Abstract: A process for extraction of a peptide from a reaction mixture resulting from a peptide coupling reaction, the reaction mixture containing the peptide and a polar aprotic solvent selected from N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidone, whereby the process includes a step a) and a step b): step a) including the addition of a component a1) and a component a2), whereby component a1) is toluene and component a2) is water, to the reaction mixture, so that a biphasic system with an organic layer and an aqueous layer is obtained; step b) including the subsequent separation of the organic layer containing the peptide from the aqueous layer. In an embodiment, a combination of toluene and an organic solvent 1 selected from n-heptane, 2-methyltetrahydrofuran, ethylacetate, isopropylacetate, acetonitrile and tetrahydrofuran is used for the process for extraction. The extraction step is preferably used in a process for preparation of a peptide in liquid phase.

Abstract: A process for extraction of a peptide from a reaction mixture resulting from a peptide coupling reaction, the reaction mixture containing the peptide and a polar aprotic solvent selected from the group consisting of N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidone, whereby the process includes a step a) and a step b): step a) including the addition of a component a1) and a component a2), whereby component a1) is 2-methyltetrahydrofuran and component a2) is water, to the reaction mixture, so that a biphasic system with an organic layer and an aqueous layer is obtained; step b) including the subsequent separation of the organic layer containing the peptide from the aqueous layer. In an embodiment, a combination of 2-methyltetrahydrofuran and an organic solvent 1 selected from the group consisting of n-heptane, toluene, ethylacetate, isopropylacetate, acetonitrile and tetrahydrofuran is used for the process for extraction.

Abstract: A process for extraction of a peptide from a reaction mixture resulting from a peptide coupling reaction, the reaction mixture containing the peptide and a polar aprotic solvent selected from N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidone, whereby the process includes a step a) and a step b): step a) including the addition of a component a1), a component a2) and a component a3), whereby component a1) is an organic solvent 1, the organic solvent 1 is selected from 2-methyltetrahydrofuran and toluene, component a2) is water, and component a3) is an organic solvent 2, the organic solvent 2 is selected from the ethylacetate, isopropylacetate, acetonitrile, tetrahydrofuran and n-heptane to the reaction mixture, so that a biphasic system with an organic layer and an aqueous layer is obtained; step b) including the subsequent separation of the organic layer containing the peptide from the aqueous layer.

Abstract: The present invention relates to an improved process for supported phase synthesis, in particular for supported phase peptide synthesis, that makes use of salts, in particular of quaternary ammonium salts.