compound

Abstract

Provided is a compound that exhibits fluorescence in a colored state, has good color development, and has good decolorization characteristics. 【Solution means】 A compound represented by the following general formula (I). JPEG2026114052000024.jpg55156 (In the general formula (I), R 11 and R 13 each independently represent an alkyl group which may have a substituent, and R 12 and R 14 each independently represent a group which is an aromatic ring having a substituent, and R 15 represents a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent, and a represents an integer from 0 to 4. When a represents an integer from 2 to 4, a plurality of R 15 may be the same or different.)

Description

[Technical Field]

[0001] This invention relates to compounds. More specifically, this invention relates to compounds that can be used as dyes. [Background technology]

[0002] Fluorane compounds, known as a type of leuco dye, change from a colorless state to a colored state upon contact with an acidic substance (also called a developer or proton donor). By controlling the contact between fluorane compounds and a developer with appropriate acidity and melting point using heat, they can be used as thermochromic materials and are applied to thermal paper, pressure-sensitive paper, etc. Furthermore, inks are known in which a crystalline substance capable of dissolving the leuco dye and developer is included in the leuco dye and developer. When the crystalline substance melts, the leuco dye and developer dissolve, breaking contact between them, and the leuco dye changes to a colorless state and becomes colorless. Patent Document 1 discloses an irreversible thermochromic aqueous ink composition containing, in an ink medium, at least a leuco dye, a developer, a substance that dissolves the leuco dye and developer having a melting point of 50°C to 85°C, and a resin soluble in the substance that dissolves the leuco dye and developer having a melting point of 50°C to 85°C. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-180412 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] As a dye that exhibits a color change between colored and colorless states, there is a need for a dye that exhibits fluorescence when colored, has high color intensity, and is visually undetectable when colorless. However, leuco dyes known to date either do not exhibit fluorescence or do not sufficiently decolorize, leaving room for improvement in decolorization properties. For example, 2'-methyl-6'-(Np-tolyl-N-ethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one, described in Patent Document 1, exhibits red color when colored and has good decolorization properties, but does not exhibit fluorescence.

[0005] The present invention aims to provide a compound that exhibits fluorescence in a colored state, has good color development, and has good decolorization properties. [Means for solving the problem]

[0006] The inventors of the present invention conducted intensive research to solve the above problems and found that a compound represented by the following general formula (I) exhibits fluorescence in the colored state, has good color development, and has good decolorization properties, with little to no color residue remaining when transitioning from the colored state to the decolorized state. Based on this finding, the inventors conducted further research and completed the present invention.

[0007] In other words, the present invention is not limited to the following, but relates to the following compounds, etc. <1> A compound represented by the following general formula (I).

[0008] [ka]

[0009] (In general formula (I), R 11 and R 13 R independently represents an alkyl group which may have substituents, 12 and R 14 R represents a group that is independently represented by the following general formula (II), 15represents a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent, and a represents an integer from 0 to 4. When a represents an integer from 2 to 4, a plurality of R 15 may be the same or different. )

[0010]

Chemical formula

[0011] (In general formula (II), R 21 and R 22 each independently represent an alkyl group which may have a substituent, and b represents an integer from 1 to 4. When b represents an integer from 2 to 4, a plurality of R 22 may be the same or different. * indicates the bonding site with the nitrogen atom in general formula (I). ) <2> R in general formula (I) 11 and R 13 each independently are an alkyl group having 6 to 12 carbon atoms which may have a substituent, or a group represented by the following general formula (III), the compound according to <1> above.

[0012]

Chemical formula

[0013] (In general formula (III), R 31 represents a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, -C(O)-R 32 、-C(O)-O-R 33 、-O-C(O)-R 34 、-SO2-R<00000!6>、a nitro group or a cyano group, and R 32 、R 33 and R 34 each independently represent a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent, and R 35R represents a hydroxyl group, an optionally substituted alkyl group, or an optionally substituted aryl group; L represents an optionally substituted alkylene group; and c represents an integer from 0 to 5. If c represents an integer from 2 to 5, multiple R 31 These may be the same or different. * indicates the bonding site with the nitrogen atom in general formula (I). <3> In general formula (I), R 11 and R 13 These are, independently of each other, an alkyl group having 6 to 12 carbon atoms, or a group represented by the above general formula (III), where R 31 These are halogen atoms, C1-C6 alkyl groups, C1-C6 alkoxy groups, and -C(O)-R 32 , -C(O)-OR 33 -OC(O)-R 34 , -SO2-R 35 , represents a nitro group or a cyano group, R 32 , R 33 and R 34 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have substituents, or an aryl group having 6 to 12 carbon atoms which may have substituents, and R 35 represents a hydroxyl group, an optionally substituted C1-C6 alkyl group, or an optionally substituted C6-C12 aryl group; L represents an alkylene group with C1-C4; c represents an integer from 0 to 2; if c is 2, then two R 31 They may be the same or they may be different, as described above. <1> or <2> The compounds described above. <4> In general formula (II), R 21 and R 22 Each of the following independently represents an alkyl group having 1 to 6 carbon atoms, and b represents an integer from 1 to 3. If b represents an integer from 2 to 3, then multiple R groups are formed. 22 They may be the same or they may be different, as described above. <1> ~ <3> A compound listed in any of the following. <5> In general formula (I), R 11 and R 13 These are groups that are independently represented by the above general formula (III), and R 15is a halogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxy group, and a represents an integer from 0 to 1. In general formula (II), R 21 and R 22 R represents an alkyl group with 1 to 4 carbon atoms, and b represents an integer from 1 to 2. If b represents 2, then two R's are... 22 They may be the same or they may be different. In general formula (III), R 31 'R' represents a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms, 'L' represents an alkylene group having 1 to 2 carbon atoms, and 'c' represents an integer from 1 to 2. If 'c' is 2, then 'R' represents two R's. 31 They may be the same or they may be different, as described above. <1> ~ <4> A compound listed in any of the following. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a compound that exhibits fluorescence in a colored state, has good color development, and has good decolorization properties. [Modes for carrying out the invention]

