CA1052381A

CA1052381A - Heterocyclic substituted fluorans

Info

Publication number: CA1052381A
Application number: CA209,895A
Authority: CA
Inventors: Jean-Claude Petitpierre; Robert Garner
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1973-09-26
Filing date: 1974-09-24
Publication date: 1979-04-10
Also published as: IT1019368B; SE7411504L; FR2257594B1; YU259674A; NL7412673A; ES430326A1; GB1463815A; YU37317B; AT331824B; DE2444297A1; JPS5064319A; CH596994A5; BE820305A; FR2257594A1; ATA772174A; US3929831A; FI272774A

Abstract

Heterocyclic substituted Fluorans Abstract of the Disclosure Heterocyclic substituted fluoran compounds of the formula

Description

T~e present invention provides novel fluoran compounds which are normally colourless or only weakly coloured but which by variation of the substituents in position 2 can give intense dark green,grey-black or red colours when contacted with an electron accepting co-reactant. The invention specifically relates to fluoran compounds, having in position 6 a nitrogen heterocyclic residue attached to the fluoran system through the nitrogen atom, and in position 2 a substituted amino group; a process for the manufacture of such compounds and their use as colour formers in pressure-sensitive or thermo-reactive recording materials.
The new fluoran compounds according to the invention correspond to the formula ~Co wherein Rl, R2 and R3 independently of the other, represent hydrogen, alkyl with 1 to 12 carbon atoms, nitro or halogen, or R2 and R3 together complete a condensed carbocyclic ring, especially a condensed benzene or tetrahydro benzene ring, Xl and X2 independently of the other, represent hydrogen, alkyl with 1 to 12 carbon atoms, alkenyl with at most 12 carbon atoms, alkoxyalkyl with 2 to 8 carbon atoms, alkoxycarbonylalkyl with 3 to 9 carbon atoms, cycloalkyl with 5 or 6 carbon atoms, acyl having 1 to 12 carbon atoms or a benzyl, phenyl or naphtyl radical which is unsubstituted or substituted by alkyl of 1 to 4 carbon atoms, aLkoxy of 1 to 4 carbon atoms, alkoxycarbonyl of 2 to 5 carbon atoms, acyl of 1 to 4 carbon atoms, nitro, halogen or by an amino group which is unsubstituted or substituted by alkyl of 1 to 4 carbon atoms or benzyl, and ~he nitrogen ring A represents a pyrrolidino or a piperidino ring, and the benzene ring B may be substituted by nitro or 1 to 4 haolgen atoms.
Halogen, in each occurrence in the defini~ions of the substituents, preferably stands for fluorine, bromine or especially chlorine.
When Rl, R2 and ~3, as well as Xl and X2 represent alkyl~ they may be straight or branched chain alkyl groups. Examples of said alkyl groups are methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec.butyl or tert.butyl, octyl or dode-~ 3 ~ ~

cyl. Rl, R2 and R3 are preferably hydrogen, halogen or allcyL
having 1 to 4 carbon atoms such as methyl or ethyl.

- Alkenyl in Xl and X2 stands e.g. for allyl, 2-meth-0~ _ --- .
allyl, 2-ethylallyl, 2-butenyl or octenyl.

Alkoxyalkyl and Alko~ycarbonylalkyl in Xl and X2 may have 1 to 4 carbon atoms in each alkyl part and stand pre~erably for ~-methoxyethyl or ~-ethoxyethyl and ~-methoxy-carbonylethyl or ~-ethoxycarbonylethyl, respectively.

