GB2109394A - Fluoran compounds and process for producing - Google Patents

Abstract

compounds, useful as black-colored dye for use in recording paper, have the formula: <IMAGE> wherein A is benzene nucleus or naphthalene nucleus optionally substituted by halogen; X is halogen atom; R<1> and R<2>, taken individually, represent alkyl group optionally having ether linkage, cycloalkyl group or phenyl group or, taken jointly, form cycloalkyl, tetralinyl or indanyl group in conjunction with on the methine carbine atom; R<5> represents alkyl, alkoxyalkyl, cycloalkyl, phenylalkyl or phenyl group and R<6> represents alkyl, alkoxyalkyl or phenylalkyl group or R<5> and R<6>, taken jointly, form <IMAGE> or -C2H4OC2H4- group, provided that p is a number of 4, 5 or 6, and the phenyl nuclei of R<5> and R<6> are optionally substituted by alkyl group or halogen. Compounds of formula I can be obtained by reacting an amide of formula IV <IMAGE> with a compound of formula V <IMAGE> Certain of the fluoran compounds are novel compounds.

Description

SPECIFICATION Fluoran compounds and process for producing same This invention relates to fluoran compounds useful as dye for use in recording paper, and to a process for producing said fluoran compounds.

The demand for pressure sensitive recording paper and heat sensitive recording paper, to which is applied the color-forming reaction by the contact between nearly colorless electron-donating substance and nearly colorless electron-accepting substance, is increasing with the current progress of information technique.In general, a pressure sensitive recording paper is constituted of a top sheet and an under sheet, where the top sheet is prepared by dissolving an electron-donating white colored dye (hereinafter, referred to as color-producing agent) into an organic solvent, emulsifying the solution until the particle size reaches several microns, making the emulsion into a microcapsule with a polymeric compound such as gelatin or the like and coating the microcapsule on a support, and the under sheet is prepared by coating an electron-accepting substance (hereinafter, referred to as color-developing agent) on a support.When both the sheet are superposed so that their coated surfaces confront each other and a pencil pressure, a striking pressure or the like is applied thereto, the microcapsule is ruptured and the color-producing agent in the capsule is released and transferred onto the color developing agent surface, as the result of which a color-forming reaction takes place to give a record image. The most usual type of heat sensitive recording paper is so constructed that a color-producing agent and a color-developing agent (for example, Bisphenol A) are supported in a binder (for example, a polymeric substance such as polyvinyl alcohol) optionally together with a solid flux so as to prevent their mutual contact and then the supported mixture is provided on a supporting material.When it is heated, at least one member of flux, color-producing agent and color-developing agent melts to cause a contact between color-producing agent and color-developing agent, as the result of which a color-forming reaction takes place to give a record image.

In electricity-carrying heat sensitive recording paper, a conductive layer containing a conductive material is provided between support and color-producing layer (it comprises a color-producing agent, a color-developing agent and optionally a flux). By applying an electrical voltage to it, heat is generated to induce a color-forming reaction and thereby a record image is obtained.

In the recent time, there is an increasing desire to obtain a color-producing agent capable of giving a black colored image, from the necessity of copying the image prepared by color-forming reaction between color-producing agent and color-developing agent under pressure or heat mentioned above.

Although it is possible in principle to obtain a black-colored image by blending together appropriate several kinds of color-producing agents different in color shade, such a technique has a fault that the color-producing agents used are different from one another in color-forming velocity and in light resistance and water resistance in the state of image, so that the color shade of image can change with the state of storage of the recording paper. Although an attempt has been made to obtain a black colored image by using a single color-producing dye, no dye satisfactory in all the points such as color shade, fastness, self-color-formability, cost, etc, has yet been found until today.

If a compound represented by the following general formula (I):

wherein Xis halogen atom; A is benzene nucleus or naphthalene nucleus optionally substituted by halogen; R5 represents alkyl, alkoxyalkyl, cycloalkyl, phenylalkyl or phenyl group and R6 represents alkyl, alkoxyalkyl or phenylaikyl group or R5 and R6, taken jointly, represent

or-C2H40C2H4- group, provided that p is a number of 4,5 or 6, and the phenyl nuclei of R5 and R6 are optionally substituted by alkyl group or halogen; and R1 and R2, taken individually represent alkyl group optionally having ether linkage, cycloalkyl group or phenyl group or, taken jointly, represent cycloalkyl, tetralinyl or indanyl group in conjunction with the carbon atom of methine group, is to be prepared, there can be considered a process which comprises reacting an imide compound represented by the following general formula (IV):

wherein R1, R2 and X are as defined above and R represents hydrogen atom or lower alkyl group, with a compound represented by the following general formula (V):

wherein R5, R6 and A are as defined above.

As a general process for producing the imide compound represented by general formula (IV), the process mentioned in Japanese Patent Application Kokai (Laid-Open) No. 142,693/80 in which an analoi gous kind of dye compound is mentioned can be referred to, for example. However, by this process, the amino group of 3 - chloro - 4 - aminophenol is alkyated with alkyl bromide or alkyl tesytate, end therefore dialkyl compound is formed as a byproduct in addition to monoalky copound and a portion of the amino compound remain unreacted which are difficult to separate in general, so that the intended imide compound cannot be obtained in a high yield and a high purity.

Further, the alkylating agent used is limited to alkyl bromide or alkyl tosylate, so that the structure of the intended imide compound is quite limited.

The present inventor conducted elaborated studies with the aim of finding out an advantageous industrial process for producing the imide compound of general formula (IV). As the result, it was found that the object can be achieved by carrying out a reductive alkylation by the use of a ketone compound. it was also found that, if the fluoran compound of general formula (i) is produced from the imide compound produced according to this process, the fluoran compound can be produced in a high yield and a high purity. Based on these findings, the present invention was accomplished.

Thus, it is an object of this invention to provide a novel fluoran compound useful as a dye for recording paper, as well as to provide a process for producing said fluoran compound.

It is another object ofthis invention to provide an imide compound usable as an intermediate for the synthesis of the above-mentioned fluoran compound, as well as to provide a process for producing said imide compound.

It is yet another object of the invention to provide a pressure sensitive or heat sensitive recording paper having said fluoran compound as an electron-donating color-producing agent on a support.

Other objects and advantages of this invention will become apparent from the description presented below.

Thus, according to this invention, there is provided a process for producing a fluoran compound represented by the following general formula (I):

wherein A is benzene nucleus or naphthalene nuc leus optionally substituted by halogen; Xis halogen atom; R1 and R2, taken individually, represent alkyl group optionally having ether linkage, cycloalkyl group or phenyl group or, taken jointly, form cycloalkyl, tetralinyl or indanyl group in conjunction with the carbon atom of methine group; and R5 represents alkyl, alkoxyalkyl, cycloalkyl, phenylalkyl or phenyl group and R6 represents alkyl, alkoxyalkyl or phenyl alkyl group, or R5 and R6, taken jointly, form

or-C2H4OH4-, provided that p is a number of 4,5 or 6 and the phenyl nuclei of R5 and R6 are optionally substituted by alkyl group or halogen, which comprises reacting an aniiine compound represented by the following general formula (@) :

wherein X is as defined above and R represents hydrogen atom or lower alkyl group, with a ketone compound represented by the following general formula (III)::

wherein R3 and R4 represent R1, R2 or a group capable of changing to R1 or R2 in the course of reaction, provided that R' and R2 are as defined above, to conduct a catalytic and reductive alkylating reaction and thereby obtaining an imide compound represented by the following general formula (IV):

wherein X, R, R1 and R2 are as defined above, followed by reacting said imide compound with a compound represented by the following general formula (V):

wherein A, R5 and R6 are as defined above, in the presence of a dehydrating condensing agent.

Thus, according to this invention, there is provided a novel fluoran compound represented by the following general formula (VI):

wherein X represents halogen atom; A represents benzene nucleus or naphthalene nucleus optionally substituted by halogen; R5 represents alkyl, alkoxyalkyl, cycloalkyl, phenylalkyl or phenyl group and R6 represents alkyl, alkoxyalkyl or phenylalkyl group or R5 and R6, taken jointly, represent

or-C2H40C2H4- group, provided that p is a number of 4,5 or 6 6 and the phenyl nuclei of R5 and R6 are optionally substituted by alkyl group or halogen; and R7 and R8, taken individually, represent alkyl group optionally having ether linkage, cycloalkyl group or phenyl group or, taken jointly, represent cycloalkyl group, tetralinyl group or indanyl group in conjunction with the carbon atom of methine group; provided that total carbon number is 3 or greater when R7 and R8 are both alkyl group and A is benzene nucleus.

In this invention, examples of the halogen atom represented by X in general formula (II) include chlorine, bromine, iodine and fluorine, among which chlorine and bromine are particularly preferable.

Examples of the lower alkyl group represented by R in general formula (11) include C1-C4 alkyl groups such as methyl group, ethyl group, propyl group, butyl group and the like.

When R3 and R4 in general formula (III) are R1 and R2, the alkyl groups of R1 and R2 may contain one or more ether linkage(s), cycloalkyl group(s) or phenyl group(s). As examples of said alkyl group, those having 1-8 carbon atoms can be referred to. Said phenyl group may have a substituent such as lower alkyl group or halogen atom.

