Cyanine compound and use thereof

Abstract

[Problem] To provide a compound having the potential of being a candidate for a new photo-oxygenation catalyst different from conventionally proposed photo-oxygenation catalysts. [Solution] The above problem can be solved by a compound represented by chemical formula 1 or a salt thereof. The symbols in chemical formula 1 are as defined in the description.

Description

Cyanine compounds and their uses

[0001] The present invention relates to a cyanine compound and uses thereof in photooxygenation catalysts, pharmaceutical compositions, and the like.

[0002] Muscular dystrophies are genetic diseases characterized by the degeneration and necrosis of skeletal muscle, leading to progressive muscle weakness. Muscle strength development requires a mechanism for transmitting tension generated in intracellular myofibrils to the extracellular basement membrane via multiple proteins. Malfunctions in the genes encoding the proteins involved in this process are the cause of muscular dystrophy. For example, in the most severe form of Duchenne muscular dystrophy, mutations in the dystrophin gene are believed to be the primary cause, resulting in the loss or dysfunction of this protein. Therefore, as a means of combating the degeneration and necrosis of skeletal muscle in muscular dystrophies, the development of treatments that increase muscle mass by inhibiting the function of myostatin (growth differentiation factor-8, GDF-8), a factor that negatively regulates skeletal muscle mass, is considered particularly useful.

[0003] Myostatin is a secreted protein belonging to the TGF-β family that is highly expressed in skeletal muscle. It is synthesized intracellularly as a precursor protein containing an N-terminal prodomain and a C-terminal mature domain. When myostatin is secreted from cells, a propeptide derived from the prodomain, called latency associated protein (LAP), associates with an active dimer derived from the mature domain, inactivating the active dimer, which is the main regulator of skeletal muscle mass. It is believed that myostatin stored in the body in an inactive state is activated when needed by enzyme degradation of the propeptide. The activated myostatin functions as a signaling molecule that negatively regulates skeletal muscle mass through binding to receptors, such as the activin type IIB receptor.

[0004] Therefore, by inhibiting myostatin in vivo using peptides derived from the myostatin propeptide, it is expected that effects such as an increase in skeletal muscle mass and treatment of muscle atrophy disorders such as muscular dystrophy can be expected. For example, Patent Document 1 discloses myostatin inhibitory peptides derived from the myostatin propeptide.

[0005] Furthermore, Patent Document 2 and Non-Patent Document 1 disclose novel myostatin inhibitory peptides as techniques for improving the in vivo stability of the myostatin inhibitory peptide described in Patent Document 1. Furthermore, Patent Document 2 and Non-Patent Document 1 also disclose a technique for conjugating the above-mentioned myostatin inhibitory peptide with a myostatin-selective photooxygenation catalyst having a structure based on the curcumin-derived near-infrared optical probe (CRANAD-2) disclosed in Non-Patent Document 2. The conjugate prepared by this technique is activated by light with a wavelength of 650 to 800 nm and selectively oxygenates myostatin, thereby exhibiting high myostatin inhibitory activity. The photooxygenation catalyst constituting this conjugate has an On / Off switch function, in which it does not exhibit catalytic activity when not bound to myostatin, but exhibits catalytic activity only when bound to its target, myostatin. As described in Non-Patent Document 1, this on / off switch function allows the excited state induced by light irradiation to rapidly relax via intramolecular bond rotation (torsional intramolecular charge transfer; TICT) when the complex is not bound to the target (switch off). Therefore, the photooxygenation catalyst does not exhibit activity. In contrast, when the complex is bound to the target (switch on), the intramolecular bond rotation required for the rapid relaxation is restricted, preventing TICT and allowing relaxation via intersystem crossing (ISC). During this relaxation, excited singlet oxygen is generated from ground-state triplet oxygen, resulting in selective oxygenation of the target molecule.

[0006] International Publication No. 2018 / 030432 International Publication No. 2022 / 009698

[0007] Okamoto et al., Chem. Commun., 2019, 55, 9018Ran et al., J. Am. Chem. Soc., 2009, 131, 15257

[0008] An object of the present invention is to provide compounds that are potential candidates for novel photooxygenation catalysts that differ from the photooxygenation catalysts that have been proposed so far.

[0009] The present inventors have conducted extensive research to solve the above problems, and in the process have surprisingly found that compounds having a specific chemical structure can be candidates for novel photooxygenation catalysts, which has led to the completion of the present invention.

[0010] That is, the above-mentioned object of the present invention can be achieved by the following subject matter: (1) A compound represented by the following chemical formula 1 or a salt thereof:

[0011]

[0012] [In chemical formula 1, R １ and R ２ each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group; R ３ and R ４ each independently represents a hydrogen atom, a halogen atom, an alkoxy group, or a substituted or unsubstituted alkyl group, and R １ and R ３ or R ２ and R ４ may be taken together to form a substituted or unsubstituted alkylene or alkenylene group, R ５ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted monovalent aliphatic hydrocarbon ring group, a substituted or unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic hydrocarbon ring group, or a substituted or unsubstituted monovalent aromatic heterocyclic group; X represents a bromine atom, an iodine atom, or a selenium atom; Y － represents a counter anion, and n is an integer of 1 to 3. (2) The compound or salt thereof according to (1), wherein n is 1; (3) R ５(4) the compound according to (1) or (2), or a salt thereof, wherein R represents a substituted or unsubstituted monovalent aliphatic hydrocarbon ring group, a substituted or unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic hydrocarbon ring group, or a substituted or unsubstituted monovalent aromatic heterocyclic group; ５ (5) The compound according to (3) or a salt thereof, wherein R represents a substituted or unsubstituted monovalent aromatic heterocyclic group; １ and R ３ and R ２ and R ４ (6) a compound according to any one of (1) to (4) or a salt thereof, wherein R ５represents a substituted alkyl group, a substituted monovalent aliphatic hydrocarbon ring group, a substituted monovalent aliphatic heterocyclic group, a substituted monovalent aromatic hydrocarbon ring group, or a substituted monovalent aromatic heterocyclic group, and the substituent substituting the alkyl group, the monovalent aliphatic hydrocarbon ring group, the monovalent aliphatic heterocyclic group, the monovalent aromatic hydrocarbon ring group, or the monovalent aromatic heterocyclic group is an -L-Z group, in which L represents a linker having a chemically stable structure, and Z represents a ligand that specifically binds to a target molecule, or a group G containing at its terminal a group capable of covalently bonding to a specific functional group of a ligand that specifically binds to a target molecule; (7) the compound or salt thereof according to (6), in which Z represents a ligand that specifically binds to a target molecule, and the target molecule that the ligand Z specifically binds to is myostatin or coronavirus 3CL protease; (8) The compound or salt thereof according to (6), wherein Z is a group G containing at its terminal a group capable of covalently bonding to a specific functional group of a ligand that specifically binds to a target molecule, and the group G contains one or more groups selected from the group consisting of an azomethine ylide group, a nitrone group, a nitrile ylide group, a diazomethyl group, an azide group, a nitrile oxide group, an alkenyl group, an alkynyl group, a carboxy group, an amino group, an N-hydroxysuccinimide ester group, an imido ester group, a pentafluorophenyl ester group, a maleimide group, a haloalkyl group, a haloacetyl group, a pyridyl disulfide group, a hydrazide group, an alkoxyamine group, a diazirine group, an aryl azide group, and an isocyanate group; (9) The compound or salt thereof according to any one of (6) to (8), wherein L has a structure represented by the following chemical formula 2:

[0013]

[0014] [in Chemical Formula 2, V represents -NH-, -O-, -S-, -C(=O)-NH-, -NH-C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)- or a triazole ring; k, o, and q each independently represent an integer of 0 or 1; l and p each independently represent an integer of 1 to 6; U and W represent -NH-, -O-, -S-, -C(=O)-NH-, -NH-C(=O)-, -C(=O)-O-, -O-C(=O)-, or -C(=O)-; *1 represents a bonding site to the alkyl group, the monovalent aliphatic hydrocarbon ring group, the monovalent aliphatic heterocyclic group, the monovalent aromatic hydrocarbon ring group, or the monovalent aromatic heterocyclic group substituted with an -L-Z group, and *2 represents a bonding site to Z. (10) A photooxygenation catalyst comprising the compound according to any one of (1) to (9) or a salt thereof; (11) An inhibitor of myostatin or coronavirus 3CL protease comprising the photooxygenation catalyst according to (10); (12) A pharmaceutical composition comprising the photooxygenation catalyst according to (10); (13) The pharmaceutical composition according to (12), which is for the prevention and / or treatment of muscle wasting disorders; (14) The pharmaceutical composition for muscle wasting disorders according to (13), wherein the muscle wasting disorder is muscular dystrophy or sarcopenia; (15) The pharmaceutical composition according to (13), wherein the muscle wasting disorder is muscle wasting disorder caused by diabetes or cancer cachexia; (16) A method for the prevention and / or treatment of muscle wasting disorders, which comprises administering an effective amount of the pharmaceutical composition according to (13) to a patient; (17) The method for preventing and / or treating muscle atrophy according to (16), wherein the muscle atrophy is muscular dystrophy or sarcopenia; (18) The method for preventing and / or treating muscle atrophy according to (16), wherein the muscle atrophy is caused by diabetes or cancer cachexia; (19) The photooxygenation catalyst according to (10), for use in inhibiting myostatin; (20) The photooxygenation catalyst according to (10), for use in preventing and / or treating muscle atrophy; (21) The pharmaceutical composition according to (12), which is for preventing and / or treating coronavirus infection; (22) The pharmaceutical composition according to (21), wherein the coronavirus infection is novel coronavirus infection (COVID-19);(23) A method for preventing and / or treating a coronavirus infection, comprising administering to a patient an effective amount of the pharmaceutical composition according to (21); (24) The method for preventing and / or treating a coronavirus infection according to (23), wherein the coronavirus infection is a novel coronavirus infection (COVID-19); (25) The photooxygenation catalyst according to (10), for use in inhibiting coronavirus 3CL protease; (26) The photooxygenation catalyst according to (10), for use in preventing and / or treating a coronavirus infection; (27) A target molecule inhibitor, comprising a photooxygenation catalyst comprising the compound according to (6) or a salt thereof, wherein Z represents a ligand that specifically binds to a target molecule, and the ligand Z specifically binds to the target molecule and inhibits the target molecule under light irradiation; (28) A precursor of a target molecule inhibitor, which comprises a photooxygenation catalyst comprising the compound according to (6) or a salt thereof, wherein Z represents a group G having at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to the target molecule, and the ligand bound to group G specifically binds to the target molecule and inhibits the target molecule under light irradiation; (29) A method for inhibiting a target molecule, comprising: contacting a photooxygenation catalyst comprising the compound according to (6) or a salt thereof, wherein Z represents a ligand that specifically binds to the target molecule, with a target molecule to which the ligand Z specifically binds, thereby causing the ligand Z to specifically bind to the target molecule; and irradiating the photooxygenation catalyst with light to oxygenate and inhibit the target molecule; (30) Reacting a photooxygenation catalyst comprising the compound according to (6) or a salt thereof, wherein Z represents a group G having at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to the target molecule, with the ligand to convert Z into a ligand that specifically binds to the target molecule; A method for inhibiting a target molecule, comprising: contacting the converted photooxygenation catalyst with a target molecule to which a ligand specifically binds, thereby allowing the ligand to specifically bind to the target molecule; and irradiating the photooxygenation catalyst with light to oxygenate and inhibit the target molecule.

[0015] According to the present invention, compounds that can be candidates for novel photooxygenation catalysts different from the photooxygenation catalysts that have been proposed so far can be provided.

