Preparation method, intermediates, and use of cyclic peptide toxin alpha-amanitin and/or amaninamide

A method for preparing a cyclic peptide toxin compound α-Amanitin and/or Amaninamide, α-Amanitin having a structure as shown in Formula 1a, and Amaninamide having a structure as shown in Formula 1b:

• wherein the method comprises the following steps:
• step 1, subjecting a compound 2 to acetylation and esterification to obtain a compound 3;
• step 2, subjecting the compound 3 to condensation and deprotection to obtain a compound 4;
• step 3, subjecting the compound 4 to condensation and deprotection to obtain a compound 5;
• step 4, subjecting the compound 5 to condensation and deprotection to obtain a compound 6;
• step 5, subjecting the compound 6 to condensation and deprotection to obtain a compound 7;
• step 6, subjecting the compound 7 to condensation and deprotection to obtain a compound 8;
• step 7, subjecting the compound 8 to condensation and deprotection to obtain a compound 9;
• step 8, subjecting the compound 9 to condensation and deprotection to obtain a compound 10;
• step 9, subjecting the compound 10 to carbon-sulfur bond ring closure in an iodine-mediated manner to obtain a compound 11;
• step 10, subjecting the compound 11 to deprotection to obtain a compound 12;
• step 11, subjecting the compound 12 to deprotection and condensation to obtain a compound 13;
• step 12, subjecting the compound 13 to oxidation to obtain a compound 14;
• and
• step 13, subjecting the compound 14 to deprotection to obtain the cyclic peptide toxin compounds α-Amanitin and Amaninamide;
• the compounds 2 to 14 have the following structures, respectively:
• wherein R in the compounds 9 to 14 is selected from the group consisting of —H and —OBn.