Pyrazole-based squarylium compound, resin composition, coloring material dispersion, ink composition, and optical filter

Abstract

This pyrazole-based squarylium compound is represented by formula (1).　In formula (1), RC represents a primary alkyl group having 2-5 carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms, and RN represents a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 4 or more carbon atoms. When RN represents a tertiary alkyl group having 4 carbon atoms, RC represents at least one selected from a cyclopropyl group, a cyclohexyl group, and a 3-pentyl group.

Description

Pyrazole-based squarylium compounds, resin compositions, colorant dispersions, ink compositions, and optical filters

[0001] This disclosure relates to pyrazole-based squarylium compounds, resin compositions, colorant dispersions, ink compositions, and optical filters.

[0002] Squallium compounds exhibit strong absorption across a wide wavelength range from visible light to near-infrared, and are widely used because they can be selectively absorbed at specific wavelengths through adjustment.

[0003] For example, an asymmetric squarylium compound metal complex and an optical recording medium using the same are known, which have high light absorption characteristics in the 300-530 nm wavelength range, which is recordable and re-recordable with a blue semiconductor laser, and which also have excellent thermal decomposition behavior and solubility in solvents, as well as excellent light resistance and durability (Patent Document 1). In addition, a squarylium compound metal complex that is used in optical recording media and has excellent recording and re-recording characteristics is known (Patent Document 2). Furthermore, a squarylium compound that can selectively reduce light in unwanted wavelength ranges in order to improve the color purity of light sources in lighting devices and display devices has been disclosed (Patent Document 3).

[0004] Patent Document 1: Japanese Unexamined Patent Publication No. 2007-131829 Patent Document 2: International Publication No. 2011 / 162190 Patent Document 3: Japanese Unexamined Patent Publication No. 2023-6191

[0005] Pyrazole-based squarylium compounds exhibit sharp absorption characteristics with no side absorption, making them excellent as selectively absorbing dyes. However, their low solubility and poor lightfastness made them difficult to use industrially. Furthermore, while the pyrazole ring provides a large dipole moment and sharp absorption characteristics, their stability as dyes was low.

[0006] One embodiment of this disclosure aims to solve the problem of providing a pyrazole-based squarylium compound with excellent lightfastness, optical properties, and solubility. Another embodiment of this disclosure aims to solve the problem of providing a resin composition, a colorant dispersion, an ink composition, and an optical filter using the above-mentioned pyrazole-based squarylium compound.

[0007] Means for solving the above problems include the following aspects. <1> A pyrazole-based squarylium compound represented by the following formula (1).

[0008]

[0009] In formula (1), R Ｃ represents a primary alkyl group having 2 to 5 carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms, and R Ｎ represents a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 4 or more carbon atoms. However, when R Ｎ represents a tertiary alkyl group having 4 carbon atoms, R Ｃ represents at least one selected from a cyclopropyl group, a cyclohexyl group, and a 3-pentyl group. <2> The pyrazole-based squarylium compound according to <1>, wherein R Ｃ is at least one selected from a cyclopropyl group, a cyclohexyl group, and a 3-pentyl group. <3> The pyrazole-based squarylium compound according to <1> or <2>, wherein R Ｎ represents a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms. <4> The pyrazole-based squarylium compound according to any one of <1> to <3>, wherein at least one of R Ｃ and R Ｎ is a substituted alkyl group. <5> The pyrazole-based squarylium compound according to any one of <1> to <4>, wherein at least one of R Ｃ and R Ｎ is an alkyl group substituted by a halogen or an alkoxy group. <6> R Ｃ and R Ｎ<1> to <5>: At least one of the pyrazole-based squarylium compounds is a cyclic alkyl group. <7> A pyrazole-based squarylium compound is a dye as described in any one of <1> to <6>. <8> A resin composition comprising a pyrazole-based squarylium compound as described in any one of <1> to <7> and a resin. <9> The resin composition as described in <8>, wherein the resin is a thermoplastic resin or a thermosetting resin. <10> The resin composition as described in <9>, wherein the thermoplastic resin is at least one selected from polycarbonate resin, polyamide resin, acrylic resin, polyester resin, and cyclic olefin resin, and the thermosetting resin is at least one selected from polyurethane resin, polythiourethane resin, allyl diglycol carbonate resin, epoxy resin, and poly(meth)acrylic resin. <11> The resin composition as described in <10>, wherein the cyclic olefin resin is a cyclic olefin copolymer. <12> A colorant dispersion containing a pyrazole-based squarylium compound described in any one of <1> to <7>, a dispersant, and a solvent. <13> An ink composition containing a pyrazole-based squarylium compound described in any one of <1> to <7> and a binder. <14> An optical filter containing a pyrazole-based squarylium compound described in any one of <1> to <7>.

[0010] According to one embodiment of the present disclosure, a pyrazole-based squarylium compound with excellent lightfastness, optical properties, and solubility can be provided. Furthermore, according to one embodiment of the present disclosure, a resin composition, a colorant dispersion, an ink composition, and an optical filter using the above-mentioned pyrazole-based squarylium compound can be provided.

[0011] The contents of this disclosure will be described in detail below. The explanation of the constituent elements described below may be based on representative embodiments of this disclosure, but this disclosure is not limited to such embodiments. In this specification, the "~" indicating a numerical range is used to mean that the numbers described before and after it are the lower and upper limits. In numerical ranges described in stages in this disclosure, the upper or lower limit described in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. Furthermore, in the notation of groups (atomic groups) in this specification, notations that do not specify substitution or unsubstituted include both those with and without substituents. For example, "alkyl group" includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups). Furthermore, the term "process" in this specification is included not only in independent processes but also in cases where it is not clearly distinguishable from other processes, as long as the intended purpose of the process is achieved. Furthermore, in this disclosure, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. Moreover, in this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. The disclosure will now be described in detail.

[0012] (Pyrazole-based squarylium compounds) A pyrazole-based squarylium compound, which is one embodiment of the present disclosure, is represented by the following formula (1).

[0013]

[0014] In formula (1), R Ｃ R represents a primary alkyl group having 2 to 5 carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms. Ｎ This represents a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms.

[0015] In one embodiment of the present disclosure, the pyrazole-squallium compound represented by formula (1) includes a plurality of pyrazole-squallium compounds having a tautomer structure of a certain pyrazole-squallium compound represented by formula (1). The cations of the pyrazole-squallium compound represented by formula (1) are delocalized, and each pyrazole-squallium compound represented by formula (1) has a plurality of tautomer structures. When the tautomer structure of a certain pyrazole-squallium compound is represented by formula (1), this tautomer squarylium compound is included in the pyrazole-squallium compound represented by formula (1). The pyrazole-squallium compound represented by formula (1) can also be said to be a dye whose at least one tautomer structure can be represented by formula (1). In one embodiment of the present disclosure, the pyrazole-squallium compound represented by formula (1) may have any tautomer structure, as long as at least one of its tautomer structures is represented by formula (1).

[0016] The tautomer structure of the pyrazole-based squarylium compound represented by formula (1) is shown, for example, by the following formula (1a).

[0017]

[0018] In the above formula (1a), R Ｃ and R Ｎ R in equation (1) is Ｃ and R Ｎ It is similar to that.

[0019] While some conventionally known pyrazole-based squarylium compounds exhibited excellent optical properties, their high planarity of the compound's skeleton and strong intermolecular electrostatic interactions sometimes resulted in low solubility. Furthermore, squarylium compounds generally had relatively low lightfastness. One embodiment of the present disclosure, a pyrazole-based squarylium compound represented by formula (1), is presumed to exhibit excellent lightfastness, optical properties, and solubility by having a specific combination of groups in the pyrazole ring portion.

[0020] In terms of optical properties, the pyrazole-squallium compound represented by formula (1), which is one embodiment of the present disclosure, is a pyrazole-squallium compound that can selectively absorb wavelengths of 480 to 520 nm. Furthermore, the resin composition, colorant dispersion, ink composition, and optical filter using the above-mentioned pyrazole-squallium compound, which is one embodiment of the present disclosure, are resin compositions, colorant dispersions, ink compositions, and optical filters that can selectively absorb wavelengths of 480 to 520 nm.

[0021] In terms of solubility, the pyrazole-based squarylium compound represented by formula (1), which is one embodiment of the present disclosure, exhibits excellent solubility in either propylene glycol methyl ether acetate (PGMEA) or toluene. However, the pyrazole-based squarylium compound represented by formula (1), which is one embodiment of the present disclosure, is not limited to these solvents and exhibits excellent solubility in other solvents as well.

[0022] In terms of lightfastness, the pyrazole-based squarylium compound represented by formula (1), which is one embodiment of the present disclosure, exhibits excellent lightfastness, as shown in the examples. Furthermore, the resin composition, colorant dispersion, ink composition, and optical filter using the above-mentioned pyrazole-based squarylium compound, which are one embodiment of the present disclosure, are resin compositions, colorant dispersions, ink compositions, and optical filters that exhibit excellent lightfastness.

[0023] R in equation (1) Ｃ R represents a primary alkyl group having 2 to 5 carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms. The alkyl group may be linear, branched, or cyclic, and may be unsubstituted or substituted. Substituents in the case of substitution include halogens, alkoxy groups, or carbonyl groups. The two R in formula (1) Ｃ R represents the same group. Ｃ is a trifluoromethyl group (CF ３ ) is also acceptable.