[0016] FIG. 1 is a graph showing the results of measuring the absorption spectra of compounds 1 to 4 and conjugates 13 to 17 at room temperature. FIG. 1(a) shows the results for compounds 1 to 4, and FIG. 1(b) shows the results for conjugates 13 to 17. FIG. 2 is a graph showing the results of evaluating the ability to generate singlet oxygen by adding the hemicyanine fluorescent dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DASPI) or compounds 1 to 4 to glycerol / water containing furfuryl alcohol and irradiating the mixture with light at room temperature using a fluorescent lamp (white light) or an LED. FIG. 2(a) shows the results after irradiation with a fluorescent lamp, and FIG. 2(b) shows the results after irradiation with an LED. Figure 3 is a graph showing the results of evaluating the ability of the photooxygenation catalyst to produce radical oxygen species by adding compounds 1 to 4 to glycerol / water containing dihydrorhodamine (DHR) 123, irradiating the mixture with an LED at room temperature, and measuring the fluorescence intensity at any time point. Figure 4 is a graph showing the results of evaluating the photooxygenation activity of the photooxygenation catalyst for methionine by adding compounds 3 and 4 to glycerol / water containing Fmoc-L-methionine, irradiating the mixture with an LED at room temperature, and quantifying Fmoc-L-methionine sulfoxide by HPLC at any time point. Figure 5 is a graph showing the results of evaluating the stability of the photooxygenation catalyst by dissolving compound 8 in water / methanol, irradiating the mixture with an LED at room temperature for 1.5 hours, or shaking the mixture in the dark at 37°C for 24 hours, and then quantifying compound 8 by HPLC. FIG. 6 shows graphs and a table showing the results for peptide 16′ and conjugates 16 and 19, in which photooxygenation catalyst conjugates 13 to 17, and 19 or peptides 13′ to 17′ were dissolved in phosphate buffer containing 20% ​​2,2,2-trifluoroethanol, and the proportions of each secondary structure were calculated from the obtained CD (circular dichroism) spectra using Read's reference.FIG. 7 shows graphs and a table showing the results of calculating the ratio of each secondary structure from the CD (circular dichroism) spectra obtained by dissolving photooxygenation catalyst conjugates 13 to 17, 19 or peptides 13′ to 17′ in phosphate buffer containing 20% ​​2,2,2-trifluoroethanol, using Read's reference, for peptides and conjugates other than peptide 16′ and conjugates 16 and 19. Figure 8 shows a graph illustrating the results of evaluating the photooxygenation activity of myostatin by the photooxygenation catalyst conjugates. To a phosphate buffer solution containing myostatin, photooxygenation catalyst conjugates 13-17, 19, or methylene blue was added, followed by 30 minutes of light irradiation using an LED at room temperature. Dithiothreitol was added to the solution, which was then incubated at 37°C for 30 minutes. Lys-C endopeptidase was then added, and the solution was incubated at 37°C for 2.5 hours. The solution was then desalted using a C-18 ZipTip, and analyzed by MALDI-TOF MS. Figure 9(a) shows the results of the experiment shown in Figure 8, comparing the photooxygenation activity of myostatin for photooxygenation catalyst conjugate 13 with and without light irradiation. Figure 9(b) shows the results of the experiment shown in Figure 8, comparing the photooxygenation activity of myostatin for photooxygenation catalyst conjugate 13 with and without degassing. Figure 10(a) is a graph showing the results of the experiment shown in Figure 8, comparing the photooxygenation activity of myostatin at different concentrations of photooxygenation catalyst conjugate 13. Figure 10(b) is a graph showing the results of the experiment shown in Figure 8, comparing the photooxygenation activity of myostatin at different light irradiation times for photooxygenation catalyst conjugate 13. Figure 11 is a graph showing the results of evaluating the myostatin inactivation effect of photooxygenation catalyst conjugates 13-17 and 19 using a luciferase reporter assay. Figure 12(a) is a graph showing the results of comparing the photooxygenation activity of myostatin with and without light irradiation for photooxygenation catalyst conjugate 13 and peptide 12, which does not have photocatalytic activity. Figure 12(b) shows the IC of myostatin inactivation by photooxygenation catalyst conjugate 13. ５０Graphs are used to calculate the cytotoxicity of the photooxygenation catalyst conjugates. Figure 13 shows the results of evaluating the photooxygenation activity of the off-target model by adding conjugates 13-17 and 19 or methylene blue to phosphate buffer containing amyloid β1-42 (Aβ42), neuropeptide Y, or substance P as an off-target model. The conjugates were irradiated with LED light at room temperature for 30 minutes, followed by analysis by MALDI-TOF MS. Figures 13(a) to 13(c) show the results using Aβ42, neuropeptide Y, or substance P as the off-target model, respectively. Figure 14 shows the results of evaluating the cytotoxicity of the photooxygenation catalyst conjugates 13-17 and 19 and methylene blue using the WST-1 reagent. Figure 14(a) shows the results at a concentration of 3 μM, and Figure 14(b) shows the results at a concentration of 9 μM. FIG. 15 shows the on / off switch function of the catalytic site of the conjugate having a photooxygenation catalyst (the photooxygenation ability is expressed only when bound to a target). Fluorophore conjugate 18 (derived from compound 9), which has a structure in which a bromine atom has been removed from the catalytic site of photooxygenation catalyst conjugate 13, was added to phosphate buffer or the same buffer containing myostatin, and after incubation at 37°C for 1 hour, the fluorescence spectrum and fluorescence intensity were measured. The concentration-fluorescence intensity curves obtained showed that K ｄ16(a) is a graph showing the results of calculating the values. Figure 16(a) shows the results of evaluating the photooxygenation activity of myostatin by the photooxygenation catalyst conjugates. To a phosphate buffer solution containing myostatin, photooxygenation conjugates 20 to 24 using myostatin-binding D-peptides or methylene blue were added, and the solution was irradiated with light using an LED at room temperature for 30 minutes. Dithiothreitol was added to the solution, and the solution was incubated at 37°C for 30 minutes. Lys-C endopeptidase was then added, and the solution was incubated at 37°C for 2.5 hours. The solution was then desalted using a C-18 ZipTip, and analyzed by MALDI-TOF MS. Figure 16(b) is a graph showing the results of evaluating the myostatin inactivation effect of photooxygenation conjugates 20 to 24 using myostatin-binding D-peptides by a luciferase-based reporter assay. Figure 17 shows an electrophoresis photograph showing the results of the following: for the purpose of evaluating the nonspecific reaction of the photooxygenation catalyst in muscle homogenate, photooxygenation catalysts 8, 10, or methylene blue were added to a phosphate buffer containing mouse tibialis anterior muscle homogenate, and the solution was irradiated with light using an LED at room temperature for 30 minutes. 6x SDS-sample buffer was added to each solution, and the solution was boiled at 95°C for 5 minutes. 10 μL of the solution was subjected to SDS-PAGE (15% gel) for electrophoresis, and then bands were detected by CBB staining. Figure 18 shows an electrophoresis photograph showing the results of the photooxygenation catalyst conjugates' photooxygenation ability to myostatin. Photooxygenation catalyst conjugates 13, 19, or methylene blue were added to a phosphate buffer solution containing myostatin, and the solution was irradiated with light using an LED at room temperature for 30 minutes. 6x SDS-sample buffer was added to each solution, and the solution was boiled at 95°C for 5 minutes. 10 μL of the solution was subjected to SDS-PAGE (15% gel) for electrophoresis, and bands were then detected by CBB staining.Figure 19 is an electrophoretic photograph showing the results of electrophoresis in which bands were detected by CBB staining after adding photooxygenation catalyst conjugate 13 or 19 to a phosphate buffer solution containing mouse tibialis anterior muscle homogenate and irradiating it with light using an LED at room temperature for 30 minutes, adding 6x SDS-sample buffer to each solution, and boiling it at 95°C for 5 minutes, and subjecting 10 µL of each sample to SDS-PAGE (15% gel) for electrophoresis, in order to evaluate the nonspecific reaction of the photooxygenation catalyst conjugate in muscle homogenate. Figure 20 shows an electrophoresis photograph showing the results of the following: for the purpose of evaluating the photooxygenation ability of the photooxygenation catalyst conjugate for myostatin in a contaminated system such as muscle homogenate, photooxygenation catalyst conjugate 13 was added to a phosphate buffer solution containing mouse tibialis anterior muscle homogenate and myostatin, and the solution was irradiated with light using an LED at room temperature for 30 minutes; 6x SDS-sample buffer was added to each solution, and the solution was boiled at 95°C for 10 minutes; 10 μL of the solution was subjected to SDS-PAGE (15% gel) for electrophoresis, and bands were detected by CBB staining. Figure 21 shows a graph depicting the results of an in vivo evaluation of the photooxygenation catalytic conjugate's photooxygenation ability. The photooxygenation catalytic conjugate 13 dissolved in a 5% glucose aqueous solution was intramuscularly injected into the tibialis anterior muscle of a mouse's right leg, and the 5% glucose aqueous solution alone was intramuscularly injected into the tibialis anterior muscle of the left leg. After that, both legs were irradiated with light from an external LED spot light source, and then again after 3-4 days. This procedure was repeated four times weekly, and the muscles were then collected and weighed to determine the percentage increase in weight due to the administration of the conjugate and light irradiation. Figure 22 shows a graph depicting the results of an evaluation of the photooxygenation catalytic conjugate's photooxygenation ability and inactivation ability of the photooxygenation catalytic conjugate against coronavirus 3CL protease. Figure 22(a) is a graph showing the results of measuring the proportion of oxygenated 3CL protease using MALDI-TOF MS after adding photooxygenation catalyst conjugates 25, 26, or methylene blue to Tris buffer containing SARS-CoV-2 3CL protease and irradiating the mixture with an LED for 30 minutes under ice cooling, adding Lys-C endopeptidase, and incubating the mixture at 37°C for 2.5 hours, followed by desalting using a C-4 ZipTip.Figure 22(b) is a graph showing the results of calculating the reaction rate ratio of the treated enzyme to the control enzyme, obtained by adding photooxygenation catalyst conjugate 25 to a Tris buffer solution containing SARS-CoV-2 3CL protease, irradiating the solution with light using an LED under ice cooling for 30 minutes, adding the diluted solution to a solution containing a fluorescent substrate of 3CL protease, measuring the fluorescence intensity, and calculating the reaction rate ratio of the treated enzyme to the control enzyme.

[0017] Hereinafter, an embodiment of the present invention will be described.

[0018] One aspect of the present invention is a compound represented by the following chemical formula 1 or a salt thereof:

[0019]

[0020] In Chemical Formula 1, R １ and R ２ each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group. In this specification, examples of the "alkyl group" include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a 1,2-dimethylpropyl group, an n-hexyl group, a 1,3-dimethylbutyl group, a 1-isopropylpropyl group, a 1,2-dimethylbutyl group, an n-heptyl group, a 1,4-dimethylpentyl group, a 2-methyl-1-isopropylpropyl group, a 1-ethyl-3-methylbutyl group, an n-octyl group, a 2-ethylhexyl group, a 3-methyl-1-isopropylbutyl group, a 2-methyl-1-isopropyl group, a 1-tert-butyl-2-methylpropyl group, an n-nonyl group, and a 3,5,5-trimethylhexyl group. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 4 carbon atoms.

[0021] Furthermore, in this specification, when a certain group is referred to as being "substituted," examples of substituents that can substitute the group include halogen atoms such as fluorine, chlorine, bromine, and iodine, alkyl groups, aryl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyloxy groups, acyl groups, alkylsulfanyl groups, arylsulfanyl groups, alkylamino groups, dialkylamino groups, arylamino groups, hydroxy groups, carboxy groups, formyl groups, mercapto groups, sulfo groups, sulfinic acid groups, guanidino groups, carbamoyl groups, thiol groups, thioether groups, mesyl groups, p-toluenesulfonyl groups, amino groups, nitro groups, cyano groups, trifluoromethyl groups, trichloromethyl groups, trimethylsilyl groups, phosphinico groups, and phosphono groups. These substituents may also be further substituted with halogen atoms, alkyl groups, aryl groups, alkoxy groups, hydroxy groups, carboxy groups, amino groups, nitro groups, cyano groups, and the like. However, substitutions in which the substituted group is within the same definition as the unsubstituted group are not considered. In addition, as will be described in detail later, R ５ is a given group, and when the group is said to be "substituted", the substituents that may replace the group may be -LZ groups.

[0022] In Chemical Formula 1, R ３ and R ４ each independently represents a hydrogen atom, a halogen atom, an alkoxy group, or a substituted or unsubstituted alkyl group. In this specification, examples of a "halogen atom" include a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom. In addition, in this specification, examples of an "alkoxy group" include a group having the above-mentioned alkyl group -O- structure. The number of carbon atoms in the alkoxy group is preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 4.

[0023] In a preferred embodiment, R １ and R ３ and / or R ２ and R ４together form a substituted or unsubstituted alkylene or alkenylene group. In this case, the alkylene or alkenylene group preferably has 2 or 3 carbon atoms. In other words, R １ and R ３ and / or R ２ and R ４ are preferably taken together to form a 5- or 6-membered ring. Examples of the "alkylene group" include a divalent group in which two hydrogen atoms of the alkyl group described above are substituted with two bonds, such as an ethylene group and a trimethylene group. Examples of the "alkenylene group" include a group in which two hydrogen atoms on adjacent carbon atoms of the alkylene group described above having two or more carbon atoms are eliminated to form a double bond, such as a vinylene group and a propenylene group. In this embodiment, particularly, as in Compound 4 and Conjugate 13 described below, R １ ~R ４ preferably taken together form a 9-julolidine ring.

[0024] In Chemical Formula 1, R ５ may represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted monovalent aliphatic hydrocarbon ring group, a substituted or unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic hydrocarbon ring group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. ５preferably represents a substituted or unsubstituted monovalent aliphatic hydrocarbon ring group, a substituted or unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic hydrocarbon ring group, or a substituted or unsubstituted monovalent aromatic heterocyclic group. In this specification, the "monovalent aliphatic hydrocarbon ring group" is preferably a group having 3 to 30 (more preferably 3 to 8, even more preferably 4 to 7, and particularly preferably 5 to 6) carbon atoms forming the ring, more preferably a monovalent group derived from cyclopropane, cyclobutane, cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, adamantane, or norbornane, and preferably a group derived from cyclopentane or cyclohexane. In this specification, the "monovalent aliphatic heterocyclic group" is preferably a group having 5 to 30 (more preferably 5 to 8, even more preferably 5 to 7, and particularly preferably 5 to 6) carbon atoms forming the ring, more preferably a group derived from pyrrolidine or piperidine. In the present specification, the "monovalent aromatic hydrocarbon ring group" is preferably a group having 5 to 30 (more preferably 5 to 8, even more preferably 5 to 7, and particularly preferably 5 to 6) carbon atoms forming the ring, more preferably a group derived from an aryl group. In the present specification, examples of the "aryl group" include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthracenyl group, a 2-anthracenyl group, and a 9-anthracenyl group. In the present specification, the "monovalent aromatic heterocyclic group" is preferably a group having 5 to 30 (more preferably 5 to 8, even more preferably 5 to 7, and particularly preferably 5 to 6) carbon atoms forming the ring, more preferably a group derived from a heteroaryl group. In this specification, examples of the "heteroaryl group" include a 2-thienyl group, a 4-pyridyl group, a 3-pyridyl group, a 2-pyridyl group, a 1-pyridyl group, a 2-furyl group, a 2-pyrimidinyl group, a 2-benzothiazolyl group, a 1-imidazolyl group, a 1-pyrazolyl group, a benzotriazol-1-yl group, and a 7-azabenzotriazol-1-yl group.