Cycloalkyl in the meaning of these X-radicals may be cyclopentyl or preferably cyclohexyl. The optional sub-stituents in the benzyl, phenyl or naphthyl group may be alkyl with l to 4 carbon atoms, alkoxy with 1 to 4 carbon atoms, alkoxycarbonyl with 2 to 5 carbon atoms, acyl having 1 to 4 carbon atoms, nitro, halogen or an amino group optionally substituted by alkyl with 1 to 4 carbon atoms or by benzyl.
Ex~nples of these aromatic or aralLphatic radicals are p-methyI-benzyl, p-chlorobenzyl, p nitrobenzyl, p-tolyl, xylyl, p-chlorphenyl, p:nitrophenyl, l-methylnaphthyl-(2) or

2-methylnaphthyl-(1)0 Among the acyl groups the alkanoyl groups contain-ing 1 to 12 carbon atoms, such as formyl, acetyl or propionyl are especially noteworthy, Further acyl substituents may be alkylsulphonyl having 1 to 12 carbon atoms, such as methylsulphonyl, as well as benzoyl or benzene-~5 sulphonyl groups which may be substituted in benzene ring by halogen, methyl or methoxy groups~

In the fluoran compoullds fall;ng under formula (1), the nitrogen ring A denotes a heterocyclic radical which is attached to the fluoran ring through the nitrogen atorn. The heterocyclic ra~ical may have 3 to 12, preferably 5 or 6 ring members~ wherein..l or ~ hetero atoms may be included as ring members It is for instance a pyrrolidinyl, piperidino, pipecolino, perhydroazepinyl, hëptamethyleneimino, octamethylen-imino, 1,2~3,4-tetrahydroquinolinyl~ indolinyl or hexahydro-carbazolyl group, or in case the hetero ring includes a further hetero atom, a morpholino, thiomorpholino, piperaæino~ N-alkyl piperazino with 1 to 4 carbon atoms in the alkyl part, or a pyrazollnyl or 3-methylpyrazolinyl group.

As halogen, the benzene ring B may contain fluorine, bromine or especially chlorine. Preferably, it is not further -substituted or contains 4 chlorine atoms.

Practically important groups of the compo~mds of formula (1) may be de~ined by the following formula , ~2) ~ ; ~ ~

wherein R4, R5 and R6 independently of the other, represent hydrogen, --- halogen ? methyl or ethyl$
X3 represents alkyl with 1 to 8 carbon atoms,-alkoxyallcyl with 2 to 8 carbon atoms; cyclo-alkyl with 5 or 6 carbon atoms, acyl with 1 to 7 carbon atoms, phenyl or benzyl optionally substituted in the ring by methyl or halogen, X4 represents hydrogen, allcyl with 1 to 8 carbon atoms, cycloalkyl with 5 or 6 carbon atoms, acyl with 1 to 7 carbon atoms or benzyl option-ally substituted in the ring by methyl or halogen, and the nitrogen ring A and the benzene ring B have the given : 15 meanings.

Particularly useful fluoran compounds oE the formulae(l) and ~2) may be represented by the formula .
. - -R6 N

~CO

u - - - - ... . . -wherein ~ 6 --R4, R5 and R6 have the meaning given under formula (2), X5 represents alkyl with 1 to 8 carbon atoms, acyl with 1 to 7 carbon atoms, phenyL or benzyl, S X~ represents hydrogen, alkyl with 1 to 8 carbon atoms, acyl with 1 to 7 carbon atoms or benæyl, the nitrogen ring Al represents a morpholino, piperazino or especially a pyrrolidinyl or piperidino ring and the benzene ring Bl may be further substituted by 1 to 4 halogen atoms~

especially chlorine atoms.

Of special interest are fluoran cornpounds falling under formulae (1) to (3), which are listed under A, B and C, respectively.

A. Compounds of the formula . . .
- .
R6 .

(4) ~ ~ 5 ~

~ ' ' -, "

.
wherein Al 9 Bl, R4, R5 and R6 have the meaning given under formula (3), X7 and X8 independently of the other,represent alkyl with 1 to 8 carbon atoms or benzyl~

These ~luoran compounds are distinguislled as dark green colour formers.
.
B. Compounds of the ~ormula C~

¢~,CO

wherein Al, Bl, R4, R5 and E~6 have the meaning given under formula (3) and Xg reprcsents alkyl -~ith 1 to 8 carbon atoms, benzyl or phenyl.
These fluoran compounds are colour formers which give a grey or black colour when contacted wi'~h an electron accepting co-reactant.