[0024] Examples of primary alkyl groups having 2 to 5 carbon atoms include linear, branched, or cyclic primary alkyl groups having 2 to 5 carbon atoms. From the viewpoint of light resistance, optical properties, and solubility, the primary alkyl groups having 2 to 5 carbon atoms include ethyl group (Et), n-propyl group (nPr), n-butyl group (nBu), i-butyl group (iBu), and n-pentyl group (nC ５ H １１ ), i-pentyl group (iC ５ H １１ ), neo-pentyl group (neoC ５ H １１ ), methoxyethyl group (CH ３ OCH ２ CH ２ ), ethoxy group (C ２ H ５ O), or ethoxyethyl group (C ２ H ５ OCH ２ CH ２ ) is preferable.

[0025] Examples of secondary alkyl groups having 3 or more carbon atoms include linear groups having 2 to 5 carbon atoms, and branched and cyclic secondary alkyl groups having 2 or more carbon atoms. From the viewpoint of light resistance, optical properties, and solubility, examples of secondary alkyl groups having 3 or more carbon atoms include i-propyl group (iPr), cyclopropyl group (cycloPr), sec-butyl group (2-Bu), diethylmethyl group (3-pentyl group), CH(C) ２ H ５ ) ２ ), cyclohexyl group (cycloC ６ H １３ ), 2-ethylhexyl group (CH ２ CH(C) ２ H ５ ) C ４ H ９ ), or sec-pentyl group (2-C ５ H １１ ) is preferable.

[0026] Examples of tertiary alkyl groups having 5 or more carbon atoms include linear, branched, or cyclic tertiary alkyl groups having 5 or more carbon atoms. From the viewpoint of lightfastness, optical properties, and solubility, tert-pentyl group (tC) is selected as a tertiary alkyl group having 5 or more carbon atoms. ５H １１ ), tert-hexyl group (C(CH ３ ) ２ (CH ２ ) ２ CH ３ ), or a 1-adamantyl group (1-adamantyl) is preferred.

[0027] From the perspective of the absorption maximum wavelength of pyrazole-based squarylium compounds, R Ｃ The introduction of a primary alkyl or secondary alkyl group is preferable.

[0028] R in equation (1) Ｎ R represents a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 4 or more carbon atoms. The alkyl group may be linear, branched, or cyclic, and may be unsubstituted or substituted. Substituents in the case of substitution include halogens, alkoxy groups, or carbonyl groups. The two R in formula (1) Ｎ R represents the same group. Ｎ is a heptyloxy group (OC ７ H １５ ), or octanoyl group (C(=O)C ７ H １５ ) is also acceptable.

[0029] Primary alkyl groups having two or more carbon atoms include linear, branched, or cyclic primary alkyl groups having two or more carbon atoms. From the viewpoint of lightfastness, optical properties, and solubility, it is preferable that the number of carbon atoms be eight or less. From the viewpoint of lightfastness, optical properties, and solubility, primary alkyl groups having two or more carbon atoms include ethyl group (Et), n-propyl group (nPr), n-butyl group (nBu), i-butyl group (iBu), and n-pentyl group (nC ５ H １１ ), i-pentyl group (iC ５ H １１ ), neo-pentyl group (neoC ５ H １１ ), n-hexyl group (nC ６ H １３ ), n-heptyl group (nC ７ H １５ ), or 2-ethylhexyl group (CH ２ CH(C)２ H ５ )(C ４ H ９ ) is preferred.

[0030] The secondary alkyl group having 3 or more carbon atoms includes each of the linear, branched, or cyclic primary alkyl groups having 3 or more carbon atoms. As the secondary alkyl group having 3 or more carbon atoms, from the viewpoints of light resistance, optical properties, and solubility, an i-propyl group (iPr), a cyclopropyl group (cycloPr), a sec-butyl group (2-Bu), a diethylmethyl group (3-pentyl group, CH(C ２ H ５ ), ２ )), a sec-pentyl group (2-C ５ H １１ ), a cyclohexyl group (cycloC ６ H １３ ), or a 2-adamantyl group (2-adamantyl) is preferred. From the viewpoints of light resistance, optical properties, and solubility, it is more preferable that the number of carbon atoms is 5 or less.

[0031] As the tertiary alkyl group having 4 or more carbon atoms, a tert-butyl group (tBu) is included. R Ｃ is preferably any one of a cyclopropyl group, a cyclohexyl group, or a 3-pentyl group. When R Ｎ is a tertiary alkyl group having 4 or more carbon atoms, R Ｃ is any one of a cyclopropyl group, a cyclohexyl group, or a 3-pentyl group.

[0032] R Ｎ is preferably a tertiary alkyl group having 5 or more carbon atoms. The tertiary alkyl group having 5 or more carbon atoms includes each of the linear, branched, or cyclic primary alkyl groups having 5 or more carbon atoms. From the viewpoints of light resistance, optical properties, and solubility, it is preferable that the number of carbon atoms is 5. As the tertiary alkyl group having 5 carbon atoms, from the viewpoints of light resistance, optical properties, and solubility, a tert-pentyl group (tC ５ H １１ ), or a 1-adamantyl group (1-adamantyl) is preferred.

[0033] R Ｃ and R ＮAt least one of them is preferably a substituted alkyl group. Also, R Ｃ and R Ｎ are each preferably an alkyl group substituted by a halogen or an alkoxy group. Also, R Ｃ and R Ｎ are each preferably a cyclic alkyl group.

[0034] The combination of R Ｃ and R Ｎ in formula (1) includes the combinations of the preferred groups mentioned above for each of R Ｃ and R Ｎ . Therefore, specific examples of the pyrazole-based squarylium compound represented by formula (1) include compounds obtained by combining any one of the following R Ｃ with any one of R Ｎ . The abbreviations in Table 1 are as shown above, and the specific chemical formulas are shown below. In the chemical formula, "*" indicates the bonding site. R Ｃ and R Ｎ may be the same group or different groups from each other.

[0035]

[0036]

[0037]

[0038] From the viewpoints of light resistance, optical properties, and solubility, the combination of R Ｃ and R Ｎ in formula (1) is such that R Ｃ is an ethyl group (Et), n-propyl group (nPr), i-propyl group (iPr), cyclopropyl group (cycloPr), n-pentyl group (nC ５ H １１ ), i-butyl group (iBu), i-pentyl group (iC ５ H １１ ), neo-pentyl group (neoC ５ H １１ ), diethylmethyl group (CH(C ２ H ５ ) ２), i-pentyl group (iC ５ H １１ ), tert-pentyl group (tC ５ H １１ ), cyclohexyl group (cycloC ６ H １１ ), ethoxy group (OC ２ H ５ ), and ethoxyethyl group (CH ２ CH ２ OC ２ H ５ ) is one of the following, and R Ｎ However, ethyl group (Et), n-propyl group (nPr), i-propyl group (iPr), n-butyl group (nBu), neo-pentyl group (neoC) ５ H １１ ), diethylmethyl group (CH(C ２ H ５ ) ２ ), 2-ethylhexyl group (CH ２ CH(C) ２ H ５ ) C ４ H ９ ), tert-pentyl group (tC ５ H １１ ), n-pentyl group (nC ５ H １１ Preferably, it is one of the following: 1-adamantyl group, and 2-adamantyl group. In the following, the diethylmethyl group is 3-C ５ H １１ It is also written as follows.

[0039] R in equation (1) Ｃ and R Ｎ From the viewpoint of lightfastness, optical properties, and solubility, the following combinations (a) to (i) are more preferable. (a) R Ｃ However, it is an ethyl group (Et), and R Ｎ However, it is either an ethyl group (Et) or an i-propyl group (iPr). (b) R Ｃ However, it is an n-propyl group (nPr), and R Ｎ However, it is one of the following: an ethyl group (Et), an n-propyl group (nPr), and an i-propyl group (iPr). (c) RＣ However, it is an i-propyl group (iPr), and R Ｎ However, ethyl group (Et), i-propyl group (iPr), n-butyl group (nBu), neo-pentyl group (neoC) ５ H １１ ), diethylmethyl group (CH(C ２ H ５ ) ２ ), n-hexyl group (nC ６ H １３ ), 2-ethylhexyl group (2-ethyl-hexyl), and tert-pentyl group (tC ５ H １１ (d) R Ｃ However, it is a cyclopropyl group (cycloPr), and R Ｎ However, i-propyl group (iPr), n-pentyl group (nC ５ H １１ ), neo-pentyl group (neoC ５ H １１ ), diethylmethyl group (CH(C ２ H ５ ) ２ ), 2-ethylhexyl group (CH ２ CH(C) ２ H ５ ) C ４ H ９ ), and tert-pentyl group (tC ５ H １１ ) is. (e)R Ｃ However, neo-pentyl group (neoC ５ H １１ ) and R Ｎ However, it is an i-propyl group (iPr). (f)R Ｃ However, the diethylmethyl group (CH(C) ２ H ５ ) ２ ) and R Ｎ However, it is an i-propyl group (iPr). (g)R Ｃ However, the diethylmethyl group (CH(C) ２ H ５ ) ２ ) or cyclohexyl group (cycloC ６ H １３ ) and R ＮHowever, the tert-pentyl group (tC ５ H １１ ) is. (h)R Ｃ However, the methoxyethyl group (CH ２ CH ２ OCH ３ ) or ethoxyethyl group (C ２ H ５ OCH ２ CH ２ ) and R Ｎ However, it is an i-propyl group (iPr). (i)R Ｃ However, it is an i-propyl group (iPr), and R Ｎ However, it is either a 1-adamantyl group or a 2-adamantyl group.

