JPS6040165A - Production of fluoran compound - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as a pigment for recording materials such as pressure-sensitive recording paper, heat-sensitive recording paper, etc., in high yield and purity, by condensing a ketocarboxylic acid with a diphenylamine compound, and hydrolyzing and cyclizing the resultant phthalide compound. CONSTITUTION:The objective compound of formula V (e.g. the compound of formula VI) can be produced by (1) condensing the ketocarboxylic acid of formula I (R1 and R2 are H, alkyl which may have water-insoluble substituent group, phenyl, cycloalkyl, etc.; R3 is H or lower alkyl) (e.g. 4'-dimethylamino-2'- hydroxybenzophenone-2-carboxylic acid) with the diphenylamine compound of formula II (R4 is R3; R5 is acyl; X and Y are lower alkoxy, lower alkyl, etc.; m and n are 0-3) (e.g. N-acetyl-2-methyl-4-methoxydiphenylamine), (2) hydrolyzing the obtained phthalide compound of formula III to the phthalide compound of formula IV, and (3) cyclizing the product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing fluoran (F) compounds useful as dyes for recording materials such as pressure-sensitive and heat-sensitive recording papers.

Conventionally, general formula (I) (( represents a phenyl group which may be substituted with a group or a water-insoluble group, or 4R1, R, may be linked to each other to form a heterocycle (, X, Y are each independently a lower It represents an alkoxy group, a lower alkyl group, a trifluoromethyl group, or a halogen atom, and m and n each independently represent an integer from 0 to 8.) ) Ketocarvone N?, 4
Method of reacting with diphenylamines in concentrated sulfuric acid:
JP-A-58-7451 Example 1).

≧) 2-Aminofluorane derivative A and arylation 1j are reacted in the presence of copper and alkali.
There are many side reactions, and there is a problem that the purity and yield of the target product are low.On the other hand, in method (1), concentrated sulfuric acid acts on the phenolic starting material (diphenylamines) and converts the sultonated product. (see page 2 of Japanese Patent Publication No. 56-88619), and bislactone compounds are produced, resulting in a lower yield of the target product and lower purity. It has the disadvantage of requiring purification.

The inventors of the present invention have completed the present invention after intensive study to solve the problems in the production of the above-mentioned full 1-lane compound.

That is, the present invention is directed to the general formula ([) (wherein "1 *" 2 is each independently a hydrogen atom, an alkyl group optionally substituted with a water-insoluble group, an aralkyl group, an alkenyl group, a cycloalkyl group) or a phenyl group optionally substituted with a water-insoluble group, or R,
, R2 may be linked to each other to form a heterocycle,
λ3 represents a hydrogen atom or a lower alkyl group. ) Ketocarboxylic acids represented by the general formula ((in the formula, 4 is a hydrogen atom or a lower alkyl group, 6 is an acyl group,
X and Y each independently represent a lower alkoxy group, a lower alkyl group, a trifluoromethyl group, or a halogen atom, m
, n each independently represents an integer from 0 to B. ) by condensing diphenylamines represented by the general formula (
[V) (wherein R1, R,, R1, R4, 5.X, Y, m.

n shows the above meaning. ) is produced and then hydrolyzed to form a phthalide compound represented by the general formula (Vl (wherein, R1+ R2s R11* R4* x* Y
m m*n indicates the above meaning. ), which is then ring-closed to form a fluoran compound represented by the general formula (Il (wherein R1, R2, X, Y, m, and n have the above-mentioned meanings)). This is an improved method for producing a fluoran compound.

According to the method of the present invention, side reactions such as sulfonation and the formation of bislactone compounds are significantly suppressed by using N-acyldiphenylamines represented by the general formula (2) during the condensation of ketocarboxylic acids and diphenylamines. As a result, the yield of the target product is greatly improved, the purity is also significantly high, and high-level purification is not required.

In the present invention, the reaction between the ketocarboxylic acids of the general formula (II) and the diphenylamines of the general formula tlII is performed using a dehydration condensing agent such as df (sulfuric acid, oleum, phosphoric anhydride, polyphosphoric acid, polyphosphoric acid ether, etc.). Preferred examples of the dehydration condensing agent include 90-10
0% sulfuric acid is mentioned. The dehydration condensation agent usually has the general formula (
It is used in large excess, preferably 5 to 20 times the amount of the compound in question. Although this reaction can be carried out under cooling, at room temperature, or under heating, it is usually carried out at -20 to 150°C.
Preferably, it proceeds suitably at -10 to 70°C, and usually,
The reaction is completed in t-too time.

The phthalide compound represented by the general formula (V) thus produced is precipitated as crystals by discharging the reaction solution into a large amount of water, and can be taken out as crystals by distributing it from house to house. In some cases, it is also possible to carry out the next hydrolysis reaction under acidic conditions without removing the crystals.

