Abstract: The present inventors found that, in the synthesis of a peptide compound involving condensation of a C-terminal-activated substance of an acid component with an amine component, the C-terminal-activated substance can be removed by mixing a solution containing a residual C-terminal-activated substance after a condensation reaction with a tertiary amine and water or an aqueous solution.

Abstract: The present invention provides methods for producing peptide compounds. The inventors have found that a cyclic peptide compound can be produced efficiently by linking the N-terminal amino acid residue and the C-terminal amino acid residue of a peptide compound in a solvent containing one or more selected from the group consisting of water-immiscible solvents, water-soluble alkyl nitriles, and water-soluble ethers.