ACRIDINE COMPOUND

Abstract

A compound represented by formula [I]:

##STR00001##

wherein R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, or C.sub.1-6 alkoxy optionally substituted with halogen; R.sup.21, R.sup.22, and R.sup.23 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, C.sub.1-6 alkoxy optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano; R.sup.3 is C.sub.1-6 alkyl or the like; and X.sup. is an anion.

Claims

1. A compound represented by formula [I]: ##STR00070## wherein R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, or C.sub.1-6 alkoxy optionally substituted with halogen; R.sup.21, R.sup.22, and R.sup.23 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, C.sub.1-6 alkoxy optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano; R.sup.3 is C.sub.1-6 alkyl or ##STR00071## wherein R.sup.32, R.sup.33, R.sup.34, R.sup.35, and R.sup.36 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, C.sub.1-6 alkoxy optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano; and X.sup. is an anion; provided that the following cases are excluded: 1) all of R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.21, R.sup.22, and R.sup.23 are hydrogen, and R.sup.3 is methyl or phenyl; 2) all of R.sup.12, R.sup.14, R.sup.16, and R.sup.3 are methyl, and R.sup.23 is hydrogen or fluorine; and 3) R.sup.12 is hydrogen or methyl, R.sup.13 is hydrogen or methyl, R.sup.14 is hydrogen or methyl, R.sup.15 is hydrogen or methyl, R.sup.16 is hydrogen or methyl, R.sup.3 is methyl or unsubstituted phenyl, and R.sup.23 is hydrogen.

2. The compound according to claim 1, wherein R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 are the same or different and are each hydrogen, fluorine, chlorine, methyl, t-butyl, trifluoromethyl, or trifluoromethoxy; R.sup.21, R.sup.22, and R.sup.23 are the same or different and are each hydrogen, fluorine, chlorine, bromine, trifluoromethyl, methoxy, pentafluorosulfanyl, nitro, or cyano; and R.sup.3 is methyl or ##STR00072## wherein R.sup.32, R.sup.33, R.sup.34, R.sup.35, and R.sup.36 are the same or different and are each hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, pentafluorosulfanyl, nitro, or cyano.

3. The compound according to claim 1, wherein R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 are the same or different and are each hydrogen, fluorine, methyl, t-butyl, trifluoromethyl, or trifluoromethoxy; R.sup.21 and R.sup.22 are hydrogen, R.sup.23 is fluorine; and R.sup.3 is methyl or 4-fluorophenyl.

4. The compound according to claim 1 selected from the following: ##STR00073## ##STR00074## ##STR00075## ##STR00076##

5. The compound according to claim 1, wherein X is perchlorate ion (ClO.sub.4.sup.), hexafluorophosphate ion (PF.sub.6.sup.), or tetrafluoroborate ion (BF.sub.4.sup.).

6. A photoredox catalyst selected from the compound according to claim 1.

7. Use of the compound according to claim 1 as a photoredox catalyst.

8. A method for producing phenol from optionally substituted benzene, comprising irradiating optionally substituted benzene with visible light in the presence of the compound according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0038] FIG. 1 is a graph showing the correlation between reduction potential at the singlet excited state and electron affinity.

[0039] FIG. 2 shows graphs of the fluorescence lifetime.

DESCRIPTION OF EMBODIMENTS

[0040] The phrases and terms used in the present specification are described in detail below.

[0041] In the present specification, halogen is fluorine, chlorine, bromine, or iodine; preferably fluorine, chlorine, or bromine; and more preferably fluorine or chlorine.

[0042] In the present specification, examples of C.sub.1-6 alkyl include C.sub.1-6 linear or branched alkyl, and specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 3-methylpentyl, and the like.

[0043] Further, C.sub.1-6 alkyl also includes C.sub.1-6 alkyl in which 1 to 7 hydrogen atoms are replaced by deuterium atoms.

[0044] In the present specification, examples of C.sub.1-6 alkyl optionally substituted with halogen include C.sub.1-6 linear or branched alkyl groups optionally substituted with 1 to 4 halogens. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 3-methylpentyl, fluoromethyl, chloromethyl, bromomethyl, iodomethyl, difluoromethyl, dichloromethyl, dibromomethyl, trifluoromethyl, trichloromethyl, 2-fluoroethyl, 2-chloroethyl, 2,2,2-trifluoroethyl, 2,2,2-trichloroethyl, 1,1,2,2-tetrafluoroethyl, 3-chloropropyl, 2,3-dichloropropyl, 4,4,4-trichlorobutyl, 4-fluorobutyl, 5-chloropentyl, 3-chloro-2-methylpropyl, 5-bromohexyl, 5,6-dibromohexyl, and the like.

[0045] In the present specification, examples of C.sub.1-6 alkoxy optionally substituted with halogen include C.sub.1-6 linear or branched alkoxy groups optionally substituted with 1 to 4 halogens. Specific examples thereof include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentoxy, isopentoxy, neopentoxy, n-hexyloxy, isohexyloxy, 3-methylpentyloxy, fluoromethoxy, chloromethoxy, bromomethoxy, iodomethoxy, difluoromethoxy, dichloromethoxy, dibromomethoxy, trifluoromethoxy, trichloromethoxy, 2-fluoroethoxy, 2-chloroethoxy, 2,2,2-trifluoroethoxy, 2,2,2-trichloroethoxy, 1,1,2,2-tetrafluoroethoxy, 3-chloropropoxy, 2,3-dichloropropoxy, 4,4,4-trichlorobutoxy, 4-fluorobutoxy, 5-chloropentyloxy, 3-chloro-2-methylpropoxy, 5-bromohexyloxy, 5,6-dibromohexyloxy, and the like.

[0046] In the present specification, examples of sulfanyl optionally substituted with halogen include pentafluorosulfanyl and the like.

[0047] In the present specification, optionally substituted benzene is benzene that may have 1 to 5 substituents. Examples of substituents include alkyl, halogen, an alkyl group having halogen as a substituent, and the like. Specific examples include benzene, toluene, fluorobenzene, chlorobenzene, bromobenzene, o-xylene, m-xylene, p-xylene, trifluoromethyl benzene, benzenesulfonic acid, and the like.