[0040] R in equation (1) Ｃ and R Ｎ From the viewpoint of lightfastness, optical properties, and solubility, the following combinations (j) to (m) are even more preferable. (j)R Ｃ However, it is an i-propyl group (iPr), and R Ｎ However, i-propyl group (iPr), n-butyl group (nBu), neo-pentyl group (neoC ５ H １１ ), diethylmethyl group (CH(C ２ H ５ ) ２ ) and 2-ethylhexyl group (CH ２ CH(C) ２ H ５ ) C ４ H ９ ), and tert-pentyl group (tC ５ H １１ (k) R Ｃ However, it is a cyclopropyl group (cycloPr), and R Ｎ However, i-propyl group (iPr), neo-pentyl group (neoC ５ H １１ ), diethylmethyl group (CH(C ２ H ５ ) ２ ) and 2-ethylhexyl group (CH ２ CH(C) ２ H５ ) C ４ H ９ ), and tert-pentyl group (tC ５ H １１ ) is. (l)R Ｃ However, the diethylmethyl group (CH(C) ２ H ５ ) ２ ) and R Ｎ However, it is an i-propyl group (iPr). (m)R Ｃ However, the diethylmethyl group (CH(C) ２ H ５ ) ２ ) or cyclohexyl group (cycloC ６ H １３ ) and R Ｎ However, the tert-pentyl group (t-C ５ H １１ )

[0041] There are no particular limitations on the method for producing the pyrazole-type squarylium compound represented by formula (1), but for example, it can be synthesized by a dehydration condensation reaction between pyrazolone and squalic acid.

[0042] The molecular weight of the pyrazole-based squarylium compound represented by formula (1) is preferably 350 to 700, and more preferably 400 to 550, from the viewpoint of coloring power, i.e., high absorption coefficient. The molecular weight of the pyrazole-based squarylium compound in one embodiment of this disclosure is determined by electrospray ionization mass spectrometry.

[0043] The pyrazole-based squarylium compound represented by formula (1) preferably has an absorption maximum wavelength in the range of 495 nm to 505 nm, and more preferably has an absorption maximum wavelength in the range of 497 nm to 503 nm. When the absorption maximum wavelength is in the range of 495 nm to 505 nm, it can be preferably used, for example, as a dye for a specific wavelength cut filter with a wavelength of 480 nm to 520 nm. The absorption maximum wavelength of the pyrazole-based squarylium compound in one embodiment of this disclosure is a value obtained from a spectrum measured in the wavelength range of 300 nm to 700 nm using a UV-3600i Plus manufactured by Shimadzu Corporation, and is the absorption maximum wavelength of the pyrazole-based squarylium compound in toluene.

[0044] In pyrazole-type squarylium compounds, for example, R in formula (1) Ｃ and R Ｎ In both cases, the introduction of bulky substituents tends to result in longer wavelengths for absorption maxima. In particular, R Ｃ When tBu is introduced, the absorption maximum wavelength exceeds 505 nm, which may prevent good absorption of light in the 480 nm to 520 nm range. On the other hand, in one embodiment of the present disclosure, the pyrazole-based squarylium compound represented by formula (1) is particularly R Ｃ and R Ｎ When primary and secondary alkyl groups are introduced, the pyrazole-based squarylium compound, which is the dye, has an absorption maximum wavelength of 495-505 nm in toluene, and exhibits excellent optical properties as a dye for a specific wavelength cut filter of 480 nm-520 nm. The mechanism by which the above effect is obtained is not clear, but R Ｃ and R Ｎ The compounds identified by this combination are presumed to be due to a favorable balance of stereochemical effects and dipole moments provided by the pyrazole ring.

[0045] The pyrazole-based squarylium compound represented by formula (1) is preferably in the form of particles or needle-shaped crystals. The needle-shaped crystals may be in any form, such as powder, particles, lumps, thin films, fibers, gels, or amorphous materials. If the compound is in the form of particles or powder crystals, the particle size (DV50) determined by particle size distribution measurement is preferably 1 μm to 200 μm, and more preferably 1 μm to 100 μm. The particle size (DV50) determined by particle size distribution measurement is the value measured using a wet particle size distribution analyzer (MT3300EXII) manufactured by Microtrac Corporation with a methanol / water mixed solution (1 / 1, v / v).

[0046] The pyrazole-based squarylium compound represented by formula (1) is preferably a dye. Examples of dye forms include dyes and pigments, and from the viewpoint of optical properties and solubility, it is preferably a dye. A dye is a pigment that is soluble in a solvent, and a pigment is a pigment that is in the form of particles and is poorly soluble in water or organic solvents.

[0047] (Resin Composition) One embodiment of the present disclosure is a resin composition comprising a pyrazole-squallium compound represented by formula (1) and a resin. As the resin, a resin conventionally known for use in resin compositions containing a pigment-squallium compound can be used, and can be selected and adopted according to the purpose and application of the resin composition. In the resin composition, one or more pyrazole-squallium compounds represented by formula (1) may be included. Preferred resins in the resin composition include thermoplastic resins and thermosetting resins. The above resin can be molded into a film or sheet using known methods such as injection molding, T-die molding, calendering, compression molding, or by melting it in an organic solvent and casting. The above resin can be compounded with generally known additives, heat-resistant anti-aging agents, lubricants, antistatic agents, etc. The thickness is usually preferably in the range of 10 μm to 5 mm. The substrate constituting such a transparent substrate may be unstretched or stretched. It may also be laminated with other substrates.

[0048] As the thermoplastic resin, at least one selected from cyclic olefin resins, polycarbonate resins, polyamide resins, acrylic resins, and polyester resins is preferably used from the viewpoint of light resistance, optical properties, and solubility of pyrazole-based squarylium compounds. The cyclic olefin resin may also be a cyclic olefin copolymer. For example, by using a polycarbonate resin as the resin, a molded article with high impact resistance, high transparency, and specific wavelength absorption function can be obtained. Alternatively, for example, by using polymethyl methacrylate as the resin, a molded article with high transparency, high UV resistance, and specific wavelength absorption function can be obtained. Alternatively, for example, by using a polyester resin, a film with high heat resistance, high chemical resistance, and specific wavelength absorption function can be obtained.

[0049] As the thermosetting resin, at least one selected from polyurethane resin, epoxy resin, poly(meth)acrylic resin, polythiourethane resin, and allyl diglycol carbonate resin is preferably used from the viewpoint of light resistance, optical properties, and solubility of the pyrazole-based squarylium compound.

[0050] A resin composition, which is one embodiment of the present disclosure, may contain other light-absorbing compounds and various additives as necessary, to the extent that the purpose of the present disclosure is not impaired. Other components may impart specific functions.

[0051] Other light-absorbing compounds include, for example, compounds that have a desired absorption in the visible light range, such as squarylium compounds, anthraquinone compounds, phthalocyanine compounds, methine compounds, azomethine compounds, oxazine compounds, azo compounds, styryl compounds, coumarin compounds, porphyrin compounds, dibenzofuranone compounds, diketopyrrolopyrrole compounds, rhodamine compounds, xanthene compounds, and pyromethene compounds.

[0052] Examples of additives include polymerization inhibitors, chain transfer agents, leveling agents, plasticizers, surfactants, defoamers, silane coupling agents, UV absorbers, adhesion promoters, antistatic agents, and fillers. The additives may also include inorganic or organic fine particles to adjust hardness and refractive index, anti-glare agents, anti-fouling agents, flame retardants, antioxidants, light stabilizers, surface modifiers, etc.

[0053] One embodiment of the present disclosure is a resin composition comprising a pyrazole-squallium compound represented by formula (1) and a resin. The content of the pyrazole-squallium compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass, and even more preferably 0.1 to 10% by mass, relative to the total amount of resin components in the composition. If the amount of colorant containing the pyrazole-squallium compound is too small, it may be difficult to obtain the desired absorption for light in unwanted wavelength ranges. Also, if the amount of colorant containing the pyrazole-squallium compound is too large, the properties of the resin may be impaired. In this disclosure, the resin component includes everything other than the solvent described above, and also includes liquid polyfunctional monomers at 25°C and liquid additives.

[0054] In a resin composition which is one embodiment of the present disclosure, depending on the application, from the viewpoint of light resistance, optical properties and solubility of the pyrazole-squallium compound, it is preferable that, for example, the pyrazole-squallium compound represented by formula (1) and the resin are contained in a proportion of 0.01% to 20% by mass of the pyrazole-squallium compound represented by formula (1) and 1% to 99.99% by mass of the resin, based on the total mass of the resin composition.

[0055] (Colorant Dispersion) A colorant dispersion according to one embodiment of the present disclosure comprises a pyrazole-type squarylium compound represented by formula (1), a dispersant, and a solvent. The colorant dispersion according to one embodiment of the present disclosure may contain one or more pyrazole-type squarylium compounds represented by formula (1). As the dispersant, dispersants conventionally known for use in colorant dispersions containing a squarylium compound as a dye can be used, and can be selected and adopted according to the purpose and application of the colorant dispersion. Preferred dispersants in the colorant dispersion include, for example, resins used in resin compositions according to one embodiment of the present disclosure, polymers made of polyfunctional monomers such as vinyl-based or epoxy-based polymers, etc. As the solvent, solvents conventionally known for use in colorant dispersions containing a squarylium compound as a dye can be used, and can be selected and adopted according to the purpose and application of the colorant dispersion, the type of dispersant, etc. Optical films and the like can be suitably manufactured using the colorant dispersion.

[0056] The colorant dispersion may contain other components such as various additives. Specific functions may be imparted by these other components. It may also contain colorants other than the pigment, which is a squarylium compound. Note that a pigment is considered a type of colorant.

[0057] In a colorant dispersion that is one embodiment of the present disclosure, depending on the application, from the viewpoint of lightfastness, optical properties and solubility of the pyrazole-squallium compound, it is preferable that, for example, the pyrazole-squallium compound represented by formula (1), the dispersant and the solvent are contained in the following proportions based on the total mass of the colorant dispersion: 0.01% to 20% by mass of the pyrazole-squallium compound represented by formula (1), 0.01% to 30% by mass of the dispersant and 50% to 99.98% by mass of the solvent.