[0025] Among the above options, R ５represents a substituted or unsubstituted monovalent aromatic heterocyclic group, more preferably a group derived from a 2-thienyl group, a 4-pyridyl group, a 3-pyridyl group, a 2-pyridyl group, a 1-pyridyl group, a 2-furyl group, or a 2-pyrimidinyl group, still more preferably a group derived from a 4-pyridyl group, a 3-pyridyl group, a 2-pyridyl group, a 1-pyridyl group, a 2-furyl group, or a 2-pyrimidinyl group, particularly preferably a group derived from a 4-pyridyl group, a 3-pyridyl group, a 2-pyridyl group, a 1-pyridyl group, or a 2-pyrimidinyl group, and most preferably a group derived from a 2-pyrimidinyl group.

[0026] In another preferred embodiment, R ５represents a substituted alkyl group, a substituted monovalent aliphatic hydrocarbon ring group, a substituted monovalent aliphatic heterocyclic group, a substituted monovalent aromatic hydrocarbon ring group, or a substituted monovalent aromatic heterocyclic group, the substituent substituting the alkyl group, the monovalent aliphatic hydrocarbon ring group, the monovalent aliphatic heterocyclic group, the monovalent aromatic hydrocarbon ring group, or the monovalent aromatic heterocyclic group is an -L-Z group. Here, L represents a linker having a chemically stable structure, and Z represents a ligand that specifically binds to a target molecule, or a group G containing at its terminal a group capable of covalently bonding to a specific functional group of a ligand that specifically binds to a target molecule. The specific structure of the linker having a chemically stable structure represented by L is not particularly limited, as long as it is not subject to chemical or biochemical cleavage in an environment where the compound of Chemical Formula 1 is present. The specific structure of such a linker is not particularly limited, and examples thereof include a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynylene group having 2 to 20 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted cycloalkenylene group having 3 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroarylene group having 3 to 20 carbon atoms, -NH-, -O-, -S-, -C(=O)-NH-, -NH-C(=O)-, -O-, -C(=O)-O-, -O-C(=O)-, -S-, -C(=O)-, a polyoxyalkylene group, an amino acid residue, a peptide chain, polyethylene glycol, and combinations thereof.

[0027] In one preferred embodiment, L has a structure represented by the following formula 2:

[0028]

[0029] In Chemical Formula 2, V represents -NH-, -O-, -S-, -C(=O)-NH-, -NH-C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, or a triazole ring. Also, o represents an integer of 0 or 1. Examples of the triazole ring include a 1,2,3-triazole-1,4-diyl group and a 1,2,4-triazole-1,3-diyl group. 1 and p each independently represent an integer of 1 to 6. 1 preferably represents an integer of 1 to 5, more preferably an integer of 1 to 4. p preferably represents an integer of 1 to 5, more preferably an integer of 1 to 4. U and W represent -NH-, -O-, -S-, -C(=O)-NH-, -NH-C(=O)-, -C(=O)-O-, -O-C(=O)- or -C(=O)-. Furthermore, k and q each independently represent an integer of 0 or 1.

[0030] In Chemical Formula 2, *1 represents the bonding site to the alkyl group, the monovalent aliphatic hydrocarbon ring group, the monovalent aliphatic heterocyclic group, the monovalent aromatic hydrocarbon ring group, or the monovalent aromatic heterocyclic group substituted with an -L-Z group. Furthermore, *2 represents the bonding site to Z. The bonding site (*2) of the linker L to Z, which represents a ligand or group G described below, is not particularly limited. For example, when Z is a peptide ligand, the bonding site (*2) of the linker L to the peptide may be the N-terminus or C-terminus of the peptide, or may be a side chain of an amino acid residue constituting the peptide ligand Z, as long as the effects of the present invention are achieved. In a preferred embodiment when Z is a peptide ligand, the linker L is bonded to the N-terminus of the peptide ligand Z. Furthermore, the bonding site (*1) when the linker L is bonded to the above-mentioned group is not particularly limited. R ５ represents a substituted alkyl group, a substituted monovalent aliphatic hydrocarbon ring group, a substituted monovalent aliphatic heterocyclic group, a substituted monovalent aromatic hydrocarbon ring group, or a substituted monovalent aromatic heterocyclic group, the binding site of the linker L may be a carbon atom or a heteroatom (preferably a nitrogen atom) constituting these groups, but is preferably bound to a carbon atom. ５When is a group derived from a 2-pyrimidinyl group, it is preferably bonded to the 5-position of the 2-pyrimidinyl group.

[0031] As mentioned above, R ５ Z in the formula (I) may represent a ligand that specifically binds to a target molecule. The specific structure of this ligand is not particularly limited, as long as it has the function of targeting the compound represented by Chemical Formula 1 to a site where a specific target molecule is present. Examples of the ligand include peptides, proteins, antibodies, small molecule drugs, and biopolymer monomers. Furthermore, the target molecule to which the ligand specifically binds is preferably myostatin or coronavirus 3CL protease. More preferably, the ligand that specifically binds to myostatin is a myostatin inhibitor that disrupts myostatin function by binding to myostatin. Examples of substances that can be used as such ligands include myostatin inhibitory peptides. Suitable examples of myostatin inhibitory peptides include the myostatin inhibitory peptide derived from the myostatin propeptide disclosed in Patent Document 1 (WO 2018 / 030432) and the myostatin inhibitory peptide composed entirely of D-amino acids disclosed in Patent Document 2 (WO 2022 / 009698). Myostatin inhibitory peptides other than these can also be used as ligands of the present invention. Furthermore, it is more preferable that the ligand that specifically binds to coronavirus 3CL protease is a 3CL protease inhibitor that disables the function of 3CL protease by binding to the 3CL protease. Suitable examples of such substances include SH-5 (see S. Konno et al., Bioorg. Med. Chem., 2013, 21, 412-424) and YH-53 (see S. Konno et al., Eur. J. Med. Chem., 2013, 68, 372-384). 3CL protease inhibitors other than these can also be used as ligands of the present invention.

[0032] Also, R ５Z in the formula (I) may represent a group G containing at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to a target molecule (see compound 8 in the Examples below). In this case, the ligand and the compound or salt thereof according to the present embodiment can be conjugated by covalently bonding the group G possessed by the compound or salt thereof according to the present embodiment to the specific functional group possessed by the ligand that specifically binds to a target molecule. In this case, the ligand may be any of the various ligands described above.

[0033] R ５Examples of the "group G containing at its terminal a group capable of covalently bonding with a specific functional group possessed by a ligand that specifically binds to a target molecule" as Z in the formula (1) include functional groups capable of undergoing 1,3-dipole cycloaddition reactions using click chemistry and general crosslinking reactive groups for protein binding. A "1,3-dipole" refers to a 4π-electron chemical species consisting of three atoms that undergoes a cycloaddition reaction with a dipolarophilic compound, such as an alkenyl group or an alkynyl group, to form a five-membered heterocyclic compound. Therefore, when R has a "1,3-dipole," the specific functional group possessed by the ligand also has a "dipoleophile," and conversely, when R has a "dipoleophile," the specific functional group possessed by the ligand can have a "1,3-dipole." Here, examples of "1,3-dipoles" applicable to Z include an azomethine ylide group, a nitrone group, a nitrile ylide group, a diazomethyl group, an azide group, and a nitrile oxide group. Examples of "dipolephiles" applicable to Z include an alkenyl group and an alkynyl group. For example, when Z is a group containing a nitrone group at its terminal, it undergoes a cycloaddition reaction with a compound having an alkenyl group to form an isoxazole ring. When Z is a group containing an azide group at its terminal, it undergoes a cycloaddition reaction with a compound having an alkynyl group to form a triazole ring (Husgen cycloaddition reaction). When Z is a group containing a nitrile oxide group at its terminal, it undergoes a cycloaddition reaction with a compound having an alkenyl group to form an isoxazole ring. In the above example, a case where Z has a "1,3-dipole" and a specific functional group possessed by the ligand has a "dipoleophile" has been exemplified, but a similar reaction can be carried out even when Z has a "dipoleophile" and a specific functional group possessed by the ligand has a "1,3-dipole". Among these, Z is preferably a group containing an alkynyl group or an azido group at its terminal, and more preferably an unsubstituted or substituted linear or branched alkynyl group having 2 to 8 carbon atoms, or an azido group having a linear or branched alkyl group having 1 to 8 carbon atoms. From the viewpoint of maintaining high hydrophilicity, an azido group having a linear or branched alkynyl group having 2 to 3 carbon atoms or a linear alkyl group having 1 to 2 carbon atoms is particularly preferred.

[0034] On the other hand, typical crosslinking reactive groups for protein binding include amide-forming reactive groups using carbodiimides such as carboxyl groups and amino groups; amine-reactive groups such as N-hydroxysuccinimide ester groups, imide ester groups and pentafluorophenyl ester groups; sulfhydryl-reactive groups such as maleimide groups, haloalkyl groups, haloacetyl groups and pyridyl disulfide groups; aldehyde-reactive groups such as hydrazide groups and alkoxyamine groups; photoreactive groups such as diazirine groups and aryl azide groups; and hydroxy-reactive groups such as isocyanate groups. Among these, amine-reactive groups or sulfhydryl-reactive groups are preferred, and N-hydroxysuccinimide ester groups, imide ester groups or maleimide groups and pyridyl disulfide groups are more preferred.

[0035] In Chemical Formula 1, X represents a heavy atom. Specifically, X represents a bromine atom, an iodine atom, or a selenium atom. Among these, X is preferably a bromine atom or an iodine atom, and particularly preferably a bromine atom.

[0036] In Chemical Formula 1, Y －represents a counter anion. There are no particular limitations on the structure of this counter anion, as long as it can electrically neutralize the positive charge (present on the nitrogen atom of the pyridine ring) contained in Chemical Formula 1. Examples of such counter anions include chloride ion, bromide ion, iodide ion, perchlorate ion, nitrate ion, benzenesulfonate ion, p-toluenesulfonate ion, methyl sulfate ion, ethyl sulfate ion, propyl sulfate ion, tetrafluoroborate ion, tetraphenylborate ion, tetrakis(pentafluorophenyl)borate ion, bis(trifluoromethanesulfone)imide ion, bis(pentafluoroethanesulfone)imide ion, pentafluoroethanesulfonetrifluoromethanesulfonimide ion, trifluoromethanesulfoneheptafluoropropanesulfonimide ion, nonafluorobutanesulfonetrifluoromethanesulfonimide ion, 1,3 -disulfonylhexafluoropropylene imide ion, hexafluorophosphate ion, benzenesulfinate ion, acetate ion, trifluoroacetate ion, propionate ion, benzoate ion, oxalate ion, succinate ion, malonate ion, oleate ion, stearate ion, citrate ion, monohydrogen diphosphate ion, dihydrogen monophosphate ion, pentachlorostannate ion, chlorosulfonate ion, fluorosulfonate ion, trifluoromethanesulfonate ion, hexafluoroarsenate ion, hexafluoroantimonate ion, molybdate ion, tungstate ion, titanate ion, zirconate ion, sulfate ion, vanadate ion, and borate ion.

[0037] In Chemical Formula 1, n represents the number of trans-vinylene groups contained in the main skeleton of Chemical Formula 1, and is an integer of 1 to 3. In particular, n is preferably 1 or 2, and particularly preferably 1.

[0038] There is no particular limitation on the method for producing the compound of Chemical Formula 1 or a salt thereof, and a person skilled in the art can produce the compound according to the present invention or a salt thereof by taking into consideration the examples described below and the common general technical knowledge at the time of filing of this application.

[0039] (Uses of the Compound of the Present Invention) The present inventors have surprisingly discovered that the compound of the present invention (or a salt thereof) described above functions as a photooxygenation catalyst. Furthermore, by binding the compound of the present invention to a ligand (e.g., a myostatin inhibitory peptide) to form a conjugate, an excellent effect of irreversibly inactivating the function of myostatin is achieved. As used herein, "conjugate" refers to a compound or a salt thereof (complex) in which the compound of the present invention (or a salt thereof) described above is bound to a ligand Z via a linker L. In view of the above, according to another aspect of the present invention, a photooxygenation catalyst comprising a compound represented by Chemical Formula 1 or a salt thereof, and a myostatin inhibitor comprising said photooxygenation catalyst are also provided. The photooxygenation catalyst provided by this aspect comprises a compound having R １ ~R ５ By changing the structure of ｍａｘ ) can be controlled. In particular, R １ and R ３ and / or R ２ and R ４ together form a substituted or unsubstituted alkylene or alkenylene group, or R ５ is a substituent other than a hydrogen atom or an alkyl group, the maximum absorption wavelength (λ ｍａｘ) is red-shifted, making it more susceptible to absorbing near-infrared light. When the photooxygenation catalyst provided by this embodiment is in the form of a conjugate, it has an On / Off switch function, which means that it does not exhibit catalytic activity when not bound to a target molecule, but exhibits catalytic activity only when bound to a target molecule. Due to this On / Off switch function, when the conjugate is not bound to a target molecule (switch Off), the excited state caused by light irradiation is rapidly relaxed by intramolecular bond rotation (torsion intramolecular charge transfer; TICT), and the photooxygenation catalyst constituting the conjugate does not exhibit activity. In contrast, when the conjugate is bound to a target molecule (switch On), the rotation of the intramolecular bond required for the rapid relaxation is restricted, so TICT does not occur, and relaxation occurs via intersystem crossing (ISC). During this relaxation, excited singlet oxygen is generated from ground-state triplet oxygen, thereby selectively oxygenating the target molecule.