[0015] The compound of the present invention is a compound represented by the following general formula (I).

[0016] [ka]

[0017] (In general formula (I), R 11 and R 13 R independently represents an alkyl group which may have substituents, 12 and R 14 R represents a group that is independently represented by the following general formula (II), 15 R represents a halogen atom, an optionally substituted alkyl group, or an optionally substituted alkoxy group, and a represents an integer from 0 to 4. If a represents an integer from 2 to 4, multiple R 15 They may be the same or they may be different.

[0018] [ka]

[0019] (In general formula (II), R 21 and R 22 R independently represents an alkyl group which may have substituents, and b represents an integer from 1 to 4. If b represents an integer from 2 to 4, multiple R 22 These may be the same or different. * indicates the bonding site with the nitrogen atom in general formula (I). In this specification, the compound represented by the above general formula (I) is also referred to as compound (I).

[0020] R in general formula (I) 11 , R 13 and R 15 , R in general formula (II) 21 and R 22 Examples of alkyl groups that may have substituents include alkyl groups having 1 to 20 carbon atoms that may have substituents. In this specification, unless otherwise specified, the number of carbon atoms in an optionally substituted group refers to the total number of carbon atoms in the group including the substituent. Examples of C1-C20 alkyl groups that may have substituents include linear, branched, or cyclic alkyl groups that may have substituents. Linear alkyl groups include, for example, linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, and n-pentadecyl groups; Isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, 2-methylbutyl group, 1-methylbutyl group, neopentyl group, 1,2-dimethylpropyl group, 1,1-dimethylpropyl group, 4-methylpentyl group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl group, 1,2-dimethylbutyl group, 1,1-dimethylbutyl group, 3-ethylbutyl group, 2-ethylbutyl group, 1-ethylbutyl group, 1,1,2-trimethylpropyl group, 1-ethyl-2-methylpropyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group Branched alkyl groups such as 1-ethylpentyl group, 2,4-dimethylpentyl group, 2-ethylhexyl group, 2,5-dimethylhexyl group, 2,5,5-trimethylpentyl group, 2,4-dimethylhexyl group, 2,2,4-trimethylpentyl group, 1,1-dimethylhexyl group, 1,1,3,3-tetramethylbutyl group, 3,5,5-trimethylhexyl group, 4-ethyloctyl group, 4-ethyl-4,5-dimethylhexyl group, 1,3,5,7-tetramethyloctyl group, 4-butyloctyl group, 6,6-diethyloctyl group, 6-methyl-4-butyloctyl group, 3,5-dimethylheptadecyl group, 2,6-dimethylheptadecyl group, 2,4-dimethylheptadecyl group, and 2,2,5,5-tetramethylhexyl group; Examples include cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups.

[0021] The substituents in the alkyl group, which may have substituents, are not particularly limited and include, for example, aryl groups having 6 to 10 carbon atoms that may have substituents (phenyl group, naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 4-fluorophenyl group, 2-chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2,4-dichlorophenyl group, 2-bromophenyl group, 2-cyanophenyl group, etc.), linear, branched, or cyclic alkoxy groups having 1 to 8 carbon atoms, amino groups, mono- or di- Examples include alkylamino groups (alkyl groups have 1 to 8 carbon atoms), halogen atoms, cyano groups, hydroxyl groups, nitro groups, carboxyl groups, alkoxycarbonyl groups with 1 to 8 carbon atoms, acyl groups with 2 to 12 carbon atoms (e.g., acetyl group, propionyl group, butyryl group, valeryl group, pivaloyl group, acryloyl group, methacryloyl group, benzoyl group, toluyl group, cinnamoyl group, anisoyl group, naphthoyl group, etc.), acyloxy groups with 2 to 12 carbon atoms, and alkenyl groups with 2 to 10 carbon atoms (e.g., vinyl group, 1-propenyl group, allyl group, butenyl group, styryl group, etc.). Examples of substituents in a cyclic alkyl group that may have substituents include linear or branched alkyl groups having 1 to 10 carbon atoms (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, 2-methylbutyl group, 1-methylbutyl group, neopentyl group, 1,2-dimethylpropyl group, 1,1-dimethylpropyl group, etc.). When an alkyl group has substituents, if there are two or more substituents, each substituent may be the same or different. In one embodiment, the substituent in the alkyl group is preferably a halogen atom, or an aryl group having 6 to 10 carbon atoms, which may have substituents.

[0022] In the present invention, examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. Preferably, fluorine atoms, chlorine atoms, and bromine atoms are used.

