JPH0358881A - Novel fluorane compound - Google Patents

Abstract

PURPOSE:To synthesize a fluorane compound represented by specific general formula effective for a recording material by condensing a 2-(2-hydroxy-4- substituted amino)benzoyl benoic acid derivative and an aniline derivative. CONSTITUTION:A 2-(2-hydroxy-4-substituted amino)benzoyl benoic acid derivative represented by formula I, wherein R1 and R2 are each a 1 - 8C alkyl group, a 3 - 8C alkoxyalkyl group, a 4 - 10C cycloalkyl group or a 1 - 4C alkyl group, and an aniline derivative represented by formula II, wherein R3 is a 1 - 6C alkyl group, a 1 - 4C alkyl group or a 3 - 8C alkoxyalkyl group and R4 is a 1 - 4C alkyl group, are condensed to obtain a fluorane derivative represented by formula (III), wherein R1, R2, R3 and R4 are each as defined above II.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is useful as a color-forming substance used in recording materials such as pressure-sensitive recording sheets, heat-sensitive recording sheets, and current-carrying recording sheets.
Concerning new fluoran compounds.

(Prior art) There are many fluoran compounds that have been disclosed in patents and are in practical use, but they have drawbacks such as color development speed, color density, color storage stability, background color development, color development start temperature, etc., and are not sufficient. It is not showing good performance.

(Problems that the Invention Attempts to Solve) The present invention provides a color-forming substance for recording materials such as pressure-sensitive recording sheets, heat-sensitive recording sheets, and current-carrying recording sheets, which eliminates the drawbacks of the conventional fluorane derivatives. An object of the present invention is to provide a novel fluoran compound for use in a commercial environment.

(Means for Solving the Problems) As a result of intensive studies to achieve the above object, the present inventors have completed the wooden invention. That is,
The fluoran compound of the present invention is a compound represented by general formula (.4).

R (in the formula, R+ and R2 have 1 to 8 carbon atoms, which may be branched)
an alkyl group, an alkoxyalkyl group having 3 to 8 carbon atoms,
Cycloalkyl L having 4 to 10 carbon atoms (, alkyl group having 1 to 4 carbon atoms, or benzyl or phenethyl group, which may be substituted with halogen, tetrahydrofuryl, furfuryl group, or lower alkyl group) represents phenyl J.!i which may be substituted with halogen, R3 is alkyl J having 1 to 6 carbon atoms, and R3 is alkyl J having 1 to 6 carbon atoms;
If the alkyl group of 4 is halogen, +. Represents a pencil group which may be substituted with yt, or an alkoxyalkyl group having 3 to 8 carbon atoms (4), R4 represents an alkyl group having 1 to 4 carbon atoms or a phenyl group which may be substituted with halogen. ) The fluoran compound of the present invention represented by the above general formula can be mainly produced by the following typical method. That is, 2-hydroxy-4 monosubstituted aminobenzoylbenzoic acid represented by the general formula (2) is synthesized by reacting the mmlh aminophenol derivative with breath water phthalic acid.

1{1 COO 1:? 2-(2-hydroxyloxy4-monosubstituted amine)
Henzoylbenzoic acid. General formula (1) is obtained by condensing the derivative with the aniline derivative represented by general formula (3).
It is possible to produce a fluoran derivative represented by

The aniline conductor represented by general formula (3) is synthesized, for example, by the following reaction scheme. That is, 1) p-
Reacting anisidine and sulfur chloride in chlorobenzene,
Synthesize llerz salt. Next, this is decomposed with an alkali to obtain an alkali metal salt of a thiophenol conductor, and this is reacted with methyl chloride to synthesize 4-methoxy-2-methylthianiline. 2) Next, multiply this by 1 to 50 times,
The desired product can be obtained by reacting preferably 5 to 20 equivalents of the halokene-substituted benzene derivative in the presence of a catalytic amount of copper under distant flow or at a temperature lower than that for 1 to 24 hours, preferably 2 to 12 hours. At this time, if necessary, 4-methoxy-2-methylthioaniline may be N-acetylated.
-Methoxy-2-methylthioacetanilide, then reacted with a halogen-substituted benzene derivative in the same manner,
Thereafter, this can be hydrolyzed and synthesized.

