A method for preparing Lixisenatide. According to a peptide sequence structure of Lixisenatide peptide, specially protected serine dipeptide is used as a raw material and coupled into a peptide sequence. Because of a ring-shaped structure similar to that of proline is formed, the rotation of a peptide bond can be effectively prevented, the contraction of a peptide chain curling agent is suppressed, so that active functional groups are fully exposed, thereby facilitating the coupling of the amino acid, and reducing the occurrence of defects and other side effects.

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

The present disclosure provides a method of solid-phase peptide synthesis from the N terminus to C terminus without detectable epimerization of the C-terminal amino acid.

To develop a protecting group that facilitates separation and purification, after reaction, of a compound including a protected functional group, without solidifying or insolubilizing the compound. A xanthene compound of by General Formula (1) ##STR00001## (wherein Y is OR.sup.17 (R.sup.17 is a hydrogen atom or an active ester-protecting group), NHR.sup.18 (R.sup.18 is a hydrogen atom, or a linear or branched C.sub.1-C.sub.6 alkyl group or aralkyl group), an azide, a halogen atom, or a carbonyl group formed together with a methylene group; at least one of R.sup.1 to R.sup.8 is represented by Formula (2);
OR.sup.9X-A(2) and a residue is a hydrogen atom, a halogen atom, a C.sub.1-C.sub.4 alkyl group, or a C.sub.1-C.sub.4 alkoxy group, wherein R.sup.9 is a linear or branched C.sub.1-C.sub.16 alkylene group; X is O or CONR.sup.19 (R.sup.19 is a hydrogen atom or a C.sub.1-C.sub.4 alkyl group); and A is represented by Formula (3) or the like ##STR00002## (wherein R.sup.10, R.sup.11, and R.sup.12, the same or different, are a linear or branched C.sub.1-C.sub.6 alkyl group or an aryl group optionally including a substituent; R.sup.13 is a single bond or a linear or branched C.sub.1-C.sub.3 alkylene group; and R.sup.14, R.sup.15, and R.sup.16 are a linear or branched C.sub.1-C.sub.3 alkylene group)).

Disclosed is a system and method for Fmoc/tBu solution-phase peptide synthesis including the development of a new benzyl-type GAP protecting group, and related uses thereto. This novel GAP protecting group is utilized in place of a polymer support, facilitating C to N Fmoc peptide synthesis without chromatography, recrystallization, or polymer supports. The GAP group can be added and removed in high yield.

The present invention relates to a method for the synthesis of a polypeptide comprising a pre-determined amino acid sequence. The method according to the invention comprises coupling cycles of coupling an N-terminally protected amino acid building block C-terminally at an unprotected N-terminal amino group of an amino acid chain, wherein at least one coupling cycle comprises a coupling step (a), a capping step (b), and a de-protecting step (c).

To develop a protecting group that facilitates separation and purification, after reaction, of a compound including a protected functional group, without solidifying or insolubilizing the compound.

A xanthene compound of by General Formula (1)

##STR00001## (wherein Y is OR.sup.17 (R.sup.17 is a hydrogen atom or an active ester-protecting group), NHR.sup.18 (R.sup.18 is a hydrogen atom, or a linear or branched C.sub.1-C.sub.6 alkyl group or aralkyl group), an azide, a halogen atom, or a carbonyl group formed together with a methylene group; at least one of R.sup.1 to R.sup.8 is represented by Formula (2);

OR.sup.9X-A(2) and a residue is a hydrogen atom, a halogen atom, a C.sub.1-C.sub.4 alkyl group, or a C.sub.1-C.sub.4 alkoxy group, wherein R.sup.9 is a linear or branched C.sub.1-C.sub.16 alkylene group; X is O or CONR.sup.19 (R.sup.19 is a hydrogen atom or a C.sub.1-C.sub.4 alkyl group); and A is represented by Formula (3) or the like

##STR00002## (wherein R.sup.10, R.sup.11, and R.sup.12, the same or different, are a linear or branched C.sub.1-C.sub.6 alkyl group or an aryl group optionally including a substituent; R.sup.13 is a single bond or a linear or branched C.sub.1-C.sub.3 alkylene group; and R.sup.14, R.sup.15, and R.sup.16 are a linear or branched C.sub.1-C.sub.3 alkylene group)).

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

Processes for performing peptide synthesis, particularly for cyclic peptide synthesis are generally described. Reaction intermediates of the peptide synthesis are also described.

The present invention provides a phenylpropanamide derivative as represented by formula (I), a manufacturing method of the derivative, application of the derivative as a -opioid receptor (KOR) agonist, and application of the derivative for manufacturing a pharmaceutical product for treating and/or preventing pain or a pain-related disease.

##STR00001##