The hydrolysis reaction of the phthalide compound is then carried out in mineral acids such as sulfuric acid and hydrochloric acid, and in some cases, toluene, benzene, xylene, monochlorobenzene, nitrobenzene, methanol, ethanol, propatool, butanol, acetic acid,
50-105℃ in the presence of an organic solvent such as propionic acid
This can be easily achieved by heating at

The thus produced phthalide compound represented by the general formula (Vl) may be optionally treated with triethylamine, tributylamine,
heating at or below reflux in the presence of organic amines such as triethanolamine, pyridine, picoline, quinoline, etc., in dilute alkaline aqueous solutions such as caustic soda, caustic potash, soda ash, potassium carbonate, and optionally toluene, xylene, benzene. , 50- in the presence of organic solvents such as decalin, monochlorobenzene, and nitrobenzene.
The fluoran compound represented by the general formula (I) can be easily ring-closed by a method of heating to 105° C. or a method of heating and melting a phthalide compound.

Ketocarboxylic acids of the general formula ([I)] can be obtained by known methods, for example, the method described in JP-A-52-82248, and diphenylamines of the general formula [11] can be obtained by a method described in JP-A-52-5489. It is easily synthesized by the method described.

As ketocarboxylic acids of the general formula (Ill), for example,
I can give you the following:

4/-dimethylamino-2'-hydroxybenzophenone-2-carboxylic acid, 41-diethylamino-2'-hydroxybenzophenone-2-carboxylic acid, 4'-dipropylamino-2/-hydroxybenzophenone-2-carboxylic acid, 4'-dibutylamino-2/-hydroxybenzophenone-2-carboxylic acid, 4I-dipentylamino-2'-hydroxybenzophenone-2-carboxylic acid, 4'-(N-ethyl-N-inpentyl)amino-2
/-methoxybenzophenone-2-carboxylic acid, 4'-β-hydrosaethylamino-2'-ethoxybenzophenone-2-carboxylic acid, 41-piperidino-2
I-Hydroxybenzophenone-2-carboxylic acid, 4'-morpholino-2/-hydroxybenzophenone-
2-carboxylic acid, 41-β-phenoxyethylamino-2'-propoxybenzophenone-2-carboxylic acid, 4'-(N-methyl-N-benzyl)amino-2/-
Butoxybenzophenone-2-carboxylic acid, 4'-(N-phenyl-N-p-)lyl)ami,'-
2-Hydroxybenzophenoxy 2-carboxylic acid.

Examples of diphenylamines represented by the general formula ([) include the following.

N-acetyl-2-methyl-4-methoxydiphenylamine, N-acetyl-chloro-4-methoxydiphenylamine, N-acetyl-2-fluoro-4-methoxydiphenylamine, N-acetyl-2-methoxy-4-methoxydiphenylamine, N-acetyl-4-methoxydiphenylamine, N-acetyl-21-fluoro-4-methoxydiphenylamine, N-7"lopionyl-2-10ro-4-ethoxydiphenylamine, N-propionyl-2-trifluoromethyl-4- Propoxydiphenylamine, N-acetyl-2,2',4
'-trimethyl-4-methoxydiphenylamine, N-acetyl-2-chloro-4-hydroxydiphenylamine, N-butyryl-2,2I-dichloro-4-butoxydiphenylamine, N-maleinyl-2-methyl-4-methoxydiphenylamine, N-acetyl-2-chloro-41-methyl-4-ethoxydiphenylamine, N-acetyl-2-chloro-3'-methyl-4-methoxydiphenylamine, N-acetyl-2-chloro-4,4'-dimethoxydiphenylamine , N-propionyl-2-methoxy-4-ethoxydiphenylamine.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the examples, parts and % mean parts by weight and electromagnetic %, respectively.

Example 1 81.8 parts of 4'-diethylamino-2'-hydroxybenzophenone-2-carboxylic acid, 25.5 parts of N-acetyl-2-methyl-4-methoxydiphenylamine, 98 parts
A mixture of 200 parts of % sulfuric acid was reacted and condensed at room temperature for 40 hours. After the reaction was completed, the reaction solution was diluted with ice water to adjust to 90% sulfuric acid, reacted at 85 to 90° C. for 3 hours to perform hydrolysis, and the reaction solution was discharged into ice water to precipitate crystals. The precipitated crystals were washed door to door, washed with water, and dried to obtain the formula (1-1
44.7 parts of a phthalide compound represented by ) were obtained.

The total amount of this phthalide compound was dissolved in 250 parts of toluene, 10 parts of toluethylamine was added, and the ring was closed by reacting under reflux for 10 hours. Then, the toluene was distilled off under reduced pressure, and then recrystallized from Impropatool. Then, fluoran compound 40 represented by formula (1-2) in Table 6
．． Obtained from 0 parts. Total yield 84%, melting point 192-1
98℃.