(Reaction scheme) R is a hydrogen atom, Alkyl prefecture with 1 to 4 carbon atoms, Ma or a halogen atom.

As a condensing agent in the condensation reaction between a 2-(2-hydroxy-4-:M?converted amino)benzoylbenzoic acid conductor and an aniline conductor, %% zinc chloride hydrate, j! ! Asahi water metal halide compounds such as aluminum chloride; single extraction or mixed catalysts such as Friedel-Crafts catalysts such as sulfuric acid, phosphorus pentoxide, phosphoric acid, polyphosphoric acid, phosphorus trichloride, and boron fluoride can be used.

A preferred example of the condensation reaction is to use 90 to 100% sulfuric acid in large excess, preferably 5 to 15%, to the compound of formula (3).
1 at -20 to 80°C, preferably O to 50°C using double the amount.
Allow to react for ~100 hours.

In the above reaction, a fluorane compound may be directly synthesized, or in most cases, a triphenylmethane conductor represented by the following general formula (4) is synthesized.

In this case, the obtained triphenylmethane derivatives are filtered and treated with alkaline substances such as sodium hydroxide aqueous solution, dilute potassium hydroxide aqueous solution, triethylamine, triethanolamine, pyridine, vicoline, and quinoline. The desired fluoran compound can be obtained by reacting at a degree of /r+'r of 1 or less.

When carrying out the reaction in a dilute aqueous sodium hydroxide solution or dilute potassium hydroxide medium, preferable results can be obtained by using a hydrophobic organic solvent such as pentene, toluene, or xylene in combination.

If necessary, the fluoran compound is recrystallized from a suitable volatile organic solvent such as isobrobyl alcohol, ether, Hensen, toluene, ethyl acetate, or the like.

A typical example of the aniline conductor represented by the general formula (3) used in the present invention is N-phenyl-4
-Methoxy-2-methylthioaniline, N-(4-methylphenyl)-4-methoxy-2-methylthioaniline, N-(2.4-dimethylphenyl)=4-methoxy2-methylthioaniline, N-(3 .4-Simethylphenyl)-4-methoxy-2-methylthioaniline, N-
(2,4.6-trimethylphenyl)-4-methoxy~
2-Methylaniline, N-(2-chlorophenyl)
-4-methoxy-2-methylthioaniline, N-(4-
(chlorophenyl)-4-methoxy-2-methoxyaniline, N-phenyl-4-methoxy-2-ethylthioaniline, N-phenyl-4-methoxy-2-butylthioaniline, N-phenyl-4-methoxy-2-pencylthioaniline, N-phenyl-4-methoxy-2-me I
-Xyethylthioaniline, N-(4-methylphenyl)-4-methoxy2-ethylthioaniline, etc.

Examples of the henzophenone-packed conductor represented by the general formula (2) include 2-hydroxy-4-dimethylamine-2゜mono-sulfoxyhenzophenone, 2-hydroxy-4-diethylamino-2'-carpoxyhenzophenone, Hydroxytodibrobylamino-2゜carpoxyhenzophenone, 2-hydroxy-4-dibutylamino-2-
Carboxybenzophenone, 2-hydroxy-4-N-
Methyl-N-cyclohexylamino-2-carboxybenzophenone, 2-hydroxyloxy4-N-methyl-N-
Bentylamino-2-carboxyhenzophenone, 2
-Hydroxyl 4-N-methyl-N-cyclohexylamino-2゜-carpoxybenzophenone, 2-hydroxy←N-ethyl-N-(i''-methylphenyl)amino-2゜-carboxybenzophenone, 2-hydroxy-4- Examples include N-methyl-N-tetrahydrofurfurylamino-2-carpoxybenzophenone.

2-anilino-3-methylthi-6-diethylaminofluorane! } Add 6.3 g of 2-hydroxy-4-diethylamino-2゜carpoxyhenzophenone to 50 g of 7% sulfuric acid, dissolve completely at a temperature of about 25°C, and then dissolve N-phenyl-4-methoxy-2-methylthio. 4.9 g of aniline was added and reacted at a temperature of 20 to 25°C for 48 hours. After the reaction,
The reaction mixture was added to about 500 ml of ice water, followed by the addition of about 10% sodium hydroxide to adjust the pH to 7-8, and the precipitate was collected by filtration.