As examples of R1 and R2, methyl group, ethyl group, propyl group, isobutyl group, amyl group, methoxymethyl group, methoxyethyl group, ethoxyethyl group, methoxyethoxyethyl group, ethoxyethoxyethyl group, benzyl group, p-chlorobenzyl group, phenetyl group, phenylpropyl group, benzy- loxymethyl group, phenethyloxymethyl group, benzyloxyethyl group, cyclohexyloxymethyl group, cyclohexyloxyethyl group, phenoxymethyl group and the like can be referred to.

R1 and R2, taken jointly, may optionally form cycloalkyl group, tetralinyl group or indanyl group in conjunction with the carbon atom of methine group, and these groups may optionally have a substituent such as lower alkyl group, alkoxy group or halogen atom.

When R3 and R4 in general formula (III) are groups capable of changing to R1 or R2 in the course of reaction, examples of such groups include vinyl group, propenyl group, 2 - methyl - 2 - hydroxypropyl group, 2 - methyl - 2- methoxypropyl group and the like.

As concrete examples of the aniline compound of general formula (II), the followings can be referred to: 3-chloro-4-aminophenol, 3-chloro-4-aminoanisole, 3-chloro-4-aminophenetole, 3-bromo-4-aminophenyl, 3-bromo-4-aminoanisole, 3-iodo-4-aminophenol, and 34luoro-4-aminophenol.

As concrete examples of the ketone compound of general formula (III), the followings can be referred to: cyclohexanone, cyclopentanone,ss-tetralone, 2-indanone, acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methoxyacetone, 4methoxy - 2 - butanone, diacetone alcohol, 4methoxy - 4 - methyl - 2 - pentanone, dimethoxyacetone, 4 - cyclohexyloxy - 2 - butanone, 4 - phenyl - 2 butanone, dibenzyl ketone and methyl vinyl ketone.

Next, the outlines practice of the reductive alkylation reaction of this invention will be mentioned. An aniline compound of general formula (II), a ketone compound of general formula (III), a solvent for the reaction and a catalyst are charged into an autoclave and reduced with hydrogen under an elevated pressure at an elevated temperature.

The ketone compound of genera formula (III) is used in an amount of 1 mole or more and preferably 1-2 moles per one mole of the aniline compound of general formula (II).

As the solvent for the reaction, alcohols such as methanol, ethanol, isopropanol, 2-methoxyethanol and 2-ethoxyethanol; ethers of polyhydric alcohols such as ethylene glycol dimethyl ether, diethylene glycol monomethyl ether and diethylene glycol dimethyl ether; dioxane; and the like can be used. It is also allowable to use the ketone compound, used as a reactant, as a solvent.

As the catalyst, platinum and palladium types of ones, particularly platinum on a carrier, are effective.

Platinum catalyst which has been poisoned with sulfur compound to a slight extent is preferable.

In this invention, it is preferable to add 1-30% by mole, based on the starting amino compound, of organic acid such as acetic acid, from the viewpoint of preventing dehalogenation.

The reaction is carried out under an elevated pressure (5-50 Kg/cm2, preferably 10-25 kg/cm2) of hydrogen and at a temperature of 80 -140 C, preferably, 110"-130"C. When the theoretical quantity of hydrogen has been absorbed and consumed, absorption of hydrogen is no longer observed and the unreacted aniline compound has been disappeared.

For isolating the intended product, the content of autoclave is filtered to remove the catalyst and then solvent or excessive ketone is removed by distilled tion or steam distillation, after which the residue is treated with cold or hot water to remove the soluble substances.

For purifying it to an additional extent, crystallization from toluene, n-hexane or the like or distillation under reduced pressure may be carried out.

Then, the imide compound of general formula (IV) thus obtained and a compound represented by general formula (V) are reacted at a molar ratio of (IV)/(V) = 0.8-2.0 and preferably 1-1.2, in the presence of a dehydrating condensing agent, at a temperature of -5" to 900C and preferably 10 to 60"C, for a time period of several hours to several ten hours and preferably 12-48 hours.

Then, the reaction mixture is charged into water, alkalified, and then treated with heat if necessary, by which a slightly colored white crystal can be obtained. By filtering, drying and recystallizing it, fluoran derivative represented by general formula (I) is obtained as a white colored crystal.

As the dehydrating agent used in the reaction for synthesizing the compound of general formula (I) from the compound of general formula (IV) and the compound of general formula (V), sulfuric acid, phosphoric acid, polyphosphoric acid and the like can be used. Advantageously, sulfuric acid having a concentration of 85-100% is used.

As the solvent for the recrystallization, n-hexane, toluene, monochlorobenzene, chloroform, methyl isobutyl ketone, methyl cellosolve, isobutanol, isopropanol, dimethylformamide, dioxane, ethylene glycol dimethyl ether or the like is used, either alone or in combination of two or more.

As examples of the imide compound represented by general formula (IV) used for the production of the fluoran compound of this invention, the followings can be referred to: 2-chloro-4-hydroxy-N-cyclohexylaniline, 2-bromo-4-hydroxy-N-cyclohexylaniline, 24luoro-4-hydroxy-N-cyclohexylaniline, 2-iodo-4-hydroxy-N-cyclohexylaniline, 2-chloro-4-hydroxy-N-cyclopentylaniline, 2-chloro-4-hydroxy-N-(ss-tetralinyl)-aniline, 2-chloro-4-hydroxy-N-(2-indanyl)-aniline, 2-chloro-4-hydroxy-N-isopropylaniline, 2-chloro-4-hydroxy-N-(1 '-methylpropyl)-aniline, 2-chloro-4-hydroxy-N-(1 '-ethylpropyl)-aniline, 2-chloro-4-hydroxy-N-(1 ',3-dimethylbutyl)aniline, 2-chloro-4-hydroxy-N-( 1 '-methylhexyl)aniline, 2-chloro-4-hydroxy-N-(1 '-methyl-2methoxyethyl)-aniline, 2-chlorn-4-hydrnxy-N-(1'-methoxymethyl-2'- methoxyethyl)-aniline, 2-chlornA-hydrnxy-N-(1 '-methyl-3'methoxypropyl)-aniline, 2-chloro-4-hydroxy-N-(1'-ethyl-2'- methoxyethyl)-aniline, 2-ch loro4-hyd roxy-N -(1 '-m ethyl-2'- methoxyethoxyethyl)-aniline, 2-chloro-4-hydroxy-N-( 1 '-methyl-2'-cyclo- hexyloxyethyl)-aniline, 2-chloro-4-hydroxy-N-(1'-methyl-3'-cyclo hexyloxypropyl)-aniiine, 2-chloro-4-hydroxy-N-(1 '-methyl-2'-benzyloxyethyl)-aniline, 2-chloro-4-hydroxy-N-(1 '-methyl-3'-benzyloxypropyl)-aniline, 2-chloro-4-hydroxy-N-(1 '-methyl-3'phenethyloxypropyl)-aniline, 2-chloro-4-hydroxy-N-(1 '-methyl-2'phenoxyethyl)-aniline, 2-chloro-4-hydroxy-N-(1 'methyl1 '-phenoxyethoxyethyl)-aniline, 2-chloro-4-hydroxy-N-(1 '-methyl-2'-phenylethyl)-aniline, 2-chloro-4-hydroxy-N-( 1 '-methyl-3'-phenylpropyl)-aniline, 2-chloro-4-hydroxy-N-( 1 '-benzyl-2'-phenylethyl)-aniline, 2-chloro-4-methoxy-N-cyclohexylaniline, 2-bromo-4-methoxy-N-cyclohexylaniline, and 2-chloro-4-methoxy-N-(1 '-methyl-3'-methoxypropyl)-aniline.