[0058] (Ink Composition) An ink composition according to one embodiment of the present disclosure comprises a pyrazole-based squarylium compound represented by formula (1) and a binder. The pyrazole-based squarylium compound represented by formula (1) may include one or more types. As the binder, a binder conventionally known for use in ink compositions containing a squarylium compound as a dye can be used, and can be selected and adopted according to the purpose and application of the ink composition.

[0059] Preferred binders in the ink composition include various polymers such as polyester, polyurethane, and acrylic. In addition to the pyrazole-based squarylium compound and binder mentioned above, the ink composition may also contain solvents, other additives, etc.

[0060] Examples of solvents include ester-based and alcohol-based solvents, which are used to adjust the viscosity, volatility, and other properties of the ink composition. Other additives include dispersants, drying agents, and defoamers to improve dispersion stability.

[0061] An ink composition containing a pyrazole-based squarylium compound represented by formula (1) can be suitably used in optical filters, security printing, decorative special inks, etc., from the viewpoint of the lightfastness, optical properties, and solubility of the pyrazole-based squarylium compound.

[0062] In an ink composition which is one embodiment of the present disclosure, depending on the application, from the viewpoint of lightfastness, optical properties and solubility of the pyrazole-squalirium compound, it is preferable that, for example, the pyrazole-squalirium compound represented by formula (1) and the binder are contained in a ratio of 0.01% to 10% by mass of the pyrazole-squalirium compound represented by formula (1) and 1% to 30% by mass of the binder, based on the total mass of the ink composition.

[0063] (Optical Filter) An optical filter according to one embodiment of the present disclosure comprises a pyrazole-squallium compound represented by formula (1). The optical filter according to one embodiment of the present disclosure may contain one or more pyrazole-squallium compounds represented by formula (1), and may also contain one or more of the aforementioned light-absorbing compounds in combination, to the extent that the effects of the present disclosure are not impaired.

[0064] The configuration of an optical filter according to one embodiment of this disclosure is not particularly limited, but various configurations can be made by combining it with layers or members having other functions, taking into consideration the desired required characteristics. An optical filter containing a pyrazole-based squarylium compound represented by formula (1), according to one embodiment of this disclosure, contains at least one pyrazole-based squarylium compound represented by formula (1) in at least one layer or member constituting the optical filter.

[0065] An optical filter containing a pyrazole-squallium compound represented by formula (1) can be manufactured using a resin composition, a colorant dispersion, or the like, which is one embodiment of the present disclosure. Methods for incorporating the pyrazole-squallium compound represented by formula (1) into an optical filter, which is one embodiment of the present disclosure, include, for example, the following methods (a) to (d): (a) Adding the pyrazole-squallium compound represented by formula (1) to a transparent adhesive to incorporate it into a transparent adhesive layer; (b) Kneading the pyrazole-squallium compound represented by formula (1) into a polymer resin to incorporate it; (c) Dispersing or dissolving the pyrazole-squallium compound represented by formula (1) in an organic solvent containing a polymer resin or resin monomer, and casting it onto various components and layers, for example; (d) Adding the pyrazole-squallium compound represented by formula (1) to an organic solvent containing a binder resin, and coating it onto various components and layers as a coating.

[0066] In this specification, "containing" includes not only being contained within each layer or transparent adhesive, which consists of various components or films, but also being applied to the surface of the components or each layer.

[0067] The shape of the optical filter, which is one embodiment of this disclosure, is not particularly limited and includes various shapes such as sheet, film, corrugated, spherical, and dome shapes. When formed into a film or sheet, its thickness may be 200 μm or less, and more preferably 150 μm or less. In particular, from the viewpoint of ensuring total light transmittance, the film is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less. The lower limit of the film thickness is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.3 μm or more.

[0068] In an optical filter according to one embodiment of the present disclosure, depending on the application, from the viewpoint of light resistance, optical properties and solubility of the pyrazole-based squarylium compound, for example, the pyrazole-based squarylium compound represented by formula (1) is preferably contained in a proportion of 0.01% to 20% by mass of the total mass of the optical filter.

[0069] An optical filter, which is one embodiment of the present disclosure, is suitable for use as a filter for image receiving elements in cameras, a filter for CMOS sensors, a filter for display panels, and for security applications.

[0070] The present disclosure will be further explained with reference to the following examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not deviate from the spirit of the present disclosure. Therefore, the scope of the present disclosure is not limited to the following specific examples. In these examples, unless otherwise specified, "%" and "parts" mean "mass percent" and "parts by mass," respectively.

[0071] One embodiment of the pyrazole-based squarylium compound of this disclosure can be obtained, for example, by synthesizing a pyrazolone derivative by reacting a hydrazine derivative with an acetoacetate ester derivative, as shown in formula (1b) below, and then reacting it with squalic acid. The pyrazolone derivative can also be used in the following reaction without purification. Tautomers exist for the pyrazolone derivative and squarylium, and they may have structures other than those depicted.

[0072]

[0073] In the above formula (1b), R Ｃ and R Ｎ R in equation (1) is Ｃ and R Ｎ It is similar to that.

[0074] Furthermore, one embodiment of the pyrazole-based squarylium compound of this disclosure has an intramolecular hydrogen bond between the oxygen atom of the carbonyl group in the squalic acid moiety and the hydrogen of the hydroxyl group substituted on the pyrazole ring, １ In 1H-NMR, the proton peak of the hydroxyl group is often broadened and not observed. Therefore, as described below... １ In structural confirmation using H-NMR, the protons of the OH group are not indicated.

[0075] (Example 1: Preparation of compound SQ(iPr,iPr)) 73 mL of ethyl isobutyryl acetate was placed in a flask and cooled to below 5°C, after which 50 g of isopropylhydrazine hydrochloride was added. The temperature was raised to 75°C to 80°C and stirred for 1 hour. After cooling to room temperature, 50 mL of distilled water was added, the precipitated intermediate was filtered off and washed with distilled water. It was dried at room temperature for at least two nights to obtain 52.8 g of 1,3-diisopropyl-5-pyrazolone. The yield of the obtained intermediate was 69.4% by mass, and the purity measured by liquid chromatography (HPLC purity [@254 nm]) was 99 area. The intermediate was identified by HNMR and mass spectrometry. １ H-NMR (MHz, CDCl ３ ) δ (ppm) 1.13, 1.17 (double, 3-CH (CH ３ )２ , 6H), 1.24, 1.36(double, 1-CH(CH ３ ) ２ ,6H),2.67,2.85(septet,3-CH(CH ３ ) ２ , 1H), 4.02, 4.37(septet, 1-CH(CH ３ ) ２ , 1H), 3.15 (singlet, 4-CH ２ , 2H), 5.27 (singlet, 4-CH, 1H)

[0076] 45.0 g of the intermediate was dissolved in 450 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 15.2 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux for 7 hours and then cooled. The reaction mixture was concentrated, dispersed in methanol, and filtered. It was dried at room temperature to obtain 31.9 g. The yield of the obtained compound was 57.6% by mass, and the purity measured by liquid chromatography (HPLC purity [@254 nm]) was 95 area. The obtained compound had the structure of the following formula (2).

[0077]

[0078] Furthermore, the obtained compound was confirmed to have the structure of formula (2) based on the analysis results below. This compound is C ２２ H ３０ N ４ O ４ It had the following composition, and its molecular weight, determined by electrospray ionization mass spectrometry, was 414.51. This compound was designated as compound SQ(iPr,iPr). The molecular weights below are determined by electrospray ionization mass spectrometry. １ H-NMR (MHz, CDCl ３ ) δ (ppm) 1.25 (double, 3-iPr-CH (CH ３ ) ２ , 12H), 1.39(double, 1-CH(CH ３ ) ２ , 12H), 3.35-3.64(multiplet, 3-CH(CH ３ ) ２, 2H), 4.44(septet, 1-CH(CH ３ ) ２ , 2H) ESI-Mass (m / z): Actual value 415.1 (M+H) ＋ Compound SQ(iPr,iPr) exhibits an absorption maximum at 501.5 nm in toluene, and its Gram extinction coefficient is 2.45 × 10⁻⁶. ５ The concentration was g / mL / cm. In this specification, the gram extinction coefficient is the value measured using a UV-Vis spectrophotometer (UV-3600i Plus, Shimadzu Corporation) in toluene, with a measurement interval of 0.5 nm and a measurement range of 300 to 700 nm.

[0079] (Example 2: Preparation of Compound SQ(Et,iPr)) 6.5 mL of ethyl 3-oxovalerate was placed in a flask and cooled to below 5°C, then 5.0 g of isopropylhydrazine hydrochloride was added. The temperature was raised to 75°C to 80°C and stirred for 0.75 hours. After cooling to room temperature, the mixture was concentrated to remove the by-products ethanol and water, yielding 8.2 g of an oily crude intermediate. 4.0 g of the crude intermediate was dissolved in 40 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.5 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux for 26.5 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. The resulting compound was dried at room temperature to obtain 0.55 g. The yield of the intermediate obtained was 11.0% by mass. The obtained compound had the structure of formula (3) below.

[0080]

[0081] Furthermore, the obtained compound was confirmed to have the structure of formula (3) based on the analysis results below. This compound is C ２０ H ２４ N ４ O ４ It had the following composition and a molecular weight of 386.45. This compound was designated as compound SQ(Et,iPr). １ H-NMR (400MHz, CDCl ３) δ (ppm) 1.24 (triplet, 3-CH ２ CH ３ , 6H), 1.40 (double, 1-CH ２ CH ３ , 12H), 2.80(quartet, 3-CH ２ Compound SQ(Et,iPr) shows an absorption maximum at 500.0 nm in toluene, with a Gram extinction coefficient of 2.58 × 10⁻¹⁰. ５ The concentration was g / mL / cm.