[0023] R in general formula (I) 11 and R 13 An example of a substituent alkyl group in is the group represented by the following general formula (III). In the compound of the present invention, R in general formula (I) 11 and R 13 Preferably, each of these is an alkyl group having 6 to 12 carbon atoms, which may have substituents, or a group represented by the following general formula (III).

[0024] [ka]

[0025] (In general formula (III), R 31 This includes halogen atoms, optionally substituted alkyl groups, optionally substituted alkoxy groups, and -C(O)-R 32 , -C(O)-OR 33 -OC(O)-R 34 , -SO2-R 35 , represents a nitro group or a cyano group, R 32 , R 33 and R 34 Each of these independently represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group, and R 35 R represents a hydroxyl group, an optionally substituted alkyl group, or an optionally substituted aryl group; L represents an optionally substituted alkylene group; and c represents an integer from 0 to 5. If c represents an integer from 2 to 5, multiple R 31 These may be the same or different. * indicates the bonding site with the nitrogen atom in general formula (I).

[0026] R 11 and R 13is, independently of each other, an alkyl group having 6 to 12 carbon atoms which may have a substituent, or when representing a group represented by the above general formula (III), as the alkyl group having 6 to 12 carbon atoms which may have a substituent, an alkyl group having 6 to 12 carbon atoms which may be substituted with a halogen atom is preferable, an alkyl group having 6 to 12 carbon atoms is more preferable, a linear or branched alkyl group having 6 to 12 carbon atoms is further preferable, a linear or branched alkyl group having 6 to 10 carbon atoms is even more preferable, a linear alkyl group having 6 to 10 carbon atoms is particularly preferable, and a linear alkyl group having 6 to 8 carbon atoms is most preferable.

[0027] In one aspect of the present invention, R 11 and R 13 are more preferably, independently of each other, a group represented by the above general formula (III). R 31 , R 32 , R 33 , R 34 and R 35 As the alkyl group which may have a substituent in, the same ones as the alkyl group which may have a substituent in R 11 , R 13 and R 15 in the above general formula (I), R 21 and R 22 in the general formula (II) can be mentioned. As the alkyl group which may have a substituent in R 31 , R 32 , R 33 , R 34 and R 35 in, an alkyl group having 1 to 6 carbon atoms which may have a substituent is preferable, an alkyl group having 1 to 6 carbon atoms (preferably a linear or branched alkyl group) is more preferable, an alkyl group having 1 to 4 carbon atoms is further preferable, a methyl group, an ethyl group, and a tert-butyl group are even more preferable, a methyl group and an ethyl group are particularly preferable, and a methyl group is most preferable.

[0028] R 31In this context, examples of optionally substituted alkoxy groups include alkoxy groups having 1 to 20 carbon atoms that may have substituents. Furthermore, examples of alkoxy groups include linear, branched, or cyclic alkoxy groups, with linear or branched alkoxy groups being preferred. Examples of linear, branched, or cyclic alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, isopentyloxy, neopentyloxy, n-hexyloxy, 2-ethylhexyloxy, cyclohexyloxy, and n-dodecyloxy groups.

[0029] The substituents in the alkoxy group, which may have substituents, are not particularly limited and include, for example, halogen atoms, hydroxyl groups, linear, branched, or cyclic alkoxy groups having 1 to 18 carbon atoms, monocyclic or polycyclic aryl groups having 6 to 16 carbon atoms, alkoxycarbonyl groups having 1 to 8 carbon atoms, amino groups, mono- or di-alkylamino groups (alkyl groups having 1 to 8 carbon atoms), and the like.

[0030] R 32 , R 33 , R 34 and R 35 Examples of optionally substituted aryl groups include aryl groups having 6 to 20 carbon atoms that may have substituents. The aryl group is not particularly limited and includes, for example, monocyclic aromatic hydrocarbon groups such as phenyl groups; and polycyclic aromatic hydrocarbon groups such as naphthyl groups, anthracenyl groups, naphthacenyl groups, pentacenyl groups, phenantrenyl groups, and pyrenyl groups. Among these, phenyl groups and naphthyl groups are preferred as aryl groups, with phenyl groups being more preferred.

[0031] The substituents in the aryl group which may have substituents are not particularly limited. For example, a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, a mono- or di-alkylamino group (alkyl having 1 to 8 carbon atoms), a halogen atom, a cyano group, a hydroxy group, a nitro group, a halogenated hydrocarbon group having 1 to 8 carbon atoms, a carboxy group, an alkoxycarbonyl group having 1 to 8 carbon atoms, a monocyclic or polycyclic aryl group having 6 to 14 carbon atoms, etc. may be mentioned. Preferably, it is a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms or a halogen atom. When the aryl group has substituents, if there are two or more substituents, each substituent may be the same or different. Examples of the aryl group having substituents include a nitrophenyl group, a cyanophenyl group, a hydroxyphenyl group, a carboxyphenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a fluorophenyl group, a chlorophenyl group, a bromophenyl group, a methoxyphenyl group, an ethoxyphenyl group, a trifluoromethylphenyl group, an N,N-dimethylaminophenyl group, a nitronaphthyl group, a cyanonaphthyl group, a hydroxynaphthyl group, a methylnaphthyl group, a fluoronaphthyl group, a chloronaphthyl group, a bromonaphthyl group, a trifluoromethylnaphthyl group, a phenoxyphenyl group, a biphenyl group, etc.

