CAS 4666-16-4 appears in our catalog under these names: Z-Glu(otbu)-osu, 97%, (S)-5-tert-Butyl 1-(2,5-dioxopyrrolidin-1-yl) 2-(((benzyloxy)carbonyl)amino)pentanedioate, 98%, Z–Glu(OtBu)–OSu, Z-L-Glu(OtBu)-OSu, Cbz-Glu(OtBu)-OSu 97%. Offered by: Combi-blocks, AmBeed, GLPBio, Iris Biotech, Chemat. Available pack sizes: 1g, 25g, 5g, 100g.