It is intended to provide a novel amino acid organic compound which can be used as a labeling precursor compound for radioactive halogen-labeled amino acid compounds including [.sup.18F]FACBC, and which prevents methanol from remaining in the radioactive halogen-labeled amino acid compounds produced therefrom. The novel amino acid organic compound is a compound represented by the following formula:

##STR00001##

wherein n is an integer of 0 or of 1 to 4; R.sup.1 is an ethyl, 1-propyl or isopropyl substituent; X is a halogen substituent or a group represented by —OR.sup.2; R.sup.2 is a straight-chain or branched-chain haloalkylsulfonic acid substituent with one to 10 carbon atoms, trialkylstannyl substituent with 3 to 12 carbon atoms, fluorosulfonic acid substituent or aromatic sulfonic acid substituent; and R.sup.3 is a protective group.

It is intended to provide a novel amino acid organic compound which can be used as a labeling precursor compound for radioactive halogen-labeled amino acid compounds including [.sup.18F]FACBC, and which prevents methanol from remaining in the radioactive halogen-labeled amino acid compounds produced therefrom. The novel amino acid organic compound is a compound represented by the following formula:

##STR00001##

wherein n is an integer of 0 or of 1 to 4; R.sup.1 is an ethyl, 1-propyl or isopropyl substituent; X is a halogen substituent or a group represented by —OR.sup.2; R.sup.2 is a straight-chain or branched-chain haloalkylsulfonic acid substituent with one to 10 carbon atoms, trialkylstannyl substituent with 3 to 12 carbon atoms, fluorosulfonic acid substituent or aromatic sulfonic acid substituent; and R.sup.3 is a protective group.

A compound represented by formula (A) exhibits excellent balance between acid generation sensitivity and capability of providing a composition with reduced discoloration.

##STR00001##

In formula (A), R.sup.1, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, and n are as defined in the description. R.sup.1 is preferably an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms or an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms.

A compound represented by formula (A) exhibits excellent balance between acid generation sensitivity and capability of providing a composition with reduced discoloration.

##STR00001##

In formula (A), R.sup.1, R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, and n are as defined in the description. R.sup.1 is preferably an optionally substituted aliphatic hydrocarbon group having 1 to 20 carbon atoms or an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms.

The invention relates to a process for producing compounds containing at least one arylamino group by means of a palladium-catalysed coupling reaction of an arylamino compound with an aryl compound, using LiOtBu as a base.

The invention relates to a process for producing compounds containing at least one arylamino group by means of a palladium-catalysed coupling reaction of an arylamino compound with an aryl compound, using LiOtBu as a base.

A PEG linker as represented by formula (I), wherein n and m are respectively an integer from 1 to 7, providing the PEG linker with 1 to 49 linking sites. A ligand drug conjugate as represented by formula (II). The conjugate uses the PEG linker to increase a drug loading capacity and drug loading diversity, thereby improving pharmaceutical efficacy.
Y1-PEG1-{R.sup.1-PEG2-{Y4}.sub.n}.sub.m  (I)
TM-{R.sup.2-PEG1-{R.sup.1-PEG2-{R.sup.3-A′-drug}.sub.n}.sub.m}.sub.l  (II)

A PEG linker as represented by formula (I), wherein n and m are respectively an integer from 1 to 7, providing the PEG linker with 1 to 49 linking sites. A ligand drug conjugate as represented by formula (II). The conjugate uses the PEG linker to increase a drug loading capacity and drug loading diversity, thereby improving pharmaceutical efficacy.
Y1-PEG1-{R.sup.1-PEG2-{Y4}.sub.n}.sub.m  (I)
TM-{R.sup.2-PEG1-{R.sup.1-PEG2-{R.sup.3-A′-drug}.sub.n}.sub.m}.sub.l  (II)

The present invention generally relates to novel synthetic methods, systems, kits, salts, and precursors useful in medical imaging. In some embodiments, the present invention provides compositions comprising an imaging agent precursor, which may be formed using the synthetic methods described herein. An imaging agent may be converted to an imaging agent using the methods described herein. In some cases, the imaging agent is enriched in .sup.18F. In some cases, an imaging agent including salt forms (e.g., ascorbate salt) may be used to image an area of interest in a subject, including, but not limited to, the heart, cardiovascular system, cardiac vessels, brain, and other organs.

The present invention generally relates to novel synthetic methods, systems, kits, salts, and precursors useful in medical imaging. In some embodiments, the present invention provides compositions comprising an imaging agent precursor, which may be formed using the synthetic methods described herein. An imaging agent may be converted to an imaging agent using the methods described herein. In some cases, the imaging agent is enriched in .sup.18F. In some cases, an imaging agent including salt forms (e.g., ascorbate salt) may be used to image an area of interest in a subject, including, but not limited to, the heart, cardiovascular system, cardiac vessels, brain, and other organs.