6-((1S,3'S,9'S,14a'R)-9'-benzyl-1',4',7',10'-tetraoxo-2,2',3,3',4',5',7',8',9',10',12',13',14',14a'-tetradecahydro-1'H-spiro[indene-1,6'-pyrrolo[1,2-a][1,4,7,10]tetraazacyclododecin]-3'-yl)hexanoic acid

benzyl 6-((1R,3'S,9'S,14a'R)-9'-benzyl-1',4',7',10'-tetraoxo-2,2',3,3',4',5',7',8',9',10',12',13',14',14a'-tetradecahydro-1'H-spiro[indene-1,6'-pyrrolo[1,2-a][1,4,7,10]tetraazacyclododecin]-3'-yl)hexanoate