Gadobutrol Impurity 135

1,4,7,10-Tetraazacyclododecane-1,4,7-triacetic acid, 10-[ (5R,6S) -6-hydroxy-2,2-dimethyl-1,3-dioxepan-5-yl]-, 1,4,7-tris (1,1-dimethylethyl) ester, rel-

1,4,7,10-Tetraazacyclododecane-1,4,7-triacetic acid,10-[ (5R,6S) -6-hydroxy-2,2-dimethyl-1,3-dioxepan-5-yl]-,1,4,7-tris (1,1-dimethylethyl) ester, rel-