JP2009286851A - Azo dye, ink sheet for thermosensitive transfer recording and thermosensitive transfer recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an azo dye that has low toxicity to organisms, an ink sheet for thermosensitive transfer recording, which contains the azo dye and a thermosensitive transfer recording method. <P>SOLUTION: The azo dye comprises a diazo component containing an acyl group at the position 2, for example, a phenyl ring containing an acetyl group, a coupling component being phenol, naphthol or an aniline derivative and has a molecular weight of ≥200 and ≤600 and CLogP value of ≥0 and ≤4.0. The azo dye has low toxicity to organisms, especially low mutagenicity in an Ames test useful in a screening examination of carcinogenesis, Consequently, the ink sheet for thermosensitive transfer recording, containing the azo dye and the thermosensitive transfer recording method using the ink sheet have high safety to organisms. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel azo dye, a thermal transfer recording ink sheet containing the azo dye, and a thermal transfer recording method.

  Azo dyes have many excellent properties such as high dyeability, fastness to heat, light and washing, and low manufacturing costs, and since ancient times, textile fibers such as cotton, wool, synthetic fibers, leather, It has been widely used for dyeing paper, plastic, fur, and food. Today, in addition to these applications, azo dyes are used for paint pigments, hair dyes, inks, inkjet printing, laser printing, copying, thermal transfer recording, optical recording materials, and organic EL. Used for light emitting materials, lasers, organic semiconductors, solar cells, fluorescent probes, nonlinear optical materials, solid-state imaging tubes and other filters, and displays such as color liquid crystals. Has been.

  In thermal transfer recording, a thermal transfer material in which a heat-meltable ink layer is formed on a support (base film) is heated by a thermal head, the ink is melted and recorded on an image receiving material, and on the support. There is a method in which a heat-sensitive transfer material having a dye-donating layer containing a heat-transferable dye is heated by a thermal head to thermally transfer the dye onto the image receiving material. The latter thermal transfer system can change the transfer amount of the dye by changing the energy applied to the thermal head, so that gradation recording is easy and is particularly advantageous for high-color full-color recording. However, there are various restrictions on the heat transferable dyes that can be used in this method, and very few satisfy all of the required performance.

The required performance includes, for example, favorable spectral characteristics for color reproduction, easy transfer, fastness to light and heat, fastness to various chemicals, and easy synthesis. It is easy to make a material for thermal transfer recording, and its toxicity is low.
However, since azo dyes produce aromatic or heterocyclic amine compounds when the azo group is reductively metabolized in vivo, concerns over safety have been pointed out in recent years (Non-patent Document 1). Therefore, development of a safe azo dye having low toxicity to the living body and low environmental burden is demanded.

  In general, as a molecular design for improving the safety of a chemical substance, a technique for increasing the molecular weight or increasing the hydrophobicity is used. However, depending on the use of the azo dye, it is not always possible to satisfy all the required performances in such a limited molecular design. In particular, in the case of a thermal transfer recording dye, there is a problem that transferability is remarkably lowered when the molecular weight of the dye is increased.

Until now, it has been reported that an azo dye having an azo group as a part of a cyclic structure and having aromaticity is stable in reductive metabolism (Patent Documents 2 and 3). However, the cyclic azo dye has a problem in colorability because the hue is broadened and the molar extinction coefficient is lowered as compared with the chain azo dye.
On the other hand, an azo dye in which an aromatic or heterocyclic amine compound generated by reductive decomposition of an azo group undergoes an intramolecular nucleophilic substitution reaction and is converted to a metabolically stable compound has been reported (Patent Document 4). . However, there is no information on actual safety tests.

R.K.Lynn et al., Toxicol. Appl. Pharmacol., 56, 248, 1980 JP 2006-143902 A JP 2006-169239 A JP 2005-139364 A

  An object of the present invention is to provide an azo dye having low toxicity to a living body. Another object of the present invention is to provide a thermal transfer recording ink sheet containing the azo dye and a thermal transfer recording method.

  As a result of intensive investigations in view of the above-mentioned actual situation, the present inventors have determined that specific conditions are satisfied among azo dyes in which an acyl group is substituted on a carbon atom adjacent to a carbon atom of an aromatic ring to which an azo group is bonded. Those who satisfy it have found that the toxicity to the living body is low, and further earnestly researched and completed the present invention.

That is, the present invention
[1] An azo dye represented by the general formula (1) and satisfying the following conditions 1 and 2.
Condition 1: The molecular weight is 220 or more and 600 or less.
Condition 2: The CLogP value is 0 or more and 4.0 or less.

[In General Formula (1), A represents a group selected from the group of aromatic groups (A) to (D) represented by the following General Formula (2), and W is an aliphatic group having 6 or less carbon atoms in total. Group or an aromatic group having 6 or less carbon atoms, and R _{1 to} R ₄ are each independently a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, a halogen atom, a cyano group, an alkoxy group, or an acyloxy group. , Amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, alkyl or arylsulfonylamino group, sulfamoyl group, alkyl or arylsulfonyl group, acyl group, alkoxycarbonyl group, carbamoyl group, or aryl or heterocyclic azo Represents a group. However, W and R ₄ are not bonded to each other to form a ring. ]

[In General Formula (2), a _{1 to} a ₄ , b _{1 to} b ₄ , c _{1 to} c ₄ and d _{1 to} d ₄ are each independently a hydrogen atom or a substituent (provided that a sulfo group and a carboxyl group are X ₁ and X ₂ each independently represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group. * Represents a binding site with the azo group of the general formula (1). ]
[2] The azo dye according to [1], wherein W in the general formula (1) is an alkyl group having a total carbon number of 3 or less.
[3] In any one of [1] to [2], A in the general formula (1) is selected from (A) of the aromatic group represented by the general formula (2). The azo dye described.
[4] An azo dye, wherein the azo dye represented by the general formula (1) is represented by the following general formula (3).