As examples of the compound represented by general formula (V) used in the production of the fluoran compound of this invention, the followings can be referred to: 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-dibutylamino2'-hydroxybenzoyl)benzoic acid, 2-(4'-N,N-diisobutylamino-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, 2-(4'-N,N-diethylamino-2'-hydroxybenzoyl)3-naphthoic acid, 2-(4'-N,N-dimethylamino-2'-hydroxybenzoyl)3-naphthoic acid, 2-(4'-N,N-bibutylamino-2'-hydroxybenzoyl)3-naphthoic acid, 2-(4'-N,N-diamylamino-2'-hydroxybenzoyl)-3naphthoic acid, 2-(4'-N-ethyl-N-butylamino-2'-hydroxybenzoyl)3-naphthoic acid, 2-(4'-N,N-diethylamino-2'-hydroxybenzoyl)-5 or 8-chloro-3-naphthoic acid, 2-(4'-N,N-diethylamino-2'-hydroxybenzoyl)-5 or 8-bromo-3-naphthoic acid, 2-(4'-N,N-dimethoxyethylamino-2-hydroxybenzoyl )-benzoic acid, 2-(4'-N,N-diethoxyethylamino-2'-hydroxybenzoyl)-benzoic acid, 2-(4'-N,N-diethoxyethylamino-2'-hydroxybenzoyl)-3-naphthoic acid, 2-(4'-N-methyl-anilino-2'-hydroxybenzoyl)-benzoic acid, 2-(4'-N-ethyl-anilino-2'-hydroxybenzoyl)benzoic acid, 2-(4'-N-methyl-p-toluidino-2-hydroxy- benzoyl)-benzoic acid, 2-(4'-N-ethyl-p-toluidino-2'-hydroxybenzoyl)benzoic acid, 2-(4'-N-ethyl-o-toluidino-2'-hydroxybenzoyl)benzoic acid, 2-(4'-N-ethyl-p-ch loroanilino-2'-hydroxybenzoyl)-benzoic acid, 2-(4'-N-ethyl-p-butylanilino-2'-hydroxybenzoyl)-benzoic acid, 2-(4'-N-ethyl-2,4-xylidino-2'-hydroxybenzoyl)benzoic acid, 2-(4'-N-ethyl-p-toluidino-2'-hydroxybenzoyl)3-naphthoic acid, 2-(4'-N-methyl-p-toluidino-2'-hydroxybenzoyl)3-naphthoic acid, 2-(4'-N-cyclohexyl-N-methylamino-2'-hydroxybenzoyl)-benzoic acid, 2-(4'-N-cyclohexyl-N-ethylamino-2'-hyd roxybenzoyl)-benzoic acid, 2-(4'-N-cyclohexyl-N-ethylamino-2'-hydroxy- benzoyl)-4-chlorobenzoic acid, 2-(4'-N-cyclohexyl-N-methylamino-2'-hydroxy benzoyl)-3-naphthoic acid, 2-(4'-N-cyclohexyl-N-benzylamino-2'-hydroxy- benzoyl)-benzoic acid, 2-(4'-N-cyclohexyl-N-benzylamino-2'-hydroxybenzoyl)-3-naphthoic acid, 2-(4'-pyrrolidino-2'-hydroxybenzoyl)benzoic acid, 2-(4'-pyrrolidino-2'-hydroxybenzoyl)-3- naphthoic acid, 2-(4'-pyrrolidino-2'-hydroxybenzoyl )-3chlorobenzoic acid, 2-(4'-piperidino-2'-hydroxybenzoyl)-benzoic acid, 2-(4'-morpholino-2'-hydroxybenozyl)-benzoic acid, and 2-(4'-isoindolino-2'-hydroxybenzoyl)benzoic acid.

Among the fluoran compounds represented by the general formula (VI), flouran compounds represented by the following general formulas (VII) and (VIII) are particularly preferred:

R9 and R each represents lower alkyl and R represents cycloalkyl group.

wherein R12 represents lower alkyl group and R7 and R8 are as defined above.

Among the fluoran compounds represented by the general formulas (VII) and (VIII), the compounds represented by the following formulas are more preferred:

Next, some of the fluoran compounds of the general formula (I) according to this invention are shown in Table 1, wherein the term "color shade" signifies the color formed on a silica gel thin layer.

Table 1

R5 -, R1 T R2 X A Color shade C2N5 C2B5 2 C1 . Black a 'Dci .... " Violet-black ..

CH3 C2H5 II 'I C2Hg II II CH3 CH3 CN2CH\ CH3 n " " C820CH3 n II n n s n " CH2CB20CH3 " " n CI!2CH2 " " CHZCH24 " " Black C}I2CH2O '. ,. Violet-black - Cont'd Table 1 (Cont'd)

C2115 C2115 CH3 CH2OCH2 C1 a Violet-black .l 'l CH2 C4H9 (n) C4B9 (n) Black C5H11(n) C51111(n) ll C2H5 C2ll5 .l Br F Cl C1g " Cl C1 Clt Green-black C1 - Cont'd Table 1 (Cont'd)

CH30C2H4 CH30C2H4 2 Cl a Black C2i C2B5 ,. Th,, Br a II 3 Cl C2H5 CH3 /CH3 Cu3 " CH3 CH2CH 3 CH3 .. ., ll CH20CH3 " C1 Biolet-black Cu3 CH3 " - Cont'd Table 1 (Cont'd)

CH3 < CH3 ) Cl C Green-black li 'I ,, C2B5 C2Hg CB3 CH2CH\ Cu3 CH20CH3 ,. ,. Black & D ,, Green-black Cu3 CH3 CH3 CH3 " - Cont'd Table 1 (Cont'd)

e285 Cl . Black CR3 Br a Cl CS3 CH3 CH3 a CH3 CB2oCH3 BBCI12' " " " D " Cu3 CH3 -Cont'd Table 1 (Cont'd) t Cl Black 0 cc According to the process of this invention, an imide compound in which the alpha carbon linked to the imino group is a tertiary carbon atom can be obtained industrially in a higher yield and a higher purity than in prior process.

By using the imide compound thus obtained, the dye compound of general formula (I) which could be obtained only in the form of a mixture with by-products, difficult to separate, according to the prior process can be obtained in very high purity and yield.

Mostofthefluoran compounds obtainable by the process of this invention are novel compounds.

Recording paper obtained by using such novel fluoran derivative having unique chemical structure as a color-producing agent can form a deep black color and is excellent in storage stability, color-for mability, light resistance and water-resistance. Thus, in the pressure sensitive recording paper using the color-producing agent of this invention, the cap sule-coated sheet is less susceptible to discoloration caused by light, and the formed color image is excellent in light resistance. In the heat sensitive recording paper, the uncolored sheets are less susceptible to coloration due to heat or moisture, and the formed color image less undergoes color change caused by heat or moisture and discolora tion caused by light.When the fluoran derivative of this invention is applied to multi-color forming heat sensitive recording paper, the color can be formed at high temperature clearly, a multi-color can be formed without mixing of color, and the recording paper can be stored stably.

Further, the color-producing agent of this inven tion is characterized in that it has a very high solubility into the organic solvents used in the production of pressure sensitive recording papers.

As above, in theflouran compounds of this invention, the faults of the commercial color-produc ing agents now available in market, as a color-pro ducing agent for use in pressure sensitive or heat sensitive recording papers, are overcome to a great extent.

Next, the results of light resistance test, carried out after forming a color from the compound of this invention by the use of activated clay, will be mentioned.A 1% solution ofthefluoran compound in toluenewas applied to the activated clay-coated under sheet of pressure sensitive recording paper to form a color, and then it was irradiated with a fluorescent lamp of 32,000 luxes for a period of 10 hours and 20 hours. The colors of unexposed sheet and exposed sheet were measured by using D65-10 as light source to obtain color values L*a* and b*, from which color difference AE* was determined.

Table 2 illustrates the light resistances of the compounds of general formula (I), in the color-forming state, in terms of A E*. A smaller value of A E* means a more excellent light resistance.

Table 2

5 6 Rl X A AR* AR* R R 2 10 hr. 20 hr.

Known compound 1 (Typical commercial C2S5 C2Hg CH3 > 10.5 12.4 product) 2 Jap. Pat. Kokai . -C6H13(n) Cl . 10.0 13.7 142.693/80 3 " . 2 " 4 2 5 H 9.6 13.4 ~ Example 16 of .. .. < .. 6.4 8.2 4 this invention 5 Example 7.5 9.8 5 Example 21 C2H5 6 6 Example 23 CE/CS3 6.7 9.9 CS2OCS3 7 Example 27 "" ',CB3 6.6 9.4 CScu2cu2ocs3 8 Example 29 n W C I ~ Con 5.7 7.8 - Contd Table 2 (Cont'd)

9 Example 31 " C285 C2H5 -CHscH3 Cl C 5.8 7.7 CR3 10 Example 30 n n " sg ee 6.4 8.9 11 Example 37 n CH35 C2S5 " ) .. a 7.3 8.2 CS 12 Example 38 " n zw -CS/, 3 5.4 8.6 '\cu3 13 Example 39 " .- .. CH20CH3 .. n 4.4 7.9 14 Example 46 " 9 CH3 .. .. D 7.2 9.5 Next, this invention will be illustrated in more detail with reference to the following examples which are presented in no limitative way.

Example 1 Into a 500 ml stirring type autoclave were charged 57.0 g of cyclohexanone, 100 g of ethanol, 71.8 g of 3 - chloro - 4 - aminophenol, 3 g of glacial acetic acid and 2 g of 5% platinum/carbon catalyst. After replacement with hydrogen, temperature was elevated to 1 20 C and a reductive alkylation was carried out under a hydrogen pressure of 20 kg/cm2. Hydrogen was several times introduced with pressure in accordance with hydrogen consumption, until 1 mole of hydrogen was consumed in the total per 1 mole of chloroaminophenol. After cooling the content to 60"C, it was filtered to remove the catalyst, which was washed with a small amount of ethanol, and then the ethanol was distilled off from the filtrate.The residue of distillation was stirred together with 1 liter of water, after which the formed crystal was filtered, washed with water and dried.

Thus, 110.8 g of 2 - chloro - 4 - hydroxy - N cyclohexylaniline (m.p. 115"-117"C) was obtained.

The product was recrystallized from toluene to give a white crystal having a melting point of 116"-117"C.

Its elementary analyses and mass spectrum coincided with calculated values.

Example 2 Into an autoclave as used in Example 1 were charged 25.2 g of cyclopentanone, 100 g of ethanol, 43.1 g of 3 - chloro - 4 - aminophenol, 2 g of glacial acetic acid and 2 g of 5% platinum/carbon catalyst.

After replacement with hydrogen, temperature was elevated to 1 200C, and a reductive alkylation was carried out under a hydrogen pressure of 20 kg/cm2.

