Carfilzomib Impurity 4 (RSSSS)

Chemical Name: N-Oxide Impurity ; 4-({[(1S)-1-{[(1S)-3-methyl-1-{[(1S)-1-{[(2R)-4-methyl-1-[(2R)-2-methyloxiran-2-yl]-1-oxopentan-2-yl]carbamoyl}-2-phenylethyl]carbamoyl}butyl]carbamoyl}-3-phenylpropyl]carbamoyl}methyl)morpholin-4-ium-4-olate

Smile: CC(C)C[C@@H](C([C@]1(C)OC1)=O)NC([C@H](CC2=CC=CC=C2)NC([C@H](CC(C)C)NC([C@H](CCC3=CC=CC=C3)NC(C[N+]4([O-])CCOCC4)=O)=O)=O)=O