[0032] In general formula (III), R 31 represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, -C(O)-R 32 , -C(O)-O-R 33 , -O-C(O)-R 34 , -SO₂-R 35 , a nitro group or a cyano group, preferably. In R 31 , the alkyl group is preferably a linear or branched alkyl group. R 31It is more preferably a halogen atom, a cyano group, or an alkyl group having 1 to 6 carbon atoms; even more preferably a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms; particularly preferably a halogen atom, a cyano group, a methyl group, an ethyl group, or a tert-butyl group; and most preferably a halogen atom, a cyano group, or a methyl group. R 31 The halogen atoms in this mixture are preferably fluorine atoms, chlorine atoms, and bromine atoms.

[0033] R 32 , R 33 and R 34 It is preferable that each of them independently represents a hydrogen atom, an optionally substituted C1-C6 alkyl group, or an optionally substituted C6-C12 aryl group, and more preferably that each independently represents a hydrogen atom or an optionally C1-C4 alkyl group. The alkyl group is preferably a linear or branched alkyl group. 35 It is preferable that this represents a hydroxyl group, an alkyl group having 1 to 6 carbon atoms which may have substituents, or an aryl group having 6 to 12 carbon atoms which may have substituents, and more preferably a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

[0034] In general formula (III), L preferably represents an alkylene group having 1 to 4 carbon atoms, the alkylene group preferably having 1 to 3 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom. L is particularly preferably a methylene group. In general formula (III), c is preferably an integer from 0 to 3, and more preferably an integer from 0 to 2. More preferably c is an integer of 0, 1, or 2.

[0035] In one embodiment, in general formula (III), R 31 It is preferable that represents a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms, L represents an alkylene group having 1 to 2 carbon atoms, and c represents an integer from 1 to 2. If c represents 2, then two R 31They may be the same or they may be different. More preferably, R 31 It is preferable that represents a fluorine atom, a chlorine atom, a bromine atom, a methyl group, an ethyl group, or a cyano group. It is preferable that L represents a C1 alkylene group (methylene group).

[0036] Preferred groups represented by general formula (III) are phenyl group, 2-methylphenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 2-chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2,4-dichlorophenyl group, 2-bromophenyl group, and 2-cyanophenyl group.

[0037] In general formula (II), R 21 and R 22 It is preferable that each of them independently represents an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. 21 and R 22 As the alkyl group in, a linear or branched alkyl group is preferred. In one embodiment, R 21 and R 22 b is more preferably a linear or branched alkyl group having 1 to 6 carbon atoms, more preferably a linear or branched alkyl group having 1 to 4 carbon atoms, even more preferably a linear or branched alkyl group having 1 to 3 carbon atoms, particularly preferably a methyl group or an ethyl group, and most preferably a methyl group. b is preferably an integer from 1 to 3, more preferably an integer from 1 to 2, and even more preferably 1.

[0038] In one embodiment, in general formula (II), R 21 and R 22 Each of the R groups independently represents an alkyl group having 1 to 4 carbon atoms, and b preferably represents an integer from 1 to 2, and more preferably represents 1. When b represents 2, two R groups are formed. 22 They may be the same or they may be different.

[0039] In general formula (I), R 15R is preferably a halogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxy group, more preferably a halogen atom or a C1-C4 linear or branched alkyl group, and even more preferably a halogen atom, a methyl group, or an ethyl group. 15 As the halogen atom in this, a fluorine atom or a chlorine atom is preferred. In general formula (I), a is preferably an integer from 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0040] In one embodiment, compound (I) is defined as R in general formula (I). 11 and R 13 Each of the above represents an 8-carbon linear alkyl group or a group represented by the general formula (III), where a is 0, and in the general formula (II), R 21 and R 22 represents a methyl group, b is 1, and in general formula (III), R 31 A compound is preferred in which represents a halogen atom, a cyano group, or a methyl group, L represents a methylene group, and c is an integer from 0 to 2. More preferably R 11 and R 13 These represent groups that are independently represented by general formula (III). In one embodiment, preferred examples of compound (I) include compounds 1 to 11 described in the examples. Among these, compounds 3 to 11 are more preferred, compounds 4 to 11 are even more preferred, and compounds 4 to 8 and 10 to 11 are particularly preferred due to their better decolorization properties.

[0041] The method for producing the compound of the present invention will be described below with an example of a synthesis method, but the method for producing the compound of the present invention is not limited to the method described below. Furthermore, when carrying out the reaction described later, functional groups other than the site in question may be protected in advance with an appropriate protecting group as needed, and then deprotected at an appropriate stage.

[0042] The compound represented by general formula (I) can be synthesized, for example, from the compound represented by general formula (V) (compound (V)), the compound represented by general formula (VI) (compound (VI)), and the compound represented by general formula (VII) (compound (VII)) by the reaction shown below.