[0040] The photooxygenation catalyst provided by this embodiment exhibits superior singlet oxygen production under white light irradiation compared to the hemicyanine fluorescent dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DASPI), and can exhibit photooxygenation catalytic activity by appropriately selecting the wavelength of light used. Furthermore, the photooxygenation catalyst provided by this embodiment exhibits high water solubility and remains stable without decomposition even when exposed to prolonged light irradiation or prolonged exposure to the in vivo environment. Furthermore, the photooxygenation catalyst provided by this embodiment has the advantage of low nonspecific adsorption, and when conjugated with a ligand via a linker, the resulting conjugate maintains its pre-conjugation secondary structure. Because the higher-order structure of the ligand peptide contributes to its affinity for the target, the photooxygenation catalyst according to this embodiment is preferred because it does not affect the secondary structure of the peptide moiety and therefore does not impair the target affinity of the conjugate.

[0041] By administering an effective amount of the above-mentioned myostatin inhibitor to a subject, effects such as maintaining, increasing, enhancing, or inhibiting the decline of muscle mass and muscle strength can be achieved. In this specification, a therapeutically "effective amount" refers to an amount effective to produce some desired therapeutic effect that is commensurate with a reasonable benefit / risk ratio. A myostatin inhibitor is a compound represented by Chemical Formula 1 according to the present invention, wherein R ５ is -L-Z, and the target molecule to which ligand Z specifically binds is myostatin, but is usually a pharmaceutical composition comprising one or more of the above photooxygenation catalysts and a pharmaceutically acceptable carrier.

[0042] As described above, since the photooxygenation catalyst as a myostatin inhibitor is effective for maintaining muscle mass and muscle strength, the pharmaceutical composition is preferably for the prevention and / or treatment of muscle atrophy disorders. Another aspect of the present invention relates to a method for inhibiting myostatin, which comprises administering an effective amount of the photooxygenation catalyst of the present invention to a patient. Another aspect of the present invention relates to the photooxygenation catalyst of the present invention for use in inhibiting myostatin.

[0043] Yet another aspect of the present invention provides a preventive and / or therapeutic agent for muscle atrophy disorders, which comprises the photooxygenation catalyst according to the present invention. By administering an effective amount of the preventive / therapeutic agent for muscle atrophy disorders to a patient, therapeutic effects such as slowing the rate of progression, inhibiting progression, halting progression, improving, curing, and / or preventing muscle atrophy disorders can be achieved. The preventive / therapeutic agent for muscle atrophy disorders is a compound represented by Chemical Formula 1 according to the present invention, in which R ５ is -L-Z, and the target molecule to which ligand Z specifically binds is myostatin, but is usually a pharmaceutical composition comprising one or more of the above photooxygenation catalysts and a pharmaceutically acceptable carrier.

[0044] Yet another aspect of the present invention relates to a method for preventing and / or treating muscle wasting disorders, which comprises administering to a patient an effective amount of the photooxygenation catalyst (or pharmaceutical composition) according to the present invention. Yet another aspect of the present invention relates to the photooxygenation catalyst (or pharmaceutical composition) according to the present invention for use in the prevention and / or treatment of muscle wasting disorders.

[0045] Myostatin inhibitors, preventive and therapeutic agents for muscle atrophy disorders, and the above-mentioned preventive and / or therapeutic methods are also effective for strengthening the tibialis anterior muscle through local administration in elderly people with walking difficulties. Simply strengthening the tibialis anterior muscle facilitates dorsiflexion of the ankle joint, leading to the prevention of falls. Furthermore, continuous local administration during space travel could contribute to shortening the rehabilitation period after returning to Earth.

[0046] Examples of the muscle atrophy disorders include, but are not limited to, muscular dystrophy, distal myopathy, congenital myopathy, inflammatory muscle diseases such as inclusion body myositis, myopathies such as mitochondrial myopathy, disuse muscle atrophy, sarcopenia, etc. The preventive and therapeutic agent for muscle atrophy disorders (including in the form of a pharmaceutical composition) is preferably used effectively for muscular dystrophy and sarcopenia. The preventive and therapeutic agent for muscle atrophy disorders (including in the form of a pharmaceutical composition) is more preferably used effectively for muscular dystrophies such as Duchenne muscular dystrophy, Becker muscular dystrophy, Fukuyama congenital muscular dystrophy, merosin-deficient congenital muscular dystrophy, limb-girdle muscular dystrophy, facioscapulohumeral muscular dystrophy, Emery-Dreifuss muscular dystrophy, Miyoshi muscular dystrophy, and infantile neuroaxonal muscular dystrophy, as well as sarcopenia, and is particularly effective for Duchenne muscular dystrophy.

[0047] Muscle wasting disorders can also result from chronic diseases such as amyotrophic lateral sclerosis, chronic obstructive pulmonary disease (COPD), cancer, AIDS, renal failure, and rheumatoid arthritis. Muscle wasting disorders can also result from metabolic disorders such as diabetes and related disorders. Therefore, the prophylactic and therapeutic agents for muscle wasting disorders (including in the form of pharmaceutical compositions) of the present invention and the above-mentioned preventive and / or therapeutic methods can be used to improve cachexia associated with muscle wasting. Furthermore, increasing muscle mass through myostatin inhibition can improve bone strength and reduce osteoporosis and other degenerative bone diseases.

[0048] Yet another aspect of the present invention relates to an agent (or pharmaceutical composition) for preventing and / or treating muscle wasting disorders caused by diabetes or cancer cachexia, which comprises the photooxygenation catalyst of the present invention. Yet another aspect of the present invention relates to a method for preventing and / or treating muscle wasting disorders caused by diabetes or cancer cachexia, which comprises administering an effective amount of the photooxygenation catalyst of the present invention to a patient.

[0049] In the above-described embodiment, the use of the compound according to one aspect of the present invention was explained using an example in which the target molecule is myostatin and the ligand is a myostatin inhibitory peptide, but when the target molecule is coronavirus 3CL protease and the ligand is a substance that specifically binds to 3CL protease (preferably a 3CL protease inhibitor), a medicament useful for applications such as the prevention and treatment of coronavirus infection is provided. That is, according to the present invention, the following aspects are also similarly provided.

[0050] - A pharmaceutical composition comprising the photooxygenation catalyst of the present invention, which is for the prevention and / or treatment of coronavirus infection (preferably, novel coronavirus infection (COVID-19)); - A method for the prevention and / or treatment of coronavirus infection (preferably, novel coronavirus infection (COVID-19)), which comprises administering an effective amount of the pharmaceutical composition to a patient; - The photooxygenation catalyst of the present invention for use in inhibiting coronavirus 3CL protease; - The photooxygenation catalyst of the present invention for use in the prevention and / or treatment of coronavirus infection.

[0051] As used herein, the terms "subject" and "patient" include humans and non-human animals including fish, but are preferably selected from mammals such as humans, dogs, cats, mice, rats, hamsters, guinea pigs, horses (including racehorses), cows, pigs, rabbits, and sheep, and poultry such as chickens, quails, and turkeys, with humans being more preferred.

[0052] The pharmaceutically acceptable carriers mentioned above are not particularly limited, but include excipients such as lactose, sucrose, mannitol, starch, corn starch, crystalline cellulose, and light anhydrous silicic acid; lubricants such as silica, talc, calcium stearate, and magnesium stearate; binders such as hydroxypropyl cellulose, hydroxypropylmethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, methyl cellulose, polyvinylpyrrolidone, crystalline cellulose, dextrin, and gelatin; antioxidants such as ascorbic acid, sodium sulfite, sodium bisulfite, and tocopherol; chelating agents such as ethylenediaminetetraacetic acid (EDTA); buffers such as borate, bicarbonate, Tris-HCl, citrate, phosphate, and other organic acids; water for injection, physiological saline, ethanol, protease inhibitors, and the like. solvents such as alcohol, ethylene glycol, propylene glycol, macrogol, olive oil, corn oil, etc.; surfactants or humectants such as Pluronic®, polyethylene glycol, sorbitan fatty acid esters, polysorbates, Triton®, lecithin, cholesterol, benzalkonium chloride, benzethonium chloride, glycerin monostearate, etc.; isotonicity agents such as sodium chloride, potassium chloride, glycerin, glucose, sorbitol, mannitol, etc.; preservatives such as benzoic acid, salicylic acid, thimerosal, phenethyl alcohol, methylparaben, propylparaben, chlorhexidine, etc.; complexing agents; amino acids; antimicrobial agents; colorants; flavoring agents and diluents; emulsifiers; salt-forming counterions such as sodium; delivery vehicles; diluents, etc. (Remington's Pharmaceutical Sciences, 18th Edition, edited by A. R. Gennaro, Mack Publishing Company, 1990).

[0053] The content of the photooxygenation catalyst of the present invention in the pharmaceutical preparation may be 0.01 to 100% by weight of the total preparation. The dosage of the photooxygenation catalyst of the present invention varies depending on age, symptoms, administration method, etc., but in the case of oral administration, it is generally about 0.1 to 100 mg, preferably about 1.0 to 50 mg, and more preferably about 1.0 to 20 mg per day for a human (assuming a body weight of 60 kg). In the case of parenteral administration, the single dose varies depending on age, symptoms, administration method, etc., but for example, in the form of an injection, it is usually convenient to administer about 0.01 to 30 mg, preferably about 0.1 to 20 mg, and more preferably about 0.1 to 10 mg per day for a human (assuming a body weight of 60 kg). In the case of animals other than humans, the amount converted to a dose per 60 kg body weight can also be administered.

[0054] Even if the target molecule is a molecule other than myostatin or coronavirus 3CL protease, by using a substance that can be oxygenated by the photooxygenation catalyst of the present invention as the target molecule and incorporating a ligand that specifically binds to the target molecule as Z into the structure of the photooxygenation catalyst, the target molecule can be inhibited by the same mechanism of action as described above. That is, according to yet another aspect of the present invention, there is provided a target molecule inhibitor that includes a photooxygenation catalyst containing the compound of the present invention containing Z or a salt thereof, where Z represents a ligand that specifically binds to the target molecule, and inhibits the target molecule under light irradiation. Furthermore, according to yet another aspect of the present invention, there is also provided a method for inhibiting a target molecule, the method comprising: contacting a photooxygenation catalyst containing the compound of the present invention containing Z or a salt thereof (where Z represents a ligand that specifically binds to the target molecule) with a target molecule to which the ligand Z specifically binds, thereby causing the ligand Z to specifically bind to the target molecule; and irradiating the photooxygenation catalyst with light to oxygenate and inhibit the target molecule. Furthermore, by incorporating into the structure of the photooxygenation catalyst a group G, which has at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to the target molecule, as Z, and using a substance that can be oxygenated by the photooxygenation catalyst of the present invention as a target molecule, the target molecule can be inhibited by the same mechanism as described above. That is, according to yet another aspect of the present invention, there is provided a target molecule inhibitor that includes a photooxygenation catalyst containing the compound of the present invention containing Z or a salt thereof, wherein Z represents a group G, which has at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to the target molecule, and the ligand bound to group G specifically binds to the target molecule and inhibits the target molecule under light irradiation.Furthermore, a method for inhibiting a target molecule is also provided, which includes reacting a photooxygenation catalyst containing the compound of the present invention or a salt thereof, wherein Z represents a group G containing at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to the target molecule, with the ligand to convert Z into a ligand that specifically binds to the target molecule; contacting the converted photooxygenation catalyst with a target molecule to which the ligand specifically binds, thereby specifically binding the ligand to the target molecule; and irradiating the photooxygenation catalyst with light to oxygenate and inhibit the target molecule.

[0055] The present invention will be described below with reference to examples, but the scope of the present invention is not limited to these examples.

[0056] [1. General Information] Nuclear magnetic resonance spectroscopy (NMR) was measured using a Bruker AVANCE-III (400 MHz). Mass spectroscopy (HRMS (ESI) m / z) was measured using a micromass LCT. １ In the H-NMR data, s is a singlet, d is a doublet, dd is a double doublet, t is a triplet, m is a multiplet, J is a coupling constant, Hz is hertz, and CDCl ３ is deuterated chloroform, CD ３ OD is deuterated methanol, CD is ３ CN is deuterated acetonitrile, D ２ O is heavy water, DMSO-D ６ means deuterated dimethyl sulfoxide. １ In the H-NMR data, hydroxyl group (OH), amino group (NH ２ In the HRMS (ESI) m / z data, M is the molecular weight, [M] ＋ , [M+H] ＋ , [M-H] － means the molecular ion peak.

[0057] [2. Synthesis of Photooxygenation Catalysts] The photooxygenation catalysts (compounds 1 to 4 and 8) according to the present invention were synthesized according to the following synthesis scheme and method. Furthermore, the photooxygenation catalyst (compound 10) and fluorophore (compound 11) were synthesized according to the description in the paper: H. Okamoto et al., Chem. Commun., 2019, 55, 9108-9111.

[0058]

[0059] [2-1. Synthesis of Compound 1]

[0060]

[0061] Iodomethane (18.1 μL, 291 μmol) was added to 3-bromo-4-methylpyridine (65.4 μL, 581 μmol), and the mixture was stirred at 80°C for 19 hours. The reaction mixture was dissolved in methanol (300 μL), and then 4-dimethylaminobenzaldehyde (46.5 mg, 291 μmol) and piperidine (30 μL) were added, followed by stirring at 50°C for 18 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The residue was then redissolved in a 0.1% aqueous TFA solution / acetonitrile (1 / 1 (v / v)) mixed solvent. The solution was filtered, and the filtrate was purified by preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA solution / acetonitrile (75 / 25 to 60 / 40), 15 minutes), and lyophilized to give Compound 1 (54 mg, 2 steps, 41%).