[0048] In the present specification, Lewis acid is an acid defined by G.N. Lewis in 1923. Specific examples include lithium tetrafluoroborate, aluminum chloride, yttrium(III) nitrate, silicon tetrachloride, ruthenium chloride, aluminum isopropoxide, aluminum(III) chloride, aluminum bromide, indium(III) chloride, copper(II) trifluoromethanesulfonate, lanthanum(III) trifluoromethanesulfonate, zinc(II) trifluoromethanesulfonate, silver trifluoromethanesulfonate, ytterbium(III) trifluoromethanesulfonate hydrate, scandium(III) trifluoromethanesulfonate, hafnium(IV) trifluoromethanesulfonate, cerium(III) trifluoromethanesulfonate, neodymium(III) trifluoromethanesulfonate, thulium(III) trifluoromethanesulfonate, yttrium(III) trifluoromethanesulfonate, ti(IV) chloride, tetraisopropyl orthotitanate, titanium(IV) chloride, boron trifluoride, and dicyclohexyl (trifluoromethanesulfonyloxy)borane. Preferred are lithium tetrafluoroborate and aluminum chloride, and more preferred is aluminum chloride.

[0049] In the present specification, X.sup. is not particularly limited as long as it is an anion. Examples include fluoride ion (F.sup.), chloride ion (Cl.sup.), bromide ion (Br.sup.), iodide ion (I.sup.), hydroxide ion (OH.sup.), cyanide ion (CN.sup.), nitrate ion (NO.sub.3.sup.), nitrite ion (NO.sub.2.sup.), hypochlorite ion (ClO.sup.), chlorite ion (ClO.sub.2.sup.), chlorate ion (ClO.sub.3.sup.), perchlorate ion (ClO.sub.4.sup.), permanganate ion (MnO.sub.4.sup.), acetate ion (CH.sub.3COO.sup.), bicarbonate ion (HCO.sub.3.sup.), dihydrogen phosphate ion (H.sub.2PO.sub.4.sup.), hydrogen sulfate ion (HSO.sub.4.sup.), hydrogen sulfide ion (HS.sup.), thiocyanate ion (SCN.sup.), hydrogen oxalate ion (H(COO).sub.2.sup.), hexafluorophosphate ion (PF.sub.6.sup.), tetrafluoroborate ion (BF.sub.4.sup.), and the like. Preferred are perchlorate ion (ClO.sub.4.sup.), hexafluorophosphate ion (PF.sub.6.sup.), and tetrafluoroborate ion (BF.sup.); and more preferred is perchlorate ion (ClO.sub.4.sup.).

[0050] In the present specification, the base is not particularly limited, but examples include inorganic bases, organic bases, and the like. Examples of inorganic bases include alkali metal hydroxides (e.g., lithium hydroxide, sodium hydroxide, and potassium hydroxide), alkaline earth metal hydroxides (e.g., magnesium hydroxide, calcium hydroxide, and barium hydroxide), alkali metal carbonates (e.g., sodium carbonate, potassium carbonate, and cesium carbonate), alkaline earth metal carbonates (e.g., magnesium carbonate, calcium carbonate, and barium carbonate), alkali metal hydrogen carbonates (e.g., sodium hydrogen carbonate and potassium hydrogen carbonate), alkali metal phosphates (e.g., sodium phosphate, potassium phosphate, and cesium phosphate), alkaline earth metal phosphates (e.g., magnesium phosphate and calcium phosphate), alkali metal alkoxides (e.g., sodium methoxide, sodium ethoxide, sodium tert-butoxide, and potassium tert-butoxide), alkali metal hydrides (e.g., sodium hydride and potassium hydride), sodium hydride, and the like. Examples of organic bases include trialkylamines (e.g., trimethylamine, triethylamine, and N,N-diisopropylethylamine (DIPEA)), dialkylamines (e.g., diethylamine and diisopropylamine), 4-dimethylaminopyridine (DMAP), N-methylmorpholine, picoline, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), and the like. One or more of these can be appropriately selected and used in combination.

[0051] In the present specification, Bronsted base is a base defined by Bronsted in 1923, and examples include inorganic bases and organic bases. Specific examples of inorganic bases include alkali metal hydrides (sodium hydride and potassium hydride) and alkaline earth metal hydrides (calcium hydride). Specific examples of organic bases include metal amides (lithium diisopropylamide, potassium hexamethyldisilazide, and lithium 2,2,6,6-tetramethylpiperidide).

[0052] In the present specification, the palladium catalyst is not particularly limited, but examples include tetravalent palladium catalysts, such as sodium hexachloropalladate(IV) tetrahydrate and potassium hexachloropalladate(IV); divalent palladium catalysts, such as [1,1-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct (Pd(dppf)Cl.sub.2.CH.sub.2Cl.sub.2), (2-dicyclohexylphosphino-2,4,6-triisopropyl-1,1-biphenyl) [2-(2-amino-1,1-biphenyl)]palladium(II) methanesulfonate (XPhos Pd G3), [(2-dicyclohexylphosphino-3,6-dimethoxy-2,4,6-triisopropyl-1,1-biphenyl)-2-(2-amino-1, 1-biphenyl)]palladium(II) methanesulfonate (BrettPhos Pd G3), palladium(II) chloride, palladium(II) bromide, palladium(II) acetate, palladium(II) acetylacetonate, dichlorobis (benzonitrile) palladium(II), dichlorobis (acetonitrile) palladium(II), dichlorobis (triphenylphosphine) palladium(II), dichlorotetraammine palladium(II), dichloro(cycloocta-1,5-diene)palladium(II), palladium(II) trifluoroacetate, and 1,1-bis(diphenylphosphino)ferrocene dichloropalladium (II)-dichloromethane complex; zero-valent palladium catalysts, such as tris(dibenzylideneacetone)dipalladium(0) (Pd.sub.2(dba).sub.3), tris(dibenzylideneacetone)dipalladium(0) chloroform complex, and tetrakis(triphenylphosphine) palladium(0) (Pd(PPh.sub.3).sub.4); and the like. These palladium catalysts may be used singly or in combination of two or more.

[0053] In the present specification, specific examples of the leaving group include halogen, C.sub.1-18 alkanesulfonyl, lower alkanesulfonyloxy, arylsulfonyloxy, aralkylsulfonyloxy, perhaloalkanesulfonyloxy, sulfonio, toluenesulfoxy, and the like. Halogen is preferred as the leaving group in the present reaction.

[0054] The halogen is fluorine, chlorine, bromine, or iodine.

[0055] Examples of the C.sub.1-18 alkanesulfonyl include C.sub.1-18 linear or branched alkanesulfonyl, and specific examples thereof include methanesulfonyl, 1-propanesulfonyl, 2-propanesulfonyl, 1-butanesulfonyl, cyclohexanesulfonyl, 1-dodecanesulfonyl, 1-octadecanesulfonyl, and the like.