[0043] [ka]

[0044] X in general formula (VI) 1 and X in general formula (VII) 2 R represents halogen atoms such as chlorine, bromine, and iodine. 11 , R 12 , R 13 , R 14 , R 15 And a are the same as in general formula (I). R in the above formula 11 , R 12 , R 13 , R 14 , R 15 The preferred embodiment of a is the same as that of general formula (I). The reaction conditions between compound (V), compound (VI), and compound (VII) are not particularly limited. The reaction is usually carried out in a solvent in the presence of a base. The solvent can be any solvent that is inert to the reaction and is not particularly limited. Examples of organic solvents include NMP (N-methyl-2-pyrrolidone), DMA (dimethylacetamide), and DMF (dimethylformamide). Examples of bases include inorganic bases such as potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, and organic bases such as triethylamine and pyrimidine. The reaction temperature can be, for example, 20 to 180°C, and is preferably 60 to 150°C. The reaction time can be, for example, 0.5 to 72 hours, and is preferably 1 to 48 hours.

[0045] Compound (I) can also be synthesized by the following route.

[0046] [ka]

[0047] R in the above formula 11 , R 12 , R 13 , R 14 , R 15 And a are the same as in general formula (I). R in the above formula 11 , R 12 , R 13 , R 14 , R 15 The preferred embodiment of a is the same as that of general formula (I). Compound (I) can also be obtained by reacting a compound represented by general formula (VIII) (compound (VIII)) with a compound represented by general formula (IX) (compound (IX)) in an acid, followed by treatment with a base. Examples of acids include sulfuric acid, hydrochloric acid, and nitric acid. The reaction is preferably carried out at -10 to 100°C, and more preferably at -10 to 80°C. Examples of bases include sodium hydroxide and potassium hydroxide, and the temperature during the base treatment is preferably 10 to 120°C.

[0048] The isolation and purification of each product in the above manufacturing method can be carried out by appropriately combining methods commonly used in organic synthesis, such as filtration, extraction, washing, drying, concentration, crystallization, and various types of chromatography.

[0049] If geometric isomers exist in the compounds of the present invention, the present invention encompasses all of those geometric isomers. Furthermore, if one or more chiral carbon atoms exist in the compounds of the present invention, the present invention encompasses compounds in which each chiral carbon atom is in an R configuration, an S configuration, or any combination thereof. Moreover, the present invention also encompasses racemic compounds, racemic mixtures, single enantiomers, and diastereomer mixtures thereof.

[0050] The compound represented by general formula (I) is usually colorless, but under acidic conditions, the lactone ring within the molecule reacts with a proton, causing ring opening and conversion to the colored compound represented by general formula (IV) below (compound (IV)). When the acidic conditions are removed, the lactone ring in compound (IV), which is in a ring-closed state, closes again, producing the compound represented by general formula (I). The compound represented by general formula (IV) below is also included in the present invention.

[0051] [ka]

[0052] In the above general formula (IV), R 11 , R 12 , R 13 , R 14 , R 15 And a are the same as in general formula (I). R in general formula (IV) above 11 , R 12 , R 13 , R 14 , R 15 The preferred embodiment of a is the same as that of general formula (I).

[0053] The compound (I) of the present invention preferably has an absorption maximum wavelength of 540 to 560 nm when colored. The absorption maximum wavelength can be measured by the method described in the examples. The compound (I) of the present invention exhibits fluorescence when colored. Compounds represented by the above general formula (IV) usually exhibit yellow to pink fluorescence. The compound of the present invention only needs to exhibit fluorescence when the light of the absorption maximum wavelength is used as the excitation wavelength in the colored state.

[0054] Compound (I) of the present invention can be made colored by reacting with a proton. For example, it can be made colored by mixing compound (I) with a color developer. Furthermore, the compound of the present invention can be converted back to a decolorized state (compound (I)) by abstracting a hydrogen atom from the open-ring state (colored state) lactone ring. The method for returning the open-ring state lactone ring to a closed-ring state is not particularly limited, but examples include contacting the lactone ring with a base, interrupting contact with the color developer, or removing a proton (diluting the concentration).

[0055] Compound (I) of the present invention exhibits fluorescence in the colored state. Furthermore, compound (I) of the present invention has good decolorization properties, as it leaves little to no color residue when it changes from the colored state to the decolorized state. Compound (I) of the present invention can be used as a leuco dye. Compound (I) of the present invention can be suitably used in a variety of applications as a material that can reversibly switch between colorless and colored states.

[0056] The compounds of the present invention are preferably compounds that dissolve in organic solvents. Examples of organic solvents include aromatic hydrocarbons (e.g., toluene, xylene, etc.), ketones (methyl ethyl ketone, acetone, cyclohexanone, 2-heptanone, 3-heptanone, etc.), ethers (e.g., propylene glycol monomethyl ether acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether, etc.), esters (e.g., methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl lactate, ethyl acetate, butyl acetate, methyl 3-methoxypropionate, etc.), and mixtures of two or more of these. The compounds of the present invention are preferably soluble in at least one of the above-mentioned organic solvents at a concentration of 0.1% by weight or more, for example, preferably soluble at a concentration of 0.1% to 50% by weight, more preferably soluble at a concentration of 1% to 40% by weight, and even more preferably soluble at a concentration of 3% to 30% by weight. More preferably, the solubility in organic solvents at 20°C is within this range. When the solubility in organic solvents is within this range, the compounds of the present invention can be suitably used, for example, in the applications described later.