This compound is a white powder that develops a black-purple color on activated clay.

Example 2 4'-diethylamino-2'-hydroxybenzophenone-2-carboxylic acid: 111.8 parts, N-acetyl-2
-27.6 parts of chloro-4-methoxydiphenylamine,
A mixture of 200 parts of 96% sulfuric acid was reacted at 40° C. for 24 hours to cause condensation. After the reaction is complete, dilute the reaction solution with ice water and
The mixture was adjusted to 80% M acid and hydrolyzed by reacting at 85 to 90°C for 3 hours, and the reaction solution was discharged into ice water to precipitate crystals. The precipitated crystals were washed door to door, washed with water, and dried. hand,
Phthalide compound represented by formula (2-1) 47.0 m
was gotten.

The total amount of this phthalide compound was dissolved in 5% caustic soda aqueous solution 2
After adding 200 parts of toluene, the mixture was reacted under reflux for 2 hours to close the ring, cooled to room temperature, and allowed to stand still for liquid separation to separate into a toluene layer and an alkaline aqueous layer. After the toluene in the toluene layer was distilled off under reduced pressure, it was recrystallized from Improper Tool to obtain 42.2 parts of a fluoran compound represented by formula (2-2). Total yield 85%, melting point 178-180°C.

This compound is a white powder that develops a black-purple color on activated clay.

Example 8 86.5 parts of 4'-(N-ethyl-N-ynamyl-2I-hydroxybenzophenone-2-carboxylic acid, N-
A mixture of 28.8 parts of propionyl-2-methyl-4-ethoxydiphenylamine and 150 parts of 100% sulfuric acid was added to 10
Condensation was carried out by reacting at ℃ for 10 hours.

After the reaction was completed, the reaction solution was discharged into ice water, neutralized with caustic soda, and the precipitated crystals were washed door to door with water to obtain the formula (
A wet cake of a phthalide compound of the formula 8-"l) was obtained.

The entire amount of this wet cake was dispersed in 250 parts of 20% hydrochloric acid and reacted at 85 to 95°C for 6 hours for hydrolysis. After discharging the reaction solution in ice water, the crystals were washed door to door with water, and the formula ( A wet cake of a phthalide compound represented by 8-2) was obtained.

Disperse the entire wet cake in 800 parts of water and adjust the pH
After adjusting to 11-12, the ring was closed by reacting at 80 to 90°C for 5 hours, and after cooling to room temperature, the precipitated crystals were washed with water and dried, and the crystals expressed by formula (L-8) were formed. 43.7 parts of a fluoran compound were obtained. Total yield 84%,
Melting point: 164-166°C This compound is a white powder, which develops a black-purple color with activated clay 1.

Example 4 In Example 1, 24.8 parts of N-7'ropionyl-2-chloro-4-methoxy-4'-methyldiphenylamine was used instead of N-acetyl-2-methyl-4-methoxydiphenylamine. , Similarly, formula (4-1)
42.9 parts of a fluoran compound represented by was obtained.

Total yield: 84%.

Melting point: 181.0-181.5°C Reference Example [A fluoran compound represented by the above formula (4-1) was synthesized according to Example 1 of JP-A-58-52366. ] 4'-diethylamide, 12.0 parts of 2'-hydroxybenzophenone-2-carboxylic acid, 2-chloro-4-
A mixture of 10.4 parts of methoxy-4'-methyldiphenylj'amine and 54 parts of 98% sulfuric acid was reacted at room temperature for 24 hours, then charged into 700 parts of ice water, and the precipitated crystals were separated by t. It was washed with water and washed with caustic soda. The crystals were recrystallized from tonolenine to obtain 11.1 parts of a fluoran compound represented by the formula (4-1).

Claims (1)

[Claims] l) General formula ([I) (wherein R, , R, each independently represents a hydrogen atom, an alkyl group optionally substituted with a water-insoluble group, an aralkyl group, an alkenyl group, Represents a phenyl group optionally substituted with a cycloalkyl group or a water-insoluble group, or R1*
R2 may be linked to each other to form a heterocycle, and R
3 represents a hydrogen atom or a lower alkyl group. ) Ketocarboxylic acids represented by the general formula [1] (in the formula,
R4 is a hydrogen atom or a lower alkyl group, Rs is an acyl group, X and Y each independently represent a lower alkoxy group, a lower alkyl group, a trifluoromethyl group or a halogen atom,
m and n each independently represent an integer of 0 to 8. ) by condensing diphenylamines represented by the general formula (
ff) (In the formula, R,, R2, R,, R4, R6, Formula ff) (In the formula, R-1, R2, RA, R4, X, Y,
rn, n indicates the above meaning. ), which is then ring-closed to form a fluoran compound represented by the general formula (I) (wherein R1+ ``2 r xe Y* '' + '' has the above-mentioned meaning). Characteristic method for producing fluoran compounds.