[0082] (Example 3: Preparation of compound SQ (cycloPr, iPr)) The procedure was the same as in Example 2, except that 6.5 mL of Ethyl 3-Oxovaleate was replaced with 7.0 mL of Ethyl 3-Cyclopropyl-3-oxopropanoate to obtain 9.9 g of an oily crude intermediate. 5.0 g of the intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.7 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105°C to 110°C) for 13 hours and then cooled. The precipitated target product was collected by filtration and washed with methanol. It was dried at room temperature to obtain 1.0 g. The yield of the obtained compound was 16.4%, and the purity measured by liquid chromatography (LC purity [@254 nm]) was 91 area%. The resulting compound had the structure shown in formula (4) below.

[0083]

[0084] Furthermore, the obtained compound was confirmed to have the structure of formula (4) based on the analysis results below. This compound is C ２２ H ２６ N ４ O ４ It had the following composition and a molecular weight of 410.47. This compound was designated as compound SQ (cycloPr,iPr). １ H-NMR (400MHz, CDCl ３ ) δ (ppm) 0.96 (quartet, 3-cycloCH (CH ２ ) ２, 8H), 1.34 (double, 1-CH ２ CH ３ , 12H), 2.45-2.67 (multiplet, 3-cycloCH(CH ２ ) ２ Compound SQ (cycloPr,iPr) shows maximum absorption at 499.0 nm in toluene, and its Gram extinction coefficient is 2.50 × 10⁻¹⁰. ５ The concentration was g / mL / cm.

[0085] (Example 4: Compound SQ(neoC) ５ H １１ Preparation of iPr) The procedure was the same as in Example 2, except that 6.5 mL of Ethyl 3-Oxovaleate was replaced with 8.5 mL of Ethyl 5,5-dimethyl-3-oxohexanoate, and the mixture was stirred for 5 hours. The mixture was concentrated in the same manner as in Example 2 to obtain 10.1 g of an oily crude intermediate. 5.0 g of the intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.5 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105°C to 110°C) for 10 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. The mixture was dried at room temperature to obtain 1.74 g. The yield of the obtained compound was 29.0%, and the purity measured by liquid chromatography (HPLC purity [@254 nm]) was 95 area%. The resulting compound had the structure shown in formula (5) below.

[0086]

[0087] Furthermore, the obtained compound was confirmed to have the structure of formula (5) based on the analysis results below. This compound is C ２６ H ３８ N ４ O ４ It had the following composition and a molecular weight of 470.61. This compound was compound SQ(neoC). ５ H １１ , iPr) was used. １ H-NMR (400MHz, CDCl ３) δ (ppm) 0.95 (singlet, 3-CH ２ C (CH ３ ) ３ , 18H), 1.40(double, 1-CH(CH ３ ) ２ , 12H), 2.73-2.85 (multiplet, 3-CH ２ C (CH ３ ) ３ , 4H), 4.47(septet, 1-CH(CH ３ ) ２ Compound SQ (neoPentyl, iPr) exhibits a maximum absorption at 501.5 nm in toluene, with a Gram extinction coefficient of 2.12 × 10⁻¹⁰. ５ The concentration was g / mL / cm.

[0088] (Example 5: Preparation of Compound SQ (nPr, iPr)) The procedure was the same as in Example 2, except that 6.5 mL of Ethyl 3-Oxovaleate was replaced with 8.3 mL of Ethyl 3-Oxohexanoate and 5.0 g of isopropylhydrazine hydrochloride was replaced with 5.7 g, and the mixture was stirred for 2 hours. The mixture was concentrated in the same manner as in Example 2 to obtain 7.9 g of an oily crude intermediate. 7.9 g of the intermediate was dissolved in 200 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 3.3 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105°C to 110°C) for 18 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. It was dried at room temperature to obtain 2.0 g. The yield of the obtained compound was 17.0% by mass, and the purity measured by liquid chromatography (HPLC purity [@490 nm]) was 98 area. The obtained compound had the structure of formula (6) below.

[0089]

[0090] Furthermore, the obtained compound was confirmed to have the structure of formula (6) based on the analysis results below. This compound is C ２２ H ３０ N ４ O ４It had the following composition and a molecular weight of 414.51. This compound was designated as compound SQ(nPr,iPr). １ H-NMR (400MHz, CDCl ３ ) δ (ppm) 0.98 (triplet, 3-CH ２ CH ２ CH ３ , 6H), 1.41 (double, 1-CH ２ CH ３ , 12H), 1.67(sixtet, 3-CH ２ CH ２ CH ３ , 4H), 2.77-2.87 (multiplet, 3-CH ２ CH ２ CH ３ Compound SQ (nPr,iPr) shows maximum absorption at 500.5 nm in toluene, with a Gram extinction coefficient of 2.33 × 10⁻¹⁰. ５ The concentration was g / mL / cm.

[0091] (Example 6: Preparation of compound SQ(nBu,iPr)) The procedure was the same as in Example 2, except that 6.5 mL of Ethyl3-Oxovaleate was replaced with 8.2 mL of Ethyl3-Oxoheptanoate, and the mixture was stirred for 2 hours. After cooling to room temperature, the mixture was concentrated to remove the by-products ethanol and water, and 10.3 g of an oily crude intermediate was obtained. 5.0 g of the intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.6 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105°C to 110°C) for 12 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. It was dried at room temperature to obtain 0.9 g. The yield of the obtained compound was 14.8%, and the purity measured by liquid chromatography (HPLC purity [@490 nm]) was 97 area. The obtained compound had the structure shown in formula (7) below.

[0092]

[0093] Furthermore, the obtained compound was confirmed to have the structure of formula (7) based on the analysis results below. This compound is C ２４ H ３４ N ４ O ４ It had the following composition and a molecular weight of 442.56. This compound was designated as compound SQ(nBu,iPr). １ H-NMR (400MHz, CDCl ３ ) δ (ppm) 0.91 (triplet, 3-CH ２ CH ２ CH ２ CH ３ , 6H), 1.40(multiplet, 1-CH(CH ３ ) ２ ,12H,3-CH ２ CH ２ CH ２ CH ３ , 4H), 1.61 (quintet, 3-CH ２ CH ２ CH ２ CH ３ , 4H), 2.77-2.88 (multiplet, 3-CH ２ CH ２ CH ２ CH ３ , 4H), 4.45(septet, 1-CH(CH ３ ) ２ Compound SQ (nBu, iPr) exhibits a maximum absorption at 500.5 nm in toluene, with a Gram extinction coefficient of 2.24 × 10⁻¹⁴. ５ The concentration was g / mL / cm.

[0094] (Example 7: Preparation of compound SQ(nPr,Et)) The reaction was carried out in the same manner as in Example 2, except that 6.5 mL of ethyl 3-oxovalentate was replaced with 8.2 mL of ethyl 3-oxohexanoate and 5.0 g of isopropylhydrazine hydrochloride was replaced with 5.0 g of ethylhydrazine dihydrochloride, and the mixture was stirred for 2 hours. The mixture was concentrated in the same manner as in Example 2 to obtain 7.5 g of an oily crude intermediate. 5.0 g of the intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.9 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105°C to 110°C) for 12 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. It was dried at room temperature to obtain 0.4 g. The yield of the obtained compound was 5.6% by mass, and the purity measured by liquid chromatography (HPLC purity [at 490 nm]) was 94 area. The obtained compound had the structure of formula (8) below.

[0095]

[0096] Furthermore, the obtained compound was confirmed to have the structure of formula (8) based on the analysis results below. This compound is C ２０ H ２６ N ４ O ４ It had the following composition and a molecular weight of 386.45. This compound was designated as compound SQ(nPr,Et). １ H-NMR (400MHz, CDCl ３ ) δ (ppm) 0.97 (double, 3-CH ２ CH ２ CH ３ , 6H), 1.37 (triplet, 1-CH ２ CH ３ , 6H), 1.66(sixtet, 3-CH ２ CH ２ CH ３ , 4H), 2.75-2.86 (multiplet, 3-CH ２ CH ２ CH ３ , 4H), 3.90 (quartet, 1-CH ２ CH ３,4H) ESI-Mass: 387.1(M+H)+ Compound SQ(nPr,Et) shows maximum absorption at 500.0 nm in toluene, and its Gram extinction coefficient is 2.46 × 10⁻⁶ ５ The concentration was g / mL / cm.

[0097] (Example 8: Preparation of Compound SQ(iPr,Et)) The procedure was the same as in Example 2, except that 6.5 mL of Ethyl 3-Oxovaleate was replaced with 8.6 mL of EthylIsobutyrylacetate and 5.0 g of isopropylhydrazine hydrochloride was replaced with 7.1 g of ethylhydrazine dihydrochloride, and the mixture was stirred for 3 hours. The mixture was concentrated in the same manner as in Example 2 to obtain 9.7 g of an oily crude intermediate. 9.7 g of the intermediate was dissolved in 240 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 5.1 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105°C to 110°C) for 8.5 hours or more, and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. It was dried at room temperature to obtain 1.7 g. The yield of the obtained compound was 14.0% by mass, and the purity measured by liquid chromatography (LC purity [@490 nm]) was 99 area. The obtained compound had the structure shown in formula (9) below.

[0098]

[0099] Furthermore, the obtained compound was confirmed to have the structure of formula (9) based on the analysis results below. This compound is C ２０ H ２６ N ４ O ４ It had the following composition and a molecular weight of 386.45. This compound was designated as compound SQ(iPr,Et). １ H-NMR (400MHz, CDCl ３ ) δ (ppm) 1.27 (double, 3-CH (CH ３ ) ２ , 12H), 1.38(triplet, 1-CH ２ CH ３ , 6H), 3.38-3.55 (multiplet, 3-CH(CH ３ ) ２, 2H), 3.91 (quartet, 1-CH ２ CH ３ ,4H) ESI-Mass: 387.1(M+H)+ Compound SQ(iPr,Et) shows maximum absorption at 501.0 nm in toluene, and its Gram extinction coefficient is 2.41 × 10⁻⁶ ５ The concentration was g / mL / cm.