[In the general formula _(3), a 1 ~a ₄ each independently represent a hydrogen atom or a substituent, _{R 3} has the same meaning as _{R 3} in the general formula (1). ]
[5] The azo dye according to any one of [1] to [4], wherein the molecular weight of the azo dye represented by the general formula (1) or the general formula (3) is from 240 to 450 .
[6] Any one of [1] to [5], wherein the ClogP value of the azo dye represented by the general formula (1) or (3) is 1.0 or more and 3.5 or less. The azo dye described in 1.
[7] The pKa of the phenolic hydroxyl group of the azo dye represented by the general formula (1) or the general formula (3) is 7.0 or less, and any one of [1] to [6] The azo dye described.
[8] An ink sheet for thermal transfer recording, comprising the azo dye according to [1].
[9] A thermal transfer recording method comprising forming an image on an image receiving material having an ink receiving layer containing a polymer on a support, using the thermal transfer recording ink sheet described in [8].

  The azo dye of the present invention has low toxicity to a living body, and in particular, has low mutagenicity in the Ames test used as a carcinogenic screening test. Therefore, it can be said that the thermal transfer recording ink sheet containing the azo dye and the thermal transfer recording method using the ink sheet are also highly safe to the living body.

The azo dye of the present invention will be described in detail below.
The azo dyes of the present invention are generally characterized by low toxicity to living organisms despite having physicochemical properties that are generally easily absorbed into living organisms, that is, low molecular weight and appropriate hydrophilicity / hydrophobicity. is there.

  First, CLogP defined in the present invention will be described. LogP means the common logarithm of the partition coefficient P (Partition Coefficient), and quantitatively shows how a chemical substance is distributed in the equilibrium of a two-phase system of oil (generally 1-octanol) and water. It is a physical property value expressed as a numerical value, and is expressed by the following formula.

LogP = log (C _oil / C _water )
Here, C _oil represents the molar concentration in the _oil phase, and C _water represents the molar concentration in the aqueous phase. The oil solubility increases when the LogP value increases to a positive value across 0, and the water solubility increases when the absolute value increases with a negative value. LogP has a negative correlation with the water solubility of chemical substances and is widely used as a parameter for estimating hydrophilicity / hydrophobicity. In principle, it is actually measured by a distribution experiment in view of its definition, but the experiment itself is quite troublesome, so estimation from the structural formula is an effective means.

Therefore, ClogP is used as the estimated value of LogP. CLogP in this specification is a C.I. Hansch, A.M. LogP value estimation program developed by Leo et al.'S Medchem project: CLogP (strictly, the system from Daylight Chemical Information Systems: CLogP program embedded in PCModels). This program is based on the Hansch-Leo fragment method, which divides the chemical structure into fragments and estimates LogP by summing the LogP contributions assigned to that fragment.
The Hansch-Leo fragment method is a method in which a two-dimensional structural formula of a chemical substance is decomposed into fragments, a contribution f of each fragment is determined from the actual measurement values, and these are summed. However, since the error from the actual measurement value is large simply by summing up, it takes a form in which various correction terms are added as in the following equation.

F in the above formula means a fragment constant, and represents the contribution of LogP determined in fragment units divided by isolated carbon atoms. a represents a coefficient of f, F represents a correction term (a correction amount of LogP in consideration of the influence of a deviation from a chain straight line, chain branching, unsaturated bond, polar group, etc.), b represents a coefficient of F To express.
The theory about CLogP is, for example, C.I. Hansch & A. Leo. Substituent Constants For Correlation Analysis in Chemistry and Biology. (John Wiley & Sons.) And A.I. J. et al. Leo. Calculating logPoch from structure. Chem. Rev. 93, 1281-1306, 1993. It is detailed in etc.

The pKa value used in the present invention is defined as a value obtained by adding a negative sign to the common logarithm of the dissociation constant Ka in an aqueous solution of a weak electrolyte, that is, pKa = −Log ₁₀ Ka. The pKa value used in the present invention is calculated by titration with HCl and NaOH standard solutions in tetrahydrofuran / water (6/4).

Next, the substituents in the compound defined in the general formula (1) or (3) will be described more specifically.
For example, halogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, cyano group, hydroxyl group, nitro group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy Group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl or arylsulfonylamino group, mercapto group Alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxy Carbonyl group, a carbamoyl group, an aryl or heterocyclic azo group, an imido group, a phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, and a silyl group.

  The aliphatic group used in the general formula (1) or (3) means an alkyl group, an alkenyl group, and an alkynyl group. Moreover, an aryl group can be mentioned as an aromatic group used in the said General formula (1) or (3).

  More specifically, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the alkyl group include linear, branched, and cyclic substituted or unsubstituted alkyl groups, including cycloalkyl groups, bicycloalkyl groups, and tricyclo structures having many ring structures. An alkyl group (for example, an alkyl group of an alkoxy group or an alkylthio group) in a substituent described below also represents an alkyl group having the same meaning. Specifically, the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, n-propyl group, isopropyl group, t-butyl group, n-octyl group, 2-chloroethyl. Group, 2-cyanoethyl group, trifluoromethyl group, and the like. Preferred examples of the cycloalkyl group include substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, such as cyclohexyl group and cyclopentyl group. The bicycloalkyl group is preferably a substituted or unsubstituted bicycloalkyl group having 5 to 10 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 10 carbon atoms, for example, Bicyclo [1,2,2] heptan-2-yl group, bicyclo [2,2,2] octan-3-yl group, and the like. That.