[0062]

[0063] [2-2. Synthesis of Compound 2]

[0064]

[0065] Iodomethane (18.1 μL, 291 μmol) was added to 3-bromo-4-methylpyridine (65.4 μL, 581 μmol), and the mixture was stirred at 80°C for 19 hours. The reaction mixture was dissolved in methanol (300 μL), and then 9-julolidinecarboxaldehyde (58.5 mg, 291 μmol) and piperidine (30 μL) were added, followed by stirring at 50°C for 18 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The residue was then redissolved in a 0.1% aqueous TFA solution / acetonitrile (1 / 1 (v / v)) mixed solvent. The solution was filtered, and the filtrate was purified by preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA solution / acetonitrile (60 / 40 to 45 / 55), 15 minutes), and lyophilized to give compound 2 (48 mg, 2 steps, 33%).

[0066]

[0067] [2-3. Synthesis of Compound 3]

[0068]

[0069] 2-Chloropyrimidine (33.9 mg, 291 μmol) was added to 3-bromo-4-methylpyridine (65.4 μL, 581 μmol), and the mixture was stirred at 80°C for 16 hours. The reaction mixture was dissolved in methanol (300 μL), and then 4-dimethylaminobenzaldehyde (44.9 mg, 291 μmol) was added, followed by stirring at 80°C for 2 hours. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The residue was then redissolved in a 0.1% aqueous TFA solution / acetonitrile (1 / 1 (v / v)) mixed solvent. The solution was filtered, and the filtrate was purified by preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA solution / acetonitrile (64 / 36 to 49 / 51), 15 minutes), and lyophilized to give compound 3 (4.6 mg, 2 steps, 3.8%).

[0070]

[0071] [2-4. Synthesis of Compound 4]

[0072]

[0073] 2-Chloropyrimidine (35.9 mg, 291 μmol) was added to 3-bromo-4-methylpyridine (65.4 μL, 581 μmol), and the mixture was stirred at 80°C for 19 hours. The reaction solution was dissolved in methanol (300 μL), and then 9-julolidinecarboxaldehyde (60.9 mg, 291 μmol) was added, followed by stirring at 80°C for 21 hours. The reaction solution was cooled to room temperature and concentrated under reduced pressure. The residue was then redissolved in a 0.1% aqueous TFA solution / acetonitrile (1 / 1 (v / v)) mixed solvent. The solution was filtered, and the filtrate was purified by preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA solution / acetonitrile (56 / 44 to 42 / 58), 14 minutes), and lyophilized to give compound 4 (17 mg, 2 steps, 11%).

[0074]

[0075] [2-5. Synthesis of Compound 5 (2-chloropyrimidine-5-carboxylic acid)]

[0076]

[0077] Ethyl 2-chloropyrimidine-5-carboxylate (1.5 g, 8 mmol) was dissolved in THF (25 mL) and cooled to 0°C. 20 mL (20 mmol) of a 1 M aqueous solution of lithium hydroxide was added to the solution, and the mixture was stirred at 0°C for 2 hours. The solution was neutralized with 1 M hydrochloric acid and then concentrated under reduced pressure. 1 M hydrochloric acid was further added to adjust the pH to less than 1 to precipitate a solid, which was then filtered to obtain compound 5 (864 mg, 68%).

[0078]

[0079] [2-6. Synthesis of Compound 6]

[0080]

[0081] 9-Julolidinecarboxaldehyde (100 mg, 500 μmol) and 2-chloropyrimidine-5-carboxylic acid (Compound 5, 80 mg, 500 μmol) were dissolved in anhydrous THF (2 mL) under an argon atmosphere, and 3-bromo-4-methylpyridine (279 μL, 2.5 mmol) was added, followed by stirring for 19 hours at 60° C. The solution was concentrated under reduced pressure, and the residue was purified by flash column chromatography (developing solvent: chloroform / methanol (5 / 1)) to obtain Compound 6 (134 mg, 57%).

[0082]

[0083] [2-7. Synthesis of Compound 7]

[0084]

[0085] 9-Julolidinecarboxaldehyde (100 mg, 500 μmol) and 2-chloropyrimidine-5-carboxylic acid (Compound 5, 80 mg, 500 μmol) were dissolved in a mixed solvent of anhydrous THF / anhydrous chloroform (4 / 1 (v / v), 5 mL) under an argon atmosphere, and 4-picoline (243 μL, 2.5 mmol) was added and stirred at 60° C. for 19 hours. The solution was concentrated under reduced pressure, and the residue was purified by flash column chromatography (developing solvent: chloroform / methanol (5 / 1)) to obtain Compound 7 (47 mg, 24%).

[0086]

[0087] [2-8. Synthesis of Compound 8]

[0088]

[0089] Compound 6 (400 mg, 833 μmol) was dissolved in anhydrous DMF (10 mL) under an argon atmosphere, and triethylamine (115 μL, 833 μmol), 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM, 422 mg, 1.5 mmol), and 3-azidopropylamine (148 μL, 1.5 mmol) were added at −20°C, followed by stirring at −20°C for 4 hours. The solution was concentrated under reduced pressure and then diluted with chloroform. The solution was washed with water and saturated brine, dried over anhydrous sodium sulfate, and the organic solvent was removed under reduced pressure. The residue was purified by flash column chromatography (developing solvent: chloroform / methanol (96 / 4 to 66 / 34)) to obtain compound 8 (249 mg, 53%).

[0090]

[0091] [2-9. Synthesis of Compound 9]

[0092]

[0093] Compound 7 (38 mg, 96 μmol) was dissolved in anhydrous DMF (4 mL) under an argon atmosphere, and triethylamine (67 μL, 480 μmol), 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM, 53 mg, 192 μmol), and 3-azidopropylamine (38 μL, 384 μmol) were added at −20°C, followed by stirring at −20°C for 4 hours. The solution was concentrated under reduced pressure and then diluted with chloroform. The solution was washed with water and saturated brine, dried over anhydrous sodium sulfate, and the organic solvent was removed under reduced pressure. The residue was purified by flash column chromatography (developing solvent: chloroform / methanol (96 / 4 to 66 / 34)) to obtain compound 9 (18 mg, 40%).

[0094]

[0095] [2-10. Synthesis of Compound 10]

[0096]

[0097] Compound 10 was synthesized by a method similar to that previously reported (H. Okamoto et al., Chem. Commun., 2019, 55, 9108-9111.).

[0098] [2-11. Synthesis of Compound 11]

[0099]

[0100] Compound 11 was synthesized by a method similar to that previously reported (H. Okamoto et al., Chem. Commun., 2019, 55, 9108-9111.).

[0101] [3. Synthesis of myostatin-binding peptide and photooxygenation catalyst conjugate (1)] In the following, a myostatin-binding peptide was synthesized and crosslinked with the compound synthesized above to synthesize a photooxygenation catalyst conjugate.

[0102] [3-1. Synthesis of Peptide 12] Peptide 12 was synthesized by a method similar to that previously reported (K. Takayama et al., J. Med. Chem., 2015, 58, 1544-1549).

[0103]

[0104] [3-2. Synthesis of Peptides 13'-17'] Myostatin-binding peptides 13'-17', each having the following structure, were synthesized according to the following synthesis method. The modifications Z, O, and X in these peptides each have the following structures. As is clear from the structural formulas below, peptide 13' has an alkynyl group at the N-terminus. Peptides 14'-16' have a 2,2-diphenylethylcarbonyl group at the N-terminus and an alkynyl group in the peptide chain. Peptide 17' has a 2,2-diphenylethylcarbonyl group at the N-terminus and an alkynyl group at the C-terminus.

[0105]

[0106] Peptides 13'-17' were synthesized by the Fmoc solid-phase synthesis method described below. First, Rink amide resin (0.37 mmol / g, 108 mg, 0.040 mmol) was swollen by stirring in dimethylformamide (DMF) for 1 hour. The 9-fluorenylmethyloxycarbonyl (Fmoc) group on the resin was removed by stirring in 20% (v / v) piperidine / DMF for 20 minutes. After washing the resin with DMF, the Fmoc-protected amino acid was condensed onto the resin by stirring with an Fmoc-protected amino acid (0.20 mmol, 5.0 eq.) in the presence of 1-((dimethylamino)(dimethylimino)methyl)-1H-[1,2,3]triazolo[4,5-b]pyridine 3-oxide hexafluorophosphate (HATU, 0.20 mmol, 5.0 eq.), 1-hydroxy-7-azabenzotriazole (HOAt, 0.20 mmol, 5.0 eq.), and N,N-diisopropylethylamine (DIPEA, 0.40 mmol, 10 eq.) in DMF for 30 minutes. After washing the resin with DMF, the Fmoc group was removed and then the next Fmoc-protected amino acid was condensed onto the resin in the same manner as above to introduce the next Fmoc-protected amino acid. The peptide chain was elongated using the following Fmoc-protected amino acids: Fmoc-L-Leu-OH, Fmoc-L-Arg(Pbf)-OH, Fmoc-L-Lys(Boc)-OH, Fmoc-L-Ser(tBu)-OH, Fmoc-L-Ile-OH, Fmoc-L-Gln(Trt)-OH, Fmoc-L-Ala-OH, Fmoc-L-Glu(OtBu)-OH, Fmoc-L-Tyr(tBu)-OH, Fmoc-L-Thr(tBu)-OH, Fmoc-L-Asn(Trt)-OH, and Fmoc-L-Gly(propargyl)-OH (0.20 mmol, 5.0 eq.). In addition, 5-hexynoic acid and 3,3-diphenylpropionic acid (0.20 mmol, 5.0 eq.) were condensed in the same manner as for the Fmoc-protected amino acid. The resin was washed with DMF, methanol, and diethyl ether and then dried. The dried resin was treated with trifluoroacetic acid (TFA) / 1,3-dimethoxybenzene / triisopropylsilane (92.5 / 5 / 2.5 (v / v / v)) for 90 minutes to remove various side chain protecting groups and the resin was removed.After removing the resin by filtration, the TFA was evaporated by nitrogen spray. Diethyl ether was added to precipitate the crude peptide, which was then centrifuged and the supernatant removed. The crude peptide was purified by preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA / acetonitrile) and lyophilized to give a white solid.

[0107]

[0108] [3-3. Synthesis of Photooxygenation Catalyst Conjugates 13 to 17] Photooxygenation catalyst conjugates 13 to 17, having the structures shown below, were synthesized according to the synthesis method described below. Note that the modifications Z, O, and X in these conjugates each represent the structures shown below. As is clear from the structural formulas shown below, conjugate 13 has a photocatalytic structure derived from compound 8 synthesized above at its N-terminus. Conjugates 14 to 16 have a 2,2-diphenylethylcarbonyl group at their N-terminus and a photocatalytic structure derived from compound 8 synthesized above in the peptide chain. Conjugate 17 has a 2,2-diphenylethylcarbonyl group at its N-terminus and a photocatalytic structure derived from compound 8 synthesized above at its C-terminus.

[0109]

[0110] Conjugates 13 to 17 were synthesized by the following method.

[0111] First, peptides 13'-17' (10 mM DMSO solution, 1.0 eq.), compound 8 (11 mM DMSO solution, 2.2 eq.), and ascorbic acid (120 mM methanol solution, 24 eq.) were dissolved in a DMSO / methanol (1 / 1 (v / v)) solution (final: 1 mM peptides 13'-17', 1.1 mM compound 8, 24 mM ascorbic acid). Tetrakis(acetonitrile)copper(I) hexafluorophosphate (7-20 eq.) was added to each solution and allowed to stand for 20 minutes. After centrifugation, the supernatant was purified by preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA / acetonitrile) and lyophilized to obtain a blue solid.

[0112]

[0113] [3-4. Synthesis of Fluorophore Conjugate 18] Fluorophore conjugate 18 having the following structure was synthesized according to the following synthesis method. Note that modification Z in this conjugate 18 has the following structure. As is clear from the following structural formula, conjugate 18 has a fluorophore structure (not containing a bromine atom in the catalytic site) derived from compound 9 synthesized above at the N-terminus.

[0114]

[0115] Conjugate 18 was synthesized as a blue solid (0.12 mg, 10%) by the same method as conjugate 13 described above, except that compound 9 was used instead of compound 8.

[0116]

[0117] 3-5. Synthesis of Photooxygenation Catalyst Conjugate 19 Conjugate 19 was synthesized using a method similar to that previously reported (H. Okamoto et al., Org. Biomol. Chem., 2021, 19, 199-207). The modified O and X in this conjugate 19 have the following structures: As is clear from the structural formula below, conjugate 19 has a 2,2-diphenylethylcarbonyl group at the N-terminus and a photocatalytic structure derived from compound 10 synthesized above in the peptide chain.

[0118]

[0119] [4. Synthesis of Peptide and Photooxygenation Catalyst Conjugate (2)] In the following, a myostatin-binding D-peptide was synthesized and crosslinked with the compound synthesized above to synthesize a conjugate.

[0120] [4-1. Synthesis of Peptides 20'-24'] Myostatin-binding D-peptides 20'-24' having the structures shown below were synthesized according to the following synthesis method. The modified amino acids b, j, u, and x, and the terminal modification z in these peptides each have the structures shown below. As is clear from the structural formulas below, peptide 20' has an alkynyl group at the N-terminus. Peptides 21'-23' have an alkynyl group in the peptide chain. Peptide 24' has an alkynyl group at the C-terminus.