[0056] Examples of the lower alkanesulfonyloxy include C.sub.1-6 linear or branched alkanesulfonyloxy, and specific examples thereof include methanesulfonyloxy, ethanesulfonyloxy, 1-propanesulfonyloxy, 2-propanesulfonyloxy, 1-butanesulfonyloxy, 3-butanesulfonyloxy, 1-pentanesulfonyloxy, 1-hexanesulfonyloxy, and the like.

[0057] Examples of the arylsulfonyloxy include phenylsulfonyloxy optionally having, on the phenyl ring, 1 to 3 groups selected from the group consisting of C.sub.1-6 linear or branched alkyl, C.sub.1-6 linear or branched alkoxy, nitro, and halogen as substituents, naphthylsulfonyloxy, and the like. Specific examples of the phenylsulfonyloxy optionally having . . . substituents include phenylsulfonyloxy, 4-methylphenylsulfonyloxy, 2-methylphenylsulfonyloxy, 4-nitrophenylsulfonyloxy, 4-methoxyphenylsulfonyloxy, 2-nitrophenylsulfonyloxy, 3-chlorophenylsulfonyloxy, and the like.

[0058] Specific examples of the naphthylsulfonyloxy include -naphthylsulfonyloxy, -naphthylsulfonyloxy, and the like.

[0059] Examples of the aralkylsulfonyloxy include phenyl-substituted C.sub.1-6 linear or branched alkanesulfonyloxy optionally having, on the phenyl ring, 1 to 3 groups selected from the group consisting of C.sub.1-6 linear or branched alkyl, C.sub.1-6 linear or branched alkoxy, nitro, and halogen as substituents; naphthyl-substituted C.sub.1-6 linear or branched alkanesulfonyloxy optionally having, on the phenyl ring, 1 to 3 groups selected from the group consisting of C.sub.1-6 linear or branched alkyl, C.sub.1-6 linear or branched alkoxy, nitro, and halogen as substituents; and the like. Specific examples of the phenyl-substituted alkanesulfonyloxy include benzylsulfonyloxy, 2-phenylethylsulfonyloxy, 4-phenylbutylsulfonyloxy, 4-methylbenzylsulfonyloxy, 2-methylbenzylsulfonyloxy, 4-nitrobenzylsulfonyloxy, 4-methoxybenzylsulfonyloxy, 3-chlorobenzylsulfonyloxy, and the like. Specific examples of the naphthyl-substituted alkanesulfonyloxy include -naphthylmethylsulfonyloxy, -naphthylmethylsulfonyloxy, and the like.

[0060] Specific examples of the perhaloalkanesulfonyloxy include trifluoromethanesulfonyloxy and the like.

[0061] Specific examples of the sulfonio include dimethylsulfonio, diethylsulfonio, dipropylsulfonio, di(2-cyanoethyl)sulfonio, di(2-nitroethyl)sulfonio, di-(aminoethyl)sulfonio, di(2-methylaminoethyl)sulfonio, di-(2-dimethylaminoethyl)sulfonio, di-(2-hydroxyethyl)sulfonio, di-(3-hydroxypropyl)sulfonio, di-(2-methoxyethyl)sulfonio, di-(2-carbamoylethyl)sulfonio, di-(2-carbamoylethyl)sulfonio, di-(2-carboxyethyl)sulfonio, di-(2-methoxycarbonylethyl)sulfonio, diphenylsulfonio, and the like.

[0062] In the present specification, the solvent may be a solvent inert to the reaction. Examples include water, ethers (e.g., dioxane, tetrahydrofuran, diethyl ether, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, and ethylene glycol dimethyl ether), halogenated hydrocarbons (e.g., methylene chloride, chloroform, 1,2-dichloroethane, and carbon tetrachloride), aromatic hydrocarbons (e.g., benzene, toluene, xylene, and chlorobenzene), C.sub.1-4 alcohols (e.g., methanol, ethanol, and isopropanol), and polar solvents (e.g., N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), hexamethylphosphoric triamide, and acetonitrile). These solvents may be used singly or in combination of two or more.

[0063] The substituents in the compound represented by formula [I] of the present invention (hereinafter referred to as compound [I]) are each described below.

[0064] In compound [I], R.sup.12, R.sup.13, R.sup.14, R.sup.15, and R.sup.16 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, or C.sub.1-6 alkoxy optionally substituted with halogen; preferably hydrogen, fluorine, chlorine, methyl, t-butyl, trifluoromethyl, or trifluoromethoxy; and more preferably hydrogen, fluorine, methyl, t-butyl, trifluoromethyl, or trifluoromethoxy.

[0065] In compound [I], R.sup.21, R.sup.22, and R.sup.23 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, C.sub.1-6 alkoxy optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano; preferably hydrogen, fluorine, chlorine, bromine, trifluoromethyl, methoxy, pentafluorosulfanyl, nitro, or cyano; and preferably hydrogen or fluorine.

[0066] In compound [I], R.sup.3 is C.sub.1-6 alkyl, and preferably methyl.

[0067] In another embodiment, in compound [I], R.sup.3 is

##STR00010##

wherein R.sup.32, R.sup.33, R.sup.34, R.sup.35, and R.sup.36 are the same or different and are each hydrogen, halogen, C.sub.1-6 alkyl optionally substituted with halogen, C.sub.1-6 alkoxy optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano; preferably hydrogen, fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, pentafluorosulfanyl, nitro, or cyano; more preferably 4-fluorophenyl, 2,4-difluorophenyl, 2,4,6-trifluorophenyl, 2,3,4,5,6-pentafluorophenyl, 4-fluoro-2-methylphenyl, 4-fluoro-2, 6-dimethylphenyl, 4-trifluoromethylphenyl, 4-cyanophenyl, 4-nitrophenyl, or 4-pentafluorosulfanylphenyl.

[0068] However, the following cases are excluded: all of R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.21, R.sup.22, and R.sup.23 are hydrogen, and R.sup.3 is methyl or phenyl; all of R.sup.12, R.sup.14, R.sup.16, and R.sup.3 are methyl, and R.sup.23 is hydrogen or fluorine; R.sup.12 is hydrogen or methyl, R.sup.13 is hydrogen or methyl, R.sup.14 is hydrogen or methyl, R.sup.15 is hydrogen or methyl, R.sup.16 is hydrogen or methyl, R.sup.3 is methyl or unsubstituted phenyl, and R.sup.23is hydrogen; and all of R.sup.12, R.sup.14, R.sup.16, and R.sup.3 are methyl at the same time.

[0069] In another embodiment, in compound [I], R.sup.21 and R.sup.22 are hydrogen, and R.sup.23 is halogen, C.sub.1-6 alkyl optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano, and preferably fluorine, chlorine, bromine, trifluoromethyl, pentafluorosulfanyl, nitro, or cyano.