Add 100m of lO% sodium hydroxide to this cake.
After adding j2 and 200 mffi of toluene and stirring at 80 to 85°C for 2 hours, the toluene layer was separated, washed with water, concentrated to dryness, and further recrystallized in isopropyl alcohol to obtain 3.4 g of white powder. The melting point of this thing is 173-17
4°C, and the absorption maximum wavelength and molecular extinction coefficient of this substance in 95% acetic acid are 598 nm (2.86
10') and 470 nm (1.97X 10'). When this material was brought into contact with paper coated with 45 L/l of silica gel, bisphenol A, phenol resin, or zinc salt of a salicylic acid conductor, it took on a black-purple color.

Note that the N-phenyl-4-methoxy 2-methylthioaniline used was produced by the method described below.

p-anisidine +2:1 in 700g of chlorohensen
．． Add 2 g of sulfur chloride and dissolve it.
70 g was slowly added at about 50°C, and after the addition of decomposed sulfur was finished, the temperature was gradually raised to ambient temperature and the reaction was carried out at 90 to 95°C for 2 hours.

The precipitate was filtered through fA, the cake was sieved with chlorohensen, and the solid was dried in vacuo. Next, this solid was heated to 10% at O~5°C.
The mixture was added to 80g of sodium hydroxide aqueous solution and stirred for 6 hours.

Next, add methyl chlorite to this solution at normal pressure at 30°C.
After about 20Q of blowing, the mackerel was extracted with ether, and the ether extract was vacuum distilled to produce an oily I-
Methoxy-2-methylthioaniline 92.28 or jil
It was done. The boiling point of this substance is 110~+15"C/:
It was lmmllg.

Next, this was N-acetylated with acetic anhydride in bilysin, and 4-methoxy-2-methylthioacetanilide was added at 1:1.
Ta. The melting point of this product was 96-97°C.

4-Methoxy-2-methylthioacetanilide 21. l
g, Promohensen 157g. Copper powder 0.42g, Asahi water potassium carbonate IO. 6g of potassium iodide and 0.2g of potassium iodide were added, and the reaction was carried out at 145 to 150°C for 8 hours. After completion of the reaction, the reaction volume was filtered and concentrated to dryness, and both crystals were crystallized from ether to give N-phenyl-4-methoxy-2-methylthioacetanilide 11. 2g was obtained. The melting point of this product was 103-105°C.

This N-phenyl-4-methoxy-2-methylacetanilide IO. Add 15 g of potassium hydroxide, 100 g of isobrobyl alcohol, and 20 g of water to 8 g and reflux 1.
After reacting for 0 hours, an oily N-phenyl-4-methoxy-2-
7.0 g of methylthianiline was obtained.

Example 2 2-(4-methylphenylamino)-3-methylthio-
Add 15.6 g of 2-hydroxy-4-diethylamino-2゜-carpoxybenzophenone to 200 g of 6-diethylaminofluorane 97% FAM, dissolve in complete metal at 25°C, and then dissolve N-(4-methylphenyl)-4-methoxy. -2-methylthianiline 123
g was added, and the reaction was carried out in the same manner as in Example 1, followed by recrystallization from isobrobyl alcohol to give white 2-(4-methylphenylamino)-3-methylthio-6-diethylaminofluorane+11. I got lg. The melting point after this is 1.82-18
4°C, maximum absorption wavelength and molecular extinction coefficient in 95% acetic acid are 602.8nm f2.78x 10')
and 473.2nm fl. 92 xlO'). In the future, silica gel, bisphenol A, phenolic resin, or salicylic acid derivatives will be added to r1=. t
When it came into contact with 5-sheet paper, the color quickly changed to a dark purple color.

The N-(4-methylphenyl)-4-methoxy-2-methyldianiline used was produced by the following method.

85 g of p-promotoluene and 10.6 g of anhydrous potassium carbonate were added to 21.1 g of 4-methoxy-2-methylthioacetanilide prepared in Example 1. After adding 420 mg of copper powder and 210 mg of potassium iodide and reacting at 165°C for 8 hours, it was filtered, condensed to dryness Ia, and recrystallized from ether.
Colorless Ni4-methylphenyl)-4-methoxy2-
15.5 g of methylthioacetanilide was obtained.

The subsequent melting point was 95-97°C. This N1 (4
(methylphenyl)-4-methoxy-2-methylthiacetanilide 23. Add 10 g of potassium hydroxide, 40 g of isobrobyl alcohol and 10 g of water to 9 g.
The reaction was carried out at a temperature of 0° C. for 8 hours, extracted with ethyl acetate, and concentrated to obtain 16.2 g of oily N-(4-methylphenyl)-4-methoxy-2-methylthianiline.

Actual example 3 2-12. Add 313 g of 2-hydroxy 4-diethylamino-2-carpoxybenzophenone to 63 g of 97% sulfuric acid (4-dimethylphenylamino)-3-methylthio-6-diethylamino at 25°C.
After completely dissolving with Ni2.4-dimethylphenyl)-
4-Methoxy-2-methylthioacetanilide 3.15
Then, 15 g of water was added to this reaction solution and the reaction was carried out at 80°C for 3 hours. Next, this reaction solution was poured into aqueous lβ, followed by addition of 10% aqueous sodium hydroxide solution to adjust the pH to 7-8, the precipitate was collected by filtration, the cake was air-dried, and then 10% hydroxide was added to the cake. 200 g of sodium aqueous solution, toluene I [
The toluene layer was concentrated to dryness and recrystallized from ether to form a white substance, 2-(2.4-dimethylphenylamino)-3.
-Methylthio-6-jethylaminofluorane was obtained.

The melting point of this product was 190-192°C. The maximum absorption wavelength and molecular extinction coefficient of this product in 95% acetic acid were 597.2 nm (3.Ixl 4) and 459.6 nm (1.72x IO'1).

This material can also be used as silica gel or bisphenol A.
When it came into contact with paper coated with phenol resin and salicylic acid resin derivatives, it quickly developed a dark green-blue color.

The N-(2,4-dimethylphenyl)-4-
Methoxy-2-methylthioacetanilide was produced by the following method.

Actual example! 23.1 g of 2,4-dimethylbromobenzene and 2.25 g of anhydrous potassium carbonate were added to 5.3 g of 4-methoxy-2-methylthiacetanilide prepared in . Iodide power Jum 100mg. Add 21) Omg of copper, react at 200°C for 8 hours, filter the reaction solution, concentrate to dryness, and recrystallize with ether to obtain a white N-(2.4
4.4 g of -dimethylphenyl)-4-methoxy-2-methylthiacetanilide was obtained. The melting point of this thing is 9
The temperature was 7-100°C.

Example 4 2-(3.4-dimethylphenylamino)-3-methylthio-6-diethylaminofluorane (N13.4-dimethylphenyl) in 200 g of 98% sulfuric acid
63 g of 4-methoxy-2-methylthioacetanilide and 6.2 g of 2-hydroxy-4-diethylamine-2-carpoxybenzophone were added and stirred at 25°C for 20 hours. After the reaction, add 50g of water to this reaction solution and bring it to 80°C.
After reacting for 3 hours at a temperature of
p117 with ice water and 10% sodium hydroxide solution.
~8, and the precipitate was collected by filtration and air-dried. Next, add 30 g of triethylamine to this. Toluene 200
g was added and reacted at a cold temperature of 80'C for 10 hours. The toluene layer was separated, concentrated to dryness, and recrystallized from isopropyl alcohol to obtain 7.9 g of white 2-+3.4-dimethylphenyl)-3-methylthio-6-diethylaminofluorane. . The melting point after this is 227-229°C
The absorption maximum wavelength and molecular extinction coefficient in 95% acetic acid are 6[]4nmf2.65X10') and 4
It was 74 nm (2.OX 10').

When this product was brought into contact with paper coated with silica gel, bisphenol A, phenol resin, or salicylic acid derivative, it rapidly developed a dark green-blue color. In addition, the N-(3.4-dimethylphenyl)-4- used here
Methoxy-2-methylthiacetanilide was produced by reacting the 4-methoxy-2-methylthiacetanilide prepared by TA in Example 1 in the same manner as in Example 3 using 3,4-dimethylbromobenzene as the starting material. The melting point of this product was 80-82°C.

Actual journey example 5 2-(2.4.6- }-limethylphenylamino)-
3-Methylthio-6-diethylaminofluorane 98%
N-12. in 116g of sulfuric acid. 5.8 g of 4.6-trimethylphenyl)-4-methoxy-2-methylthianiline and 6.2 g of 2-hydroxy-2-monocarpoxybenzophenone were added, reacted in the same manner as in Example 1, and recrystallized from ether. A pale yellow solid was obtained. The melting point of this 6 is 20
The temperature ranged from 7 to 209°C. In addition, the maximum absorption wavelength and molecular extinction coefficient of this substance in 95% acetic acid are 598 nm.
(3.5x l(I'). and 456nm f1.
67X l[I'). This stuff is silica gel,
Or, when it comes into contact with paper coated with bisphenol A, phenol resin, or salidylic acid derivatives, the color develops quickly.
6 It turned blue. In addition, the Ni2.4.
5-trimethylphenyl)-4-methoxy-2-methylthianiline was prepared by adding 7.3 g of 4-methoxy-2-methylthianiline prepared in Example 1, 430 g of 2,4.6-trimethylbromobenzene, and anhydrous carbonic acid. Potassium 2.25g,
Copper powder 200mg. and potassium iodide I OOmg
was added and reacted at a temperature of 200°C for 8 hours. This reaction solution was filtered, the filtrate was concentrated to dryness, and purified by column chromatography using hexane as an eluent and silica gel as a packing material to obtain an oily N-(2.4.6-1-rimedylphenyl)-4-methoxy. -2-Methylthioaniline8.
2g was obtained.

Example 6 2-(2-chlorophenylamino)-3-methylthi-
7.8 g of 2-hydroxy-4-diethylamino-2-carpoxybenzophenone was added to 6-diethylaminofluorinated 97% saccharic acid long and completely dissolved at a temperature of 25°C, and then N-12- The product was prepared by adding chlorophenyl-4-methoxy-2-methylthianiline and reacting in the same manner as in Example 1.

This substance is a pale color solid with a melting point of 100-1
The temperature was 02°C. The absorption maximum wavelength and molecular extinction coefficient in 95% acetic acid are 560 nm (3.27x
l04) and 461. nm (1.37x lO'l
Met. When this material was brought into contact with paper coated with silica gel, bisphenol A, phenol resin, or salicylic acid derivatives, it rapidly developed a reddish-purple color. Note that N-(2-chlorophenyl) used here
-4-Methoxy-2-methylthioaniline was prepared using 4-methoxy-2-methylthioacetanilide prepared in Example 1 and 2-promochlorobenzene as starting materials.
reacts in the same manner as Ni2-chlorophenyl)-4-methoxy-2-methylthioacetanilide (melting point 130-13
This product was reacted with potassium hydroxide in isopropyl alcohol in the same manner as in Example 1 to form N-(2-
chlorophenyl)-4-methoxy2-methylthioaniline was produced.

All of the compounds of the present invention obtained in Examples 1 to 6 were colorless or light-colored and stable for a long period of time.

The molecular extinction coefficient of this compound at the absorption maximum wavelength in 95% acetic acid was extremely high compared to the black fluoran compounds used in practical use.

When the fluoran compound of the present invention is used in a pressure-sensitive recording sheet 1 or a heat-sensitive recording sheet, it is stable when no color is developed, and the image obtained by the color-developing operation has a black tone and high density.
Stable for long periods of time against light, humidity, temperature, atmosphere, etc.
Almost no discoloration was observed, but it remained stable over Nagatomo, and almost no discoloration was observed.

(Effects of the Invention) As described above, the novel fluoran compound of the present invention is extremely useful as a color-forming substance used in recording media.

Claims (1)

[Claims] A novel fluoran compound represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) In the formula, R_1 and R_2 have carbon numbers of 1 to 8, which may be branched.
an alkyl group, an alkoxyalkyl group having 3 to 8 carbon atoms,
cycloalkyl group having 4 to 10 carbon atoms, alkyl group having 1 to 4 carbon atoms, benzyl group or phenethyl group optionally substituted with halogen, tetrahydrofuryl group,
Represents a furfuryl group, a lower alkyl group, or a phenyl group optionally substituted with a halogen, and R_3 is an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or a benzyl group optionally substituted with a halogen. , or an alkoxyalkyl group having 3 to 8 carbon atoms. R
_4 represents an alkyl group having 1 to 4 carbon atoms or a phenyl group which may be substituted with halogen.