[0121]

[0122] Peptides 20'-24' were synthesized by the Fmoc solid-phase synthesis method described below. First, Rink amide resin (0.35-0.49 mmol / g, peptide 20': 0.070 mmol, peptides 21'-24': 0.045 mmol) was swollen by stirring in DMF for 1 hour. The Fmoc group on the resin was removed by stirring in 20% (v / v) piperidine / DMF for 20 minutes. After washing the resin with DMF, the Fmoc-protected amino acid (3.0 eq.) was condensed onto the resin by stirring in DMF for 90 minutes with the Fmoc-protected amino acid in the presence of N,N'-diisopropylcarbodiimide (DIPCI, 3.0 eq.) and 1-hydroxybenzotriazole (HOBt, 3.0 eq.). After washing the resin with DMF, the Fmoc group was removed and the subsequent Fmoc-protected amino acid was condensed in the same manner as above to introduce the next Fmoc-protected amino acid. The peptide chain was elongated using the following Fmoc-protected amino acids: Fmoc-D-homoPhe-OH, Fmoc-D-Tyr(tBu)-OH, Fmoc-D-Ile-OH, Fmoc-D-Arg(Pbf)-OH, Fmoc-D-Lys(Boc)-OH, Fmoc-D-Chg-OH, Fmoc-D-Ala(2-Naph)-OH, Fmoc-D-Leu-OH, and Fmoc-D-Gly(propargyl)-OH (3.0 eq.). In addition, 4-pentynoic acid (3.0 eq.) was condensed in the same manner as for the Fmoc-protected amino acid. After removing the N-terminal Fmoc group, the resin was washed with DMF, methanol, and diethyl ether and dried. The dried resin was treated with trifluoroacetic acid (TFA) / 1,3-dimethoxybenzene / triisopropylsilane (92.5 / 5 / 2.5 (v / v / v)) for 90 minutes to remove various side chain protecting groups and depolymerize the resin. The resin was removed by filtration, and the TFA was evaporated by nitrogen spray. Diethyl ether was added to precipitate the crude peptide, which was then centrifuged and the supernatant removed. The crude peptide was purified by preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA / acetonitrile) and lyophilized to obtain a white solid.

[0123]

[0124] [4-2. Synthesis of Photooxygenation Catalyst Conjugates 20 to 24] Photooxygenation catalyst conjugates 20 to 24 having the structures shown below were synthesized according to the synthesis method described below. Note that the modified amino acids b, j, and u, and the modifications x and z in these conjugates each have the structures shown below. As is clear from the structural formulas shown below, conjugates 20 to 24 all have modified amino acids b, j, and u. Conjugate 20 also has a photocatalytic structure derived from compound 8 synthesized above at its N-terminus. Conjugates 21 to 23 also have a photocatalytic structure derived from compound 8 synthesized above in the peptide chain. Conjugate 24 also has a photocatalytic structure derived from compound 8 synthesized above at its C-terminus.

[0125]

[0126] Conjugates 20 to 24 were synthesized in the same manner as conjugate 13 described above, except that peptides 20' to 24' were used instead of peptide 13'.

[0127]

[0128] [5. Measurement of Absorption Spectra] Compounds 1 to 4 and conjugates 13 to 17 (10 μM) were each dissolved in phosphate buffer (10 mM, pH 7.4), and the absorption spectra were measured at room temperature. The results for compounds 1 to 4 are shown in Figure 1(a), and the results for conjugates 13 to 17 are shown in Figure 1(b).

[0129] As shown in Figure 1(a), a red shift was observed in Compounds 1 to 4 by modifying their structures, and Compound 4 also absorbs near-infrared light. ｍａｘ ) were 490 nm, 540 nm, 590 nm, and 640 nm, respectively. Conjugates 13 to 17 all have the structure of Compound 4, but as shown in Figure 1(b), there is no effect of the linkage to the peptide chain, and all of the conjugates exhibit near-infrared absorption similar to Compound 4.

[0130] [6. Evaluation of the singlet oxygen production ability of photooxygenation catalysts] The hemicyanine fluorescent dye trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide (DASPI) or compounds 1 to 4 (200 μM) were each added to glycerol / water (75:25 (v / v)) containing furfuryl alcohol (FA, 1 mM). The solution was irradiated with light at room temperature using a fluorescent lamp (white light) or an LED (wavelength 730 nm (near-infrared light), 27 mW). FA was then quantified at any desired time point using HPLC. FA is a singlet oxygen scavenger and undergoes decomposition upon reaction with singlet oxygen. Therefore, a decrease in FA indicates the generation of singlet oxygen. Furthermore, even when photoexcited, the photooxygenation catalyst of the present invention does not exhibit photooxygenation activity due to twisted intramolecular charge transfer (TICT). However, in this experiment, since glycerol with high viscosity was used as the solvent, TICT was suppressed, and active oxygen could be generated. The results for irradiation with fluorescent light are shown in Figure 2(a), and the results for irradiation with LED are shown in Figure 2(b).

[0131] As shown in Figure 2(a), compound 1 exhibited superior singlet oxygen production ability under white light irradiation compared to DASPI. Furthermore, as shown in Figure 2(b), compounds 1 and 2 hardly produced singlet oxygen under near-infrared light irradiation, while compounds 3 and 4 (particularly compound 4) produced singlet oxygen under near-infrared light irradiation. These results demonstrate that the photooxygenation catalyst of the present invention can exhibit catalytic activity for photooxygenation by appropriately selecting the wavelength of irradiated light. Furthermore, it is clear that compound 4 in particular can undergo photooxygenation using near-infrared light that is bioavailable.

[0132] [7. Evaluation of the Radical Oxygen Species Production Ability of Photooxygenation Catalysts] Dihydrorhodamine (DHR) 123 is a superoxide radical detection probe that reacts with superoxide radicals and is oxidized to a fluorescent molecule. Compounds 1 to 4 (200 μM) were added to glycerol / water (75:25 (v / v)) containing DHR 123 (200 μM). The solution was irradiated with light using an LED (wavelength 730 nm, 27 mW) at room temperature. Fluorescence intensity (excitation wavelength: 500 nm, emission wavelength: 526 nm) was measured at any given time point. The stronger the fluorescence intensity measured, the higher the photooxygenation activity of the compound. The results are shown in Figure 3.

[0133] As shown in FIG. 3, compound 1 hardly produced superoxide radicals when irradiated with near-infrared light at a wavelength of 730 nm, as in the results shown in FIG. 2(b), whereas compounds 2 to 4 (particularly compounds 3 and 4) showed superoxide radical-producing activity when irradiated with near-infrared light at a wavelength of 730 nm.

[0134] [8. Photooxygenation of methionine using a photooxygenation catalyst] Compounds 3 and 4 (200 μM) were added to glycerol / water (75:25 (v / v)) containing Fmoc-L-methionine (500 μM). The solution was irradiated with light using an LED (wavelength 730 nm, 27 mW) at room temperature. Fmoc-L-methionine sulfoxide was then quantified by HPLC at any given time point. The results are shown in Figure 4. Note that the horizontal axis of the graph in Figure 4 indicates the irradiation time, and the vertical axis indicates the percentage of oxygenated substrate.

[0135] As shown in Figure 4, the substrate Fmoc-L-methionine was oxygenated to Fmoc-L-methionine sulfoxide in the presence of both compounds 3 and 4. It is also clear that the longer the irradiation time, the more substrate was oxygenated, and that compound 4 exhibited more pronounced oxygenation activity with near-infrared light at a wavelength of 730 nm. This suggests that the photooxygenation catalyst of the present invention exhibits high photooxygenation activity even when targeting peptides or proteins containing L-methionine.

[0136] 9. Stability of Photooxygenation Catalyst Compound 8 (25 μM) was dissolved in water / methanol (9:1 (v / v), containing 1 vol% DMSO) and irradiated with an LED (wavelength 730 nm, 27 mW) at room temperature for 1.5 hours or shaken in the dark at 37°C for 24 hours. Compound 8 was then quantified by HPLC. The results are shown in Figure 5.

[0137] The results shown in FIG. 5 show that Compound 8 can exist stably without decomposition even when exposed to light for 1.5 hours or to a temperature condition of 37° C. for 24 hours.

[0138] [10. Comparison of Water Solubility of Photooxygenation Catalysts] Solid compounds 8 and 10 were each suspended in water and shaken at room temperature for 2 hours. After centrifugation, the amounts of compounds 8 and 10 in the supernatant (saturated aqueous solution) were quantified by HPLC.

[0139] The saturation concentration of compound 10, which constitutes a conventionally known catalytic site, was <0.034 mg / mL (<50 μM), which was below the limit of quantification by HPLC. This indicates that compound 10 is poorly water-soluble. On the other hand, the saturation concentration of compound 8, which constitutes a catalytic site according to the present invention, was calculated to be 0.304 mg / mL (452 ​​μM), confirming that it exhibits high water solubility.

[0140] [11. Comparison of Nonspecific Adsorption] Compound 9 (0-15 μM) or compound 11 (0-0.4 μM) was added to phosphate buffer (10 mM, pH 7.4) or the same buffer containing bovine serum albumin (BSA) (1 μM), and the fluorescence intensity was measured. In this experiment, BSA was used as a model off-target substance. Furthermore, compound 9 derived from the catalyst of the present invention and compound 11 derived from a conventionally known catalyst have a structure in which the bromine atom has been removed from each catalyst. Because the heavy atom effect of the bromine atom is lost, photooxygenation does not occur, and instead, fluorescence is emitted. In other words, these compounds emit fluorescence upon binding to albumin, resulting in the inhibition of TICT. Therefore, the fluorescence intensity measured in this experiment indicates the amount of the compound bound to albumin. From the obtained concentration-fluorescence intensity curve, K was calculated using KaleidaGraph 4.5 (Synergy Software). ｄ The value was calculated.ｄ A larger value indicates a lower binding to BSA and less non-specific adsorption.

[0141] The K of Compound 11, which constitutes a conventionally known catalyst, to BSA ｄ The calculated value was 5.1±0.6 nM. On the other hand, the K ｄ The value was 2.2±0.3 μM, which was 400 times higher than that of the catalyst of the present invention. This indicates that the catalyst of the present invention has very little nonspecific adsorption.

[0142] [12. CD Analysis of Photooxygenation Catalyst Conjugates] Photooxygenation catalyst conjugates 13-17, 19, or peptides 13'-17' (5 μM) were dissolved in phosphate buffer (10 mM, pH 7.4) containing 20% ​​2,2,2-trifluoroethanol, and CD (circular dichroism) spectra were measured. The proportion of each secondary structure was then calculated from the obtained spectra using Read's reference. The results for peptide 16' and conjugates 16 and 19 are shown in Figure 6, and the results for the other compounds are shown in Figure 7.

[0143] The results shown in Figure 6 indicate that the primary secondary structure of peptide 16' without a catalytic structure is α-helix, whereas the primary secondary structure of conjugate 19 with a conventional catalytic structure is β-strand. In contrast, conjugate 16 with a catalytic structure according to the present invention maintains an α-helix-dominant structure. Because the higher-order structure of a ligand peptide contributes to affinity for a target, the finding that the catalytic site according to the present invention does not affect the secondary structure of the peptide site suggests that the conjugate is superior in terms of target affinity. Furthermore, as shown in Figure 7, conjugates 13-15 and 17 also exhibit secondary structure compositions similar to the corresponding peptides 13'-15' and 17' without a catalytic structure, suggesting superior target affinity.

[0144] [13. Photooxygenation of Myostatin by Photooxygenation Catalyst Conjugates] Photooxygenation catalyst conjugates 13-17, 19 (1 μM or 3 μM) or methylene blue (MB, 3 μM) were added to myostatin (1 μM) in phosphate buffer (10 mM, pH 7.4). Methylene blue was used as a control to induce non-selective oxygenation. These solutions were irradiated with an LED (730 nm wavelength, 27 mW) at room temperature for 30 minutes. Dithiothreitol (50 mM) was added to the solution, and the solution was incubated at 37°C for 30 minutes. Lys-C endopeptidase (1 / 20 of the protein amount) was then added and incubated at 37°C for 2.5 hours. After desalting with a C-18 ZipTip, the samples were analyzed by MALDI-TOF MS. For studies under degassed conditions, the sample solution was frozen and degassed before being irradiated with light under an argon atmosphere. The results are shown in Figures 8, 9 and 10.

[0145] First, the results shown in Figure 8 indicate that conjugates 13 to 17 all exhibit photooxygenation activity equal to or greater than that of methylene blue and superior to that of conjugate 19, which uses a conventional photooxygenation catalyst. Furthermore, the results shown in Figure 9(a) indicate that conjugate 13 exhibits photooxygenation activity upon light irradiation, but myostatin was not oxygenated in the absence of conjugate 13 or under light irradiation. Furthermore, the results shown in Figure 9(b) indicate that light irradiation after degassing suppressed myostatin oxygenation. These results indicate that conjugate 13 exhibits photooxygenation activity under light irradiation, thereby oxygenating myostatin. Furthermore, the results shown in Figure 10(a) indicate that conjugate 13 oxygenates myostatin in a concentration-dependent manner, and the results shown in Figure 10(b) indicate that conjugate 13 oxygenates myostatin in a light irradiation time-dependent manner.

[0146] 14. Myostatin Inactivation by Photooxygenation Catalyst Conjugates. Human embryonic kidney 293 (HEK293) cells were seeded at 20,000 cells / well in 10% FBS-containing DMEM onto a poly-D-lysine-coated 96-well plate and cultured at 37°C under a 5% carbon dioxide atmosphere for 24 hours. OptiMEM containing reporter vector (pGL4.48[luc2P / SBE / Hygro]), control vector (pGL4.74[hRluc / TK]), and FuGENE HD was added at 8 μL / well (final concentration: 100 ng / well of reporter vector, 10 ng / well of control vector, total DNA:FuGENE HD = 1:3). The cells were then cultured under the same conditions for 24 hours. After washing and replacing with serum-free DMEM, the cells were cultured under the same conditions for 8 hours.