Hydrogen was several times introduced with pressure in accordance with consumption of hydrogen, until 1 mole of hydrogen was consumed in the total per 1 mole of chloroaminophenol. After cooling the content to 60"C, it was filtered to remove the catalyst, which was washed with a small amount of ethanol, and then the ethanol was distilled off from the filtrate. Then, the residue was distilled under reduced pressure to obtain 57.7 g of 2 - chloro - 4 hydroxy - N - cyclopentylaniline (white crystal) having a boiling point of 142"-143"C/1.5 mm Hg. Its melting point was 68 -69 C.

Example 3 A reductive alkylation was carried out at 12000 in the same manner as in Example 1 by using 14.6 g of fi-tetralone, 50 g of methanol, 14.4 g of 3 - chloro - 4 aminophenol, 3 g of glacial acetic acid and 1.5 g of 5% platinum/carbon catalyst. After 1 mole of hydrogen had been consumed per 1 mole of the chloroaminophenol, the content was filtered to remove the catalyst, and methanol was distilled off from the filtrate. The residue was stirred together with 1 liter of hot water, and then an oily layer (26.8 g) was separated. The oily layer (26.8 g) was recrystallized from an equal amount of toluene to obtain 23.8 g of 2 - chloro - 4 - hydroxy - N - V3 - tetralinyl) - aniline having a melting point of 81 -83 C as a white crystal.

Example 4 A reductive alkylation was carried out in an autoclave as used in Examples 1 at 120"C by using 13.9 g of acetone, 40 g of ethanol, 28.7 g of 3 - chloro -4- aminophenol, 1.2 g of glacial acetic acid and 0.8 g of 5% platinum/carbon catalyst, with 1 mole of hydrogen per 1 mole of the chloroaminophenol.

After filtering the catalyst and distilling off ethanol from the filtrate, the residue was washed with hot water and an oily layer was separated. The oily product was recrystallized from a small amount of toluene to obtain 20 g of 2 - chloro - 4 - hydroxy - N isopropylaniline (white crystal) having a melting point of 85 -86 C.

Example 5 Reductive alkylation, after-treatment and recrystallization were carried out in the same manner as in Example 4, except that the acetone was replaced with 25.6 g of diacetone alcohol or 28.6 g of diacetone alcohol methyl ether. Thus, 18 g and 24 g, respectively, of 2 - chloro - 4 - hydroxy - N isopropylaniline was obtained. The melting point of the products were 85"-86"C, respectively.

The structure of said compounds were confirmed by means of FD mass spectrum and NMR spectrum.

Example 6 Reductive alkylation was carried out with hydrogen at 12000 by using 130 g of 3-pentanone, 43.1 g of 3 - chloro - 4 - aminophenol, 3 g of acetic acid and 2 g of 5% platinum/carbon catalyst. The catalyst and the excess 3-pentanone were removed, the residue was washed with water, and then the oily product was distilled under reduced pressure. Thus, 55 g of 2 - chloro - 4- hydroxy - N - (1' - ethylpropyl) - aniline having a boiling point of 120 -121 C/1.2 mm Hg was obtained. It was an oily product.

Example 7 Reductive alkylation was carried out with hyd rogen in an autoclave as used in Example 1 at 12000 by using 150 g of methyl isobutyl ketone, 71.8 g of 3 chloro - 4 - aminophenol, 5 g of glacial acetic acid and 2 g of 5% platinum/carbon catalyst. After filtering off the catalyst and distilling off the methyl isobutyl ketone from the filtrate by steam distillation, the oily product was separated and distilled under reduced pressure. Thus, 80.5 g of 2 - chloro - 4 hydroxy - N - 1',3' - dimethylbutyl) - aniline (white crystal) having a boiling point of 136 -137 C/2 mm Hg was obtained. Its melting point was 64"-65.5"C.

Example 8 Reductive alkylation was carried out with hydrogen at 12000 by using 42.1 g of dibenzyl ketone, 28.7 g of 3 - chloro - 4 - aminophenyl, 3 g of acetic acid; 100 g of ethanol and 2 g of 5% platinum/carbon catalyst. After removing the catalyst and the ethanol from the reaction mixture and washing the residue with water, the product was recrystallized from toluene. Thus, 63.5 g of 2 - chloro - 4 - hydroxy - N (1' - phenylmethyl - 2' - phenylethyl) - aniline (white crystal) having a melting point of 95"-97"C was obtained.

Example 9 Reductive alkylation was carried out with hydrogen at 12000 by using 22.2 g of 4- phenyl - 2 butanone, 21.5 g of 3 - chloro - 4 - aminophenol, 3 g of acetic acid, 40 g of ethanol and 2 g of 5% platinum/carbon catalyst. After removing the catalyst and the ethanol from the reaction mixture, the residue was washed with water and distilled under reduced pressure to obtain 2 - chloro - 4 hydroxy - N - (1' - methyl - 3 - phenylpropyl) - aniline having a boiling point of 146 -147 C/1.5 mm Hg.

Example 10 Reductive alkylation was carried out with hydrogen at 12000 by using 20 g of methoxyacetone, 32.6 g of 3 - chloro - 4 - aminophenol, 100 g of ethanol, 2 g of acetic acid and 2 g of 5% platinum carbon catalyst. After removing the catalyst and the ethanol from the reaction mixture, the residue was washed with water and then recrystallized from toluene to obtain 25 g of 2 - chloro - 4 - hydroxy - N (1' - methyl - 2' - methoxyethyl) - aniline (white crystal) having a melting point of 820.8300.

Example 11 Reductive alkylation was carried out in the same manner as in Example 10, except that the methoxyacetone was replaced with 25.5 g of 4 - methoxy - 2 butanone. After removing the catalyst and the ethanol from the reaction mixture, the residue was washed with water to obtain 30 g of 3 - chloro - 4 - (1' - methyl - 3, - methoxypropylamino) - phenol as an oily product.

Example 12 Reductive alkylation was carried out with hydrogen at 12000 by using 28.5 g of cyclohexanone, 100 g of methanol, 39.4 g of 3 - chloro - 4 - aminoanisole, 1.5 g of glacial acetic acid and 2 g of 5% platinum/ carbon catalyst. After removing the catalyst and the methanol from the reaction mixture, the residue was washed with water and then recrystallized from n-hexane. Thus, 50 g of 2 - chloro - 4 - methoxy - N cyclohexylaniline (white crystal) having a melting point of 47"-48"C was obtained.

Example 13 The procedure of Example 12 was repeated, except that the cyclohexanone was replaced with methyl ethyl ketone and 1 mole of hydrogen was consumed per 1 mole of the amine, or that the cyclohexanone was replaced with methyl vinyl ketone and 2 moles of hydrogen was consumed per 1 mole of the amine. Thus, 2 - chloro - 4 - methoxy N - (1' - methylpropyl) - aniline was obtained as an oily product.

Example 14 Reductive alkylation was carried out with hydrogen at 120"C by using 16.2 g of cyclohexanone, 40 g of ethanol, 28.2 g of 3 - bromo - 4 - aminophenol, 0.9 g of glacial acetic acid and 0.5 g of 5% platinum/carbon catalyst. After removing the catalyst and the ethanol from the reaction mixture, the residue was washed with water and then recrystallized from toluene and n-hexane. Thus, 36.2 g of 2 - bromo - 4 - hydroxy - N - cyclohexylaniline having a melting point of 103 -104 C was obtained as a white crystal.

Example 15 Reductive alkylation was carried out in the same manner as in Example 14, except that the 3 - bromo 4 - aminophenol was replaced with 30.3 g of 3 bromo - 4 - aminoanisole. After removing the catalyst and the ethanol from the reaction mixture, the residue was washed with hot water to obtain 35 g of 2 - bromo - 4 - methoxy - N - cyclohexylaniline as an oily product.

Example 16 Into 219 g of 98% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 22.6 g of 2 - chloro - 4 - hydroxy - N cyclohexylaniline at a temperature of 30 C or below.

Then the mixture was stirred and kept heated at 500-550C for 24 hours to complete the reaction. Then, the reaction mixture was charged into a solution consisting of 2,000 g of ice water and 270 g of 28% aqueous ammonia to alkalify it, and the resulting precipitate was collected by filtration. It was washed with 2,000 g of warm water and dried. Thus, 41.2 g of 3 - diethylamino - 6 - chloro - 7 - cyclohexylaminofluoran was obtained. The product was recystallized from isopropyl alcohol to give 37.9 g of white crystal having a melting point of 197"-198"C. Its structure was confirmed by referring to elementary analyses, mass spectrum, and NMR spectrum.

Example 17 Into 219 g of 98% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2'- hydroxybenzoyl) benzoic acid and 21.2 g of 2 - chloro - 4 - hydroxy - N cyclopentylaniline at a temperature of 30 C or below, and the resulting solution was stirred at 50"-55"C for 24 hours. Then, it was charged into 2,000 g of ice water and alkalified with 710 g of 25" sodium hydroxide solution, and the resulting precipitate was collected by filtration. After washing the precipitate with 2,000 g of warm water, it was dried. Thus, 39.2 g of 3 - diethylamino - 6 - chloro - 7 - cyclopentylaminofluoran was obtained. The product was recrystallized from isopropyl alcohol to give 32.0 g of white crystal having a melting pointofl62.50-163.50C.

Example 18 Into 219 g of 98% sulfuric acid were dissolved 39.8 g of 2 - (4' - diamylamino - 2' - hydroxybenzoyl) benzoic acid and 22.6 g of 2 - chloro - 4 - hydroxy - N cyclohexylaniline, and the solution was stirred at 50"-55"C for 24 hours.