C. Compounds of the formula .. . . .

~KD~X lo . .~. -' ' , -wherein Al, Bl, R4, R5, R6 and X9 have the given meanings and X10 represents acyl. having 1 ~o 7 carbon atoms,for examp~le,alkanoyl with 1 to 4 S carbon atoms, such as formyl, acetyl or propionyl, or benzoyl a methyl-sulphonyl or p-tolylsulphonyl J
These fluoran compounds are scarlet-red colo-lr formers.
i The new fluoran compounds of the formulae (1') to (6) .
10 are obtained by a method known in the art, The process o ~ -~
manufacturing the fluoran compounds of formuLa,(l) comprises reacting a benæophenone compound o the formula ~ N ~ ~ / OZ~

(~) C.=O

l~ , .. . .
with a compound o~ the formula - , -. - R3 (8) Z~O ~ ~ R2 X

' Rl 2 wherein A, B, Rl, R2, R3, Xl and X2 have the given Ineani~g~
and Zl and Z2 represent hydrogen or alkyl having 1 to 4 carbon atoms, such as methyl,ethyl or butyl. Preferably, of Zl and Z2 one is hydrogen, methyl or ethyl and the other is hydrogen. Most preferably, Zl is hydrogen and ~2 i~
hydrogen or methyl.
The reaction is advantageously carried out at 10 to lOO~C by allo~ring the reactants o~ formuLae (7) and (8) to react together in the presence of an aciclic condensing agent.
Examples o~ suitable condensing agents are acetic anhydride, sulphuric acid, zinc chloride or phosphorous oxy-chloride. This reaction is preferably completed by the addition of a base. The bases may be organic or inorganic and can ln-c~ude, for example, alkali metal hydroxides, such as sodium hydroxide or potassium hydroxide, as well as aliphatic amines, such as triethylalnine or trihydroxyethylamine.

~he starting compounds of formula (7) are new and are generally prepared by reacting 3 phthalic anhydride of the ~ormuLa (9) ~ : ' with a compound of the formula f~ 0~- , . .
(10) ~ ~3~ . .
.
wher~in Zl represents hydrogen or alkyl having 1 to 4 carbon atoms and A and B have the meaning described above.

~c~

This reaction is suitably carried out in an organic solvent, such as acetone, benzene, toluene, xylene, or a chloroben-zene, preferably at temperatures at or below the boiling ~,,, _._.
point of such solvents.
The compounds of formula (10) may be produced by condensing the heterocyclic base ~ NH, in which the c~cle A
has the meaning described above, with resorcinol or a mono-alkyl ether derivative thereof at temperatures between 50 and 250C and cptionaL~ ullder pressure. This reaction may or may not be assisted by the use of a condensing agen~, examples of which are zinc chloride, aluminium chloride or sulphanilic acid. Alternatively, the compounds of formula (10) may be prepared from the reaction of meta hydroxy- or alkoxy-aniline with a ,~-dihalogenoalkanes in which the halogen is, for example, bromine or chlorine but more usually bromine.

- Compounds of formula (1), wherein Xl or X2 or both re-present acyl may be manufactured by reacting a compound of formula (1), wherein at least one of Xl and X2 represents hydro_ gen, with acylatil~g agents having at most 12 carbon atoms, e.g.
reactive functional derivatives of aliphatic carboxylic or sulphonic acids, particulaxly fatty acid halides and anhydrides such as acetyl chloride, acetyl bromide or acetic anhydride or of aromatic carboxylic or sulphonic acids such as benzoic acid halides or benzene sulphonic acid halides.