Examples of the alkenyl group include linear, branched, and cyclic substituted or unsubstituted alkenyl groups, and include cycloalkenyl groups and bicycloalkenyl groups. Specifically, the alkenyl group preferably includes a substituted or unsubstituted alkenyl group having 2 to 10 carbon atoms, such as a vinyl group, an allyl group, a prenyl group, and the like, and the cycloalkenyl group preferably A substituted or unsubstituted cycloalkenyl group having 3 to 10 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 10 carbon atoms, such as a 2-cyclopenten-1-yl group, 2 -Cyclohexen-1-yl group, etc. The bicycloalkenyl group is a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 10 carbon atoms, that is, a double bond. A monovalent group in which one hydrogen atom of a bicycloalkene is removed, for example, bicyclo [2,2,1] hept-2- Down-1-yl group, a bicyclo [2,2,2] oct-2-en-4-yl group and the like.
The alkynyl group is preferably a substituted or unsubstituted alkynyl group having 2 to 10 carbon atoms, such as an ethynyl group, a propargyl group, and a trimethylsilylethynyl group.

The aryl group is preferably a substituted or unsubstituted aryl group having 6 to 15 carbon atoms, such as a phenyl group, a p-tolyl group, a naphthyl group, and an m-chlorophenyl group.
The heterocyclic group is preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound, and more preferably And a 5- or 6-membered aromatic heterocyclic group having 3 to 10 carbon atoms such as a 2-furyl group, a 2-thienyl group, a 2-pyrimidinyl group, and a 2-benzothiazolyl group.
The alkoxy group is preferably a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms such as a methoxy group, an ethoxy group, an isopropoxy group, a t-butoxy group, and a 2-methoxyethoxy group. .

The aryloxy group is preferably a substituted or unsubstituted aryloxy group having 6 to 10 carbon atoms, such as a phenoxy group, 2-methylphenoxy group, 4-t-butylphenoxy group, 3-nitrophenoxy group. Etc.
The silyloxy group is preferably a substituted or unsubstituted silyloxy group having 0 to 10 carbon atoms, such as a trimethylsilyloxy group.
The heterocyclic oxy group is preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 10 carbon atoms, such as 1-phenyltetrazol-5-oxy group and 2-tetrahydropyranyloxy group. It is done.
The acyloxy group is preferably a formyloxy group, a substituted or unsubstituted alkylcarbonyloxy group having 2 to 10 carbon atoms, a substituted or unsubstituted benzoyloxy group having 6 to 10 carbon atoms, a p-methoxyphenylcarbonyloxy group, and the like. Is mentioned.
Substituted arylcarbonyloxy group, for example, acetyloxy group, pivaloyloxy group The carbamoyloxy group is preferably a substituted or unsubstituted carbamoyloxy group having 1 to 10 carbon atoms, for example, N, N-dimethylcarbamoyloxy group. Group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group and the like.

The alkoxycarbonyloxy group is preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 10 carbon atoms, such as a methoxycarbonyloxy group, an ethoxycarbonyloxy group, a t-butoxycarbonyloxy group, and the like.
The aryloxycarbonyloxy group is preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 10 carbon atoms, such as a phenoxycarbonyloxy group and a p-methoxyphenoxycarbonyloxy group.
The amino group includes an alkylamino group, an arylamino group, and a heterocyclic amino group, and is preferably an amino group, a substituted or unsubstituted alkylamino group having 1 to 10 carbon atoms, or a substituted group having 6 to 10 carbon atoms. Or an unsubstituted anilino group, for example, a methylamino group, a dimethylamino group, an anilino group, an N-methyl-anilino group, etc. are mentioned.
The acylamino group is preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 10 carbon atoms, a substituted or unsubstituted arylcarbonylamino group having 6 to 10 carbon atoms, such as acetylamino Group, pivaloylamino group, benzoylamino group and the like.

The aminocarbonylamino group is preferably a substituted or unsubstituted aminocarbonylamino group having 1 to 10 carbon atoms, such as carbamoylamino group, N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonyl. An amino group, a morpholinocarbonylamino group, etc. are mentioned.
The alkoxycarbonylamino group is preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 10 carbon atoms, such as a methoxycarbonylamino group, an ethoxycarbonylamino group, a t-butoxycarbonylamino group, or an N-methyl group. A methoxycarbonylamino group etc. are mentioned.
The aryloxycarbonylamino group is preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 10 carbon atoms, such as a phenoxycarbonylamino group and a p-chlorophenoxycarbonylamino group.
The sulfamoylamino group is preferably a substituted or unsubstituted sulfamoylamino group having 0 to 10 carbon atoms, such as sulfamoylamino group, N, N-dimethylaminosulfonylamino group, N- An n-octylaminosulfonylamino group and the like can be mentioned.

The alkyl or arylsulfonylamino group is preferably a substituted or unsubstituted alkylsulfonylamino group having 1 to 10 carbon atoms, a substituted or unsubstituted arylsulfonylamino group having 6 to 10 carbon atoms, such as methylsulfonyl Examples include an amino group, a butylsulfonylamino group, a phenylsulfonylamino group, a 2,3,5-trichlorophenylsulfonylamino group, and a p-methylphenylsulfonylamino group.
The alkylthio group is preferably a substituted or unsubstituted alkylthio group having 1 to 10 carbon atoms, such as a methylthio group or an ethylthio group.
Preferred examples of the arylthio group include substituted or unsubstituted arylthio groups having 6 to 10 carbon atoms such as a phenylthio group, a p-chlorophenylthio group, and an m-methoxyphenylthio group.
The heterocyclic thio group is preferably a substituted or unsubstituted heterocyclic thio group having 2 to 10 carbon atoms, such as 2-benzothiazolylthio group, 1-phenyltetrazol-5-ylthio group, and the like. It is done.
The sulfamoyl group is preferably a substituted or unsubstituted sulfamoyl group having 0 to 10 carbon atoms, such as N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group. Group, N-benzoylsulfamoyl group and the like.

