2,2',2''-(10-(2-Oxo-6,9,12,15-tetraoxa-3-azaoctadec-17-yn-1-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid

2,2',2''-(10-(2-Oxo-6,9,12,15-tetraoxa-3-azaoctadec-17-yn-1-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid,