The invention provides a method for the cleavage of Fmoc group characterized by using a solution comprising 3-(diethylamino)propylamine. In particular, it provides a method for the preparation of peptides in solid phase wherein Fmoc protected amino acids are used and the Fmoc group is cleaved by a solution comprising 3-(diethylamino)propylamine.

Methods of producing a peptide containing an N-substituted amino acid or N-substituted amino acid analog of the present invention include the steps of: preparing an Fmoc-protected amino acid, an Fmoc-protected amino acid analog, or an Fmoc-protected peptide; deprotecting a protecting group which have an Fmoc skeleton of the Fmoc-protected amino acid and such by using a base; and forming an amide bond by adding a new Fmoc-protected amino acid and such; and when the peptide is produced by a solid-phase method, the obtained peptide is cleaved off from the solid phase under conditions of weaker acidity than TFA. Furthermore, at least one side chain of the obtained peptide has a protecting group that is not deprotected under basic conditions and is deprotected under conditions of weaker acidity than TFA.

Methods of producing a peptide containing an N-substituted amino acid or N-substituted amino acid analog of the present invention include the steps of: preparing an Fmoc-protected amino acid, an Fmoc-protected amino acid analog, or an Fmoc-protected peptide; deprotecting a protecting group which have an Fmoc skeleton of the Fmoc-protected amino acid and such by using a base; and forming an amide bond by adding a new Fmoc-protected amino acid and such; and when the peptide is produced by a solid-phase method, the obtained peptide is cleaved off from the solid phase under conditions of weaker acidity than TFA. Furthermore, at least one side chain of the obtained peptide has a protecting group that is not deprotected under basic conditions and is deprotected under conditions of weaker acidity than TFA.

Methods are disclosed for producing highly purified recombinant human insulin (RHI) having a purity of 99.0% (w/w) or greater, a Total Impurity (not including the related substance desamido Asn.sup.A21-RHI, as specified by USP) of 0.8% (w/w) or less, and an impurity C of 0.1% (w/w) or less. Also disclosed are API compositions of highly purified RHI having a purity of 99.0% (w/w) or greater, a Total Impurity of 0.8% (w/w) or less, and an impurity C of 0.1% (w/w) or less.

A synthesis method for low-racemization impurity liraglutide comprises the following steps: performing synthesis to obtain a propeptide, coupling 2 to 5 peptides comprising Thr-Phe on the propeptide by using a solid-phase synthesis method; further, performing solid-phase synthesis to obtain a liraglutide resin; the liraglutide resin is cracked after modification, or the liraglutide resin is directly cracked, purified and frozen dry, so as to obtain the liraglutide. The provided liraglutide synthesis method effectively restrains or reduces the generation of racemization impurity D-Thr.sup.5 highly similar to a product property, which facilitates the purification of the coarse liraglutide, and the high yield of the liraglutide is ensured, thereby greatly reducing production costs; during the synthesis of the liraglutide, the syntheses between dipeptide fragments, tripeptide fragments, the tetrapeptide fragments and pentapeptide fragments and the Gly-resin or the syntheses between the combination of the dipeptide fragments, the tripeptide fragments, the tetrapeptide fragments and pentapeptide fragments and the Gly resin can be carried out at the same time, and accordingly the synthesis time is shortened to some extent.

A synthesis method for low-racemization impurity liraglutide comprises the following steps: performing synthesis to obtain a propeptide, coupling 2 to 5 peptides comprising Thr-Phe on the propeptide by using a solid-phase synthesis method; further, performing solid-phase synthesis to obtain a liraglutide resin; the liraglutide resin is cracked after modification, or the liraglutide resin is directly cracked, purified and frozen dry, so as to obtain the liraglutide. The provided liraglutide synthesis method effectively restrains or reduces the generation of racemization impurity D-Thr.sup.5 highly similar to a product property, which facilitates the purification of the coarse liraglutide, and the high yield of the liraglutide is ensured, thereby greatly reducing production costs; during the synthesis of the liraglutide, the syntheses between dipeptide fragments, tripeptide fragments, the tetrapeptide fragments and pentapeptide fragments and the Gly-resin or the syntheses between the combination of the dipeptide fragments, the tripeptide fragments, the tetrapeptide fragments and pentapeptide fragments and the Gly resin can be carried out at the same time, and accordingly the synthesis time is shortened to some extent.

The purpose of the present invention is to provide a protecting group which improves the solubility of a compound having a functional group protected with the protecting group in an organic solvent and which is easily separated and purified after a reaction with avoiding solidification or insolubilization. Provided is a benzyl compound represented by Formula (1) where X.sup.1 represents —CH.sub.2OR.sup.14 (where R.sup.14 represents a hydrogen atom, a halogenocarbonyl group, or an active ester-type protecting group), —CH.sub.2NHR.sup.5 (where R.sup.15 represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or an aralkyl group), a halogenomethyl group, a methyl azide group, a formyl group, or an oxime; and at least one of R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 is a group represented by Formula (2), and the remainders each represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, where R.sup.6 represents a linear or branched alkylene group having 1 to 16 carbon atoms; X.sup.2 represents O or CONR.sup.16 (where R.sup.16 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms); and A represents a group represented by Formula (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), or (13).

The present invention comprises conjugates comprising a monoclonal antibody conjugated to a cyclic PYY peptide. The invention also relates to pharmaceutical compositions and methods for use thereof. The novel conjugates are useful for preventing, treating or ameliorating diseases and disorders disclosed herein.

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.

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.