The alkyl or arylsulfinyl group is preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 10 carbon atoms, a substituted or unsubstituted arylsulfinyl group having 6 to 10 carbon atoms, such as a methylsulfinyl group or an ethylsulfinyl group. , Phenylsulfinyl group, p-methylphenylsulfinyl group and the like.
The alkyl or arylsulfonyl group is preferably a substituted or unsubstituted alkylsulfonyl group having 1 to 10 carbon atoms, a substituted or unsubstituted arylsulfonyl group having 6 to 10 carbon atoms, such as a methylsulfonyl group, an ethylsulfonyl group, a phenyl group. A sulfonyl group, p-methylphenylsulfonyl group, etc. are mentioned.
The acyl group is preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 10 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 10 carbon atoms, or a substituted group having 2 to 10 carbon atoms. Or a heterocyclic carbonyl group bonded to a carbonyl group with an unsubstituted carbon atom, such as an acetyl group, a pivaloyl group, a 2-chloroacetyl group, a benzoyl group, a 2-pyridylcarbonyl group, a 2-furylcarbonyl group, and the like. It is done.
The aryloxycarbonyl group is preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 10 carbon atoms, such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group and the like. It is done.

The alkoxycarbonyl group is preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 10 carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, or a t-butoxycarbonyl group.
The carbamoyl group is preferably a substituted or unsubstituted carbamoyl group having 1 to 10 carbon atoms, such as carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N- (methylsulfonyl) carbamoyl. Groups and the like.
The aryl or heterocyclic azo group is preferably a substituted or unsubstituted arylazo group having 6 to 10 carbon atoms, a substituted or unsubstituted heterocyclic azo group having 3 to 10 carbon atoms, such as phenylazo, p- Examples include chlorophenylazo, 5-ethylthio-1,3,4-thiadiazol-2-ylazo and the like.

As said imide group, Preferably, N-succinimide group, N-phthalimide group, etc. are mentioned.
The phosphino group is preferably a substituted or unsubstituted phosphino group having 0 to 15 carbon atoms, such as a dimethylphosphino group, a diphenylphosphino group, a methylphenoxyphosphino group, and the like.
The phosphinyl group is preferably a substituted or unsubstituted phosphinyl group having 0 to 15 carbon atoms, such as a phosphinyl group or a diethoxyphosphinyl group.
The phosphinyloxy group is preferably a substituted or unsubstituted phosphinyloxy group having 0 to 15 carbon atoms, such as a diphenoxyphosphinyloxy group.
The phosphinylamino group is preferably a substituted or unsubstituted phosphinylamino group having 0 to 15 carbon atoms such as a dimethoxyphosphinylamino group and a dimethylaminophosphinylamino group.
The silyl group is preferably a substituted or unsubstituted silyl group having 0 to 10 carbon atoms, such as a trimethylsilyl group, a t-butyldimethylsilyl group, and a phenyldimethylsilyl group.

  Among the above substituents, those having a hydrogen atom may be further substituted with the above substituent. Examples of such a substituent include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group, and a benzoylaminosulfonyl group.

  The azo dye of the present invention is represented by the above general formula (1) or general formula (3). First, the azo dye represented by the general formula (1) will be described in detail.

[In General Formula (1), A represents a group selected from the group of aromatic groups (A) to (D) of the following General Formula (2), and W represents an aliphatic group or a total of 6 or less carbon atoms in total. Represents an aromatic group having 6 or less carbon atoms, and R _{1 to} R ₄ each independently represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, a halogen atom, a cyano group, an alkoxy group, an acyloxy group, or an amino group. , An acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an alkyl or arylsulfonylamino group, a sulfamoyl group, an alkyl or arylsulfonyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, or an aryl or heterocyclic azo group . However, W and R ₄ are not bonded to each other to form a ring. ]

[In General Formula (2), a _{1 to} a ₄ , b _{1 to} b ₄ , c _{1 to} c ₄ and d _{1 to} d ₄ are each independently a hydrogen atom or a substituent (provided that a sulfo group and a carboxyl group are X ₁ and X ₂ each independently represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group. * Represents a binding site with the azo group of the general formula (1). However, a ₁ and a ₂ , a ₃ and a ₄ , b _{1 to} b ₄ , c ₁ and c ₂ , c ₃ and c _4, and d _{1 to} d ₄ may be bonded to each other to form a ring. ]

  In general formula (1), W is preferably an alkyl group having 6 or less carbon atoms or a phenyl group, more preferably an alkyl group having 3 or less carbon atoms, and particularly preferably a methyl group, An ethyl group or a trifluoromethyl group.

In general formula (1), R ₁ is preferably a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, a cyano group, or an alkoxy group, more preferably a hydrogen atom or a chlorine atom, Preferably, it is a hydrogen atom.

In general formula (1), R ₂ is preferably a hydrogen atom, a halogen atom, an alkyl group, an acylamino group, or an acyl group, more preferably a hydrogen atom, a halogen atom, or an alkyl group. Preferably, it is a hydrogen atom.

In general formula (1), R ₃ is preferably a hydrogen atom, halogen atom, aliphatic group, cyano group, alkoxy group, amino group, acylamino group, sulfamoyl group, alkyl or arylsulfonyl group, alkoxycarbonyl group, carbamoyl group. Or an aryl or heterocyclic azo group, more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a sulfamoyl group, an alkyl or arylsulfonyl group, an alkoxycarbonyl group, or a carbamoyl group, particularly preferably Is a hydrogen atom, a chlorine atom, a cyano group, a sulfamoyl group, an alkylsulfonyl group, or a carbamoyl group.

