Tris-NTA per-Tert-butyl Ester

(alpha1S,alpha4S,alpha8S)-alpha1,alpha4,alpha8-tris[bis[2-(1,1-dimethylethoxy)-2-oxoethyl]amino]-11-[6-[[(1,1-dimethylethoxy)carbonyl]amino]-1-oxohexyl]-delta1,delta4,delta8-trioxo-1,4,8,11-Tetraazacyclotetradecane-1,4,8-tripentanoic Acid alpha1,alpha4,alpha8-Tris(1,1-dimethylethyl) Ester

CC(C)(C)OC(=O)CN(CC(=O)OC(C)(C)C)C(CCC(=O)N1CCCN(CCN(CCCN(CC1)C(=O)CCCCCNC(=O)OC(C)(C)C)C(=O)CCC(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(=O)OC(C)(C)C)C(=O)CCC(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(=O)OC(C)(C)C)C(=O)OC(C)(C)C