The present invention provides a method for producing a PNA oligomer. More specifically, the method comprises a step for reacting a PNA block and a PNA block in a solution to produce a PNA oligomer, and thus a PNA oligomer of interest can be produced with remarkably improved purity and yield.

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.

A preparation method for semaglutide. The method comprises: producing a semaglutide resin by means of a solid-phase synthesis, producing crude semaglutide by cleavage and deprotection, producing refined semaglutide by purification and freeze-drying, comprising the solid-phase synthesis of a semaglutide 1-6 peptide fragment resin, which is cleaved and purified to serve as a first peptide fragment; and synthesizing a lysine having a sidechain group at locus 20 of semaglutide to serve as a second peptide fragment. In the method, prepared is a semaglutide loci 1-6 fully protected peptide fragment, which serves as a key starting material applied in the solid-phase synthesis of semaglutide, thus reducing the generation of D-His, D-Glu, D-Thr, D-Phe racemic impurities and +Gly impurities, reducing the difficulty of coarse product purification, increasing the purity and yield of semaglutide, reducing synthesis costs, and favoring industrialized large-scale production.

Synthesis of O-benzotriazole and O-imidazole synthons are described. Uses of synthons in synthesis of azapeptides and other peptidomimetics, azapeptides and other peptidomimetics synthesized from the synthons and uses of azapeptides and other peptidomimetics are also described.

A continuous, solvent-free and non-enzymatic method for synthesizing a compound of formula (I): Ra-POLYPEP-Rc (I) wherein: POLYPEP is a poly-amino acid compound, Ra and Rc are as specified, the method including the steps of: a) feeding an extrusion reactor with (1) a compound of formula (II) Ra-PEPNt-Rg (II) wherein; PEPNt is a mono- or a poly-amino acid compound, Ra and Rg are as specified, and (2) a compound of formula (III) H-PEPCt-Rc (III) wherein: PEPCt is a mono- or a poly-amino acid compound, and Rc is as defined in the absence of any solvent, so that the compound of formula (II) and the compound of formula (III) react together for generating a compound of formula (I), and b) collecting the compound of formula (I) from the extrusion reactor.

The present invention provides methods of making α4β7 peptide monmer and dimer antagonists. Methods of the present invention include solid phase and solution phase methods, as well as synthesis via condensation of smaller peptide fragments. Methods of the present invention further include methods directed to the synthesis of peptides comprising one or more penicillamine residues.

Methods for making an arylomycin ring of formula t

##STR00001##

or salts or solvates thereof, wherein R, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.5, R.sup.10 and Pg.sup.1 are as defined herein.

The present disclosure relates to site-selective labeling compounds, and methods of using such compounds.

The invention provides a method for producing a peptide by (1) removing the N-terminal protective group of an amino acid or peptide compound of formula (I):

##STR00001##

wherein Y represents a residue of an N-protected amino acid or an N-protected peptide, and each of R.sup.1, R.sup.2, and R.sup.3 independently represents an aliphatic hydrocarbon group which may have a substituent or an aromatic hydrocarbon group which may have a substituent, wherein the total number of carbon atoms in the R.sup.1R.sup.2R.sup.3Si group is 18 to 80, and the R.sup.1R.sup.2R.sup.3SiCH.sub.2CH.sub.2 group is bonded to the C-terminus of the amino acid or peptide residue in Y; and (2) causing condensation of an N-protected amino acid or an N-protected peptide and the N-terminus of the C-protected amino acid or C-protected peptide obtained in the step (1).