[0070] In another embodiment, in compound [I], R.sup.22 and R.sup.23 are hydrogen, and R.sup.21 is halogen, C.sub.1-6 alkyl optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano, and preferably fluorine, chlorine, trifluoromethyl, pentafluorosulfanyl, nitro, or cyano.

[0071] In another embodiment, in compound [I], R.sup.21 and R.sup.23 are hydrogen, and R.sup.22 is halogen, C.sub.1-6 alkyl optionally substituted with halogen, sulfanyl optionally substituted with halogen, nitro, or cyano, and preferably fluorine, chlorine, trifluoromethyl, pentafluorosulfanyl, nitro, or cyano.

[0072] In still another embodiment, in compound [I], R.sup.22 is hydrogen, and R.sup.21 and R.sup.23 are fluorine.

[0073] In another embodiment, in compound [I], R.sup.23 and R.sup.34 are each hydrogen, halogen, alkyl optionally substituted with halogen, sulfanyl optionally substituted with halogen, cyano, or nitro, and preferably hydrogen, fluorine, trifluoromethyl, pentafluorosulfanyl, cyano, or nitro.

[0074] Preferred specific embodiments are the following compounds.

##STR00011## ##STR00012## ##STR00013## ##STR00014##

[0075] In a preferred specific embodiment, the anion (X.sup.) that forms a salt with an acridine compound is perchlorate ion (ClO.sub.4.sup.), hexafluorophosphate ion (PF.sub.6.sup.), or tetrafluoroborate ion (BF.sub.4.sup.).

[0076] In a preferred specific embodiment, the anion (X.sup.) that forms a salt with an acridine compound is perchlorate ion (ClO.sub.4.sup.).

[0077] In the present specification, presentation of preferred embodiments and options regarding different features of the compound, method, and composition of the present invention also includes presentation of combinations of preferred embodiments and options regarding the different features, as long as these are combinable and consistent.

[0078] The method for producing compound [I] is described below. Compound [I] can be produced, for example, by any of the production methods shown below. The production methods shown below are merely examples, and the method for producing compound [I] is not limited thereto.

[0079] In the following reaction formulas, when performing an alkylation reaction, a hydrolysis reaction, an amination reaction, an esterification reaction, an amidation reaction, an etherification reaction, a nucleophilic substitution reaction, an addition reaction, an oxidation reaction, a reduction reaction, etc., these reactions can be performed according to known methods. Examples of such methods include those described in, for example, Experimental Chemistry Course (5th ed., edited by the Chemical Society of Japan, Maruzen Co., Ltd.); Organic Functional Group Preparations, 2nd ed., Academic Press, Inc., published in 1989; Comprehensive Organic Transformations, VCH Publishers Inc., published in 1989; and P. G. M. Wuts and T. W. Greene, Greene's Protective Groups in Organic Synthesis (4th ed., 2006).

General Synthetic Route for Compound [I]

1) Method (1) for Producing Compound [IV]

##STR00015##

wherein Y.sup.1 is a leaving group, and the other symbols are as defined above.

[0080] Compound [IV], which is an intermediate of compound [I] of the present invention, can be produced by the reaction shown in the above reaction formula. Specifically, compound [II] and compound [III] are subjected to a cross-coupling reaction in the presence of a base using a palladium catalyst in a solvent inert to the reaction, whereby compound [IV] can be produced.

[0081] Compound [II] and compound [III] are both known compounds, or compounds that can be easily produced by known methods.

[0082] Other reaction conditions (reaction temperature, reaction time, etc.) can be appropriately determined based on known cross-coupling reactions.

2) Method (1) for Producing Compound [VI]

##STR00016##

wherein Y.sup.2 is a leaving group, and the other symbols are as defined above.

[0083] Compound [VI], which is an intermediate of compound [I] of the present invention, can be produced by the reaction shown in the above reaction formula. Specifically, compound [IV] and compound [V] are reacted in the presence of a Bronsted base in a solvent inert to the reaction, whereby compound [VI] can be produced.

[0084] Compound [V] is a known compound, or a compound that can be easily produced by a known method.

[0085] Other reaction conditions (reaction temperature, reaction time, etc.) can be appropriately determined based on known reactions.

3) Method (2) for Producing Compound [VI]

##STR00017##

wherein Y.sup.3 is a leaving group, and the other symbols are as defined above.

[0086] Compound [VI], which is an intermediate of compound [I] of the present invention, can be produced by the reaction shown in the above reaction formula. Specifically, compound [IV] and compound [VII] are reacted in the presence of a base using a palladium catalyst in a solvent inert to the reaction, whereby compound [VI] can be produced.

[0087] Compound [VII] is a known compound, or a compound that can be easily produced by a known method.

[0088] Other reaction conditions (reaction temperature, reaction time, etc.) can be appropriately determined based on known reactions.

4) Method (1) for Producing Compound [I]

##STR00018##

wherein Y.sup.4 is a leaving group, R.sup.+ is a cation, X.sup. is an anion, and the other symbols are as defined above.

[0089] Compound [I] of the present invention can be produced by the reaction shown in the above reaction formula. Specifically, compound [VI] and compound [VIII] are reacted in the presence of a Lewis acid without a solvent or in a solvent inert to the reaction. This step may be performed under microwave irradiation. Further, a salt (R.sup.+.Math.X.sup.) is acted, whereby compound [I] can be produced. Here, R is, for example, an alkali metal atom, and preferably sodium.

[0090] Compound [VIII] is a known compound, or a compound that can be easily produced by a known method.

[0091] Other reaction conditions (reaction temperature, reaction time, etc.) can be appropriately determined based on known reactions.

5) Method (2) for Producing Compound [I]

##STR00019##

wherein Y.sup.5 is a leaving group, and the other symbols are as defined above.

[0092] Compound [I] of the present invention can be produced by the reaction shown in the above reaction formula. Specifically, compound [IX] and compound [X] are reacted in a solvent inert to the reaction, and a salt (R.sup.+.Math.X.sup.) is further acted, whereby compound [I] can be produced.

[0093] Compound [IX] and compound [X] are both known compounds, or compounds that can be easily produced by known methods.

[0094] Compound [X] can also be produced from its precursor halide and magnesium, and can be used as it is in the present reaction.

[0095] Other reaction conditions (reaction temperature, reaction time, etc.) can be appropriately determined based on known reactions.

