4548-48-5 519-24-4 Cyclic(D-alpha-hydroxyisovaleryl-N-methyl-L-isoleucyl-D-alpha-hydroxyisovaleryl-N-methyl-L-isoleucyl) Cyclo(3-methyl-D-2-hydroxybutanoyl-N-methyl-L-isoleucyl-3-methyl-D-2-hydroxybutanoyl-N-methyl-L-isoleucyl) Isoleucine, N-(2-hydroxy-3-methylbutyryl)-N-methyl-, bimol. cyclic ester