[0100] (Example 9: Preparation of compound SQ (cycloPr,Et)) The reaction was carried out in the same manner as in Example 2, except that 6.5 mL of ethyl 3-oxovaleate was replaced with 8.1 mL of ethyl 3-cyclopropyl-3-oxopropanoate and 5.0 g of isopropylhydrazine hydrochloride was replaced with 4.1 g of ethylhydrazine dihydrochloride, and the mixture was stirred for 2 hours. The mixture was concentrated in the same manner as in Example 2 to obtain 8.7 g of crude oily intermediate. 5.0 g of the intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.9 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105°C to 110°C) for 12 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. It was dried at room temperature to obtain 0.1 g. The yield of the obtained compound was 1.4% by mass, and the purity measured by liquid chromatography (HPLC purity [at 490 nm]) was 95 area. The obtained compound had the structure of formula (10) below.

[0101]

[0102] Furthermore, the obtained compound was confirmed to have the structure of formula (10) based on the analysis results below. This compound is C ２０ H ２２ N ４ O ４ It had the following composition and a molecular weight of 382.42. This compound was designated as compound SQ (cycloPr,Et). １ H NMR (400MHz, CDCl ３ ) δ (ppm) 0.98 (quartet, 3-cycloCH (CH ２ ) ２ , 8H), 1.32 (triplet, 1-CH ２ CH ３, 6H), 2.45-2.67 (multiplet, 3-cycloCH(CH ２ ,) ２ , 2H), 3.84 (quartet, 1-CH ２ CH ３ ,4H) ESI-Mass: 383.1(M+H)+ Compound SQ(cycloPr,Et) shows maximum absorption at 498.5 nm in toluene, and its Gram extinction coefficient is 2.48 × 10⁻⁶ ５ The concentration was g / mL / cm.

[0103] (Example 10: Compound SQ(iPr,tC) ５ H １１ (Preparation) 6.5 mL of ethyl 3-oxovalerate was replaced with 10.0 mL of ethyl isobutyryl acetate, and 5.0 g of isopropylhydrazine hydrochloride was replaced with 7.7 g of tert-pentylhydrazine hydrochloride. The same procedure as in Example 2 was followed to obtain 14.3 g of an oily crude intermediate. The obtained intermediate was used directly in the next reaction without purification. 4.0 g of this obtained intermediate was dissolved in 40 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.3 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105-110°C) for 15 hours and then cooled. The reaction mixture was concentrated, dispersed in methanol, and then filtered. It was dried at room temperature to obtain 1.4 g. The yield of the obtained compound was 28.3%, and the purity measured by liquid chromatography (HPLC purity [at 254 nm]) was 96 area. The obtained compound had the structure of formula (11) below.

[0104]

[0105] Furthermore, the obtained compound was confirmed to have the structure of formula (11) based on the analysis results below. This compound is C ２６ H ３８ N ４ O ４ It had the following composition and a molecular weight of 470.61. This compound was named compound SQ(iPr,tC ５ H １１) １ H NMR (400MHz, CDCl ３ ) δ (ppm) 0.9-1.3 (multiplet, 22H), 1.55 (singlet, 1-CCH ３ , 12H), 3.3-3.6(multiplet, 3-CH(CH ３ )2,2H) ESI-Mass: 471.6(M+H)+ Compound SQ(iPr,tC ５ H １１ It shows maximum absorption at 505.0 nm in toluene, and its Gram extinction coefficient is 2.15 × 10⁻⁶. ５ The concentration was g / mL / cm.

[0106] (Example 11: Compound SQ(cycloPr,tC) ５ H １１ (Preparation) 6.5 mL of ethyl 3-oxovalerate was replaced with 7.0 mL of ethyl 3-cyclopropyl-3-oxopropanoate, and 5.0 g of isopropylhydrazine hydrochloride was replaced with 5.6 g of tertiary pentylhydrazine hydrochloride. The procedure was the same as in Example 2 to obtain 9.2 g of an oily crude intermediate. The obtained product was used directly in the next reaction without further purification. 5.0 g of this intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.6 g of squalic acid was added, and the mixture was heated until refluxed. The mixture was stirred under reflux (105-110°C) for 22 hours and then cooled. The reaction mixture was concentrated, dispersed in methanol, and then filtered. It was dried at room temperature to obtain 1.3 g. The yield of the obtained compound was 21.1%, and the purity measured by liquid chromatography (HPLC purity [at 254 nm]) was 94 area. The obtained compound had the structure of formula (12) below.

[0107]

[0108] Furthermore, the obtained compound was confirmed to have the structure of formula (12) based on the analysis results below. This compound is C ２４ H ３４ N ４ O ４It had the following composition and a molecular weight of 466.58. This compound was named compound SQ(cycloPr,tC ５ H １１ ) １ H NMR (400MHz, CDCl ３ ) δ (ppm) 0.9-1.4 (mul tiplet, 18H), 1.51 (singlet, 1-CCH ３ , 12H), 2.4-2.7(multiplet, 3-cycloCH(CH ２ )2,2H) ESI-Mass: 467.53(M+H)+ Compound SQ(cycloPr,tC ５ H １１ It shows maximum absorption at 502.5 nm in toluene, and its Gram extinction coefficient is 2.17 × 10⁻⁶. ５ The concentration was g / mL / cm.

[0109] (Example 12: Compound SQ(cycloPr, neoC) ５ H １１ (Preparation) 6.5 mL of ethyl 3-oxovalerate was replaced with 5.6 mL of ethyl 3-cyclopropyl-3-oxopropanoate, and 5.0 g of isopropylhydrazine hydrochloride was replaced with 5.0 g of neopentylhydrazine hydrochloride. The procedure was the same as in Example 2 to obtain 7.1 g of crude oily intermediate. The obtained product was used directly in the next reaction without further purification. 5.0 g of this intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.5 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105-110°C) for 12 hours and then cooled. The reaction mixture was concentrated, dispersed in methanol, and then filtered. It was dried at room temperature to obtain 0.2 g. The yield of the obtained compound was 3.2%, and the purity measured by liquid chromatography (HPLC purity [at 254 nm]) was 96 area. The obtained compound had the structure of formula (13) below.

[0110]

[0111] Furthermore, the obtained compound was confirmed to have the structure of formula (13) based on the analysis results below. This compound is C ２６ H ３４ N ４ O ４ It had the following composition and a molecular weight of 466.58. This compound was named compound SQ (cycloPr, neoC). ５ H １１ ) １ H NMR (400MHz, CDCl ３ ) δ (ppm) 0.95-0.99 (multiplet, 26H), 2.5 (multiplet, 3-cycloCH (CH ２ ) ２ , 2H), 3.6 (singlet, 1-CH ２ C (CH ３ ) ３ , 4H) ESI-Mass: 467.58 (M+H) + Compound SQ (cycloPr, neoC ５ H １１ ) shows maximum absorption at 499.5 nm in toluene, and its Gram extinction coefficient is 2.17 × 10⁻⁶. ５ The concentration was g / mL / cm. ESI-Mass: 467.58 (M + H) +

[0112] (Example 13: Compound SQ(cycloPr,3-C) ５ H １１(Preparation) 6.5 mL of ethyl 3-oxovalerate was replaced with 3.3 mL of ethyl 3-cyclopropyl-3-oxopropanoate, 5.0 g of isopropylhydrazine hydrochloride was replaced with 3.0 g of 3-pentylhydrazine hydrochloride, and 3.5 mL of methanol was used as the solvent. The procedure was the same as in Example 2 to obtain 4.5 g of an oily crude intermediate. The obtained product was used directly in the next reaction without further purification. 4.5 g of this intermediate was dissolved in 50 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 1.2 g of squalic acid was added, and the mixture was heated until refluxed. The mixture was stirred under reflux (105-110°C) for 15 hours and then cooled. The reaction mixture was concentrated, dispersed in methanol, and then filtered. The compound was dried at room temperature to obtain 0.6 g. The yield of the obtained compound was 10.4%, and the purity measured by liquid chromatography (HPLC purity [@254 nm]) was 95 area. The obtained compound had the structure of formula (14) below.

[0113]

[0114] Furthermore, the obtained compound was confirmed to have the structure of formula (14) based on the analysis results below. This compound is C ２６ H ３４ N ４ O ４ It had the following composition and a molecular weight of 466.58. This compound was named compound SQ(cycloPr,3-C). ５ H １１ ) １ H NMR (400MHz, CDCl ３ ) δ(ppm) 0.8(triplet, 1-CH(CH ２ CH ３ ) ２ , 12H), 0.97(triplet, 3-cycloCH(CH ２ ) ２ , 8H), 1.6-1.8(multiplet, 1-CH(CH ２ CH ３ ) ２ , 8H), 2.5(multiplet, 3-cycloCH(CH２ ) ２ , 2H), 3.9(multiplet, 1-CH(CH ２ CH ３ ) ２ , 2H) ESI-Mass: 467.53 (M+H) + Compound SQ (cycloPr, 3-C ５ H １１ It exhibits maximum absorption at 498.5 nm in toluene, and its Gram extinction coefficient is 2.23 × 10⁻⁶. ５ The concentration was g / mL / cm.

