37553-64-3

19460-86-7

GENERAL PROCEDURE: To a stirring solution of Nα-Boc-protected peptide (1 mmol) in dichloromethane (2 mL) was slowly added a solution of 3.3 M HCl in dioxane (5 mL) at 0 °C. The reaction system was gradually warmed up to 20 °C and maintained at this temperature for 1 hour. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was placed in anhydrous ether and stirred to induce precipitation of the crystalline product. For poorly crystalline or strongly hygroscopic compounds, the residue is dissolved in dry chloroform, the solvent is subsequently evaporated, and the product is placed in a vacuum desiccator and dried using P4O10 or KOH as the desiccant. Part of the product needs to be purified by silica gel column chromatography using eluent mixture B or gel filtration through biogel P2 or Fractogel TCK HW 40 followed by lyophilization to obtain the pure product.