Then, it was after-treated in the same manner as in Example 16 to obtain 41.2 g of 3 - diamylamino - 6 chloro - 7 - cyclohexylaminofluoran. The product was recrystallized from isopropyl alcohol to give 32.0 g of white crystal having a melting point of 130.5 -131.5 C.

Example 19 Into 219 g of 95% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 27.4 g of 2 - chloro - 4 - hydroxy - N (ss - tetralinyl) - aniline, and the solution was stirred at 30 C for 25 hours. Then, after-treated was carried out in the same manner as in Example 16 to obtain 25.3 g of 3 - diethylamino - 6 - chloro - 7 - (ss tetralinylamino) - fluoran having a melting point of 172"-175"C as a white crystal.

Example 20 Into 219 g of 98% sulfuric acid were dissolved 31.3 of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 18.6 g of 2 - chloro - 4 - hydroxy - N isopropyl - aniline, and the solution was stirred at 50"-55"C for 24 hours. Then, after-treatment was carried out in the same manner as in Example 16 to obtain 36.6 g of 3 - diethylamino - 6 - chloro - 7 isopropylaminofluoran. The product was recrystallized from isopropyl alcohol to give 34.0 g of white crystal having a melting point of 199.5 -200.5 C.

Example 21 Into 219 g of 98% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 21.4 g of 2 - chloro - 4 - hydroxy - N (1' - ethylpropyl) - aniline, and the solution was stirred at 50"-55"C for 24 hours. Then after-treatment was carried out in the same manner as in Example 16 to obtain 38.6 g of 3 - diethylamino - 6 - chloro - 7 (1 ' - ethylpropylamino) - fluoran. The product was recrystallized from isopropyl alcohol to give 34.9 g of white crystal having a melting point of 140"-141"C.

Example 22 Into 219 g of 98% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 22.8 g of 2 - chloro - 4 - hydroxy - N (1',3' - dimethylbutyl) - aniline, and the solution was stirred at 50"-55"C for 24 hours. Then, after-treatment was carried out in the same manner as in Example 16 to obtain 40.5 g of 3 - diethylamino - 6 - chloro - 7 (1,3' - dimethylbutylamino) - fluoran. The product was recrystallized from isopropyl alcohol to give 30 g of white crystal having a melting point of 156"-1 58"C.

Example 23 Into 219 g of 94% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 21.57 g of 2 - chloro - 4 - hydroxy - N -(1' - methyl - 2' - methoxyethyl) - aniline, and the solution was stirred at 40 -50 C for 24 hours. Then, after-treatment was carried out in the same manner as in Example 17 to obtain 29.8 g of 3 - diethylamino - 6 - chloro - 7 - (1' - methyl - 2' - methoxyethylamino) - fluoran. The product was recrystallized from isop ropyl alcohol to give 15.2 g of white crystal having melting point of 183"-185"C.

Example 24 Into 238 g of 90% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 33.8 g of 2 - chloro - 4 - hydroxy - N -(1' - phenylmethyl 2' phenylethyl) - aniline, and the solution was stirred at 600C for 24 hours. Then it was charged into 2,000 g of ice water, alkalified with 710 g of 25% sodium hydroxide solution, and extracted with toluene three times. The toluene solution was concentrated under reduced pressure, and the concentrate was recrystallized from isopropyl alcohol. Thus, g of 3 - diethylamino - 6 chloro - 7 - (1' - benzyl - 2' - phenylethylamino) fluoran having a melting point of 134"-137"C was obtained as a white crystal.

Example 25 Into 219 g of 98% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 24.0 g of 2 - chloro - 4 - methoxy - Ncyclohexylaniline, and the solution was stirred at 50 -55 C for 24 hours. Then it was charged into 2,000 g of ice water, alkalified with 710 g of 25% sodium hydroxide solution, and heated to 80"C and kept at this temperature for 1 hour, after which the precipitate was collected by filtration and washed with water. After drying the precipitate, it was boiled together with an equal amount of o - dichlorobenzene and then cooled. By diluting it with isopropyl alcohol, there was obtained 35 g of 3 - diethylamino 6 - chloro - 7 - cyclohexylaminofluoran. It was just identical with the product obtained by the process of Example 16.

Example 26 Into 219 g of 93% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 26.0 g of 2 - chloro - 4 - hydroxy - N (1' - methyl - 3' - phenylpropyl) - aniline, and the solution was stirred at 30 C for 36 hours. Then, after-treatment was carried out in the same manner as in Example 16 to obtain 3 - diethylamino - 6 chloro - 7 - (1 ' - methyl - 3' - phenylpropylamino) fluoran. The product was recrystallized from isopropyl alcohol to give 25.7 g of white crystal having a melting point of 1800-1830C.

Example 27 Into 219 g of 94% sulfuric acid were dissolved 31.3 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 23.0 g of 2 - chloro - 4 - hydroxy - N (1' - methyl - 3' - methoxypropyl) - aniline, and the solution was stirred at 40 C for 24 hours. Then, after-treatment was carried out in the same manner as in Example 17, and the product was recrystallized from isopropanol. Thus, 3 - diethylamino - 6 - chloro 7 - (1' - methyl - 3' - methoxypropylamino) - fluoran having a melting point of 172"-174"C was obtained as a white crystal.

Example 28 Into 45 g of 98% sulfuric acid were dissolved 6.26 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) benzoic acid and 5.4 g of 2 - bromo - 4 - hydroxy - N cyclohexylaniline, and the solution was stirred at 45 -50 C for 15 hours. Then, after-treatment was carried out in the same manner as in Example 17, and the product was recrystallized from a solvent consisting of 1:2 mixture of toluene and isopropanol. Thus, 7.5 g of 3 - diethylamino - 6 - bromo - 7 cyclohexylaminofluoran having a melting points of 177 -178 C was obtained as a white crystal.

Example 29 Into 60 g of 98% sulfuric acid was dissolved 7.28 g of 2 - (4' - diethylamino - 2' - hydroxybenzoyl) - 3 naphthoic acid at a temperature of 30 C or below, into which was further dissolved 4.52 g of 2 - chloro 4 - hydroxy - N - cyclohexylaniline. The mixture was stirred at 30 C for 36 hours, and then charged into 300 g of ice water, alkalified with sodium hydroxide solution and heated to 70 C. Thereafter the resulting precipitate was coliected by filtration, washed with water and dried. Thus, 4.50 g of 3 - diethylamino - 6 chloro - 7 - cyclohexylamino - benzofluoran-was obtained. The product was recrystallized from isop ropyl alcohol to give a white crystal having a melting pointof172"-173"C.

Example 30 The procedure of Example 29 was repeated, except that 2 - chloro - 4 - hydroxy - N - cyclohexyla niline was replaced with 4.23 g of 2 - chloro - 4 hydroxy - N - cyclopentylaniline. Thus 4.23 g of 3 diethylamino - 6 - chloro - 7 - cyclopentylamino benzofluoran was obtained. The product was recrystallized from isopropanol to give a white crystal having a melting point of 210 -211 C.

Example 31 Using 60 g of 98% sulfuric acid, 7.28 g of 2 - (4' diethylamino - 2' - hydroxybenzoyl) - 3 - naphthoic acid and 3.71 9 of 2 - chloro - 4 - hydroxy - N - isopropylaniline, a reaction was carried out at3000 for 36 hours in the same manner as in Example 29 and then after-treatment was carried out in the same manner as in Example 29. Thus, 5.15 g of 3 diethylamino - 6 - chloro - 7 - isopropylamino benzofluoran was obtained. The product was recrystallized from isopropanol to give a white crystal having a melting point of 216"-217.5"C.

Example 32 The procedure of Example 31 was repeated, except that the 2 - chloro -4- hydroxy- N isopropylaniline was replaced with 4.55 g of 2 chloro - 4 - hydroxy - N - (1,3' - dimethylbutyl) aniline. Thus, 4.86 g of 3 - diethylamino - 6 - chloro - 7 - (1,3' - dimethylbutylamino) - benzofluoran was obtained. The product was recrystallized from isopropanol to give a white crystal having a melting point of 108 -112 C.

Example 33 By using 3.99 9 of 2 - chloro - 4 - methoxy - N - isopropylaniline in place of the 2 - chloro - 4 hydroxy - N -isopropylaniline used in Example 31, its condensation with 2 (4' - diethylamino - 2' hydroxybenzoyl) - 3 - naphthoic acid was carried out in 98% sulfuric acid. The reaction mixture was charged into ice water and alkalified, and the resulting crystal was dried. The crystal was heated to 17000 together with an equal amount of o - dichloro benzene and then cooled and diluted with isopropa nol. Thus, 3 - diethylamino - 6 - chloro - 7 isopropylamino - benzofluoran, just identical with the product of Example 31, was obtained.

Example 34 The procedure of Example 31 was repeated, except that 2 - chloro - 4 - hydroxy - N -isopropylani line was replaced with 4.32 g of 2 - chloro - 4 hydroxy - N -(1' - methyl - 2' - methoxyethyl) - aniline.

Thus, 5.2 g of 3 - diethylamino - 6 - chloro - 7 - (1' methyl 2' - methoxyethylamino) - benzofluoran was obtained. The product was recrystallized from isop ropanol to give a white crystal having a melting point of 204"-205"C.

