JPH0250910B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel fluoran compound and a method for producing the same. More specifically, the present invention relates to the general formula () [In the formula, R ₁ and R ₂ are alkyl groups having 1 to 10 carbon atoms,
R ₃ represents an alkyl group, an alkoxyalkyl group or a phenylalkyl group having 1 to 10 carbon atoms.
R ₄ is an alkyl group having 1 to 10 carbon atoms, an alkoxyalkyl group, an alkoxyalkoxyalkyl group, a cycloalkoxyalkyl group, a phenylalkoxyalkyl group, a phenoxyalkyl group, a cycloalkyl group, a phenylalkyl group, an acylalkyl group , represents a carboamide alkyl group, a furyl alkyl group, a furyl alkyloxyalkyl group, a tetrahydrofuryl alkyl group or a tetrahydrofuryl alkyloxyalkyl group, and the phenyl group contained in R ₃ or R ₄ is substituted with an alkyl group or a halogen. It's okay. Also, R ₃ and
R ₄ together with -CH is a cycloalkyl group,
A tetralinyl group or an indanyl group may also be formed. X represents hydrogen or halogen, and n represents an integer of 1 to 4. ] A fluoran compound represented by the following and a method for producing the same. Pressure-sensitive recording paper and heat-sensitive recording paper, which utilize a coloring reaction caused by contact between an almost uncolored electron-donating substance and an almost uncolored electron-accepting substance, are in high demand with the development of the current information age. is increasing.
Generally, pressure-sensitive recording paper is made by dissolving an electron-donating white dye (hereinafter referred to as a coloring agent) in an organic solvent, emulsifying it to a size of several microns, micro-encapsulating it with a polymer compound such as gelatin, and placing this on a support. It consists of an upper paper coated with a support, and a lower paper coated with an electron-accepting substance (hereinafter referred to as a color developer) on the support. This is a recording method in which the microcapsules are destroyed, the color forming agent in the capsules is released, and the color forming agent is transferred to the surface of the color developing agent to cause a color reaction and obtain a copied image. In addition, in thermal recording paper, a color forming agent and a color developing agent are supported in a binder (for example, a polymeric material such as polyvinyl alcohol) together with a solid flux, if necessary, so that the two do not come into contact with each other. The most common type of recording method is one in which at least one of a fluxing agent, a color former, or a color developer is melted by heating, and the color former and the color developer come into contact to cause a coloring reaction and obtain a recorded image. In addition, current-carrying heat-sensitive recording paper has a conductive layer containing a conductive agent between the support and the color forming layer (containing a color forming agent, a color developer, and a fluxing agent if necessary), and when a voltage is applied. This is a recording method in which a recorded image is obtained by generating heat and causing a coloring reaction. In recent years, there has been an increasing demand for color formers that can produce black images due to the need to make copies from recording paper on which images have been obtained by the color reaction between the color former and the color developer under pressure or heat as described above. Ta. In principle, it is possible to obtain a black image by mixing several suitable coloring agents with different hues, but the coloring speed may vary depending on the type of coloring agent, and the light resistance of the image may vary depending on the type of coloring agent. However, since the recording paper differs in water resistance, the hue may change depending on the storage condition of the recording paper. Therefore, efforts have been made to develop dyes that can produce black images using a single coloring agent, but no dye has yet been found that produces black images that are satisfactory in all aspects, including hue, fastness, self-color development, and cost. The current situation is that this is not the case. The present inventors have discovered that the fluoran derivative represented by the general formula () itself is a white crystal with no coloration, but when it comes into contact with an acidic substance, it develops a black tone,
It has been found that this dye is useful as a coloring agent for pressure-sensitive or heat-sensitive recording paper, which has extremely excellent light resistance and water resistance, and has strong fastness. The fluoran compound of the present invention can be produced, for example, as follows. (A) General formula () [In the formula, R ₁ , R ₂ , X, and n have the above-mentioned meanings. ] Compound represented by and general formula () [In the formula, R represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and R ₃ and R ₄ have the above-mentioned meanings. ] The compound represented by is reacted with the compound shown in the formula at -5°C to about 90°C for several hours to several tens of hours in the presence of a dehydration condensation agent. Next, the mixture is poured into water, made alkaline, and further heat-treated if necessary to obtain slightly colored white crystals. Separately, this is dried and recrystallized to obtain a fluoran derivative represented by the general formula () as white crystals. Here, sulfuric acid, phosphoric acid, polyphosphoric acid, etc. are used as the dehydrating agent when synthesizing the compound of the general formula () from the compound represented by the general formula () and the compound of the general formula (). is 85% ~
100% strength sulfuric acid is used. Further, as a recrystallization solvent, toluene, monochlorobenzene, chloroform, methyl isobutyl ketone, methyl cellosolve, isobutanol, isopropanol, dioxane, ethylene glycol dimethyl ether, etc. are used. Pressure-sensitive or heat-sensitive recording paper can be produced by a conventional method using one or more of the color formers thus obtained, or in combination with other color formers. The fluoran derivative represented by the general formula () of the present invention is a novel compound itself, and the recording paper using this compound is also novel. The fluoran derivative represented by the general formula () contains chlorine as a substituent at the 6-position and at the same time
In this position, there is an imino group bonded to the tertiary carbon, i.e.

[Formula] is characterized by containing a group. Recording paper obtained by using a fluoran derivative with such a novel and unique chemical structure as a coloring agent develops a deep black color.
It has particularly excellent storage stability, color development, and water resistance. In other words, in the pressure-sensitive paper using this coloring agent, there is less discoloration due to light on the capsule-coated paper.
In addition, the light fastness of the colored image is excellent, and in the case of thermal paper, uncolored paper is less likely to be colored by light, temperature and humidity.
Another great feature is that the colored image is less likely to change color due to temperature and humidity, or to change color or fade due to light. Furthermore, when applied to multicolor thermosensitive recording paper, the color development when heated is clear, multicolor development occurs without color mixing, and it is stable in storage. Furthermore, this color former has an extremely high solubility in organic solvents used in the production of pressure-sensitive recording paper. As described above, the fluoran compound of the present invention is a coloring agent for use in pressure-sensitive recording paper or heat-sensitive recording paper that has greatly improved in all respects the drawbacks of coloring agents currently used on the market. , is of extremely high industrial value. Next, examples of the compound represented by the general formula () used in the production of the fluoran compound of the present invention include the following. 2-(4'-N,N-diethylamino-2'-hydroxybenzoyl)-benzoic acid 2-(4'-N,N-dimethylamino-2'-hydroxybenzoyl-benzoic acid 2-(4'-N, N-dipropylamino-2'-hydroxybenzoyl)-benzoic acid 2-(4'-N,N-dibutylamino-2'-hydroxybenzoyl)-benzoic acid 2-(4'-N,N-diisopropylamino-
2'-hydroxybenzoyl)-benzoic acid 2-(4'-N,N-diamylamino-2'-hydroxybenzoyl)-benzoic acid 2-(4'-N,N-dihexylamino-2'-hydroxybenzoyl)- Benzoic acid 2-(4'-N,N-dioctylamino-2'-hydroxybenzoyl-benzoic acid 2-(4'-N-ethyl-N-butylamino-
2'-hydroxybenzoyl)-benzoic acid 2-(4'-N,N-diethylamino-2'-hydroxybenzoyl)-4-chlorobenzoic acid 2-(4'-N,N-diethylamino-2'-hydroxybenzoyl) )-3,4,5,6-tetrachlorobenzoic acid Examples of the compound represented by the general formula () include the following. Next, some examples of the fluoran compound represented by the general formula () of the present invention will be described. The hue indicates the hue when the color was developed on a thin layer of silica gel.

【table】

【table】

[Table] Hereinafter, the present invention will be explained in more detail with reference to Examples. In the text, parts represent parts by weight. Example 1 (Synthesis of compound No. 1) 2-(4'-diethylamino-
31.3 parts of 2'-hydroxybenzoylbenzoic acid and 2-
22.6 parts of chloro-4-hydroxy-N-cyclohexylaniline (melting point 116-117°C) is dissolved at 30°C or below, and then stirred and kept at 50-55°C for 24 hours to complete the reaction. Then 2000 parts ice water and 28% ammonia water
The reaction solution is made alkaline by pouring it into a solution consisting of 270 parts, and the precipitate formed is separated. hot water 2000
After cleaning, dry. 41.2 parts of 3-diethylamino-6-chloro-7-cyclohexylaminofluorane were obtained. This product was recrystallized from isopropyl alcohol to obtain 37.9 parts of white crystals with a melting point of 197-198°C. elemental analysis, mass spectra,
The NMR spectrum confirmed this structure. Example 2 (Synthesis of compound No. 2) 2-(4'-diethylamino-) was added to 219 parts of 98% sulfuric acid.
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Chlor-4-hydroxy-N-cyclopentylaniline (melting point 142-143℃/1.5mmHg, melting point 68-
69℃) 21.2g is melted below 30℃, and 24g is melted at 50-55℃.
Stir for an hour. Then inject into 2000 parts of ice water and 25
Add 710 parts of % caustic soda solution to make it alkaline.
Separate the formed precipitate. After washing with 2000 parts of warm water,
dry. 39.2 parts of 3-diethylamino-6-chloro-7-cyclopentylaminofluorane were obtained. This product was recrystallized from isopropyl alcohol to produce white crystals with a melting point of 162.5-163.5°C.
I got the department. Example 3 (Synthesis of compound No. 33) 2-(4'-diamylamino-
39.8 parts of 2'-hydroxybenzoylbenzoic acid and 2-
22.6 parts of chloro-4-hydroxy-N-cyclohexylaniline was dissolved and stirred at 50 to 55°C for 24 hours. Thereafter, the same post-treatment as in Example 1 was carried out to obtain 41.2 parts of 3-diamylamino-6-chloro-7-cyclohexylaminofluorane. This was recrystallized from isopropyl alcohol to give a melting point of
32.0 parts of white crystals having a temperature of 130.5-131.5°C were obtained. Example 4 (Synthesis of compound No. 3) 2-(4'-diethylamino-) was added to 219 parts of 95% sulfuric acid.
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
27.4 parts of -chloro-4-hydroxy-N-(β-tetralinyl)aniline (melting point 81-83°C) was dissolved and stirred at 30°C for 25 hours. Below, Example 1
After treatment in the same manner as above and recrystallization from isopropyl alcohol, 25.3 parts of 3-diethylamino-6-chloro-7-(β-tetralinylamino)fluorane was obtained. It is a white crystal with a melting point of 128-131°C. Example 5 (Synthesis of compound No. 5) 2-(4'-diethylamino-) was added to 219 parts of 98% sulfuric acid.
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Dissolve 18.6 parts of chloro-4-hydroxy-N-isopropylaniline (melting point 80-81℃) and add 50-55
The mixture was stirred and kept warm at ℃ for 24 hours. After the same post-treatment as in Example 1, 36.6 parts of 3-diethylamino-
6-chloro-7-isopropylaminofluorane was obtained. This was recrystallized from isopropyl alcohol to produce white crystals with a melting point of 199.5-200.5℃.
I got the department. Example 6 (Synthesis of compound No. 6) 2-(4'-diethylamino-) was added to 219 parts of 98% sulfuric acid.
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Chlor-4-hydroxy-N-(1'-ethylpropyl)aniline (boiling point 120-121℃/1.2mmHg)
21.4 parts were dissolved and stirred at 50 to 55°C for 24 hours. Hereafter, the same post-treatment as in Example 1 was carried out, and 38.6
3-diethylamino-6-chloro-7-
(1′-ethylpropylamino)fluorane was obtained.
This was recrystallized from isopropyl alcohol,
34.9 parts of white crystals with a melting point of 140-141°C were obtained. Example 7 (Synthesis of compound No. 9) 2-(4'-diethylamino-) was added to 219 parts of 98% sulfuric acid.
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Chloro-4-hydroxy-N-(1',3'-dimethylbutyl)aniline (boiling point 136-137℃/2mm
Dissolve 22.8 parts of Hg, melting point 64-65.5℃, 50-55℃
The mixture was kept warm and stirred for 24 hours. After the same post-treatment as in Example 1, 40.5 parts of 3-diethylamino-6-
Chloro-7-(1'-3'-dimerbutylamino)fluoran was obtained. This was recrystallized from isopropyl alcohol to obtain 30 parts of white crystals with a melting point of 156-158°C. Example 8 (Synthesis of compound No. 10) 2-(4'-diethylamino-
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Chloro-4-hydroxy-N-(1'methyl-
2′-methoxyethyl)aniline (melting point 82-83℃)
21.57 parts were dissolved and stirred at 40 to 50°C for 24 hours. Hereafter, the same post-processing as in Example 2 was carried out, and 29.8
3-diethylamino-6-chloro-7-
(1′-Methyl-2′-methoxyethylamino)fluoran was obtained. This was recrystallized from isopropyl alcohol to obtain 15.2 parts of white crystals with a melting point of 183-185°C. Example 9 (Synthesis of compound No. 20) 2-(4'-diethylamino-) was added to 238 parts of 90% sulfuric acid.