[0147] Photooxygenation catalyst conjugates 13-17 and 19 (1 nM) or peptide 12 (1 nM) (a peptide without photocatalytic activity (WRQNTRYSRIEAIKIQILSKLRL-amide) described in J. Med Chem., 2015, 58, 1544) were added to serum-free DMEM containing myostatin (0.6 nM). The solution was irradiated with LED light (730 nm wavelength, 27 mW) at room temperature for 30 minutes. The culture medium in the cell plate was replaced with this reaction solution and incubated at 37°C for 4 hours under a 5% carbon dioxide atmosphere. After removing the culture medium and washing with PBS, 50 μL / well of passive lysis buffer was added to lyse the cells. After centrifugation, the luminescence intensity of the supernatant was measured using a Dual-Luciferase Reporter 1000 Assay System (Promega). The relative activity of myostatin was calculated from the luminescence intensity. The results are shown in Figures 11 and 12.

[0148] First, the results shown in Figure 11 indicate that the luminescence intensity of luciferase was significantly reduced in the presence of conjugates 13-17, indicating that these conjugates inactivated myostatin by photooxygenation. The myostatin inactivation effect of conjugates 13-17 was stronger than that of conjugate 19, which uses a conventional photooxygenation catalyst. Furthermore, the results shown in Figure 12(a) indicate that myostatin was not inactivated when light was not irradiated in the presence of conjugate 13, or when light was irradiated in the absence of conjugate 13. Furthermore, peptide 12, which does not have photocatalytic activity, did not inactivate myostatin at the above-mentioned 1 nM concentration (ChemMedChem, 2016, 11, 849). ５０ Furthermore, the IC value of myostatin inactivation by conjugate 13 is estimated to be 3.5 μM. ５０ was calculated to be 0.43±0.08 nM. Therefore, it can be said that conjugate 13 exhibits 8000-fold or more myostatin inhibitory activity compared to peptide 12 due to irreversible and catalytic inhibition.

[0149] 15. Comparison of Photooxygenation of Off-Target Models by Photooxygenation Catalyst Conjugates. Conjugates 13-17 and 19 (3 ​​μM) or methylene blue (MB, 3 μM) were added to phosphate buffer (10 mM, pH 7.4) containing amyloid β1-42 (Aβ42), neuropeptide Y, or substance P (20 μM) as off-target models. Methylene blue was used as a control to nonselectively induce oxygenation. The solution was irradiated with an LED (wavelength 730 nm, 27 mW) at room temperature for 30 minutes and then analyzed by MALDI-TOF MS. The results are shown in Figure 13.

[0150] As shown in Figure 13(a), none of conjugates 13-17 and 19 exhibited photooxygenation activity toward Aβ42. In contrast, as shown in Figure 13(b), conjugate 19 having a conventionally known catalyst exhibited photooxygenation activity toward neuropeptide Y, whereas conjugates 13-17 having a catalyst according to the present invention did not exhibit photooxygenation activity toward neuropeptide Y. Furthermore, as shown in Figure 13(c), when the same experiment was performed using substance P, a significant difference was observed in off-target photooxygenation between conjugates 13-17 and conjugate 19. These results demonstrate that the catalyst according to the present invention has higher selectivity for myostatin than the conventionally known catalyst.

[0151] [16. Comparison of selectivity among TGF-β superfamily members by photooxygenation catalyst conjugates] Since myostatin is a protein belonging to the TGF-β superfamily, the inactivation activity against other proteins belonging to the same family was measured to evaluate selectivity for myostatin.

[0152] Specifically, photooxygenation catalytic conjugate 13 or 19 (0.01-100 nM) was added to serum-free DMEM containing activin A (0.6 nM), GDF-11 (0.6 nM), or TGF-β (0.2 nM). The solution was irradiated with LED (wavelength 730 nm, 27 mW) at room temperature for 30 minutes. The relative activity of each protein was calculated from the luminescence intensity using the method described in "14. Inactivation of myostatin by photooxygenation catalytic conjugates," and the IC ５０ The results are shown in Table 1 below.

[0153]

[0154] The results shown in Table 1 indicate that conjugate 13 having a catalyst according to the present invention exhibits superior myostatin selectivity compared to conjugate 19 having a conventionally known catalyst. This superior selectivity is thought to be due to the fact that the catalyst according to the present invention is less susceptible to nonspecific adsorption and has less effect on the secondary structure of the ligand peptide.

[0155] 17. Cytotoxicity of Photooxygenation Catalyst Conjugates HEK293 cells were seeded at 20,000 cells / well in 10% FBS-containing DMEM onto a poly-D-lysine-coated 96-well plate and cultured at 37°C under a 5% carbon dioxide atmosphere for 48 hours. After washing with serum-free DMEM, 100 μL / well of serum-free DMEM containing conjugates 13-17 and 19 (3 ​​μM or 9 μM) or methylene blue (MB, 3 μM or 9 μM) was added. The cell plate was irradiated with LED (730 nm wavelength, 27 mW) at 37°C for 30 minutes. The cells were then cultured at 37°C under a 5% carbon dioxide atmosphere for 24 hours, after which cell viability was calculated using WST-1 reagent (Roche). The results are shown in Figure 14.

[0156] As shown in Figure 14(a), none of the conjugates exhibited cytotoxicity at a concentration of 3 µM, regardless of whether light irradiation was performed or not. In contrast, as shown in Figure 14(b), at a concentration of 9 µM, conjugate 19 containing a conventionally known catalyst exhibited cytotoxicity under light irradiation, whereas conjugates 13 to 17 containing the catalyst of the present invention did not exhibit cytotoxicity even under light irradiation. This indicates that the catalyst of the present invention has low toxicity to cells, and this low toxicity is thought to be due to the excellent target selectivity of the conjugates containing the catalyst of the present invention.

[0157] 18. Evaluation of the On / Off Switch Function of the Conjugates. The high target selectivity exhibited by the conjugates containing the photooxygenation catalysts of the present invention is thought to be due not only to the target affinity of the ligand peptide moiety but also to the on / off switch function of the catalytic moiety (i.e., photooxygenation activity is only expressed upon binding to the target). If the catalytic structure is modified to lack a bromine atom, the heavy atom effect of the bromine atom is lost, and excitation energy is consumed by fluorescence rather than photooxygenation. This fluorescence can visualize the on / off switch function based on TICT. To this end, we performed fluorescence measurements on fluorophore conjugate 18 (derived from compound 9), which has a structure in which the bromine atom has been removed from the catalytic moiety of photooxygenation catalyst conjugate 13.

[0158] Specifically, fluorophore conjugate 18 (2 μM) was added to phosphate buffer (10 mM, pH 7.4) or the same buffer containing myostatin (1 μM), and after incubation at 37°C for 1 hour, the fluorescence spectrum and fluorescence intensity (excitation wavelength 448 nm, fluorescence wavelength 592 nm) were measured. Furthermore, K was calculated from the obtained concentration-fluorescence intensity curve using KaleidaGraph 4.5 (Synergy Software). ｄ The values ​​were calculated, and the results are shown in FIG.

[0159] The results shown in Figure 15 indicate that in the absence of myostatin, TICT occurred and the fluorescence intensity was weak (switch off), whereas in the presence of myostatin, TICT was suppressed by binding to myostatin, resulting in strong fluorescence intensity (switch on). This indicates that the on / off switch functions depending on the binding to myostatin.

[0160] [19. Photooxygenation catalytic conjugates utilizing myostatin-binding D-peptides] The functions of photooxygenation conjugates 20 to 24 utilizing myostatin-binding D-peptides were evaluated using the same methods as those described in Sections [13. Photooxygenation of myostatin by photooxygenation catalytic conjugates] and [14. Inactivation of myostatin by photooxygenation catalytic conjugates]. The results are shown in Figure 16.

[0161] As shown in Figure 16(a), conjugates 20 to 22 in particular exhibited the ability to photooxygenate myostatin, and as shown in Figure 16(b), these conjugates also exhibited the ability to inactivate myostatin. These results demonstrate that the photooxygenation catalyst of the present invention functions even when the peptide site is modified.

[0162] 20. Nonspecific Reaction of Photooxygenation Catalyst in Muscle Homogenate. Photooxygenation catalysts 8, 10, or methylene blue (MB) (3 μM) were added to mouse tibialis anterior muscle homogenate (0.1 mg / mL) in phosphate buffer (10 mM, pH 7.4). These solutions were irradiated with LED light (730 nm wavelength, 27 mW) at room temperature for 30 minutes. 6x SDS-sample buffer was added to each solution, and the mixture was boiled at 95°C for 5 minutes. 10 μL of the mixture was subjected to SDS-PAGE (15% gel) electrophoresis. Bands were then detected by CBB staining. The results are shown in Figure 17.

[0163] The results shown in Figure 17 indicate that the bands of methylene blue, a nonspecific photosensitizer, disappeared upon light irradiation, and that proteins reacted randomly upon photooxygenation. Furthermore, while the conventionally known photooxygenation catalyst 10 also caused some proteins to react upon light irradiation, the photooxygenation catalyst 8 of the present invention was less likely to cause a reaction. This suggests that the photooxygenation catalyst of the present invention is less likely to cause nonspecific photooxygenation reactions than the conventionally known photooxygenation catalysts.

[0164] 21. Photooxygenation of myostatin using photooxygenation conjugates. Myostatin (1 μM) was added to phosphate buffer (10 mM, pH 7.4) containing photooxygenation catalyst conjugates 13 and 19, or methylene blue (MB) (3 μM). These solutions were irradiated with LED light (730 nm wavelength, 27 mW) at room temperature for 30 minutes. 6×SDS-sample buffer was added to each solution, and the mixture was boiled at 95°C for 5 minutes. 10 μL of the mixture was subjected to SDS-PAGE (15% gel) electrophoresis. Bands were then detected by CBB staining. The results are shown in Figure 18.

[0165] 18 shows that the myostatin band was weaker when treated with conjugate 13 having a photooxygenation catalyst according to the present invention than when treated with conjugate 19 having a conventionally known photooxygenation catalyst or methylene blue. This indicates that the conjugate having a photooxygenation catalyst according to the present invention has a superior photooxygenation ability for myostatin compared to conjugates having conventionally known photooxygenation catalysts.

[0166] 22. Nonspecific Reaction of Photooxygenation Catalyst Conjugates in Muscle Homogenates Photooxygenation catalyst conjugates 13 or 19 (3 ​​μM) were added to mouse tibialis anterior muscle homogenate (0.1 mg / mL) in phosphate buffer (10 mM, pH 7.4). These solutions were irradiated with LED light (730 nm wavelength, 27 mW) at room temperature for 30 minutes. 6×SDS-sample buffer was added to each solution, and the mixture was boiled at 95°C for 5 minutes. 10 μL of each sample was subjected to SDS-PAGE (15% gel) electrophoresis. Bands were then detected by CBB staining. The results are shown in Figure 19.

[0167] 19 shows that the protein in conjugate 19 having a conventionally known photooxygenation catalyst reacted upon light irradiation, whereas the protein in conjugate 13 having a photooxygenation catalyst according to the present invention reacted less readily. This indicates that the conjugate having a photooxygenation catalyst according to the present invention is less likely to undergo nonspecific photooxygenation reactions than conjugates having conventionally known photooxygenation catalysts.

[0168] 23. Photooxygenation of myostatin by the photooxygenation conjugate in muscle homogenate. Photooxygenation catalytic conjugate 13 (0.3 μM or 3 μM) was added to mouse tibialis anterior muscle homogenate (0.1 mg / mL) and myostatin (1 μM) in phosphate buffer (10 mM, pH 7.4). These solutions were irradiated with LED light (730 nm wavelength, 27 mW) at room temperature for 30 minutes. 6x SDS-sample buffer was added to each solution, and the mixture was boiled at 95°C for 10 minutes. 10 μL of the mixture was subjected to SDS-PAGE (15% gel) electrophoresis. Bands were then detected by CBB staining. The results are shown in Figure 20.

[0169] 20, when myostatin in muscle homogenate was photooxygenated using photooxygenation conjugate 13 and light irradiation, the myostatin band became weaker. This indicates that the conjugate having the photooxygenation catalyst according to the present invention can selectively photooxygenate myostatin even in a contaminated system such as muscle homogenate.

[0170] 24. Photooxygenation in Mice. Five-week-old ICR mice received an intramuscular injection of 10 μM (40 μL) of photooxygenated conjugate 13 dissolved in 5% glucose solution into the tibialis anterior muscle of the right leg. The left tibialis anterior muscle received an intramuscular injection of 40 μL of 5% glucose solution alone. Both legs were then irradiated for 10 minutes using an external LED spot light source (wavelength 630 nm) (day 0). A separate non-irradiated control group was also prepared. On days 7, 14, and 21, each mouse underwent the same treatment (intramuscular injection of the sample and 10 minutes of light irradiation). Three or four days after each conjugate 13 administration, additional 10 minutes of light irradiation alone was administered. On Day 28, the muscles were collected and weighed, and the weight of the right tibialis anterior muscle (administered the conjugate) was calculated relative to the weight of the left tibialis anterior muscle (not administered the conjugate) which was set at 100. The results are shown in Figure 21.