Example 35 By using 5.4 9 of 2 - bromo - 4 - hydroxy - N - cyclohexylaniline in place of the 2 - chloro - 4 hydroxy - N -cyclohexylaniline used in Example 29, a reaction was carried out at 25"C for 18 hours and then after-treatment was carried out in the same manner as in Example 29. Thus, 5.4 g of 3-diethylamino - 6 - bromo - 7 - cyclohexylaminofluoran was obtained. The product was recrystallized from isopropanol to give 2.6 g of a white crystal having a melting pointof 167 -168 C.

Example 36 Into 13 g of 98% sulfuric acid were dissolved 1.82 g of 2 - (4' - N - methyl - p - toluidino - 2' hydroxybenzoyl) - benzoic acid and 1.13 g of 2 chloro -4 - hydroxy - N -cyclohexylaniline at a temperature of 30"C or below. Then the solution was stirred at 30"C for 48 hours to complete the reaction.

Then, the reaction mixture was charged into 100 ml of ice water and alkalified with 16 g of 28% aqueous ammonia. The resulting precipitate was collected by filtration, washed with 200 g of warm water and dried. Thus, 2.3 g of 3 - (N - methyl - p toluidino) - 6 - chloro - 7 - cyclohexylaminofluoran was obtained. The product was recrystallized from isopropyl alcohol to give 37.9 9 of a white crystal having a melting point of 218"-219.5"C. Its structure was confirmed by referring to elementary analyses, mass spectrum and NMR spectrum.

Example 37 The procedure of Example 36 was repeated, except that 2 - (4' - N - methyl - p - toluidino - 2' hydroxybenzoyl) - benzoic acid was replaced with 1.88 9 of 2 - {4' - N - ethyl - p - toluidino - 2' - hydroxybenzoyl) - benzoic acid. Thus, 2.3 g of 3 - (N ethyl - p - toluidino) - 6 - chloro - 7- cyclohexylaminofluoran was obtained. The product was recrystallized from isopropyl alcohol to give a white crystal having a melting point of 187 -188 C.

Example 38 Into 13 g of 98% sulfuric acid were dissolved 1.88 g of 2 - (4' - N - ethyl - p - toduidino - 2' - hydroxy benzoyl) - benzoic acid and 0.93 g of 2 - chloro - 4 hydroxy - N - isopropylaniline, and the solution was stirred at 300C for 48 hours to complete the reaction.

Thereafter, the procedure of Example 36 was repeated to obtain 3 - (N - ethyl - p - toluidino) - 6 - chloro 7 - isopropylaminofluoran. The product was recrystallized from isopropyl alcohol to give a white crystal having a melting point of 159 -160 C.

Example 39 The procedure of Example 36 was repeated by using 13 g of 98% sulfuric acid, 1.88 g of 2 - (4' - N methyl - p - toluidino - 2' - hydroxybenzoyl) - benzoic acid and 1.08g of 2 - chloro - 4 - hydroxy N - (1'methyl - 2' - methoxyethyl) - aniline. Thus, 3- (N - ethyl - p - toluidino) - 6 - chloro - 7 - (1' - methyl - 2' methoxyethylamino) - fluoran was obtained. The product was recrystallized from isopropyl alcohol to give a white crystal having a melting point of 149"-152"C.

Example 40 The procedure of Example 36 was repeated by using 13 g of 98% sulfuric acid, 1.88 g of 2 - (4' - N ethyl - p - toluidino - 2' - hydroxybenzoyl) - benzoic acid and 1.06 9 of 2 - chloro -4 - hydroxy - N - cyclopentylaniline. Thus, 3- (N - ethyl - p - toluidino) - 6 - chloro - 7 - cyclopentylaminofluoran was obtained. The product was recrystallized from isopropyl alcohol to give a white crystal having a melting point of 200"-202"C.

Example 41 The procedure of Example 36 was repeated by using 13 g of 98% sulfuric acid, 1.88 g of 2 - (4' - N ethyl - p - toluidino - 2' - hydroxybenzoyl) - benzoic acid and 1.07g of 2 - chloro - 4 - hydroxy - N -(1'- ethylpropyl) - aniline. Thus, 3 - (N - ethyl - p toluidino) - 6 - chloro - 7 - (1' - ethylpropylamino) - fluoran was obtained. The product was recrystallized from isopropyl alcohol and hexane to give a white crystal having a melting point of 128"-130"C.

Example 42 The procedure of Example 36 was repeated by using 219 g of 94% sulfuric acid, 1.88 g of 2 - (4' - N ethyl - p - toluidino 2' - hydroxybenzoyl) - benzoic add and 1.14 9 of 2 - chloro - 4 - hydroxy - N - {1 ',3' - dimethylbutyl) - aniline. Thus, 3 - (N - ethyl - p - toluidino - 6 - chloro - 7 - (1',3' - dimethylbutylamino) - fluoran was obtained. The product was recrystallized from isopropyl alcohol and hexane to give a white crystal having a melting point of 184 -186 C.

Example 43 Into 13 g of 98% sulfuric acid were dissolved 1.88 g of 2 - 14'- N -ethyl - p - toluidino - 2' - hydroxybenzoyl) - benzoic acid and 1.25 g of 2 chloro - 4 - methoxy - N - cyclohexylaniline at a temperature of 30"C or below, and the solution was stirred at 30 C for 48 hours. Then, the reaction mixture was charge into 200 ml of ice water, alkalified with 25% sodium hydroxide solution, and heated to 60 C and kept at this temperature for 1 hour. Then, the precipitate was collected by filtration and washed with water. After drying the precipitate, it was boiled together with an equal amount of o dichlorobenzene, cooled and then diluted with isopropyl alcohol. Thus,3 - (N - ethyl - p - toluidino) - 6 - chloro - 7 - cyclohexylaminofluoran was obtained.

The product was recrystallized from isopropyl alcohol to give a white crystal which was identical with the product obtained by the process of Example 37.

Example 44 Into 60 g of 98% sulfuric acid was dissolved 7.35 g of 2 - (4' - N - cyclohexyl - N - ethylamino - 2' hydroxybenzoyl) - benzoic acid at a temperature of 20 C or below, into which was then dissolved 4.52 g of 2 - chloro - 4 - hydroxy - N - cyclohexylaniline.

After stirring the solution at 25"C for 48 hours, it was charged into 300 g of ice water and alkalified with sodium hydroxide solution. The resulting precipitate was collected by filtration, washed with water and dried. Thus, 8.2 g of 3 - (N - cyclohexyl - N ethylamino) - 6 - chloro - 7 - cyclohexylaminofluoran was obtained. The product was recrystallized from isopropyl alcohol to give a white crystal having a melting point of 222 -223 C.

Example 45 Into 25 g of 98% sulfuric acid was dissoived 3.55 g of 2-(4'-N-cyclohexyl-N-methylamino-2'hydroxybenzoyl)-benaoic acid at a temperature of 20 C or 'celow, into which was then dissolved 2.26 g of 2 - chloro-4-hydroxy-N-cyclohexylaniline.

After stirring the solution at 25 C for 48 hours, it was charged into 300 g of ice water and alkalified with aqueous ammonia. The resulting precipitate was collected by filtration, washed with water and dried.

Thus, 5.3 g of 3-(N-cyclohexyl-N-methylamino)3 - chloro - 7 - cyclohexylaminofluoran was obtained.

The croduct was recrystallized from toluene and isopropyl alcohol to give a white crystal having a melting point of 225 -226 C.

Example 46 The procedure of Example 45 was repeated, except that 2 - chloro - 4 - hydroxy - N - cyclohexylaniline was replaced with 2.16 g of 2 - chloro - 4 hydroxy-N-(1'-methyl-2'-methoxyethyl)-aniline.

Thus, 5.6g of 3-(N-cyclohexyl-N-ethylamino)-6chloro-7-(1'-methyl-2'-methoxyethylamino)fluoran was obtained. The product was recrystallized from isopropanol to give a white crystal having a melting point of 168 -171 C.

Example 47 The he procedure of Example 45 was repeated, except that 2 - chloro - 4 - hydroxy - N - cyclohexyla niline was replaced with 1.86 g of 2 - chloro - 4 hydroxy-N-isopropylaniline. Thus, 5.3 g of 3-(N cyclohexyl-N-ethylamino)-6-chloro-7 isopropylaminofluoran was obtained. The product "as recrystallized from isopropanol to give a white crystal having a melting point of 207 -208.5 C.

example 48 Ti.e procedure of Example 45 was repeated, except that 2- chloro - 4 - hydroxy - N N -cvclohexyla- gline was replaced with 2.12 9 of 2 - chloro - 4 hydroxy - N - cyclopentylaniline. Thus, 4.5 9 of 3 - (N -cyclohexyl-N-ethylamino)-6-chloro-7 cyciopentylaminofluoran was obtained. The product ';'as recrystallized from isopropanol to give a white crystal having a melting point of 208 -210 C.

Example 49 the procedure of Example 45 was repeated, except that 2 - chloro - 4 - hydroxy - N - cyclohexyla- aniline was replaced with 2.70 g of 2 - bromo - 4 hydroxy- N - cyclohexylaniline. Thus, 5.5 g of 3 - (N cyclohexyl-N-ethylamino)-6-bromo-7 cyclohexylaminofluoran was obtained. The product was recrystallized from isopropanol to give a white crystal having a melting point of 228 - 230 C.

