Disclosed herein is an improved process for preparing abaloparatide. The process generally utilizes solid phase peptide synthesis employing an Fmoc-protection scheme. Incorporating a systematic recoupling step of a glutamine residue (Gln.sup.16) has been found to minimize the formation of an undesirable des-Gln.sup.16 abaloparatide impurity, which is often obtained in significant quantities in the conventional process.

A bis-alkoxyl amide alkyl cationic peptide lipid has a chemical structure as below:

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wherein the bis-alkoxyl amide alkyl cationic peptide lipid is dispersed in water to obtain the cationic peptide liposome which are high in stability and uniform in dispersion and have about 120 nm of average grain diameter and Zeta electric potential between 30 and 50 mV. The liposome can effectively compress the plasmids DNA and siRNA, can efficient transfection both in-vitro and in-vivo, and almost does not have toxicity to cells and mice, so that the liposome can be widely applied in gene delivery as a gene vector.

The present invention aims to provide a compound superior in broad utility and stability, which is useful as a protecting reagent (anchor) of amino acid and/or peptide in liquid phase synthesis and the like of a peptide having a C-terminal etc., which are of a carboxamide (CONHR)-type, an organic synthesis reaction method (particularly peptide liquid phase synthesis method) using the compound, and a kit for peptide liquid phase synthesis containing the compound, and has found that the object can be achieved by a particular compound having a diphenylmethane skeleton.

Novel synthesized amino acids of glutamine and lysine that are directly PEGylated with small, monodisperse PEGs, and a novel process for creating novel amino acid monomers using PEGylation. These amino acids are readily incorporated into peptides for a range of different applications.

The present invention provides a particular branched chain-containing aromatic compound. The branched chain-containing aromatic compound of the present invention is easily-soluble in isopropyl acetate superior in liquid-separation operability, and can be used for a production method of peptide and the like, which provides a final product simply by extraction separation, without crystallization and isolation of each intermediate in each step.

Provided are a method for producing a peptide compound including a step of using an aromatic heterocyclic compound represented by Formula (1); a protective group-forming reagent including the compound; and the compound. In Formula (1), a ring A represents an aromatic heterocyclic ring, Y.sup.A's each independently represent OH, NHR, SH, or X.sup.0, where X.sup.0 represents Cl, Br, or I, R.sup.A and R.sup.C each independently represent an aliphatic hydrocarbon group or an organic group having an aliphatic hydrocarbon group, R.sup.Bs' each independently represent a monovalent aliphatic hydrocarbon group, a (1+c)-valent aromatic group, or a (1+c)-valent heteroaromatic group, where, in a case where both a and c is 0, R.sup.B is a monovalent aliphatic hydrocarbon group, and the number of carbon atoms in at least one aliphatic hydrocarbon group of R.sup.A, R.sup.B, or R.sup.C is 12 or more ##STR00001##