[0096] In each of the reactions of the above reaction formulas, the product can be used as the reaction liquid or as the crude product for the next reaction. Alternatively, it can be isolated from the reaction mixture according to a conventional method and easily purified by a general separation method. Examples of general separation methods include recrystallization, distillation, and chromatography.

[0097] The starting raw material compound, intermediate compound, and target compound, as well as compound [I] in each of the above steps include geometric isomers, stereoisomers, optical isomers, and tautomers. Various isomers can be separated by common optical resolution methods. Such optical isomers can also be produced from suitable optically active raw material compounds.

[0098] Compound [I] can be produced by the synthesis method shown in each of the above reaction formulas or by a method equivalent thereto.

[0099] The raw material compounds in the production of compound [I] may be commercially available or produced according to known methods or equivalent methods, unless a specific production method is described.

[0100] The starting raw material compound and target compound in each of the above steps can be used in appropriate salt forms. Such salts include those similar to those exemplified below as salts of compound [I].

[0101] The present invention also includes various hydrates, solvates, and crystal polymorphs of compound [I].

[0102] Compound [I] includes compounds in which one or more atoms are replaced by one or more isotopic atoms. Examples of isotopic atoms include deuterium (.sup.2H), tritium (.sup.3H), .sup.13C, .sup.15N, .sup.18O, and the like.

[0103] Compound [I] may be a co-crystal or a co-crystal salt. Co-crystals or co-crystal salts refer to crystalline substances composed of two or more unique solids at room temperature, each having different physical properties (e.g., structure, melting point, and heat of fusion). Co-crystals and co-crystal salts can be produced by applying known co-crystallization methods.

[0104] Since the excitation wavelength (maximum absorption wavelength) of compound [I] is visible light (360 nm to 830 nm), and preferably 365 nm to 435 nm, it can be used as a photoredox catalyst to oxidize substances (various compounds).

[0105] Since compound [I] has strong oxidizing power, it can be used as a photoredox catalyst to oxidize an aromatic compound, thereby converting the aromatic hydrogen into a hydroxyl group in high yield. For example, compound [I] can be used as a photoredox catalyst to produce phenol from benzene in high yield.

[0106] Compound [I] can be used as a photoredox catalyst to produce oxidized metabolites of pharmaceutical products.

[0107] When compound [I] is used as a photoredox catalyst, compound [I] can be added in an amount of 0.001 mol to 10 mol equivalent per mol of the substrate.

Method for Producing Phenols

[0108] The method for producing phenols using compound [I] as a photoredox catalyst is a method for producing phenols, comprising an oxidation step of converting aromatic compounds to phenols by oxidation, characterized in that in the oxidation step, aromatic compounds are oxidized using the photoredox catalyst of the present invention.

[0109] In the production method of the present invention, the aromatic compound that serves as a raw material for phenols may have substituents. When the aromatic compound has substituents, the number of substituents is not limited as long as there is one or more points of conversion to phenols. Specifically, the aromatic compound may have one substituent, or two or more substituents. When the aromatic compound has two or more substituents, the substituents may be the same or different. Examples of such substituents include halogen, alkyl, alkoxy, carboxy, and the like. The aromatic ring serving as the skeleton of the aromatic compound is not particularly limited, but examples include benzene, naphthalene, anthracene, phenanthrene, pyrene, and fullerene. Specific examples of the aromatic compound include benzene, fluorobenzene, chlorobenzene, bromobenzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, ethylbenzene, naphthalene, 1-chloronaphthalene, 2-chloronaphthalene, 1-bromonaphthalene, 2-bromonaphthalene, 1-methylnaphthalene, 2-methylnaphthalene, anthracene, phenanthrene, pyrene, and the like.

[0110] In the oxidation step, the photoredox catalyst of the present invention oxidizes aromatic compounds and converts them into phenols, as described above. For example, the oxidation reaction proceeds by photoexcitation of the photoredox catalyst of the present invention. The irradiation light in the photoreaction is also not particularly limited, but is preferably visible light in terms of further simplicity of the reaction etc. More specifically, it is more preferable that the photoredox catalyst of the present invention has an absorption band in the visible light region and can be excited by visible light. Of the wavelengths of the visible light to be irradiated, a more preferred wavelength depends on the absorption band of the photoredox catalyst of the present invention; however, it is more preferably, for example, 300 to 450 nm, even more preferably 360 to 450 nm, and particularly preferably 365 to 435 nm.

[0111] The reaction temperature in the oxidation step is also not particularly limited, but is, for example, 100 to 250 C., preferably 0 to 40 C., and more preferably 0 to 30 C. For example, the oxidation reaction can be accelerated by irradiation with visible light at room temperature.

[0112] The photoreaction can be easily carried out by using, for example, visible light contained in natural light, such as sunlight. Instead of or in addition to the natural light, for example, a light source, such as an LED light, a xenon lamp, a halogen lamp, a fluorescent lamp, or a mercury lamp, may be used as appropriate. Furthermore, a filter that cuts off wavelengths other than the necessary wavelengths may be used as appropriate.

[0113] The disclosures of all patent and non-patent literature cited herein are incorporated herein by reference in their entirety.

EXAMPLES

[0114] The present invention is described in more detail with reference to the Test Examples, Reference Examples, and Examples shown below. However, these examples do not limit the present invention and may be changed without deviating from the scope of the present invention.

[0115] The following abbreviations may be used in the present specification.

TABLE-US-00001 TABLE 1 Abbreviation Phrase REX Reference Example number EX Example number STR Structural formula RProp Production method (the number indicates that the compound was produced using corresponding raw materials, as in the Reference Example compound having that number as the Reference Example number) Prop Production method (the number indicates that the compound was produced using corresponding raw materials, as in the Example compound having that number as the Example number) Data Physical property data (NMR1: (ppm) in .sup.1H-NMR in DMSO-d.sub.6; NMR2: (ppm) in .sup.1H-NMR in CDCl.sub.3; NMR3: (ppm) in .sup.1H-NMR in CD.sub.3CN) AcOEt Ethyl acetate AlCl.sub.3 Aluminum chloride BrettPhos Pd G3 [(2-Di-cyclohexylphosphino-3,6-dimethoxy-2,4,6-triisopropyl-1,1- biphenyl)-2-(2-amino-1,1-biphenyl)]palladium(II) methanesulfonate DCM Dichloromethane Hexane Hexane IPE Isopropyl ether CH.sub.3I Methyl iodide NaH Sodium hydride NaClO.sub.4 Sodium perchlorate

[0116] The term room temperature in the following Examples generally refers to about 10 C. to about 35 C. Ratios shown for mixed solvents indicate volume ratios unless otherwise specified. % indicates wt % unless otherwise specified.

