| —— | 
                                        (2R,5S)-(6-ethoxy-5-isopropyl-2-methyl-3-oxo-2,3,4,5-tetrahydro-pyrazin-2-yl)-acetic acid benzyl ester | 
                                        908298-94-2 | 
                                        C19H26N2O4 | 
                                        346.426 | 
                                    
                                                                                                                                            
                                        | —— | 
                                        (2R,5S)-(6-ethoxy-5-isopropyl-2-methyl-3-oxo-2,3,4,5-tetrahydro-pyrazin-2-yl)-acetic acid pentafluorophenyl ester | 
                                        908299-17-2 | 
                                        C18H19F5N2O4 | 
                                        422.352 | 
                                    
                                                                                                                                            
                                        | —— | 
                                        (2R,5S,2'S,5'R)-8'-(6-ethoxy-5-isopropyl-2-methyl-3-oxo-2,3,4,5-tetrahydro-pyrazin-2-yl)-3',6'-diaza-4',7'-dioxo-2'-isopropyl-5'-methyl-5'-(benzyloxycarbonylmethyl)octanoic acid ethyl ester | 
                                        908299-02-5 | 
                                        C31H46N4O8 | 
                                        602.728 | 
                                    
                                                                                                                                            
                                        | —— | 
                                        4-(dibenzylamino)-N-{2-[(2R,5S)-6-ethoxy-2,3,4,5-tetrahydro-2-methyl-5-isopropyl-3-oxopyrazin-2-yl]acetyl}-L-isovalyl-L-valine ethyl ester | 
                                        1268691-61-7 | 
                                        C38H55N5O6 | 
                                        677.885 | 
                                    
                                                                                                                                            
                                        | —— | 
                                        4-(dibenzylamino)-N-{2-[(2R,5S)-6-ethoxy-2,3,4,5-tetrahydro-2-methyl-5-isopropyl-3-oxopyrazin-2-yl]acetyl}-D-isovalyl-L-valine ethyl ester | 
                                        1268691-47-9 | 
                                        C38H55N5O6 | 
                                        677.885 | 
                                    
                                                                                                                                            
                                        | —— | 
                                        N2-{2-[(2R,5S)-6-ethoxy-2,3,4,5-tetrahydro-2-methyl-5-isopropyl-3-oxopyrazin-2-yl]acetyl}-N5,N5-dibenzyl-2-methyl-L-ornithyl-L-valine ethyl ester | 
                                        1268691-62-8 | 
                                        C39H57N5O6 | 
                                        691.911 | 
                                    
                                                                                                                                            
                                        | —— | 
                                        N2-{2-[(2R,5S)-6-ethoxy-2,3,4,5-tetrahydro-2-methyl-5-isopropyl-3-oxopyrazin-2-yl]acetyl}-N5,N5-dibenzyl-2-methyl-D-ornithyl-L-valine ethyl ester | 
                                        1268691-49-1 | 
                                        C39H57N5O6 | 
                                        691.911 |