[0057] The compounds of the present invention can be mixed with, for example, a resin to form a dye composition. The above resins are not particularly limited, and thermoplastic resins, photocurable resins, thermosetting resins, etc., can be appropriately selected depending on the application of the colored composition. Examples include polyvinyl alcohol resin, polyacrylamide resin, acrylic resin, polycarbonate resin, polystyrene resin, low-density polyethylene resin, polypropylene resin, polyurethane resin, polyamide resin, polyacetal resin, polyphenylene sulfide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polycycloolefin resin, polysulfone resin, polyethersulfone resin, fluororesin, silicone resin, polyester resin, epoxy resin, phenolic resin, melamine resin, and other resins. These may be used individually or in combination of two or more.

[0058] The amount of compound (I) in the dye composition is preferably 0.001 to 50% by mass, and more preferably 0.01 to 40% by mass, relative to the total solid content of the dye composition.

[0059] The pigment composition may contain optional components other than the compounds and resins of the present invention, depending on its intended use. Examples of optional components include color developers, antioxidants, defoaming agents, other pigments (dyes, pigments, etc.), ultraviolet absorbers, infrared absorbers, polymerizable monomers, polymerization initiators, sensitizers, and dispersants. The method for producing the pigment composition is not particularly limited; for example, the compound and resin of the present invention, along with any optional components that may be added, may be mixed.

[0060] In one embodiment, the dye composition preferably contains a color developer. The color developer is a compound that can cause compound (I) to develop color, and preferably has proton-donating properties. Examples of color developers include compounds having phenolic hydroxyl groups and metal salts of compounds having phenolic hydroxyl groups. As a color developer, for example, tert-butylcatechol, n-stearylphenol, o-phenylphenol, hexafluorobisphenol, n-butyl p-hydroxybenzoate, n-octyl p-hydroxybenzoate, dodecyl gallate, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenylsulfone, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, bis(4-hydroxyphenyl)sulfide, 1-phenyl-1,1-bis(4-hydroxyphenyl)ethane, 1,1-bis(4-hydroxyphenyl)-3-methylbutane, 1,1-bis(4-hydroxyphenyl)-2-methylpropane, 1,1-bis Examples include s(4-hydroxyphenyl)n-hexane, 1,1-bis(4-hydroxyphenyl)n-heptane, 1,1-bis(4-hydroxyphenyl)n-octane, 1,1-bis(4-hydroxyphenyl)n-nonane, 1,1-bis(4-hydroxyphenyl)n-decane, 1,1-bis(4-hydroxyphenyl)n-dodecane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)ethylpropionate, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(4-hydroxyphenyl)n-heptane, and 2,2-bis(4'-hydroxyphenyl)n-nonane. One of these may be used, or two or more may be used. The amount of color developer is not particularly limited, but for example, the amount of color developer can be 0.1 to 100 parts by mass per 1 part by mass of compound (I).

[0061] Compound (I) of the present invention and the dye composition containing Compound (I) of the present invention are suitably used, for example, in the manufacture of inks for writing instruments (e.g., ballpoint pens, felt-tip pens, markers), printing inks, pressure-sensitive paper, thermal paper, and the like. The method for producing an ink containing compound (I) of the present invention is not particularly limited. For example, it can be produced by mixing compound (I) of the present invention or a dye composition containing compound (I) of the present invention with other raw materials used in ink production. [Examples]

[0062] The following are examples illustrating the present invention in more detail, but the present invention is not limited to these examples.

[0063] The instruments used to measure the physical properties of the obtained compounds are as follows: (LC / MS) Shimadzu Corporation High Performance Liquid Chromatograph Mass Spectrometer LCMS-2010EV (ESI method) The analysis was performed on a mixed solution of parallel and antiparallel conformations.

[0064] <Example 1> Manufacturing of Compound 1 In a reactor equipped with a thermometer and a condenser, a mixture of 25.85 g of dichlorofluorane, 140 mL of sulfolane, 26.7 g of magnesium chloride, and 50.9 g of 2,6-dimethylaniline, prepared by the method described in Japanese Patent Publication No. 2005-015808, was heated and stirred at 150°C for 24 hours. After the reaction was complete, 420 mL of 1N hydrochloric acid was added dropwise to the reaction solution at 80°C and stirred for 1 hour. Subsequently, the precipitate was filtered and added to a mixture of 194 mL of methanol, 6.2 g of potassium carbonate, and 117 mL of water, and stirred at 60°C for 30 minutes. After cooling, the precipitate was filtered, washed with methanol, and dried at 100°C to obtain 18 g of the compound represented by the following formula (1-1) (compound 1-1).

[0065] [ka]

[0066] LC-MS: m / z = 539 [M + H] +

[0067] In a reactor equipped with a thermometer and condenser, 10.2 g of compound 1-1, 22.8 g of iodooctane, 60 mL of N-methylpyrrolidone, and 13.1 g of potassium carbonate were mixed and heated and stirred at 105°C for 6 hours. Subsequently, 30 mL of water and 8 g of potassium carbonate were added and heated and stirred at 95°C for 9 hours. After the reaction was complete, the mixture was drained into water, extracted with toluene, and the solvent was concentrated under reduced pressure to obtain the crude product. The product was purified by silica gel column chromatography to obtain 4.2 g of compound 1. LC-MS: m / z = 763 [M + H] +

[0068] <Example 2> Manufacturing of Compound 2 Compound 2-1, represented by the following formula (2-1), was obtained in the same manner as in the synthesis of compound 1-1 of Example 1, except that 2,6-dimethylaniline was replaced with 2,4-dimethylaniline.