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Chlor-4-hydroxy-N-(1'-phenylmethyl-2'-phenylethyl)aniline (melting point 95
~97°C) was dissolved and stirred at 60°C for 24 hours. Next, the mixture was poured into 2000 parts of ice water, made alkaline by adding 710 parts of 25% caustic soda solution, and extracted three times with toluene. The toluene solution was concentrated under reduced pressure, and the concentrate was recrystallized from isopropyl alcohol to obtain 3-diethylamino-6-chloro-7-(1'-benzyl-2'-phenylethylamino)fluorane with a melting point of 134-137°C. 10 parts of white crystals were obtained. Example 10 (Synthesis of compound No. 22) 2-(4'-diethylamino-
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Chloro-4-hydroxy-N-(1'-methyl-
2′-acetylethyl)aniline (melting point 62-64℃)
22.8 parts of the solution was dissolved and stirred at 50°C for 36 hours. Hereinafter, the same post-processing as in Example 1 was carried out, and 34.4 parts of 3
-diethylamino-6-chloro-7-(1'-methyl-2'-acetylethylamino)fluoran was obtained. This was recrystallized from isopropyl alcohol to obtain 26.8 parts of white crystals with a melting point of 198-200°C. Example 11 2-(4'-diethylamino-) in 219 parts of 98% sulfuric acid
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
24.0 parts of -chloro-4-methoxy-N-cyclohexylaniline was dissolved and stirred at 50 to 55°C for 24 hours. Next, it was poured into 2000 parts of ice water, made alkaline by adding 710 parts of 25% caustic soda solution, and heated to 80°C.
After raising the temperature to 100 mL and keeping the temperature for 1 hour, the precipitate was separated and washed with water. After drying the cake, it was boiled with the same amount of orthodichlorobenzene, cooled, and diluted with isopropyl alcohol to obtain 35 parts of 3-diethylamino-6-chloro-7-cyclohexylaminofluorane. This was exactly the same as that obtained by the method of Example 1. Example 12 (Synthesis of compound No. 18) 2-(4'-diethylamino-
31.3 parts of 2′-hydroxybenzoyl)benzoic acid and 2
-Chloro-4-hydroxy-N-(1'-methyl-
26.0 parts of 3'-phenylpropyl)aniline (oil) was dissolved and stirred at 30°C for 36 hours. Thereafter, the product was post-treated in the same manner as in Example 1 and recrystallized from isopropyl alcohol to obtain 25.7 parts of white crystals.

Claims (1)

[Claims] 1 General formula () [In the formula, R ₁ and R ₂ are alkyl groups having 1 to 10 carbon atoms,
R ₃ represents an alkyl group, an alkoxyalkyl group or a phenylalkyl group having 1 to 10 carbon atoms.
R ₄ is an alkyl group having 1 to 10 carbon atoms, an alkoxyalkyl group, an alkoxyalkoxyalkyl group, a cycloalkoxyalkyl group, a phenylalkoxyalkyl group, a phenoxyalkyl group, a cycloalkyl group, a phenylalkyl group, an acylalkyl group , represents a carboamide alkyl group, a furyl alkyl group, a furyl alkyloxyalkyl group, a tetrahydrofuryl alkyl group or a tetrahydrofuryl alkyloxyalkyl group, and the phenyl group contained in R ₃ or R ₄ is substituted with an alkyl group or a halogen. It's okay. Also R ₃ and R ₄
may be combined with --CH to form a cycloalkyl group, tetralinyl group or indanyl group. X represents hydrogen or halogen, and n represents an integer of 1 to 4. ] A fluoran compound represented by 2 General formula () [In the formula, R ₁ and R ₂ are alkyl groups having 1 to 10 carbon atoms,
X represents hydrogen or halogen, and n represents an integer of 1 to 4. ] The compound represented by the general formula () [In the formula, R ₃ represents an alkyl group, an alkoxyalkyl group, or a phenylalkyl group having 1 to 10 carbon atoms. R ₄ is an alkyl group having 1 to 10 carbon atoms, an alkoxyalkyl group, an alkoxyalkoxyalkyl group, a cycloalkoxyalkyl group, a phenylalkoxyalkyl group, a phenoxyalkyl group, a cycloalkyl group, a phenylalkyl group, an acylalkyl group , represents a carboamide alkyl group, a furyl alkyl group, a furyl alkyloxyalkyl group, a tetrahydrofuryl alkyl group or a tetrahydrofuryl alkyloxyalkyl group, and the phenyl group contained in R ₃ or R ₄ is substituted with an alkyl group or a halogen. It's okay. Also with R ₃
R ₄ may be combined with —CH to form a cycloalkyl group, a tetralinyl group or an indanyl group. R represents hydrogen or an alkyl group having 1 to 4 carbon atoms. ] The general formula () is characterized by reacting the compound represented by in the presence of a dehydration condensation agent. [In the formula, R ₁ , R ₂ , R ₃ , R ₄ , X, and n have the above-mentioned meanings. ] A method for producing a fluoran compound shown in