[Problem] To provide a novel means capable of generating highly stereoselective and/or highly efficient amidation reactions in a variety of substrates having a carboxyl group and an amino group, and capable of producing amide compounds.

[Solution] A reaction agent for amide reactions between carboxyl groups and amino groups and including a silane compound indicated by general formula (A) and/or general formula (B).

##STR00001##

(In general formulas (A) and (B), each substituent represents the definition described in the Claims.)

An object of the present invention is to provide a method for producing a peptide with high efficiency, and a method for producing a peptide which comprises the following steps (1) and (2): (1) a step of mixing an N-protected amino acid or an N-protected peptide with a carboxylic acid halide represented by the formula (I)

##STR00001##

(wherein X represents a halogen atom,
R.sup.1, R.sup.2 and R.sup.3 each independently represent an aliphatic hydrocarbon group which may have a substituent, and a total number of the carbon atoms in R.sup.1, R.sup.2 and R.sup.3 is 3 to 40); and (2) a step of mixing the product obtained in the step (1) and a C-protected amino acid or a C-protected peptide
is provided.

A method for producing a polypeptide, includes at least one native ligation step using a peptide functionalized with a selenium group. The selenium peptides and compounds are also described.

The invention provides a method for producing a peptide which includes a step of reacting a peptide in which a C-terminal carboxy group is activated which is obtained by reacting an N-protected peptide represented by the formula (I):

P-AA.sub.1-OH  (I)

a tertiary amine represented by the formula (II):

##STR00001##

and an acid halide in a flow reactor, with a silylated amino acid or peptide obtained by reacting an amino acid or peptide represented by the formula (III):

H-AA.sub.2-OH  (III)

with a silylating agent, in a flow reactor, wherein, in the formulae (I) to (III), AA.sub.1, AA.sub.2, P, R.sup.1, R.sup.2 and R.sup.3 are as defined herein.

Provided is a method of preparing an N-acetyl dipeptide and an N-acetyl amino acid, the method including producing the N-acetyl dipeptide and the N-acetyl amino acid by reaction of an amino acid with acetic anhydride or acetyl chloride.

Compositions and methods for optically-verified, sequence-controlled polymer synthesis are described.

The invention provides a method for producing a peptide which comprises the following steps (1) and (2): (1) a step of condensing a C-protected amino acid or a C-protected peptide to a C-terminal of an N-protected amino acid or an N-protected peptide represented by the formula (I):

##STR00001##

wherein Y represents an amino acid in which a C-terminal is unprotected or a peptide in which a C-terminal is unprotected, R.sup.1, R.sup.2 and R.sup.3 each independently represent an aliphatic hydrocarbon group which may have a substituent(s), a total number of the carbon atoms in the R.sup.1R.sup.2R.sup.3Si group is 10 or more, and the R.sup.1R.sup.2R.sup.3SiOC(O) group is bonded to the N-terminal in Y, and (2) a step of removing the protective group at the C-terminal of the peptide obtained in step (1).

Compositions and methods for optically-verified, sequence-controlled polymer synthesis are described.

A method for preparing a cyclic peptide, derivative or analogue thereof is described. The method comprises contacting a peptide, derivative or analogue thereof with a fluoro-heteroaromatic compound to cyclise the peptide, derivative or analogue thereof.

Compositions and methods for optically-verified, sequence-controlled polymer synthesis are described.