In the course of the following study, the molecular structures of the dioxotriazines were modified based on pharmacokinetic/pharmacodynamic (PK/PD) analyses. As a result of these SAR studies, Sivopixant (S-600918) was identified as a clinical candidate with potent and selective antagonistic activity (P2X3 IC50, 4.2 nM; P2X2/3 IC50, 1100 nM) and a strong analgesic effect in the rat partial sciatic nerve ligation model (Seltzer model) of allodynia (ED50, 0.4 mg/kg).
Asunto(s)
Compuestos de Anilina/farmacología , Descubrimiento de Drogas , Antagonistas del Receptor Purinérgico P2X/farmacología , Piridinas/farmacología , Receptores Purinérgicos P2X3/metabolismo , Triazinas/farmacología , Compuestos de Anilina/síntesis química , Compuestos de Anilina/química , Relación Dosis-Respuesta a Droga , Estructura Molecular , Antagonistas del Receptor Purinérgico P2X/síntesis química , Antagonistas del Receptor Purinérgico P2X/química , Piridinas/síntesis química , Piridinas/química , Relación Estructura-Actividad , Triazinas/síntesis química , Triazinas/químicaRESUMEN
Significant advances have been achieved in the fields of peptide/protein synthesis, permitting the preparation of large, complex molecules. Shortcomings, however, continue to exist in the area of peptide purification. This paper details some studies we undertook to develop a new strategy for peptide purification based on a reactivity of alpha-ketoacyl groups in peptides. The alpha-ketoacyl peptide was generated from N(epsilon)-acyl-lysyl-peptide in the solid phase via a transamination reaction using glyoxylic acid and nickel(II) ion. Cleavage of the alpha-ketoacyl group with o-phenylenediamine gave the target peptide in an acceptable yield and purity. We first carried out a careful step-by-step optimization of the purification conditions using a model peptide. The strategy was then used in the purification of a transmembrane peptide that could not be effectively purified using a conventional RP-HPLC system due to the strong hydrophobicity of the peptide and its high tendency to aggregate.
Asunto(s)
Péptidos/química , Péptidos/aislamiento & purificación , Cromatografía de Afinidad , Cromatografía Líquida de Alta Presión , Estructura Molecular , Péptidos/síntesis químicaRESUMEN
An efficient method of peptide thioester synthesis is described. The reaction is based on an N-4,5-dimethoxy-2-mercaptobenzyl (Dmmb) auxiliary-assisted N-S acyl shift reaction after assembling a peptide chain by Fmoc-solid phase peptide synthesis. The Dmmb-assisted N-S acyl shift reaction proceeded efficiently under mildly acidic conditions, and the peptide thioester was obtained by treating the resulting S-peptide with sodium 2-mercaptoethanesulfonate. No detectable epimerization of the amino acid residue adjacent to the thioester moiety in the case of Leu was found. The reactions were also amenable to the on-resin preparation of peptide thioesters. The utility was demonstrated by the synthesis of a 41-mer peptide thioester, a phosphorylated peptide thioester and a 33-mer peptide thioester containing a trimethylated lysine residue.