Patent ID: 7910556

Claim:
A compound or a salt thereof, comprising: a structure of general formula (1): Ar—CO-AA 1 -AA 2 -AA 3 -AA 4 -NH—X—NR 1 R 2 (1) wherein Ar represents a phenyl group or an aromatic heterocyclic group, the phenyl group or an aromatic heterocyclic group optionally having substituent(s) selected from the group consisting of C 1 -C 8 straight-chain or branched alkyl group, an alkoxy group consisting of C 1 -C 8 straight-chain or branched alkyl group, and halogen atom(s); wherein AA 1 represents a hydrophobic amino acid selected from the group consisting of β-cyclohexylalanine, phenylalanine, isoleucine, luecine, and valine; wherein AA 2 represents an amino acid selected from the group consisting of glycine, α-fluoroglycine, and α,α-difluoroglycine; wherein AA 3 represents an amino acid selected from the group consisting of glycine, α-fluoroglycine, and α,α-difluoroglycine; wherein AA 4 represents a hydrophobic amino acid selected from the group consisting of β-cyclohexylalanine, phenylalanine, isoleucine, luecine, and valine; wherein X represents a straight-chain group represented by the following formula: —(CH 2 ) n — wherein n represents integer number 2 to 6; and wherein —NR 1 R 2 group is selected from the group consisting of a dimethylamino group, diethylamino group, di-n-propylamino group, diisopropylamino group, ethylmethylamino group, N-methyl-N-n-propylamino group, N-methyl-N-isopropylamino group, N-ethyl-N-n-isopropylamino group, N-ethyl-N-isopropylamino group, N-n-propyl-N-isopropylamino group, 1-pyroridinyl group, and 1-piperidinyl group.