[0117] .sup.1HNMR (proton nuclear magnetic resonance) spectra were measured by Fourier transform NMR (Bruker AVANCE III 400 (400 MHz) or Bruker AVANCE III HD (500 MHz)).

Reference Examples

Reference Example 1: Production of 4-fluoro-N-(4-fluorophenyl)-N-methylaniline

[0118] 4-Fluoro-N-(4-fluorophenyl) benzenamine (3.80 g) was dissolved in DMF (30 mL), and NaH (2.424 g) was added under ice-cooling, followed by stirring at room temperature for 15 minutes. After ice-cooling again, CH.sub.3I (1.389 mL) was added, followed by stirring under ice-cooling for 5 minutes, further followed by stirring at room temperature for 1 hour. Water was added to the reaction liquid under ice-cooling, followed by extraction with AcOEt. The organic layer was concentrated, and the residue was purified in a medium-pressure column (Biotage Sfar D 50 g, Hexane/AcOEt), thereby obtaining a target product (3.77 g).

[0119] Using corresponding raw material compounds, the compound of Reference Example 2 was produced in the same manner as in Reference Example 1.

Reference Example 3: Production of 4-fluoro-N,N-bis(4-fluorophenyl)-2-methylaniline

[0120] Bis(4-fluorophenyl)amine (1.0 g) and 2-bromo-5-fluorotoluene (0.724 mL) were dissolved in toluene (5 mL), and BrettPhos Pd G3 (0.022 g) and sodium tert-butoxide (1.171 g) were added, followed by stirring in a nitrogen atmosphere with heating under reflux. The disappearance of the raw materials was confirmed by LC-MS. Water was added to the reaction liquid. After stirring for a while, the resultant was filtered through Celite, and the filtrate was extracted with AcOEt. The organic layer was concentrated, and the residue was purified in a medium-pressure column (Yamazen Hi-Flash Column, 2 L, Hexane/AcOEt), thereby obtaining a target product (1.21 g).

[0121] Table 2 shows the structural formulas and physicochemical data of the compounds of Reference Examples 1 to 3.

TABLE-US-00002 TABLE 2 REX Str RProp Data 1 [00020] 1 NMR2: 6.99-6.94 (m, 4H), 6.93- 6.89 (m. 4H), 3.23 (s, 3H) 2 [00021] 1 NMR2: 7.00-6.94 (m, 2H), 6.83-6.77 (m, 4H), 3.22 (s, 3H) 3 [00022] 3 NMR2: 7.03 (dd, J = 8.68, 5.44 Hz, 1H), 6.96-6.84 (m, 10H)

EXAMPLES

Example 1 (1): Production (1) of 2,7-difluoro-10-methyl-9-(perfluorophenyl)acridin-10-ium perchlorate

[0122] AlCl.sub.3 (0.608 g) was added to a DCM (20 mL) solution of 4-fluoro-N-(4-fluorophenyl)-N-methylaniline (1.0 g), followed by stirring in a nitrogen atmosphere at room temperature for 15 minutes. The reaction liquid was ice-cooled, a DCM (3.0 mL) solution of pentafluorobenzoyl chloride (0.945 mL) was added dropwise with a dropping funnel over 15 minutes, and the mixture was heated to room temperature. After 22 hours, water was added to the reaction liquid, followed by washing with hexane. A 1.0 M NaClO.sub.4 aqueous solution was added to the aqueous layer, followed by extraction with DCM. The organic layer was separated and concentrated. The residue was dispersed and washed with IPE, thereby obtaining a target product (0.212 g).

Example 1 (2): Production (2) of 2,7-difluoro-10-methyl-9-(perfluorophenyl)acridin-10-ium perchlorate

[0123] AlCl.sub.3 (547 mg) was added to a mixture of 4-fluoro-N-(4-fluorophenyl)-N-methylaniline (1.00 g) and pentafluorobenzoyl chloride (945 L), followed by stirring at room temperature. A 1.0 M NaClO.sub.4 aqueous solution was added to the reaction liquid, followed by washing with hexane. The target product was extracted with DCM from the aqueous layer. The organic layer was separated and concentrated. The residue was crystallized with DCM/IPE, followed by filtration, thereby obtaining a target product (0.070 g).

Example 5. Production of 2,7-difluoro-10-methyl-9-phenylacridin-10-ium perchlorate

[0124] In a MW test tube, 4-fluoro-N-(4-fluorophenyl)-N-methylaniline (300 mg) was dissolved in chlorobenzene (5 mL), and benzoyl chloride (189 L) and Tf-OH (trifluoromethanesulfonic acid) (122 L) were added, followed by stirring under microwave irradiation at 160 C. for 1 hour. The reaction liquid was diluted with DCM, and the organic layer was washed with water and a 1 M NaC104 aqueous solution, and concentrated. The residue was dissolved in a small amount of DCM, and IPE was added to precipitate crystals. Then, IPE was further added, and the crystals were filtered and washed with IPE, thereby obtaining a target product (140 mg).

Example 20. Production of 10-(4-fluorophenyl)-9-phenylacridin-10-ium perchlorate

[0125] 10-(4-fluorophenyl)acridin-9(10H)-one (300 mg) was dissolved in THF (10 mL), and phenylmagnesium bromide (691 L) was added under ice-cooling in a nitrogen atmosphere, followed by stirring at room temperature. The disappearance of the raw materials was confirmed, and the reaction liquid was concentrated. The residue was dissolved in DCM, washed with water and 1 M NaClO.sub.4, and concentrated. The residue was dissolved in a small amount of DCM, and IPE was gradually added to precipitate crystals. The crystals were filtered and washed with IPE, thereby obtaining a target product (174 mg).

[0126] Using corresponding raw material compounds, the compounds of Example 2 to 4, 6 to 19, and 21 were produced in the same manner as in Examples 1, 5, and 20.

[0127] Tables 3 to 8 show the structural formula and physicochemical data of the compounds of Examples 1 to 21. In the tables, Prop 1 (1) refers to Example 1 (1), and Prop 1 (2) refers to Example 1 (2).