[0115] (Example 14: Compound SQ(3-C) ５ H １１ Preparation of iPr) 6.5 mL of ethyl 3-oxovalerate was replaced with 7.59 g of ethyl 4-ethyl-3-oxohexanoate, and 5.0 g of isopropylhydrazine hydrochloride was replaced with 4.5 g. The procedure was the same as in Example 2, except that 5 mL of methanol was used as the solvent. An oily crude intermediate was obtained. The obtained product was used directly in the next reaction without further purification. 8.9 g of this intermediate was dissolved in 90 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 2.7 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105-110°C) for 15 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. It was dried at room temperature to obtain 2.5 g. The yield of the obtained compound was 22.4%, and the purity measured by liquid chromatography (HPLC purity [at 254 nm]) was 95 area. The obtained compound had the structure of formula (15) below.

[0116]

[0117] Furthermore, the obtained compound was confirmed to have the structure of formula (15) based on the analysis results below. This compound is C ２６ H ３８ N ４ O ４ It had the following composition and a molecular weight of 470.61. This compound was called compound SQ(3-C). ５ H １１ , iPr) was used.１ H NMR (400MHz, CDCl ３ ) δ(ppm) 0.8(triplet, 3-CH(CH ２ CH ３ ) ２ , 12H), 1.4(double, 1-CH(CH ３ ) ２ , 12H), 1.7(multiplet, 3-CH(CH ２ CH ３ ) ２ , 8H), 3.1(quintet, 3-CH(CH ２ CH ３ ) ２ , 2H), 4.5(multiplet, 1-CH(CH ３ ) ２ , 2H) ESI-Mass: 471.61 (M+H) + Compound SQ (3-C ５ H １１ iPr) exhibits maximum absorption at 501.5 nm in toluene, and its Gram extinction coefficient is 2.08 × 10⁻⁶. ５ The concentration was g / mL / cm.

[0118] (Example 15: Compound SQ(3-C) ５ H １１ ,3-C ５ H １１(Preparation) 6.5 mL of ethyl 3-oxovalerate was replaced with 4.0 mL of ethyl 4-ethyl-3-oxohexanoate, 5.0 g of isopropylhydrazine hydrochloride was replaced with 3.0 g of 3-pentylhydrazine hydrochloride, and 4 mL of methanol was used as the solvent. The procedure was the same as in Example 2 to obtain 4.5 g of an oily crude intermediate. The obtained product was used directly in the next reaction without further purification. 3.5 g of this intermediate was dissolved in 35 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 0.9 g of squalic acid was added, and the mixture was heated until refluxed. The mixture was stirred under reflux (105-110°C) for 22 hours and then cooled. The reaction mixture was concentrated, dispersed with methanol, and then filtered. It was dried at room temperature to obtain 0.8 g. The yield of the obtained compound was 14.3%, and the purity measured by liquid chromatography (HPLC purity [at 254 nm]) was 97 area%. The obtained compound had the structure of formula (16) below.

[0119]

[0120] Furthermore, the obtained compound was confirmed to have the structure of formula (16) based on the analysis results below. This compound is C ３０ H ４６ N ４ O ４ It had the following composition and a molecular weight of 526.72. This compound was called compound SQ(3-C). ５ H １１ ,3-C ５ H １１ ) １ H NMR (400MHz, CDCl ３ ) δ (ppm) 0.8 (multiplet, 24H), 1.7-1.9 (multiplet, 16H), 3.1 (septet, 3-CH (CH ２ CH ３ ) ２ , 2H), 4.0(septet, 1-CH(CH ２ CH ３ ) ２ , 2H) ESI-Mass: 527.72 (M+H) + Compound SQ (3-C５ H １１ ,3-C ５ H １１ It shows maximum absorption at 501.5 nm in toluene, and its Gram extinction coefficient is 1.99 × 10⁻⁶. ５ The concentration was g / mL / cm.

[0121] (Example 16: Preparation of compound SQ (cyclohexyl, iPr)) 6.5 mL of ethyl 3-oxovalerate was replaced with 7.4 mL of cyclohexanepropanoic acid, β-oxo-,ethyl ester, and 5.0 g of isopropylhydrazine hydrochloride was replaced with 4.2 g. The same procedure as in Example 2 was followed to obtain 9.6 g of an oily crude intermediate. The obtained product was used directly in the next reaction without further purification. 9.6 g of this intermediate was dissolved in 100 mL of a toluene and butanol mixture (toluene:butanol = 65:35, volume ratio), 2.5 g of squalic acid was added, and the mixture was heated until reflux was achieved. The mixture was stirred under reflux (105-110°C) for 14 hours and then cooled. The reaction mixture was concentrated, dispersed in methanol, and then filtered. It was dried at room temperature to obtain 3.2 g. The yield of the resulting compound was 27.8%, and the purity (HPLC purity [at 254 nm]) measured by liquid chromatography was 95 area. The resulting compound had the structure shown in formula (17) below.

[0122]

[0123] Furthermore, the obtained compound was confirmed to have the structure of formula (17) based on the analysis results below. This compound is C ２８ H ３８ N ４ O ４ It had the following composition and a molecular weight of 494.64. This compound was designated as compound SQ (cyclohexyl, iPr). １ H NMR (400MHz, CDCl ３ ) δ (ppm) 1.3-1.9 (multiplet, 32H), 3.0 (multiplet, 3-cycloCH (CH ２ )5,2H),4.4(septet,1-CH(CH ３) ２ Compound SQ (cyclohexyl, iPr) exhibits a maximum absorption at 502.5 nm in toluene, with a Gram extinction coefficient of 2.06 × 10⁻¹⁵. ５ The concentration was g / mL / cm.

[0124] (Comparative Examples 1 to 10) The following compounds SQ were prepared in the same manner as in the Examples, but with the compounds used in production being replaced. Comparative Examples 1 to 11 are pyrazole-based squarylium compounds having a structure similar to that of formula (1), and R Ｃ and R Ｎ The basis for this is "compound SQ(R) Ｃ , R Ｎ )” is shown below. Comparative Example 1: Compound SQ (Me, Me) Comparative Example 2: Compound SQ (Me, tBu) Comparative Example 3: Compound SQ (Et, Me) Comparative Example 4: Compound SQ (Et, tBu) Comparative Example 5: Compound SQ (iPr, Me) Comparative Example 6: Compound SQ (iPr, tBu) Comparative Example 7: Compound SQ (cycloPr, Me) Comparative Example 8: Compound SQ (tBu, Me) Comparative Example 9: Compound SQ (tBu, iPr) Comparative Example 10: Compound SQ (tBu, tBu)

[0125] (Comparative Example 11: Production of Compound SQ (methoxyethyl, Me)) 2.8 mL of methyl 5-methoxy-3-oxovalerate was placed in a flask and cooled to 5°C or lower. Then, 1.0 mL of methylhydrazine was charged, and the reaction solution was stirred for several minutes until crystallization occurred. After returning to room temperature, the precipitated intermediate was collected by filtration and washed with 40 mL of diisopropyl ether. It was dried at room temperature for more than two nights to obtain 2.4 g of a light pink solid intermediate. 2.0 g of this intermediate was dissolved in 40 mL of a mixed solution of toluene and butanol (toluene:butanol = 65:35, volume ratio), 0.7 g of squaric acid was charged, and the temperature was raised until refluxing. The mixture was stirred at the reflux state (105 - 110°C) for 1.5 hours and then cooled. The precipitate was collected by filtration, washed with 40 mL of heptane, and dried at 60°C to obtain 1.6 g. The yield of the obtained compound was 63.5%, and the purity measured using liquid chromatography (HPLC purity [@254 nm]) was 95 area%. The obtained compound had the structure of the following formula (18).

[0126]

[0127] In addition, from the following analysis results, it was confirmed that the obtained compound was a compound having the structure of formula (18). This compound had a composition of C １８ H ２０ N ４ O ６ and a molecular weight of 388.38. This compound was designated as compound SQ (methoxyethyl, Me). １ H NMR (400 MHz, CDCl ３ ) δ (ppm) 3.1 (triplet, 3-CH ２ CH ２ OCH ３ , 4H), 3.4 (singlet, 1-CH ３ , 6H), 3.6 (singlet, 3-CH ２ CH ２ OCH ３ , 6H), 3.7 (triplet, 3-CH ２ CH ２ OCH ３, 4H) ESI-Mass: 389.38 (M+H)+ Compound SQ(methoxyethyl, Me) showed a maximum absorption at 500.0 nm in toluene, and the gram absorption coefficient was 2.25×10 ５ g / mL / cm.

[0128] (Comparative Example 12: Preparation of Compound SQ(methoxymethyl, Me)) 3.9 g of an orange intermediate was obtained in the same manner as in Example 17, except that 2.8 mL of 5-methoxy-3-oxovalerate was changed to 4.5 mL of 4-Methoxyacetoacetic Acid Methyl Ester. 3.2 g of this intermediate was dissolved in 40 mL of a mixed solution of toluene and butanol (toluene:butanol = 65:35, volume ratio), 1.3 g of squaric acid was charged, and the temperature was raised until refluxing. The mixture was stirred at the reflux state (105-110 °C) for 3.5 hours and then cooled. The precipitate was collected by filtration, washed with methanol, and dried at 60 °C to obtain 1.6 g. The yield of the obtained compound was 9.6%, and the purity measured by liquid chromatography (HPLC purity[@254nm]) was 95 area%. The obtained compound had the structure of the following formula (19).

[0129]

[0130] In addition, it was confirmed from the following analysis results that the obtained compound was a compound having the structure of formula (19). This compound had a composition of C １６ H １６ N ４ O ６ and a molecular weight of 360.33. This compound was designated as Compound SQ(methoxymethyl, Me). １ H NMR (400 MHz, CDCl ３ ) δ (ppm) 3.5 (singlet, 1-CH ３ , 6H), 3.6 (singlet, 3-CH ２ OCH ３ , 6H), 4.6 (singlet, 3-CH ２ OCH ３,4H) ESI-Mass: 361.33(M+H)+ Compound SQ (methoxymethyl,Me) shows maximum absorption at 503.0 nm in toluene, and its Gram extinction coefficient is 2.22 × 10⁻⁶. ５ The concentration was g / mL / cm.