In general formula (1), R ₄ is preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkylsulfonyl group, or an acyl group, more preferably a hydrogen atom or a chlorine atom. Particularly preferred is a hydrogen atom.

In (A) in the aromatic group of the general formula (2), a ₁ or a ₄ are preferably each independently a hydrogen atom, a halogen atom, an aliphatic group, a heterocyclic group, a cyano group, an alkoxy group, an acylamino group Group, aminocarbonylamino group, sulfamoylamino group, alkyl or arylsulfonyl group, alkyl or arylsulfonylamino group, alkoxycarbonyl group, carbamoyl group, sulfamoyl group, or acyl group, more preferably a hydrogen atom, A fluorine atom, a chlorine atom, an alkyl group, a cyano group, an acylamino group, a carbamoyl group, or a sulfamoyl group, particularly preferably a hydrogen atom, a fluorine atom, a chlorine atom, a carbamoyl group, or a sulfamoyl group.
In (A) in the aromatic group of the general formula (2), a ₂ or a ₃ is preferably a hydrogen atom, a halogen atom, an aliphatic group, a hydroxyl group, an alkoxy group, a carbamoyl group, an amino group, or an acylamino group. , An alkylsulfonyl group, or an alkyl or arylsulfonylamino group, more preferably a hydrogen atom, a chlorine atom, or an alkyl group, and particularly preferably a hydrogen atom.
However, a ₁ and a ₂ , a ₃ and a ₄ may be bonded to each other to form a non-aromatic ring, an aromatic ring (for example, naphthalene ring) or a heterocyclic ring (for example, quinoline ring).

In (B) in the aromatic group of the general formula (2), b ₁ , b ₃ or b ₄ are preferably each independently a hydrogen atom, a halogen atom, an aliphatic group, an alkoxy group, a carbamoyl group, or A sulfamoyl group, more preferably a hydrogen atom, an alkyl group or a sulfamoyl group, and particularly preferably a hydrogen atom.
In (B) of the aromatic group of the general formula (2), b ₂ is preferably a hydrogen atom, a halogen atom, an alkyl group, a cyano group, an alkoxy group, or a sulfamoyl group, and more preferably a chlorine atom. , An alkyl group, an alkoxy group or a cyano group, particularly preferably a chlorine atom or an alkoxy group.

In (C) in the aromatic group of the general formula (2), preferred examples of c _{1 to} c ₄ are the same as the preferred examples of a _{1 to} a _{4 in} (A) of the aromatic group.
In (C) in the aromatic group group of the general formula (2), X ₁ is preferably a hydrogen atom, an aliphatic group, an acyl group, or an alkyl or arylsulfonyl group, more preferably an alkyl group, An acyl group or an alkylsulfonyl group, particularly preferably an acyl group having a total carbon number of 3 or less, or an alkylsulfonyl group having a total carbon number of 3 or less.

In (D) in the aromatic group of the general formula (2), preferred examples of d _{1 to} d ₄ are the same as the preferred examples of b _{1 to} b ₄ of the aromatic group (B).
Preferred examples of X ₂ in the general formula aromatic Motogun in the (2) (D) is the same as the preferred embodiment X ₁ (C) is an aromatic Motogun.

  In general formula (1), A is preferably a group selected from (A) in the aromatic group represented by general formula (2). The azo dye of the present invention is most preferably an azo dye represented by the following general formula (3).

In General Formula (3), a _{1 to} a ₄ have the same meanings as a _{1 to} a _{4 in} (A) in the aromatic group represented by General Formula (2), and preferred examples are also the same.
In General Formula (3), R ₃ has the same meaning as R ₃ in General Formula (1), and preferred examples are also the same.

  The preferred combinations of substituents of the compounds represented by the general formulas (1) to (3) are preferably compounds in which at least one of the various substituents is the preferred group, and more various substitutions. More preferred are compounds in which the group is the preferred group, and most preferred are compounds in which all substituents are the preferred groups.

The azo dye represented by the general formula (1) or the general formula (3) of the present invention further satisfies the following conditions 1 and 2.
Condition 1: Molecular weight is 220 or more and 600 or less Condition 2: CLogP value is 0 or more and 4.0 or less

  The molecular weight of the azo dye is preferably 220 or more and 500 or less, and more preferably 240 or more and 450 or less. When the molecular weight is within the preferred range, transferability is improved during thermal transfer recording. If the molecular weight is too large, transferability is deteriorated at the time of thermal transfer recording, and if it is too small, it is easily absorbed into a living body and the risk of developing toxicity increases.

  The ClogP value of the azo dye is preferably 0.5 or more and 4.0 or less, and more preferably 1.0 or more and 3.5 or less. When the CLogP value is within a preferred range, the solubility in a methyl ethyl ketone / toluene mixed solvent is improved and the storage stability of the ink sheet with time is improved in the production of an ink sheet for thermal transfer recording. If this value is too large, the storage stability of the ink sheet deteriorates, and if it is too small, the solubility in a methyl ethyl ketone / toluene mixed solvent decreases.

  The pKa value of the phenolic hydroxyl group of the azo dye is preferably 9.0 or less, more preferably 7.0 or less, and particularly preferably 5.0 or less. The lower limit of the pKa value is not particularly limited, but is usually 3.0 or more. When the pKa value is in the preferred range, the colorability of the cationic medium is improved.

Next, a method for synthesizing the azo dye of the present invention will be described.
The compound represented by the general formula (1) (or (3)) can be synthesized according to the following reaction scheme.