Example 50

Into 100 g of &alpha;-(3,4-dimethylphenyl)&alpha;- phenylethane was dissolved 2.0 g of a fluoran compound represented by the above-mentioned structural formula, and then it was emulsified with a solution consisting of 20 9 of gum arabic and 160 g of water. After adding thereto 20 g of acid-treated gelatin and 1 160 g of water, pH was adjusted to 5 by adding acetic acid with a constant stirring and then 50 g of water was added to make progress a coacervation. After adjusting pH to 4.4 by adding acetic acid, 4 g of 37% formalin was added to form a rigid film.

All the above-mentioned procedures were carried out at 50 C. Then, the system was cooled to 10 C to make progress the gelation of the thick liquid film and to enhance the film-hardening effect. After adjusting pH to 9 by adding an aqueous solution of sodium hydroxide, the mixture was allowed to stand for several hours to obtain a capsule emulsion. Then, the capsule emulsion was mixed with 30 g of finely powdered cellulose and 100 g of 10% aqueous solution of oxidized starch, and the resulting mixture was coated on a paper and dried to obtain a top sheet.

The top sheet was superposed on an under sheet, and a pressure of pencil or a typing pressure of typewriter was applied thereto. Thus, a black color was formed. That is, a black colored clear ietter appeared when the under sheet used was coated with a polymer of p - phenylphenol, as well as when the under sheet used was coated with an acid-tre - ated activated clay.

The pressure sensitive recording paper obtained in this example was excellent in storage stability and had a high color-forrning velocity. The colored letter formed thereon was resistant to a longterm expo sure to light and was not discolored even if wet with water.

ExampleSl

A pressure sensitive recording paper was prepared in the same manner as in Example 50 by using a fluoran compound represented by the structural formula shown above.

When a typing pressure was applied to this pressure sensitive recording paper, a black colored image was formed.

This pressure sensitive recording paper was excellent in storage stability and had a high color-forming velocity. The colored letter formed thereon was excellent in resistances to light and water.

Example 52

A pressure sensitive recording paper was prepared in the same manner as in Example 50 by using afluoran compound represented by the structural formula shown above.

When a typing pressure was applied to this pressure sensitive recording paper, a black colored image was formed.

This pressure sensitive recording paper was excellent in storage stability and had a high color-forming velocity. The colored letter formed thereon was excellent in resistances to light and water.

Example 53

By means of a sand mill, 30 g of a fluoran compound represented by the structural formula shown above was dispersed into a mixture of 150 g of 10% aqueous solution of polyvinyl alcohol and 65 g of water (this is referred to as "component A"). On the other hand, 35 g of Bisphenol A and 150 g of 10% aqueous solution of polyvinyl alcohol were dispersed into 65 g of water in the same manner as above (this is referred to as "component B").

Then, 33 g of component A and 67 g of component B were mixed together, and the resulting mixture was coated on a sheet so as to give a dry coating weight of about 5 g/m2. The sheet thus obtained was usuable as a heat sensitive recording paper in itself alone. By means of a heat sensitive recording machine, it gave an excellent black colored image.

The heat sensitive recording paper of this example was a beautiful sheet free from self-color-formability and has a high color-forming velocity. The colored letter formed thereon was excellent in resistances to light and water.

Example 54

A heat sensitive recording paperwas prepared in the same manner as in Example 53 by using a fluoran compound represented by the structural formula shown above.

This heat sensitive recording paper was free from self - color - formability and had a high color-forming velocity. The colored letter formed thereon was excellent in resistances to light and water.

Example 55

A heat sensitive recording paper was prepared in the same manner as in Example 53 by using 28 g of fluoran compound represented by the structural formula shown above and 2 g of 3 - diethylamino - 6, 7 - benzofluoran.

This heat sensitive recording paper had properties similar to the properties of the heat sensitive recording paper of Example 53.

Claims (41)

1. A process for producing a fluoran compound represented by the following general formula (I):

wherein A represents benzene nucleus or naphthalene nucleus optionally substituted by halogen; X represents halogen atom; R' and R2,taken individually, represent alkyl group optionally having ether linkage, cycloalkyl group or phenyl group or, taken jointly, represent cycloalkyl group, tetralinyl group or indanyl group in conjunction with the carbon atom of methine group; and R5 represents alkyl, alkoxyalkyl,cycloalkyl, phenylalkyl or phenyl group and R6 represents alkyl, alkoxyalkyl or phenylalkyl group or R5 and R6, taken jointly, represent

or-C2H40C2H4- group, providedthatp is a number of 4, 5 or 6 and the phenyl nuclei of R5 and R6 are optionally substituted by alkyl group or halogen, which comprises reacting an aniline compound represented by the following general formula (ill):

wherein X is as defined above and R represents hydrogen atom or lower alkyl group, with a ketone compound represented by the following general formula (Ill)::

wherein R3 and R4 represent R1, R2 as defined above or a group capable of changing to R' or R2 in the course of reaction, under the conditions of a catalytic and reductive alkylation to form an imide compound represented by the following general formula (IV)

wherein X, R, R' and R2 are as defined above, followed by reacting said imide compound represented by general formula (IV) with a compound represented by the following general formula (V):

wherein A, R5 and R6 are as defined above, in the presence of a dehydrating condensing agent.

2. A process according to Claim 1, wherein the reaction between the compound of general formula (II) and the compound of general formula (III) is carried out under an elevated pressure of hydrogen at an elevated temperature in the presence of a solvent and a catalyst.

3. A process according to Claim 2, wherein the reaction is carried out in the presence of an organic acid.

4. A process according to Claim 3, wherein said organic acid is acetic acid.

5. A process according to any one of claims 2-4, wherein platinum supported on a carrier is used as said catalyst.

6. A process according to any one of claims 2-5, wherein the reaction is carried out at a temperature of 80- 1400C.

7. A process according to any one of claims 2-6, wherein the reaction is carried out under a hydrogen pressure of 5-50kg/cm2.

8. A process according to any one of the preceding claims, wherein said aniline compound of general formula (II) is: 3 - chloro - 4 - aminophenol, 3 - chloro - 4 - aminoanisole, 3 - chloro - 4 - aminophenetole, 3 - bromo - 4 - aminophenol, 3 - bromo - 4 - aminianisole, 3 - iodo - 4 - aminophenol, or 3 - fluoro - 4 - aminophenol.

9. A process according to any one of the preceding claims, wherein said ketone compound of general formula (III) is cyclohexanone, cyclopentanone, ss - tetralone, 2 - indanone, acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methoxyacetone, 4 - methoxy - 2 - butanone, diacetone alcohol, 4 - methoxy - 4 - methyl -2-pen- tanone, dimethoxyacetone, 4 - cyclohexyloxy -2- butanone, 4 - phenyl -2 - butanone, dibenzyl ketone or methyl vinyl ketone.

10. A process according to any one of the preced ing claims, wherein the molar ratio of the ketone compound of general formula (Ill) to the aniline compound of general formula (II) is 1:1 to 2:1.

11. A process according to any one of the preced ing claims, wherein the reaction between the imide compound of general formula (IV) and the compound of general formula (V) is carried out at a temperature of -5"C to 90 C.

12. A process according to any one of the preceding claims, wherein said dehydrating condensing agent is sulfuric acid having a concentration of 85-1 00%.

13. A process according to any one of the preceding claims, wherein said imide compound of general formula (IV) is: 2 - chloro - 4 - hydroxy - N - cyclohexylaniline, 2 - bromo - 4 - hydroxy - N - cyclohexylaniline, 2 - fluoro - 4 - hydroxy - N - cyclohexylaniline, 2 - iodo - 4 - hydroxy - N - cyclohexylaniline, 2 - chloro - 4 - hydroxy - N - cyclopentylaniline, 2 - chloro - 4 - hydroxy - N - (p - tetralinyl) - aniline, 2 - chloro - 4 - hydroxy - N - (2 - indanyl) - aniline, 2 - chloro - 4 - hydroxy - N - isopropylaniline, 2 - chloro - 4 - hydroxy - N - (1 ' - methylpropyl) aniline, 2 - chloro - 4 - hydroxy - N - (1 ' - ethylpropyl) - aniline, 2 - chloro - 4 - hydroxy - N - (1', 3' - dimethylbutyl) aniline, 2 - chloro - 4 - hydroxy - N - (1' - methylhexyl) - aniline, 2-chloro-4-hydroxy- N-(l'-methyl-2'- methoxy- ethyl) - aniline, 2 - chloro - 4 - hydroxy - N - (1 ' - methoxymethyl - 2' - methoxyethyl) - aniline, 2-chloro-4-hydroxy- N-(l'-methyl-3'- methoxypropyl) - aniline, 2 - chloro - 4 - hydroxy - N - (1' - ethyl - 2' - methoxyethyl) - aniline, 2-chloro-4-hydroxy- N-(l'-methyl-2'- methoxyethoxyethyl) - aniline, 2-chloro-4- hydroxy-N- (l'-methyl-2' - cyclohexyloxyethyl) - aniline, 2-chloro-4-hydroxy- N-(l'-methyl-3' - cyclohexyloxypropyl) - aniline, 2-chloro-4-hydroxy-N-(1'-methyl-2'- benzyloxyethyl) - aniline, 2-chloro-4- hydroxy-N- (l'-methyl-3' - benzyloxypropyl) - aniline, 2-chloro-4-hydroxy- N-(l'-methyl-3' - phenethyloxypropyl) - aniline, 2-chloro-4-hydroxy- N-(l'-methyl-2' - phenoxyethyl) - aniline, 2-chloro-4-hydroxy- N-(1'-methyl-2'- phenoxyethoxyethyl) - aniline, 2-chloro-4-hydroxy- N-(l'-methyl-2'- phenylethyl) - aniline, 2-chloro-4-hydroxy-N-(1 -methyl-3'- phenylpropyl) - aniline, 2-chloro-4-hydroxy- N-(?' -benzyl-2' - phenylethyl) - aniline, 2 - chloro - 4 - hydroxy - N - cyclohexylaniline, 2 - bromo - 4 - methoxy - N - cyclohexylaniline, or 2-chloro-4-hydroxy- N-(l'-methyl-3' - methoxypropyl) - aniline.