[0171] 21, the muscle weight was significantly greater in the irradiated group than in the non-irradiated group, suggesting that light irradiation treatment using the conjugate 13 having a photooxygenation catalyst according to the present invention can increase muscle mass.

[0172] [25. Synthesis of Photooxygenation Catalyst Conjugate for 3CL Protease] Conjugate 25 (photooxygenation catalyst conjugate 25) of the photooxygenation catalyst according to the present invention and a ligand for 3CL protease was synthesized according to the following synthesis scheme and method. Similarly, conjugate 26 (photooxygenation catalyst conjugate 26) of a previously proposed photooxygenation catalyst and a ligand for 3CL protease was also synthesized. Here, the ligand for 3CL protease was SH-5, a known 3CL protease inhibitor (S. Konno et al., Bioorg. Med. Chem., 2013, 21, 412-424.) (in compound 29, the terminal phenyl group of SH-5 has been converted to an ethynyl group).

[0173]

[0174] [25-1. Synthesis of Compound 27]

[0175]

[0176] Compound 27 was synthesized by a method similar to that previously reported (RG Bhat et al., Tetrahedron Lett., 2002, 43, 2467-2469).

[0177] [25-2. Synthesis of Compound 28]

[0178]

[0179] Compound 28 was synthesized by a method similar to that previously reported (S. Konno et al., Bioorg. Med. Chem., 2013, 21, 412-424).

[0180] [25-3. Synthesis of Compound 29]

[0181]

[0182] Compound 28 (59 mg, 0.15 mmol), compound 27 (35 mg, 0.18 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (34 mg, 0.18 mmol), and 1-hydroxybenzotriazole (24 mg, 0.18 mmol) were dissolved in dichloromethane (3 mL). Triethylamine (41 μL, 0.29 mmol) was then added dropwise at 0° C., and the mixture was stirred at room temperature for 1 hour. The solution was diluted with ethyl acetate and then diluted with 5% aqueous citric acid, saturated NaHCO ３ The residue was purified by column chromatography (eluent: ethyl acetate / methanol (20 / 1)) to give Compound 29 (31 mg, 37%).

[0183]

[0184] [25-4. Synthesis of Compound 25]

[0185]

[0186] First, compound 29 (10 mM DMSO solution, 1.0 eq., 16 mg), compound 8 (11 mM DMSO solution, 2.2 eq., 33 mg), and ascorbic acid (120 mM methanol solution, 24 eq., 121 mg) were dissolved in a DMSO / methanol (1 / 1 (v / v)) solution (final: 1 mM compound 29, 1.1 mM compound 8, 24 mM ascorbic acid). Tetrakis(acetonitrile)copper(I) hexafluorophosphate (7-12 eq.) was then added to the solution and allowed to stand for 20 minutes. After centrifugation, the supernatant was purified using preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA / acetonitrile), and lyophilized to yield compound 25 (7.6 mg, 25%).

[0187]

[0188] [25-5. Synthesis of Compound 26]

[0189]

[0190] Compound 26 was synthesized in a similar manner to that used to synthesize compound 25. First, compound 29 (10 mM DMF solution, 1.0 eq., 0.8 mg), compound 10 (11 mM DMF solution, 2.2 eq., 2.1 mg), and ascorbic acid (120 mM methanol solution, 24 eq., 6.5 mg) were dissolved in a DMF / methanol (1 / 1 (v / v)) solution (final: 1 mM compound 29, 1.1 mM compound 10, 24 mM ascorbic acid). Tetrakis(acetonitrile)copper(I) hexafluorophosphate (7-12 eq.) was then added to the solution and allowed to stand for 20 minutes. After centrifugation, the supernatant was purified using preparative reverse-phase HPLC (eluent: 0.1% aqueous TFA / acetonitrile), and lyophilized to obtain compound 26 (0.7 mg, 40%).

[0191]

[0192] 26. Photooxygenation of 3CL protease by photooxygenation catalyst conjugates. To a Tris buffer solution (20 mM, pH 7.4) containing SARS-CoV-2 3CL protease (1 μM), the photooxygenation catalyst conjugates 25 and 26 synthesized above or methylene blue (MB) (1 μM) were added. Note that methylene blue was used as a control to induce non-selective oxygenation. These solutions were irradiated with an LED (wavelength 730 nm, 27 mW) for 30 minutes under ice cooling. Lys-C endopeptidase (1 / 20 of the protein amount) was added to the solution and incubated at 37°C for 2.5 hours. After desalting using a C-4 ZipTip, the percentage of oxygenated 3CL protease was measured using MALDI-TOF MS. The results are shown in Figure 22(a).

[0193] 22(a) shows that conjugate 25 having the photooxygenation catalyst according to the present invention photooxygenated 3CL protease more efficiently than conjugate 26 using a conventionally known photooxygenation catalyst. This indicates that the conjugate having the photooxygenation catalyst according to the present invention exhibits superior photooxygenation activity to conjugates using conventionally known photooxygenation catalysts.

[0194] 27. Inactivation of 3CL Protease by Photooxygenation Catalyst Conjugate Photooxygenation Catalyst Conjugate 25 (5 μM) was added to a Tris buffer solution (20 mM, pH 7.4) containing SARS-CoV-2 3CL protease (3 μM). This solution was irradiated with an LED (wavelength 655 nm, 24 mW) for 30 minutes under ice cooling. The diluted solution was added to a solution containing a fluorescent substrate for 3CL protease (Dabcyl-KTSAVLQSGFRKME(Edans)-amide), and the fluorescence intensity was measured. The reaction rate ratio of the treated enzyme to the control enzyme was calculated. The results are shown in Figure 22(b).

[0195] 22(b), the activity of 3 CL protease was significantly reduced when light irradiation was performed in the presence of conjugate 25, indicating that conjugate 25 inactivated 3 CL protease by photooxygenation. Note that 3 CL protease was not inactivated when light irradiation was performed in the absence of conjugate 25 or when light irradiation was not performed in the presence of conjugate 25.

[0196] The amino acid sequences (N-terminus to C-terminus) of the peptides and their corresponding conjugates used in the above-mentioned Examples, as well as the chemical structures of modified amino acids contained in these amino acid sequences, are shown below. In Table 2, capital letters of amino acids represent L-amino acids, and lowercase letters represent D-amino acids.

[0197]

[0198]

[0199] This application is based on Japanese Patent Application No. 2023-186693, filed on October 31, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A compound represented by the following chemical formula 1 or a salt thereof: [In chemical formula 1, R １ and R ２ each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group; R ３ and R ４ each independently represents a hydrogen atom, a halogen atom, an alkoxy group, or a substituted or unsubstituted alkyl group, in which R １ and R ３ Or R ２ and R ４ may be taken together to form a substituted or unsubstituted alkylene or alkenylene group, R ５ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted monovalent aliphatic hydrocarbon ring group, a substituted or unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic hydrocarbon ring group, or a substituted or unsubstituted monovalent aromatic heterocyclic group; X represents a bromine atom, an iodine atom, or a selenium atom; Y － represents a counter anion, and n is an integer of 1 to 3.

2. The compound or salt thereof according to claim 1, wherein n is 1.

3. R ５ represents a substituted or unsubstituted monovalent aliphatic hydrocarbon ring group, a substituted or unsubstituted monovalent aliphatic heterocyclic group, a substituted or unsubstituted monovalent aromatic hydrocarbon ring group, or a substituted or unsubstituted monovalent aromatic heterocyclic group, or a salt thereof.

4. R ５ The compound according to claim 3, or a salt thereof, wherein represents a substituted or unsubstituted monovalent aromatic heterocyclic group.

5. R １ and R ３ And R ２ and R ４ and each taken together form a substituted or unsubstituted alkylene or alkenylene group forming a 5- or 6-membered ring, respectively, or a salt thereof.

6. R ５ represents a substituted alkyl group, a substituted monovalent aliphatic hydrocarbon ring group, a substituted monovalent aliphatic heterocyclic group, a substituted monovalent aromatic hydrocarbon ring group, or a substituted monovalent aromatic heterocyclic group, and a substituent substituting the alkyl group, the monovalent aliphatic hydrocarbon ring group, the monovalent aliphatic heterocyclic group, the monovalent aromatic hydrocarbon ring group, or the monovalent aromatic heterocyclic group is an -L-Z group, in which L represents a linker having a chemically stable structure, and Z represents a ligand that specifically binds to a target molecule, or a group G that contains at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to a target molecule, or a salt thereof.

7. The compound or salt thereof according to claim 6, wherein Z represents a ligand that specifically binds to a target molecule, and the target molecule to which the ligand Z specifically binds is myostatin or coronavirus 3CL protease.

8. The compound or salt thereof according to claim 6, wherein Z is a group G containing at its terminal a group capable of covalently bonding with a specific functional group of a ligand that specifically binds to a target molecule, said group G containing one or more groups selected from the group consisting of an azomethine ylide group, a nitrone group, a nitrile ylide group, a diazomethyl group, an azide group, a nitrile oxide group, an alkenyl group, an alkynyl group, a carboxy group, an amino group, an N-hydroxysuccinimide ester group, an imido ester group, a pentafluorophenyl ester group, a maleimide group, a haloalkyl group, a haloacetyl group, a pyridyl disulfide group, a hydrazide group, an alkoxyamine group, a diazirine group, an aryl azide group and an isocyanate group.

9. The compound according to claim 6, wherein L has a structure represented by the following chemical formula 2, or a salt thereof: [in chemical formula 2, V represents -NH-, -O-, -S-, -C(=O)-NH-, -NH-C(=O)-, -C(=O)-O-, -O-C(=O)-, -C(=O)- or a triazole ring; k, o and q each independently represent an integer of 0 or 1; l and p each independently represent an integer of 1 to 6; U and W represent -NH-, -O-, -S-, -C(=O)-NH-, -NH-C(=O)-, -C(=O)-O-, -O-C(=O)- or -C(=O)-; *1 represents a bonding site to the alkyl group, the monovalent aliphatic hydrocarbon ring group, the monovalent aliphatic heterocyclic group, the monovalent aromatic hydrocarbon ring group, or the monovalent aromatic heterocyclic group substituted with an -L-Z group, and *2 represents a bonding site to Z.] 10. A photooxygenation catalyst comprising the compound according to any one of claims 1 to 9 or a salt thereof.

11. An inhibitor of myostatin or coronavirus 3CL protease, comprising the photooxygenation catalyst according to claim 10.

12. A pharmaceutical composition comprising the photooxygenation catalyst according to claim 10.

13. The pharmaceutical composition according to claim 12, which is for the prevention and / or treatment of muscle wasting disorders.

14. The pharmaceutical composition for muscle wasting disorder according to claim 13, wherein the muscle wasting disorder is muscular dystrophy or sarcopenia.

15. The pharmaceutical composition according to claim 13, wherein the muscle wasting disorder is a muscle wasting disorder caused by diabetes or cancer cachexia.

16. A method for preventing and / or treating a muscle wasting disorder, comprising administering to a patient an effective amount of the pharmaceutical composition according to claim 13.

17. The method for preventing and / or treating a muscle wasting disorder according to claim 16, wherein the muscle wasting disorder is muscular dystrophy or sarcopenia.

18. The method for preventing and / or treating muscle wasting disorders according to claim 16, wherein the muscle wasting disorder is caused by diabetes or cancer cachexia.

19. The photooxygenation catalyst of claim 10 for use in inhibiting myostatin.

20. The photooxygenation catalyst described in claim 10 for use in the prevention and / or treatment of muscle wasting disorders.

21. The pharmaceutical composition according to claim 12, for the prevention and / or treatment of coronavirus infection.

22. The pharmaceutical composition of claim 21, wherein the coronavirus infection is novel coronavirus disease (COVID-19).

23. A method for preventing and / or treating a coronavirus infection, comprising administering to a patient an effective amount of the pharmaceutical composition according to claim 21.

24. The method for preventing and / or treating a coronavirus infection according to claim 23, wherein the coronavirus infection is novel coronavirus infection (COVID-19).

25. The photooxygenation catalyst according to claim 10 for use in inhibiting coronavirus 3CL protease.

26. The photooxygenation catalyst described in claim 10 for use in the prevention and / or treatment of coronavirus infection.

27. A target molecule inhibitor comprising a photooxygenation catalyst containing the compound according to claim 6 or a salt thereof, wherein Z represents a ligand that specifically binds to a target molecule, and the ligand Z specifically binds to the target molecule and inhibits the target molecule under light irradiation.

28. A precursor of an inhibitor of a target molecule, comprising a photooxygenation catalyst containing the compound according to claim 6 or a salt thereof, wherein Z represents a group G having at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to a target molecule, and the ligand bound to group G specifically binds to the target molecule and inhibits the target molecule under irradiation with light.

29. A method for inhibiting a target molecule, comprising: contacting a photooxygenation catalyst containing the compound or salt thereof according to claim 6, wherein Z represents a ligand that specifically binds to a target molecule, with a target molecule to which the ligand Z specifically binds, thereby causing the ligand Z to specifically bind to the target molecule; and irradiating the photooxygenation catalyst with light to oxygenate and inhibit the target molecule.

30. A method for inhibiting a target molecule, comprising: reacting a photooxygenation catalyst containing the compound or salt thereof according to claim 6, wherein Z represents a group G containing at its terminal a group capable of covalently bonding to a specific functional group possessed by a ligand that specifically binds to a target molecule, with a ligand to convert Z into a ligand that specifically binds to a target molecule; contacting the converted photooxygenation catalyst with a target molecule to which the ligand specifically binds, thereby specifically binding the ligand to the target molecule; and irradiating the photooxygenation catalyst with light to oxygenate and inhibit the target molecule.

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