4,7,10,13-Tetraoxa-16,19-diazatetracosanoic acid, 18-ethyl-24-[(3aS,4S,6aR)-hexahydro-2-oxo-1H-thieno[3,4-d]imidazol-4-yl]-17,20-dioxo-, 2,5-dioxo-1-pyrrolidinyl ester
4,7,10,13-Tetraoxa-16,19-diazatetracosanoic acid, 18-ethyl-24-[(3aS,4S,6aR)-hexahydro-2-oxo-1H-thieno[3,4-d]imidazol-4-yl]-17,20-dioxo-, 2,5-dioxo-1-pyrrolidinyl ester