A method for producing an amide includes: dehydrating and condensing carboxylic acids and then reacting them with a base, and reacting them with an amine.

Provided herein are polymeric -hydroxy aldehyde or -hydroxy ketone reagents which can be conjugated to amine-containing compounds to form stable conjugates in a single-step reaction. In selected embodiments, the polymeric reagent itself incorporates an internal proton-abstracting (basic) functional group, to promote more efficient reaction. The substituent is appropriately situated, via a linker if necessary, to position the group for proton abstraction, preferably providing a 4- or 5-bond spacing between the abstracting atom and the hydrogen atom on the -carbon. Also provided are methods of using the reagents and stable, solubilized conjugates of the reagents with biologically active compounds. In preferred embodiments, the polymeric component of the reagent or conjugate is a polyethylene glycol.

Provided herein are polymeric -hydroxy aldehyde or -hydroxy ketone reagents which can be conjugated to amine-containing compounds to form stable conjugates in a single-step reaction. In selected embodiments, the polymeric reagent itself incorporates an internal proton-abstracting (basic) functional group, to promote more efficient reaction. The substituent is appropriately situated, via a linker if necessary, to position the group for proton abstraction, preferably providing a 4- or 5-bond spacing between the abstracting atom and the hydrogen atom on the -carbon. Also provided are methods of using the reagents and stable, solubilized conjugates of the reagents with biologically active compounds. In preferred embodiments, the polymeric component of the reagent or conjugate is a polyethylene glycol.

Provided is a method for solid phase synthesis of Etelcalcetide, comprising synthesizing Etelcalcetide backbone peptide resin, removing the side chain protecting group of Cys in the peptide chain, and then activating the sulfydryl group of the Cys side chain on the peptide resin with 2,2-dithiodipyridine and constructing a disulfide bond with L-Cys, such that a crude Etelcalcetide peptide is obtained by cleaving. The method does not require undergoing multi-step purification, the yield and purity of the obtained crude peptide are relatively high, and the total yield of the refined peptide after purification is greatly increased.

The invention provides methods for producing a protein in a cell free protein synthesis system such that the protein does not contain an asparagine (Asn or N) residue at serine (Ser or S) positions. Also provided are compositions and nucleic acid templates for use in the methods described herein.

A method of producing a polypeptide compound, wherein a peptide compound represented by formula (P) is obtained by inducing an amide formation reaction between an amino-protected lactam compound represented by formula (R1) and an amino acid ester or peptide ester compound represented by formula (R2).

##STR00001##

The definitions for the reference signs in formulae (R1), (R2), and (P) are as set forth in the claims.

Macrocyclization of amino acids or linear peptides upon reaction with amphoteric amino aldehydes and isocyanides is provided.

The invention is directed to a method of making a target peptide comprising reacting a mixed anhydride compound of Formula (I) with a second moiety which is an amino acid or peptide, wherein Formula (I) has the following structure:

##STR00001##

and wherein R.sup.1-R.sup.3 are as defined in the disclosure.

The present invention provides a novel means capable of producing an amide compound by highly stereoselectively and/or highly efficiently causing an amide reaction in various substrates having a carboxyl group and an amino group. This reaction agent causes an amide reaction between a carboxyl group and an amino group, and contains a silane compound represented by general formula (C1) or the like.

##STR00001##

(In general formula (C1), each substituent is as defined in the claims)

A method for preparing interleukin-2 or an interleukin-2 analogue formed by at least three building blocks including the steps of: a) Synthesizing the at least three building blocks, whereby the C-terminal amino acid of each building block is linked to an a-keto group and the N-terminal amino acid of each building block is linked to a cyclic hydroxylamine, b) Coupling the at least three building blocks by KAHA ligation resulting in a depsipeptide, c) Rearrangement of the depsipeptide to obtain interleukin-2 or an interleukin-2 analogue.