[0131] (Evaluation) Each compound SQ obtained in the examples and comparative examples was evaluated as follows.

[0132] Evaluation 1) Absorption Maximum Wavelength was measured for each compound SQ obtained in Examples 1 to 16 and Comparative Examples 1 to 10. The measurement method was the same as described above, and the values ​​were obtained from spectra measured in the wavelength range of 300 nm to 700 nm using a UV-3600i Plus manufactured by Shimadzu Corporation. The measurement results and evaluation results are shown in Table 2. Evaluations A and B are pass, and evaluation C is fail.

[0133] <Evaluation Criteria> A: Within the range of 497 nm to 503 nm B: Within the range of 495 nm to less than 497 nm or greater than 503 nm and less than or equal to 505 nm C: Less than 495 nm or greater than 505 nm

[0134]

[0135] As shown in Table 2, Ｃ and R Ｎ As the bulk increases with the primary alkyl, secondary alkyl, and tertiary alkyl substituents, the wavelength of the absorption maximum shifts to a longer wavelength. In particular, R Ｃ Compounds SQ(tBu,Me), SQ(tBu,iPr), and SQ(tBu,tBu), which were introduced with a tertiary alkyl group having 4 carbon atoms, all failed because their absorption maximum wavelengths exceeded 505 nm. On the other hand, R Ｃ Compounds into which primary and secondary alkyl groups were introduced showed good absorption maximum wavelengths, with the exception of comparative compound SQ (iPr, tBu). From the viewpoint of the absorption maximum wavelength of the compound, R Ｃ It was found that the introduction of a primary or secondary alkyl group is preferable. Also, R ＮRegarding this as well, while the introduction of a primary or secondary alkyl group is preferred, it has been found that some compounds exhibit absorption maximum wavelengths shorter than 505 nm depending on the combination of substituents. Ｃ Compounds with a cyclopropyl group have a wavelength several nanometers shorter than compounds with an isopropyl group, and the compound SQ(cyclopropylPr, tC ５ H １１ In this case, the absorption maximum wavelength was 502.5 nm, which was acceptable. From the above results, it was found that cyclic alkyl is preferable from the viewpoint of absorption maximum wavelength. Also, R Ｎ It was found that even tertiary alkyl groups can be compounds that exhibit good absorption maximum wavelengths depending on the combination.

[0136] Evaluation 2) Solubility The solubility of the compounds obtained in Examples 1 to 16, Comparative Examples 1, 2, 4, 5, and Comparative Examples 8 to 12 in propylene glycol methyl ether acetate (PGMEA) or toluene was measured. For solubility, 100 mg of the compound was placed in a sample tube, 10.0 g of the predetermined solvent PGMEA or toluene was added, and the mixture was irradiated with ultrasound for 1 minute. Solubility was then confirmed using an ultraviolet-visible spectrophotometer or visually. The measurement results and evaluation results are shown in Table 4. Compounds with an evaluation of A or B for either PGMEA or toluene were considered acceptable, while compounds with an evaluation of C or D for both PGMEA or toluene were considered unacceptable.

[0137] <Evaluation Criteria> A: 1.0% by mass or more B: 0.5% by mass or more and less than 1.0% by mass C: 0.1% by mass or more and less than 0.5% by mass D: Less than 0.1% by mass

[0138]

[0139] As shown in Table 3, R Ｃ Compounds in which substituents consisting of a methyl group or a combination of a t-butyl group were introduced did not achieve sufficient solubility. Ｃ A primary alkyl group having 2 or more carbon atoms or a linear or branched secondary alkyl group having 3 or more carbon atoms is introduced, and R ＮCompounds into which a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group have been introduced show improved solubility in PGMEA, for example, compound SQ(Et,iPr), compound SQ(iPr,tC ５ H １１ ), compound SQ(iPr,iPr) and compound SQ(Et,tBu) passed the solubility tests in PGMEA and toluene. Furthermore, as can be seen from the comparison between compound SQ(iPr,iPr) and compound SQ(tBu,iPr), R Ｃ In compounds to which a tBu group has been introduced, the solubility deteriorates significantly, therefore, from the viewpoint of solubility, R Ｃ It was found that introducing a tertiary alkyl group with 4 carbon atoms is undesirable. Compound SQ (cycloPr, iPr) and Compound SQ (cycloPr, tC ５ H １１ ) had a solubility in PGMEA of 0.5% by mass or less and was therefore unacceptable, R Ｎ iPr group, tC ５ H １１ Introducing bulky substituents such as a nucleotide group improved solubility in toluene, resulting in a passing grade.

[0140] Evaluation 3) A resin solution was prepared by dissolving 10 g of methacrylic resin (Delpet, manufactured by Asahi Kasei, 80N (model number)) in 90 g of a light-resistant toluene / ethyl acetate mixed solution (toluene:ethyl acetate = 1:1, volume ratio). Compound SQ(iPr,iPr), which is the compound of Example 1, was dissolved in the resin solution as a dye to prepare dye resin solution A. Compound SQ(Et,iPr), which is the compound of Example 2, was dissolved in the resin solution as a dye to prepare dye resin solution B. Dye resin solution A was spin-coated onto a glass plate and dried to obtain plate A. Dye resin solution B was spin-coated onto a glass plate and dried to obtain plate B. Both plate A and plate B had a transmittance in the range of 10% to 30%.

[0141] For the compounds obtained in Examples 1 to 16, and Comparative Examples 3 to 5, 11, and 12, plates were obtained by spin-coating the dye resin solution in the same manner as in Example 1. Using each of these plates, a lightfastness evaluation test was conducted using a lightfastness tester to measure the percentage of dye absorption remaining after 200 hours. The percentage of dye absorption remaining was measured using a UV-Vis spectrophotometer (UV-Vis spectrophotometer, Shimadzu Corporation, UV-3600i Plus) and calculated using the following formula.

[0142] Percentage of pigment absorption remaining (%) = Transmittance after lightfastness test / Transmittance before lightfastness test × 100

[0143] The evaluation criteria are as follows. The measurement results and evaluation results are shown in Table 5. Evaluations A to C are passing grades, and evaluation D is a failing grade.

[0144] <Evaluation Criteria> A: 80% or higher B: 65% or higher but less than 80% C: 50% or higher but less than 65% D: Less than 50%

[0145]

[0146] As shown in Table 4, R Ｃ and R Ｎ As the number of carbon atoms of the substituents increases and the bulk of the alkyl group increases from primary to secondary and from secondary to tertiary, the lightfastness tends to improve. It was found that Examples 1, 3, 10, and 11 of the present invention showed improved lightfastness compared to Comparative Examples 3 to 5 and Comparative Example 12. This is presumed to be due to the steric hindrance of the substituents on the dye preventing the reactive species from contacting the dye skeleton.

[0147] As shown in Tables 2 to 4, the compound of one embodiment of the present disclosure has been demonstrated to be a pyrazole-based squarylium compound with excellent lightfastness, absorption maximum wavelength, and solubility.

[0148] The disclosure of Japanese Patent Application No. 2024-204269, filed on 22 November 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A pyrazole-type squarylium compound represented by the following formula (1). In formula (1), R Ｃ R represents a primary alkyl group having 2 to 5 carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms. Ｎ R represents a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 4 or more carbon atoms. Ｎ If R represents a tertiary alkyl group with 4 carbon atoms, Ｃ This represents at least one selected from a cyclopropyl group, a cyclohexyl group, and a 3-pentyl group.

2. R Ｃ The pyrazole-based squarylium compound according to claim 1, wherein is at least one selected from a cyclopropyl group, a cyclohexyl group, and a 3-pentyl group.

3. R Ｎ The pyrazole-based squarylium compound according to claim 1, wherein is a primary alkyl group having 2 or more carbon atoms, a secondary alkyl group having 3 or more carbon atoms, or a tertiary alkyl group having 5 or more carbon atoms.

4. R Ｃ and R Ｎ The pyrazole-based squarylium compound according to claim 1, wherein at least one of the elements is a substituted alkyl group.

5. R Ｃ and R Ｎ The pyrazole-based squarylium compound according to claim 1, wherein at least one of them is an alkyl group substituted by a halogen or an alkoxy group.

6. R Ｃ and R Ｎ The pyrazole-based squarylium compound according to claim 1, wherein at least one of the members is a cyclic alkyl group.

7. A pyrazole-based squarylium compound according to claim 1, which is a dye.

8. A resin composition comprising a pyrazole-based squarylium compound and a resin according to any one of claims 1 to 7.

9. The resin composition according to claim 8, wherein the resin is a thermoplastic resin or a thermosetting resin.

10. The resin composition according to claim 9, wherein the thermoplastic resin is at least one selected from polycarbonate resin, polyamide resin, acrylic resin, polyester resin, and cyclic olefin resin, and the thermosetting resin is at least one selected from polyurethane resin, polythiourethane resin, allyl diglycol carbonate resin, epoxy resin, and poly(meth)acrylic resin.

11. The resin composition according to claim 10, wherein the cyclic olefin resin is a cyclic olefin copolymer.

12. A colorant dispersion comprising a pyrazole-based squarylium compound according to any one of claims 1 to 7, a dispersant, and a solvent.

13. An ink composition comprising a pyrazole-based squarylium compound according to any one of claims 1 to 7 and a binder.

14. An optical filter comprising a pyrazole-based squarylium compound according to any one of claims 1 to 7.

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