[0069] [ka]

[0070] LC-MS:539[M+H] +

[0071] Compound 2 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that Compound 1-1 was replaced with Compound 2-1. LC-MS: m / z = 763 [M + H] +

[0072] <Example 3> Manufacturing of Compound 3 Compound 3 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with 2-methylbenzyl bromide. LC-MS: m / z = 747 [M + H] +

[0073] <Example 4> Manufacturing of Compound 4 Compound 4 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with 2-chlorobenzyl bromide. LC-MS: m / z = 787 [M + H] +

[0074] <Example 5> Manufacturing of compound 5 Compound 5 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with 2,4-dichlorobenzyl chloride. LC-MS: m / z = 855 [M + H] +

[0075] <Example 6> Manufacturing of compound 6 Compound 6 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with 2-bromobenzyl bromide. LC-MS: m / z = 875 [M + H] +

[0076] <Example 7> Manufacturing of compound 7 Compound 7 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with 2-fluorobenzyl chloride. LC-MS: m / z = 755 [M + H] +

[0077] <Example 8> Manufacturing of compound 8 Compound 8 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with 3-chlorobenzyl chloride. LC-MS: m / z = 787 [M + H] +

[0078] <Example 9> Manufacturing of compound 9 Compound 9 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with benzyl bromide. LC-MS: m / z = 719[M+H] +

[0079] <Example 10> Manufacturing of compound 10 Compound 10 was obtained in the same manner as in the synthesis of compound 1 of Example 1, except that iodooctane was replaced with 4-chlorobenzyl chloride. LC-MS: m / z = 787 [M + H] +

[0080] <Example 11> Manufacturing of Compound 11 Compound 11 was obtained in the same manner as in the synthesis of Compound 1 of Example 1, except that iodooctane was replaced with 2-cyanobenzyl chloride. LC-MS: m / z = 769 [M + H] +

[0081] Compounds 1 to 11 prepared in Examples 1 to 11 are represented by the following general formula (IA), where R 11 , R 12 , R 13 and R 14 However, these are compounds with the groups shown in Table 1. R shown in Table 1 11 , R 12 , R 13 and R 14 In this example, * indicates the bonding site with the nitrogen atom in general formula (IA).

[0082] [ka]

[0083] [Table 1]

[0084] <Comparative Example 1> A compound represented by the following formula (C1) (compound C1) was synthesized by the method described in Japanese Patent Publication No. 2001-164245.

[0085] [ka]

[0086] LC-MS: m / z = 691[M+H] +

[0087] <Comparative Example 2> The compound represented by the following formula (C2) (compound C2) (Merck, Rhodamine B-based) was used.

[0088] [ka]

[0089] <Comparative Example 3> A compound represented by the following formula (C3) (compound C3) was synthesized by the method described in Japanese Patent Publication No. 48-060719.

[0090] [ka]

[0091] LC-MS: m / z = 448 [M + H] +

[0092] <Comparative Example 4> The compound represented by the following formula (C4) (compound C4) was synthesized by the following method.

[0093] [ka]

[0094] Compound C4-1 was obtained in the same manner as in the synthesis of compound 1-1 of Example 1, except that 2,6-dimethylaniline was replaced with 4-butylaniline. The compound represented by the following formula (C4-1) was obtained.

[0095] [ka]

[0096] LC-MS: m / z = 595 [M + H] +

[0097] Compound C4 was obtained in the same manner as in the synthesis of compound 1 of Example 1, except that compound 1-1 was replaced with compound C4-1 and iodooctane was replaced with ethyl iodide. LC-MS: m / z = 651 [M + H] +

[0098] (Evaluation of color development and decolorization characteristics) The color development (coloring) and decolorization properties of the compounds (dyes) produced in the examples and comparative examples were evaluated by the following methods. The measuring instrument used was a V-560 UV-Vis spectrophotometer manufactured by JASCO Corporation. (1) Preparation of acetic acid solution of dye 4 mg (±0.2 mg) of the compound (dye) was weighed and dissolved in 50 mL of acetic acid to prepare dye solution A. (2) Color development state (ring-open state) Dye solution A was diluted 10-fold with acetic acid, and the absorption spectrum was measured using a spectrophotometer to determine the wavelength of absorption maximum (λmax). The molar extinction coefficient was calculated from the absorbance at the wavelength of absorption maximum. Table 2 shows the wavelengths of absorption maximum (λmax) for the color development state. (3) Decolorized state (closed ring state) Dye solution A was diluted 10-fold with toluene, and the absorption spectrum was measured using a spectrophotometer. The molar extinction coefficient was calculated from the absorbance at the absorption maximum wavelength of the color development state determined in (2) above. (4) Residual color rate The residual color percentage was calculated using the following formula and evaluated according to the following criteria. The results are shown in Table 2. Residual color percentage (%) = 100 × (Molar extinction coefficient in the decolorized state) / (Molar extinction coefficient in the colored state) (Evaluation Criteria) A: Color retention rate is less than 4% B: Color retention rate is between 4% and 8%. C: Color retention rate is 8% or more but less than 12% D: Color retention rate of 12% or more A lower residual color rate indicates less color retention, meaning better decolorization properties.