TABLE-US-00003 TABLE 3 Ex Str Prop Data 1 [00023] 1 (1) NMR1; 9.09 (dd, J = 10.1, 4.40 Hz, 2H), 8.55-8.51 (m, 2H), 8.16 (br d, J = 7.25 Hz, 2H), 5.04 (s, 3H) 2 [00024] 1 (1) NMR2; 7.97-7.94 (m, 4H), 7.74 (dd, J = 10.1, 4.43 Hz, 2H), 7.63-7.56 (m, 4H) 3 [00025] 1 (2) NMR3; 8.78 (dd, J = 10.2, 4.42 Hz, 2H), 8.32-8.27 (m, 2H), 7.80-7.77 (m, 2H), 7.35-7.29 (m, 2H), 4.92 (s, 3H)

TABLE-US-00004 TABLE 4 4 [00026] 1 (2) NMR2; 8.16 (dd, J = 8.88, 5.02 Hz, 1H), 8.02-7.97 (m, 2H), 7.71 (dd, J = 10.0, 4.41 Hz, 2H), 7.60 (br d, J = 7.26 Hz, 2H), 7.47 (td, J = 8.06, 3.10 Hz, 1H), 7.40 (dd, J = 8.37, 2.32 Hz, 1H), 1.83 (s, 3H) 5 [00027] 5 NMR2; 8.83 (dd, J = 10.1, 4.31 Hz, 2H), 8.15-8.12 (m, 2H), 7.76-7.12 (m, 3H), 7.54 (dd, J = 8.39, 2.72 Hz, 2H), 7.49 (br d, J = 8.39 Hz, 2H), 5.10 (s, 3H) 6 [00028] 5 NMR2; 8.80 (dd, J = 9.97, 4.09 Hz, 2H), 8.16-8.12 (m, 2H), 7.74 (d, J = 7.97 Hz, 2H), 7.63 (dd, J = 8.52, 2.47 Hz, 2H), 7.41 (d, J = 7.97 Hz, 2H), 5.10 (s, 3H), 1.49 (s, 9H) 7 [00029] 5 NMR2; 8.84 (dd, J = 9.95, 4.15 Hz, 2H), 8.16-8.12 (m, 2H), 7.68-7.65 (m, 2H), 7.56 (br d, J = 7.05 Hz, 1H), 7.39 (dd, J = 8.14, 2.49 Hz, 2H), 5.12 (s, 3H)

TABLE-US-00005 TABLE 5 8 [00030] 5 NMR2; 8.75 (dd, J = 9.95, 4.05 Hz, 2H), 8.14-8.10 (m, 2H), 8.07-8.06 (m, 2H), 7.92-7.90 (m, 2H), 7.59-7.57 (m, 2H), 7.23 (dd, J = 8.11, 2.46 Hz, 2H), 5.10 (s, 3H) 9 [00031] 5 NMR2; 7.88-7.81 (m, 4H), 7.75-7.74 (m, 3H), 7.70-7.68 (m, 2H), 7.64 (dd, J = 8.51, 2.38 Hz, 2H), 7.59-7.55 (m, 4H) 10 [00032] 5 NMR2; 7.97 (dd, J = 8.47, 4.42 Hz, 2H), 7.89-7.85 (m, 2H), 7.67 (dd, J = 9.84, 4.17 Hz, 2H), 7.60 (t, J = 8.24 Hz, 2H), 7.47 (dd, J = 8.04, 2.34 Hz, 2H), 7.19 (s, 2H), 2.50 (s, 3H), 1.90 (s, 6H) 11 [00033] NMR2; 8.95 (dd, J = 9.93, 4.10 Hz, 2H), 8.19-8.15 (m, 2H), 7.53 (t, J = 8.70 Hz, 1H), 7.37-7.33 (m, 4H), 5.19 (s, 3H), 1.80 (s, 6H)

TABLE-US-00006 TABLE 6 12 [00034] 5 NMR2; 7.95 (dd, J = 8.63, 4.35 Hz, 2H), 7.89-7.85 (m, 2H), 7.68 (dd, J = 8.90, 4.35 Hz, 2H), 7.59-7.53 (m, 3H), 7.42 (dd, J = 8.08, 2.47 Hz, 2H), 7.38 (d, J = 7.70 Hz, 2H), 1.93 (s, 6H) 13 [00035] 5 NMR2; 8.99 (dd, J = 9.96, 4.09 Hz, 2H), 8.18-8.14 (m, 2H), 7.34 (dd, J = 7.96, 2.49 Hz, 2H), 7.11 (d, J = 9.06 Hz, 2H), 5.17 (s, 3H), 1.80 (s, 6H) 14 [00036] 5 NMR2; 7.95 (dd, J = 8.70, 4.40 Hz, 2H), 7.90-7.86 (m, 2H), 7.68 (dd, J = 9.91, 4.28 Hz, 2H), 7.58 (t, J = 8.26 Hz, 2H), 7.41 (dd, J = 8.07, 2.53 Hz, 2H), 7.12 (d, J = 9.04 Hz, 2H), 1.94 (s, 6H) 15 [00037] 5 NMR2; 8.83 (dd, J = 9.98, 4.17 Hz, 2H), 8.15-8.11 (m, 2H), 7.86 (d, J = 8.40 Hz, 1H), 7.68 (t, J = 7.44 Hz, 1H), 7.43-7.39 (m, 3H), 6.98 (d, J = 7.68 Hz, 2H), 5.14 (s, 3H), 2.49 (s, 3H), 1.00 (s, 9H)

TABLE-US-00007 TABLE 7 16 [00038] 5 NMR2; 8.24-8.21 (m, 1H), 7.85-7.81 (m, 3H), 7.67 (t, J = 7.42 Hz, 1H), 7.62- 7.58 (m, 4H), 7.54 (td, J = 8.36, 2.49 Hz, 1H), 7.49-7.46 (m, 3H), 7.41 (d, J = 7.47 Hz, 1H), 5.14 (s, 3H), 1.06 (s, 9H) 17 [00039] 5 NMR2; 8.28-8.25 (m, 1H), 7.98 (d, J = 7.65 Hz, 1H), 7.88-7.82 (m, 3H), 7.72 (t, J = 7.66 Hz, 1H), 7.66 (d, J = 8.46 Hz, 1H), 7.63-7.60 (m, 3H), 7.57-7.56 (m, 2H), 7.49 (dd, J = 8.30, 2.39 Hz, 2H) 18 [00040] 5 NMR2; 8.32-8.29 (m, 1H), 8.06 (d, J = 7.84 Hz, 1H), 8.02 (d, J = 7.42 Hz, 1H), 7.96 (t, J = 7.44 Hz, 1H), 7.91 (t, J = 7.68 Hz, 1H), 7.86-7.82 (m, 2H), 7.64-7.59 (m, 3H), 7.54 (d, J = 5.61 Hz, 2H), 7.33 (dd, J = 8.12, 2.32 Hz, 2H) 19 [00041] 5 NMR2; 7.44-7.38 (m, 3H), 7.26 (dt, J = 6.71, 1.44 Hz, 2H), 6.82 (t, J = 2.18 Hz, 1H), 6.69 (d, J = 2.18 Hz, 2H), 6.43 (d, J = 2.30 Hz, 2H), 6.18 (d, J = 2.30 Hz, 2H), 3.92 (s, 6H), 3.82 (s, 6H), 3.41 (s, 6H)