Next, an example of a method for producing the azo dye represented by the above (formula 7) will be described. For example, the diazonium salt represented by the above (Formula 5) is produced using the aniline derivative represented by the above (Formula 4) using a diazotizing agent under acidic conditions, and this diazonium salt and the above (Formula 6) are represented. The azo dye represented by the above (formula 7) can be produced by performing a coupling reaction with a compound to be subjected to a post-treatment by a conventional method.
The reaction for obtaining the diazonium salt represented by the above (formula 5) from the aniline derivative represented by the above (formula 4) with a diazotizing agent is, for example, an acidic solvent such as sulfuric acid, phosphoric acid, acetic acid, hydrochloric acid, methanesulfonic acid, etc. The reaction can be carried out by reacting a diazotizing agent such as sodium nitrite, nitrosylsulfuric acid, isoamyl nitrite and the like at a temperature of 15 ° C. or lower for about 10 minutes to 6 hours.
The reaction for obtaining the azo dye represented by the above (formula 7) by the coupling reaction between the diazonium salt represented by the above (formula 5) and the phenol derivative represented by the above (formula 6) is carried out in an organic solvent or water, The reaction can be performed at 40 ° C. or lower, preferably 25 ° C. or lower for about 10 minutes to 12 hours.
In some cases, crystals are precipitated in this way, but in general, water or an alcohol solvent is added to the reaction solution to precipitate the crystals, and the crystals can be collected by filtration. it can. The crystals collected by filtration are washed and dried as necessary to obtain the azo dye represented by the above (formula 7).

  Specific examples of the azo dye represented by the general formula (1) or the general formula (3) of the present invention are shown in Chemical formulas 7 to 9, and the respective molecular weights and CLogP values are shown in Table 1. However, the azo dyes used in the present invention are not limited to the following examples.

  In the present invention, even when a tautomer exists depending on the structure of the compound, it is described in one of the representative forms in the present invention, but a tautomer different from the description of the present invention is also present in the present invention. It is contained in the compound.

In the present invention, the compounds represented by the general formulas (1) to (3) can be applied even if they contain isotopes (for example, ² H, ³ H, ¹³ C, ¹⁵ N).

[Ink sheet for thermal transfer recording]
The ink sheet for thermal transfer recording of the present invention can be produced according to a conventional method except that it contains the azo dye represented by the general formula (1). This thermal transfer recording ink sheet generally has a structure in which a dye-donating layer is formed on a support, and the dye-donating layer contains an azo dye represented by the general formula (1). The ink sheet for thermal transfer recording of the present invention is prepared by dissolving an azo dye represented by the general formula (1) in a solvent together with a binder, or by dispersing fine particles in a solvent. It can be produced by coating an ink liquid on a support and drying it appropriately to form a dye-donating layer.

  More specifically, as the support for the ink sheet for thermal transfer recording of the present invention, any conventionally used support for an ink sheet can be appropriately selected and used. For example, the material described in paragraph No. 0050 of JP-A-7-137466 can be preferably used. The thickness of the support is preferably 2 to 30 μm.

The binder resin that can be used in the dye-donating layer of the ink sheet for thermal transfer recording of the present invention is particularly high as long as it has high heat resistance and does not prevent the dye compound from moving to the image receiving material when heated. The type is not limited. For example, what is described in paragraph number 0049 of JP-A-7-137466 can be given as a preferred example. As the solvent for forming the dye-donating layer, a conventionally known solvent can be appropriately selected and used, and those described in Examples of JP-A-7-137466 can be preferably used.
The content of the dye compound represented by the general formula (1) in the dye-donor layer is preferably ^{0.03~1.0g / m 2, 0.1~0.6g / m} 2 is more preferable. Further, the thickness of the dye-donating layer is preferably 0.2 to 5 μm, and more preferably 0.4 to 2 μm.
The ink sheet for thermal transfer recording of the present invention may have a layer other than the dye-donating layer as long as the effect of the present invention is not excessively inhibited. For example, it may have an intermediate layer between the support and the dye-donating layer, or it may have a back layer on the support surface opposite to the dye-donating layer (hereinafter also referred to as “back surface”). There may be. Examples of the intermediate layer include an undercoat layer and a diffusion prevention layer (hydrophilic barrier layer) for preventing diffusion of the dye in the direction of the support. Examples of the back layer include a heat resistant slip layer, and can prevent adhesion of the thermal head to the ink sheet.

  In order to apply the present invention to a thermal transfer recording material capable of recording a full color image, a cyan ink sheet containing a heat diffusible cyan dye capable of forming a cyan image, and a heat diffusibility capable of forming a magenta image. It is preferable that a magenta ink sheet containing a magenta dye and a yellow ink sheet containing a heat-diffusible yellow dye capable of forming a yellow image are sequentially coated on a support. In addition, an ink sheet containing a black image forming substance may be further formed as necessary.

[Thermal transfer recording]
When performing thermal transfer recording using the ink sheet for thermal transfer recording of the present invention, it can be performed by combining a heating means such as a thermal head and an image receiving material by a conventional method. For example, thermal energy is applied to the ink sheet from the thermal head in accordance with the image recording signal, and the portion of the dye to which the thermal energy is applied moves to the image receiving material and is fixed, thereby recording an image. The image receiving material usually has a structure in which an ink receiving layer containing a polymer is provided on a support. As the configuration and materials used of the image receiving material, for example, those described in paragraph numbers 0056 to 0074 of JP-A-7-137466 can be preferably used.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

