Purity ≥99% (HPLC and TLC). Carfilzomib is a second-generation proteasome inhibitor that is used as a treatment in relapsed and refractory multiple myeloma. Synonyms: (αS)-α-[[2-(4-Morpholinyl)acetyl]amino]benzenebutanoyl-L-leucyl-N-[(1S)-3-methyl-1-[[(2R)-2-methyl-2-oxiranyl]carbonyl]butyl]-L-phenylalaninamide; (αS)-α-[(4-Morpholinylacetyl)amino]benzenebutanoyl-L-leucyl-N-[(1S)-3-methyl-1-[[(2R)-2-methyloxiranyl]carbonyl]butyl]-L-phenylalaninamide; PR 171 CAS No: 868540-17-4