TABLE-US-00008 TABLE 8 20 [00042] 20 NMR2; 8.01-8.05 (m, 4H), 7.84-7.81 (m, 2H), 7.77-7.71 (m, 7H), 7.58-7.52 (m, 4H) 21 [00043] 1 (1) NMR2; 7.85-7.79 (m, 4H), 7.76-7.68 (m, 4H), 7.62-7.60 (m, 2H), 7.58-7.53 (m, 4H), 1.49 (s, 9H)

[0128] Using corresponding raw material compounds, the compounds of Examples 22 to 40 can be produced in the same manner as in Example 1, 5, or 20. Tables 9 to 12 show the structural formulas of the compounds of Examples 22 to 40.

TABLE-US-00009 TABLE 9 Ex Str 22 [00044] Election Affinity (eV): 6.44 23 [00045] Election Affinity (eV): 6.55 24 [00046] Election Affinity (eV): 6.88 25 [00047] Election Affinity (eV): 5.99 26 [00048] Election Affinity (eV): 6.12 27 [00049] Election Affinity (eV): 6.06

TABLE-US-00010 TABLE 10 28 [00050] Election Affinity (eV): 6.30 29 [00051] Election Affinity (eV): 5.80 30 [00052] Election Affinity (eV): 5.83 31 [00053] Election Affinity (eV): 5.92 32 [00054] Election Affinity (eV): 6.43 33 [00055] Election Affinity (eV): 6.46

TABLE-US-00011 TABLE 11 34 [00056] Election Affinity (eV): 6.63 35 [00057] Election Affinity (eV): 6.79 36 [00058] Election Affinity (eV): 6.34 37 [00059] Election Affinity (eV): 6.61 38 [00060] Election Affinity (eV): 6.31 39 [00061] Election Affinity (eV): 6.54

TABLE-US-00012 TABLE 12 40 [00062] Election Affinity (eV): 6.07 41 [00063] Election Affinity (eV): 6.06sh

Test Examples

[0129] The test results of representative compounds of the present invention are shown below, and the effects of the compounds are explained; however, the present invention is not limited to these Test Examples.

Test Example 1 (Measurement of Reduction Potential at the Singlet Excited State)

Sample Preparation

[0130] The compounds of the present invention or the comparative compounds shown in Table 13 below (5 mmol/L) and TBAPF6 (100 mmol/L) were dissolved in acetonitrile (1 mL) to prepare samples.

Cyclic Voltammetry (CV) Measurement

[0131] Each sample was injected into a volumetric cell, electrodes were attached in an argon atmosphere, and the cell was set in a device and measured. The one-electron reduction potential (E.sub.red) was determined from the average of the peak potentials. [0132] Electrolyte: tetrabutylammonium hexafluorophosphate (TBAPF6) [0133] Working electrode: platinum disk electrode (produced by BAS) [0134] Counter electrode: platinum wire (produced by BAS) [0135] Reference electrode: Ag/AgNO.sub.3 (produced by BAS) [0136] Sweep speed: 100 mV/s [0137] Device: Electrochemical Analyzer Model 610E (produced by BAS)

Maximum Absorption Wavelength Measurement

[0138] Each sample was measured using a UV-visible spectroscopy system 8454 (produced by Agilent Technologies).

Maximum Fluorescence Wavelength Measurement

[0139] Each sample was measured using a FluoroMax-4P fluorescence spectrometer (produced by HORIBA, Ltd.).

Reduction Potential at the Singlet Excited State was Calculated

[0140] Singlet excitation energy was calculated from the maximum absorption wavelength and maximum fluorescence wavelength. The singlet excitation energy was added to the one-electron reduction potential determined by cyclic voltammetry to calculate the reduction potential at the singlet excited state.

[0141] FIG. 1 shows the results.

TABLE-US-00013 TABLE 13 Comparative Example 1 [00064] Comparative Example 2 [00065] Comparative Example 3 [00066] Comparative Example 4 [00067] Comparative Example 5 [00068]

Test Example 2 (Measurement of Fluorescence Lifetime)

[0142] The compounds of the present invention (0.1 mmol/L) were each dissolved in acetonitrile (3 mL), sealed in a 1-cm square cell, and replaced in an argon atmosphere to prepare samples. The samples were measured using a fluorescence lifetime system (DeltaFlex: produced by HORIBA, Ltd.).

[0143] FIG. 2 shows the measurement results.

Test Example 3 (DFT Calculation: Electron Affinity)

[0144] DFT calculations were performed using the following system. [0145] Hardware: High-Performance Computer (produced by HPC Systems, Inc.) [0146] Software: Gaussian 09 Rev D.01

[0147] The following calculations were performed. [0148] 1. Structural optimization (cation) (M06-2X/6-31++G(d)) and energy value [0149] 2. HOMO and LUMO levels [0150] 3. Structural optimization (neutral radical) (UM06-2X/6-31++G(d)) and energy value [0151] 4. Calculation of electron affinity

[0152] FIG. 1 shows the results.

Test Example 4 (Production of Phenol)

##STR00069##

[0153] The compound of the present invention (8 mol %), benzene (0.1 M), water (72 L, optional), and a deuterated acetonitrile solution (2 mL) were irradiated with an LED lamp (product name: Aldrich (trademark) Micro Photochemical Reactor, produced by Merck) in an oxygen atmosphere using the wavelength and irradiation time shown in Table 14. Further, Acr.sup.+-Mes (Comparative Example 1) was used for comparison.

[0154] Table 14 shows the results. The yield indicates the yield of phenol produced, and the residual ratio indicates the ratio of benzene used as a raw material.

[0155] The yield and residual ratio were calculated from the NMR chart using 1,3,5-trimethoxybenzene as the internal standard reagent.

TABLE-US-00014 TABLE 14 Example Irradiation Time Water Yield Residual No. wavelength (nm) (h) addition* (%) ratio (%) 1 405 66 Not added 32 2 1 435 66 Not added 24 0 1 365 15 Not added 38 4 1 405 15 Not added 70 15 1 435 15 Not added 73 12 1 435 15 Added 80 12 2 435 15 Added 63 26 Comparative 365 15 Not added 0 100 Example 1 Comparative 405 15 Not added 0 100 Example 1 *Water was added at the beginning of the reaction and 10 hours after the start of the reaction.