[Example 1]
<Synthesis of Exemplary Compound (D-1)>
To 13.5 g (0.1 mol) of 2-aminoacetophenone, 60 mL of water and 25 mL (0.3 mol) of 12N hydrochloric acid were added, and the mixture was ice-cooled to an internal temperature of 10 ° C. or less. 7.25 g (0.105 mol) of sodium nitrite ) Was dissolved in 18 mL of water. The reaction solution was stirred for 1 hour under ice-cooling, 150 mg of sulfamic acid was added, and the mixture was further stirred for 15 minutes to prepare diazo solution A.
To 8.94 g (0.095 mol) of phenol, 80 mL of methanol and 8.94 g of a 28% methanol solution of sodium methoxide were added and ice-cooled to an internal temperature of 10 ° C. or lower, and the diazo solution A was added dropwise. The reaction solution was stirred at room temperature for 30 minutes, and then the reaction system was acidified with a dilute aqueous hydrochloric acid solution, followed by separation and extraction with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried over magnesium sulfate, the organic layer was concentrated under reduced pressure, and purified by silica gel column to give 16.5 g of exemplified compound (D-1) (yellow powder, yield 72%). It was. Melting point 105 ° C

[Example 2]
Exemplified compounds in the same manner as in Example 1 except that equimolar amounts of o-cyanophenol, o-hydroxybenzamide, o-hydroxyphenylmethanesulfonamide or p-methoxyphenol were used instead of the phenol used in Example 1. (D-3), (D-4), (D-5), and (D-16) were synthesized. For each of the azo dyes thus obtained, the melting point and λmax and εmax in the dimethylacetamide solvent were measured. The results are shown in Table 2 below. However, Exemplified compounds (D-3), (D-4), and (D-5) were measured for λmax and εmax by adding a small amount of triethylamine to a dimethylacetamide solvent.

[Example 3]
The Ames test (azo reduction method) was performed on the exemplified compound (D-1) of the present invention and the comparative azo dyes (E-1) and (E-2) according to the following procedure. The azo reduction method is known as a test method having a high reductive metabolic activity of an azo group and having a higher sensitivity than a normal Ames test. J. Prival, and V. D. Mitchell, Mutation Research, 97, 103-116 (1982).

[Test substance]
Exemplified compound (D-1) of the present invention, comparative azo dyes (E-1), and (E-2) were 50 mg / mL, 12.5 mg / mL, 3.13 mg / mL, 0 using dimethyl sulfoxide, respectively. Those prepared to be .78 mg / mL and 0.20 mg / mL were used as test substance solutions in the test.
[Test bacteria used]
Salmonella typhimurium TA100
Salmonella typhimurium TA98
[Positive control substance used]
AF-2: Frill flamide TB: Trypan blue

[Composition of medium and S9mix]
1) Top agar The following aqueous solutions (A) and (B) were mixed at a volume ratio of 10: 1.
(A) Bact agar (Difco): 0.6%
Sodium chloride: 0.5%
(B) L-histidine: 0.5 mM
Biotin: 0.5 mM
2) Synthetic medium As the medium, a minimal agar medium manufactured by Nisshin Flour Milling Co., Ltd. was used. In addition, the composition per 1L of culture media is as follows, and 30 mL was flowed and solidified for each 90 mm diameter petri dish.
Magnesium sulfate heptahydrate: 0.2g
Citric acid monohydrate: 2.0 g
Dipotassium hydrogen phosphate: 10g
Sodium ammonium hydrogenphosphate tetrahydrate: 3.5g
Glucose: 20g
Bact agar (Difco): 15g
3) S9mix
S9: 0.3 mL
NADH: 4 μmol
Magnesium chloride: 8μmol
NADPH: 4 μmol
Potassium chloride: 33 μmol
0.2 M phosphate buffer (pH 7.4): 1000 μmol
Glucose-6 phosphate: 5 μmol
FMN: 2 μmol
However, S9 used in the azo reduction method was S9 (Kikkoman Co., Ltd.) prepared from an uninduced liver of an 8-week-old male Syrian Hamster.

[Test method]
Tests were performed by the direct method and metabolic activation method using the preincubation method.
In a sterilized small test tube, 0.1 mL of the test bacterial solution, 0.1 mL of the test substance solution, and 0.5 mL of 0.1 M phosphate buffer (S9mix: 0.5 mL in the metabolic activation method) are mixed, and 37 ° C. For 20 minutes. Furthermore, 2 mL of top agar was quickly mixed and poured onto a synthetic medium plate and hardened. At the same time, a control test was performed using two positive control substance solutions instead of the test substance solution. Culturing was carried out at 37 ° C. for 48 hours, the number of mutant colonies produced was calculated, and the average value was obtained for each. The presence or absence of antibacterial activity was judged from the state of the fungal membrane on the surface of the agar under the naked eye or under a stereomicroscope.

[Criteria]
Of the two types of test bacteria used (TA100, TA98), the number of revertant colonies on the plate containing the test substance increased more than twice that of the negative control, and the increase was reproducible or A positive dose was determined when dose dependency was observed.

  Table 3 shows the results of the Ames test (azo reduction method) of the exemplary compound (D-1) of the present invention, comparative azo dyes (E-1), and (E-2).

  From the above results, since the azo dye of the present invention is negative in both the direct method and metabolic activation method of the Ames test, it is clear that the toxicity to the living body is lower than that of the comparative compound.

[Example 4]
<Preparation of thermal transfer recording ink sheet>
Using a 6.0 μm thick polyester film (Lumirror, trade name, manufactured by Toray Industries, Inc.) with a heat-resistant slip treatment applied to the back surface by thermosetting acrylic resin (thickness 1 μm) on the front side of the film The following dye composition for forming a dye-donating layer was applied and formed by wire bar coating so that the thickness when dried was 1 μm, and ink sheet 1 was prepared.