[0099] [Table 2]

[0100] (Measurement of fluorescence intensity) The fluorescence intensity of the compounds (dyes) produced in the examples and comparative examples was evaluated by the following method. (1) Preparation of acetic acid solution of dye 4 mg (±0.2 mg) of the compound (dye) was weighed and dissolved in 50 mL of acetic acid to prepare dye solution A. (2) Fluorescence intensity in the colored state (ring-open state) Dye solution A was diluted 100-fold with acetic acid, and the fluorescence spectrum was measured using a spectrofluorometer (Horiba, Ltd., product name FluoroMax-4). The excitation wavelength was the absorption maximum wavelength (λmax) for each dye shown in Table 2, and the fluorescence intensity at the fluorescence maximum wavelength was evaluated. The fluorescence intensity of each compound was evaluated according to the following criteria. The results are shown in Table 3. (Evaluation Criteria) A: Fluorescence intensity of 400,000 or higher B: Fluorescence intensity between 200,000 and 400,000 C: Fluorescence intensity between 100,000 and 200,000 D: Fluorescence intensity less than 100,000

[0101] [Table 3]

[0102] Compounds 1-11 obtained in Examples 1-11 exhibited fluorescence levels equivalent to those of compounds C1 and C2, which are used as fluorescent dyes, in the colored state. Compounds 1-11 showed strong fluorescence intensity and good color development in the colored state. Furthermore, the compounds obtained in the examples had low residual color rates and good decolorization properties. Compounds 3-11 showed particularly good decolorization properties.

Claims

1. A compound represented by the following general formula (I). 【Chemistry 1】 (In general formula (I), R １１ and R １３ R independently represents an alkyl group which may have substituents, １２ and R １４ R represents a group that is independently represented by the following general formula (II), １５ represents a halogen atom, an optionally substituted alkyl group, or an optionally substituted alkoxy group, and a represents an integer from 0 to 4. If a represents an integer from 2 to 4, then multiple R １５ They may be the same or they may be different. 【Chemistry 2】 (In general formula (II), R ２１ and R ２２ each independently represent an alkyl group which may have a substituent, and b represents an integer from 1 to 4. When b represents an integer from 2 to 4, the plurality of R ２２ may be the same or different. * indicates the bonding site with the nitrogen atom in general formula (I).)

2. R in general formula (I) １１ and R １３ The compound according to claim 1, wherein each of the three groups is independently a C6-C12 alkyl group which may have substituents, or a group represented by the following general formula (III). 【Transformation 3】 (In general formula (III), R ３１ This includes a halogen atom, an optionally substituted alkyl group, an optionally substituted alkoxy group, and -C(O)-R ３２ , -C(O)-OR ３３ , -O-C(O)-R ３４ , -SO ２ -R ３５ , represents a nitro group or a cyano group, R ３２ , R ３３ and R ３４ R independently represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group. ３５ R represents a hydroxyl group, an optionally substituted alkyl group, or an optionally substituted aryl group; L represents an optionally substituted alkylene group; and c represents an integer from 0 to 5. If c represents an integer from 2 to 5, multiple R ３１ These may be the same or different. * indicates the bonding site with the nitrogen atom in general formula (I).

3. In general formula (I), R １１ and R １３ These are, independently of each other, an alkyl group having 6 to 12 carbon atoms, or a group represented by the general formula (III), where R ３１ This includes halogen atoms, C1-C6 alkyl groups, C1-C6 alkoxy groups, and -C(O)-R ３２ , -C(O)-OR ３３ , -O-C(O)-R ３４ , -SO ２ -R ３５ , represents a nitro group or a cyano group, R ３２ , R ３３ and R ３４ Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have substituents, or an aryl group having 6 to 12 carbon atoms which may have substituents, R ３５ R represents a hydroxyl group, an optionally substituted C1-C6 alkyl group, or an optionally substituted C6-C12 aryl group; L represents a C1-C4 alkylene group; c represents an integer from 0 to 2; if c is 2, then two R ３１ The compound according to claim 1 or 2, wherein the compounds may be the same or different.

4. In general formula (II), R ２１ and R ２２ Each of the following independently represents an alkyl group having 1 to 6 carbon atoms, and b represents an integer from 1 to 3. If b represents an integer from 2 to 3, then multiple R ２２ The compound according to claim 1 or 2, wherein the compounds may be the same or different.

5. In general formula (I), R １１ and R １３ These are groups that are independently represented by the general formula (III), and R １５ is a halogen atom, a C1-C4 alkyl group, or a C1-C4 alkoxy group, and a represents an integer from 0 to 1. In general formula (II), R ２１ and R ２２ R represents an alkyl group with 1 to 4 carbon atoms, and b represents an integer from 1 to 2. When b represents 2, two R ２２ They may be the same or they may be different. In general formula (III), R ３１ represents a halogen atom, a cyano group, or an alkyl group having 1 to 4 carbon atoms; L represents an alkylene group having 1 to 2 carbon atoms; c represents an integer from 1 to 2; if c represents 2, then two R ３１ The compound according to claim 1 or 2, wherein the compounds may be the same or different.

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