14. A process according to any one of the preceding claims, wherein said compound represented by general formula (V) is: 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 - diisobutylamino - 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, 2 - (4' - N, N - diethylamino - 2' - hydroxybenzoyl) 3 - naphthoic acid, 2 - (4' - N, N - dimethylamino - 2' - hydroxybenzoyl) - 3 - naphthoic acid, 2 - (4' - N, N - dibutylamino - 2' - hydroxybenzoyl) 3 - naphthoic acid, 2 - (4' - N, N - diamylamino - 2' - hydroxybenzoyl) 3 - naphthoic acid, 2 - (4' - N - ethyl - N - butylamino - 2' - hydroxybenzoyl) - 3 - naphthoic acid, 2 - (4' - N, N - diethylamino - 2' - hydroxybenzoyl) 5 or 8 - chloro - 3 - naphthoic acid, 2 - (4' - N, N - diethylamino - 2' - hydroxybenzoyl) 5 or 8 - bromo - 3 - naphthoic acid, 2 - (4' - N, N - dimethoxyethylamino - 2' - hydroxybenzoyl) - benzoic acid, 2 - (4' - N, N - diethoxyethylamino - 2' - hydroxybenzoyl) - benzoic acid, 2 - (4' - N, N - diethoxyethylamino - 2' - hydroxybenzoyl) - 3 - naphthoic acid, 2 - (4' - N - methyl - anilino - 2' - hydroxybenzoyl) benzoic acid, 2 - (4' - N - ethyl - anilino - 2' - hydroxybenzoyl) benzoic acid, 2 - (4' - N - methyl - p - toluidino - 2' - hydroxybenzoyl) - benzoic acid, 2 - (4' - N - ethyl - p - toluidino - 2' - hydroxyben zoyl) - benzoic acid, 2 - (4' - N - ethyl - o - toluidino - 2' - hydroxyben zoyl) - benzoic acid, 2 - (4' - N - ethyl - p - chloroanilino - 2' hydroxybenzoyl) - benzoic acid, 2 - (4' - N - ethyl - p - butylanilino - 2' hydroxybenzoyl) - benzoic acid.

2 - (4' - N - ethyl - 2,4 - xylidino - 2' - hydroxyben zoyl) - benzoic acid, 2 - (4' - N - ethyl - p - toluidino - 2' - hydroxyben zoyl) - 3 - naphthoic acid.

2 - (4' - N - methyl - p - toluidino - 2' hydroxybenzoyl) -3 - naphthoic acid, 2 - (4' - N - cyclohexyl - N - methylamino - 2' hydroxybenzoyl) - benzoic acid, 2 - (4' - N - cyclohexyl - N - ethylamino - 2' hydroxybenzoyl) - benzoic acid, 2 - (4' - N - cyclohexyl - N - ethylamino - 2' hydroxybenzoyl) - 4 - chlorobenzoic acid, 2 - (4' - N - cyclohexyl - N - methylamino - 2' hydroxybenzoyl) - 3 - naphthoic acid, 2 - (4' - N - cyclohexyl - N - benzylamino - 2' hydroxybenzoyl) - benzoic acid, or 2 - (4' - N - cyclohexyl - N - benzylamino - 2' hydroxybenzoyl) - 3 - naphthoic acid.

15. A process according to any one of the preceding claims, wherein the molar ratio of the imide compound of general formula (IV) and the compound of general formula (V) is (IV)/(V) = 0.8:1 to 2.0:1.

16. A process for producing an imide compound represented by the following general formula (IV):

wherein X represents halogen atom; R represents hydrogen atom or lower alkyl group; and R1 and R2, taken individually, represent alkyl group optionally having ether linkage, cycloalkyl group or phenyl group or, taken jointly, represent cycloalkyl group, tetralinyl group or indanyl group in conjunction with the carbon atom of methine group, which comprises reacting an aniline compound represented by the following general formula (ill):

wherein X and R are as defined above, with a ketone compound represented by the following general formula (III)::

wherein R3 and R4 represent R1, R2 or a group capable of changing to R1 or R2 in the course of reaction, where R1 and R2 are as defined above, under the conditions of a catalytic and reductive alkylation to form a compound represented by general formula (IV).

17. A process according to Claim 16, wherein the reaction between the compound of general formula ;(it) and the compound of general formula (III) is carried out under an elevated pressure of hydrogen, at an elevated temperature, in the presence of a solvent and a catalyst.

18. A process according to Claim 16 or 17, wherein the reaction is carried out in the presence of an organic acid.

19. A process according to Claim 18, wherein said organic acid is acetic acid.

20. A process according to any one of Claims 16-19, wherein platinum supported on a carrier is used as said catalyst.

21. A process according to any one of Claims 16-20, wherein the reation is carried out at a temperature of 80"C to 140 C.

22. A process according to any one of Claims 516-21, wherein the reaction is carried out under a hydrogen pressure of 5-50 kg/cm2.

23. A process according to any one of Claims 16-22, wherein said aniline compound of general formula (II) is: ) 3 - chloro - 4 - aminophenol, 3 - chloro - 4 - aminoanisole, 3 - chloro - 4 - aminophenetole, 3 - bromo - 4 - aminophenol, 3 - bromo - 4 - aminoanisole, 3 - iodo - 4 - aminophenol, or 3 - fluoro - 4 - aminophenol.

24. A process according to any one of Claims 16-23, wherein said ketone compound of general formula (III) is cyclohexanone, cyclopentanone,8 tetralone, 2 - indanone, acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methoxyacetone, 4 - methoxy - 2- butanone, diacetone alcohol, 4 - methoxy - 4 - methyl - 2 pentanone, dimethoxyacetone, 4 - cyclohexyloxy -2 - butanone, 4 - phenyl - 2 - butanone, dibenzyl ketone or methyl vinyl ketone.

25. A process according to any one of Claims 16-24, wherein the molar ratio of the ketone com pound of general formula (II) is 1:1 to 2:1.

26. Afiuoran compound represented by the following general formula (VI):

wherein X represents halogen atom; A represents benzene nucleus or naphthalene nucleus optionally substituted by halogen; R5 represents alkyl, alkoxyalkyl, cycloalkyl, phenylalkyl or phenyl group and R6 represents alkyl, alkoxyalkyl or phenylalkyl group or R5 and R6, taken jointly, represent

or-C2H40C2H4- group, provided that p is a number of 4,5 or 6 and the phenyl nuclei of R5 and R6 are optionally substituted by alkyl group or halogen; and R7 and R8, taken individually, represent alkyl group optionally having ether linkage, cycloalkyl group or phenyl group or, taken jointly, represent cycloalkyl group, tetralinyl group or indanyl group in conjunction with the carbon atom of methine group;; provided that total carbon number is 3 or greater when R7 and R8 are both alkyl group and A is benzene nucleus.

27. Afluroan compound of Claim 26, which is represented by the following general formula (VII).

R9 and R10 each represents lower alkyl and R11 represents cycloalkyl group.

28. Afluoran compound of Claim 26, which is represented by the following formula,

29. Afluoran compound of Claim 26, which is represented by the following general formula (VIII),

wherein R12 represents lower alkyl group and R7 and R8 are as defined above.

30. Afluoran compound of Claim 26, which is represented by the following formula,

31. A fluoran compound of Claim 26, which is represented by the following formula,

32. A pressure sensitive or heat sensitive recording paper having a fluoran compound represented by the following general formula (Vl):

wherein X, A, R5, R6, R7 and R8 are as defined in Claim 26, as an electron - donating color - producing agent on a support.

33. A process for the production of a fluoran of the general formula I as defined in Claim 1 which comprises reacting an imide compound of the general formula IV as defined in Claim 1 with a compound of the general formula V as defined in Claim 1 in the presence of a dehydrating agent.

34. A process according to Claim 33 wherein the imide is as defined in Claim 13.

35. A process according to Claim 33 or 34 wherein the compound of formula V is as defined in Claim 14.

36. A process according to any one of Claims 33-35 wherein the molar ratio of compound IV to compound V is 0.8:1 to 2.0:1.

37. A process according to Claim 33 substantially as hereinbefore described with reference to any one of the Examples.

38. A process according to Claim 1 substantially as hereinbefore described with reference to any one of the Examples.

39. A process according to Claim 16 substantially as herein before described with reference to any one of the Examples.

40. A recording paper according to Claim 32 substantially as hereinbefore described with reference to any one of the Examples.

41. Afluoran according to claim 26 hereinbefore specifically mentioned.