(Coating composition for forming dye-donating layer)
Illustrative compound (D-3) 5.5 parts by mass Polyvinyl butyral resin 4.5 parts by mass (ESREC BX-1, trade name, manufactured by Sekisui Chemical Co., Ltd.)
90 parts by mass of methyl ethyl ketone / toluene (1/1)

  Next, except that the exemplified compound (D-3) was changed to the exemplified compounds (D-4) and (D-5), comparative azo dyes (E-3) and (E-4) of the present invention, respectively. In the same manner as in the preparation of the ink sheet 1, ink sheets 2 to 5 of the present invention were prepared.

<Production of image receiving material>
Synthetic paper (YUPO FPG200, trade name, manufactured by YUPO Corporation, thickness 200 μm) is used as a support, and a white intermediate layer-forming coating composition and a receiving layer-forming coating composition having the following composition are placed on one side in this order. Application was performed by a coater. The amount of each coating was such that the white intermediate layer was 1.0 g / m ² and the receiving layer was 4.0 g / m ² during drying, and the drying was performed at 110 ° C. for 30 seconds.

(White intermediate layer forming coating composition)
Polyester resin (Byron 200, trade name, manufactured by Toyobo Co., Ltd.) 10 parts by weight Optical brightener (Uvitex OB, trade name, manufactured by Ciba Geigy) 1 part by weight Titanium oxide 30 parts by weight Methyl ethyl ketone / toluene (1/1) 90 parts by mass

(Coating composition for receiving layer formation)
100 parts by weight of vinyl chloride-vinyl acetate resin (Solvine A, trade name, manufactured by Nissin Chemical Industry Co., Ltd.)
Amino-modified silicone 5 parts by mass (X22-3050C, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Epoxy-modified silicone 5 parts by mass (X22-300E, trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Methyl ethyl ketone / toluene (= 1/1) 400 parts by mass Benzotriazole UV absorber 5 parts by mass (Tinuvin 900, trade name, manufactured by Ciba Specialty Chemicals)

<Image recording and evaluation>
The ink sheet 1 obtained above and the image receiving material are overlapped so that the dye-donating layer and the image-receiving layer are in contact, and a thermal head is used from the back side of the dye-donating material, and the output of the thermal head is 0.25 W / dot, When printing was performed under conditions of a pulse width of 0.15 to 15 milliseconds and a dot density of 6 dots / mm, and a yellow dye was imaged on the image receiving layer of the image receiving material, image recording without uneven transfer was obtained. Obtained. When image recording was performed in the same manner except that the ink sheet 1 was changed to each of the ink sheets 2 to 5, a recorded image having no transfer unevenness was obtained.

  The status A reflection density at a solid density (100% halftone dot density) of each image obtained was measured. The transfer density was evaluated in three stages. The obtained results are shown as transfer density in Table 4 below.

  Regarding ink sheet storage stability, each of the ink sheets 1 to 5 obtained as described above was wound into a roll, and aged for 24 hours under conditions of a temperature of 60 degrees and a humidity of 70% RH. Each case was printed, and the case where the white background was hardly colored was evaluated as ◯, the case where it was slightly colored as Δ, and the case where it was very colored as x, which was evaluated visually in three stages. The obtained results are shown in Table 4 below as ink sheet storage stability.

  As is apparent from Table 4 above, according to the thermal transfer recording ink sheet of the present invention, a recorded matter excellent in transfer density and storage stability with time can be obtained.

Claims (9)

An azo dye represented by the general formula (1) and satisfying the following conditions 1 and 2.
Condition 1: The molecular weight is 220 or more and 600 or less.
Condition 2: The CLogP value is 0 or more and 4.0 or less.

[In General Formula (1), A represents a group selected from the group of aromatic groups (A) to (D) represented by the following General Formula (2), and W is an aliphatic group having 6 or less carbon atoms in total. Group or an aromatic group having 6 or less carbon atoms, and R _{1 to} R ₄ are each independently a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, a halogen atom, a cyano group, an alkoxy group, or an acyloxy group. , Amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, alkyl or arylsulfonylamino group, sulfamoyl group, alkyl or arylsulfonyl group, acyl group, alkoxycarbonyl group, carbamoyl group, or aryl or heterocyclic azo Represents a group. However, W and R ₄ are not bonded to each other to form a ring. ]

[In General Formula (2), a _{1 to} a ₄ , b _{1 to} b ₄ , c _{1 to} c ₄ and d _{1 to} d ₄ are each independently a hydrogen atom or a substituent (provided that a sulfo group and a carboxyl group are X ₁ and X ₂ each independently represent a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, an acyl group, an alkylsulfonyl group, or an arylsulfonyl group. * Represents a binding site with the azo group of the general formula (1). ]   The azo dye according to claim 1, wherein W in the general formula (1) is an alkyl group having 3 or less carbon atoms.   3. The azo dye according to claim 1, wherein A in the general formula (1) is selected from the aromatic group (A) represented by the general formula (2). An azo dye represented by the general formula (1) is represented by the following general formula (3).

[In the general formula _(3), a 1 ~a ₄ each independently represent a hydrogen atom or a substituent, _{R 3} has the same meaning as _{R 3} in the general formula (1). ]   The azo dye according to any one of claims 1 to 4, wherein the molecular weight of the azo dye represented by the general formula (1) or (3) is 240 or more and 450 or less.   The azo dye according to any one of claims 1 to 5, wherein the ClogP value of the azo dye represented by the general formula (1) or (3) is 1.0 or more and 3.5 or less. .   The azo dye according to claim 1, wherein the pKa of the phenolic hydroxyl group of the azo dye represented by the general formula (1) or (3) is 7.0 or less.   An ink sheet for thermal transfer recording, comprising the azo dye according to claim 1.   A thermal transfer recording method comprising forming an image on an image receiving material having an ink receiving layer containing a polymer on a support, using the thermal transfer recording ink sheet according to claim 8.