How is L-Threonine, N-[[4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetyl]-D-phenylalanyl-L-cysteinyl-L-tyrosyl-D-tryptophyl-L-lysyl-L-threonyl-L-cysteinyl-, cyclic (2→7)-disulfide, acetate (salt) (CAS: 177943-89-4) typically synthesized?

L-Threonine, N-[[4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetyl]-D-phenylalanyl-L-cysteinyl-L-tyrosyl-D-tryptophyl-L-lysyl-L-threonyl-L-cysteinyl-, cyclic (2→7)-disulfide, acetate is typically synthesized through a multi-step peptide synthesis process. This involves coupling amino acids using solid-phase peptide synthesis (SPPS) techniques. The use of a protecting group strategy and appropriate coupling reagents (such as HBTU or Fmoc) is crucial for the successful synthesis. The final product is then converted to the acetate salt form using acetic anhydride and pyridine. The synthesis yields are moderate to good, with high selectivity and purity.