~ 11 -

3~13L

The acylation is generally carried out by known methods, e.g. in the presence oE acid binding agents such as alkali me~al carbonates or tertiary nitrogen bases such as pyridine and optiona~ly ln the presence of inert orgallic solvents such as acetone, isopropanol, chlorobenzene or ni~robenzene.

The new 1uorans, according to the invention, are more or less colourless compounds which are particularly useful when they are brought into contact with an acidic co-reactant sub-stance, that is an-electron-accepting substance. Typical co-reactants are, for example, attapulgus clay, silton clay, silica,bentonite, halloysite, aluminium o~ide, aluminium phosphate, kaolin or any acidic clay, or an acid reacting polymeric material such as a phenolic polymer, an alkylphenpl acetylene pol~ner, a maleic acid-rosin resin or a partially or wholly hydrolysed polymer o maleic anhydride with styrene, ethylene, vinyl methylether or carboxy polymethylenes.

The prefereed co-reactants are attapulgus clay, silton clay or a phenol-formaldehyde resin, these electron acceptors, preferably, are coated on the front side of the receiving sheet.

As indicated above, the fluoran compounds of formula (4~ behave as dark green colour formers, while com-pounds of formula ~5) behave as grey or black colour formers.
On the other side, the fluoran compounds o the ormula (6) behave as red or scarle~-red colour ormers~

~, By varying the structure of this new range of fl~torans certain properties may be "built-in", for example, the colour as described in the previous paragraph, fade stability for com-patibility with other colour formers in mixtures, and any solubility charac~eristics which wouLd allow greater flexibility in the choice of solvents used in microencapsulation and other modes of application.
As already mentioned, these colour formers above all are suitable for tne use in so-called pressure-sensitive recording ma~eriaL.Such a material e.g. includes a~ l~ast one pair of sheets, which comprises at least a colour former of ~ormula (1) dissolved in an organic solvent, preferably contained in pressure ruptura~le microcapsules and an electron accepting substance.

' The colour ormer, upon coming into contact with the electron accepting substance being able to produce a coloured marking at the points where the pressure is applied.
These colour formers which are comprised in the pressure-sensitive copying material are prevented from becom-ing active by being separated from the electron accepting sub-stance. As a rule this is done by incorporating these colour formers into a foam-, sponge- or honeycomb~like structure, Preferably however these colour formers are microencapsulated.

When these colo-trless eolour formers o~ ormula (1) are dissolved in an organic solvent, they may be su~jected to a microencapsulation process and subsequently used for making pressu~-~sensitive papers. When the capsules are ruptured by pressure from e.g. a pencil and the colour former solution is .. . .
- thus transferred into an adjacent sheet coated with a substrate capable of acting as an electron acceptor, a coloured image is produced. This new colour results rom the thus produced dyestuff which ab~orbs in the visible region of the electrow magnetic spectrum.

The general art o maki-ng Inicrocapsules oE some character has long been Icnown. I~ell known methods e.g. are disclosed in US Patent Specification 2,183,053~ 2,800,457, 2,800~458, 3,265~630, 2,964,331, 3,~18,656, 3,418,25~, 3,016,308, 3,42~,827, 3,4~7,250, 3,405,071, 3,171,878, and 2,7979201. Further methods are disclosed in British Patent Specifications 989,264 and above all 1,156,725. Any of these and other methods are suitable for encapsulating the present colour formers.

Preferably the present colour ormers are encapsulated dissolved in organic solvents. Suitable solvents are preferably non-volatile e.g. polyhalogenated diphenyl such as trichloro-diphenyl and its mixture with liquid paraffin, tricl~esyl phos-phate 9 di-n-butyl phtlalate, dioctyl phthalate, trichlorobenzene , - 25 nitrobenzene, trichloroethyl-phosphate, petroleumether, hydro-carbon oils, such as paraffinJ condensated derivatives of di-phenyl or triphenyl J chlorinated or hydrogena~:ed condensed aroma~ic hydrocarbons. The capsule walls preferably have been obtained by coacervation forces evenly around the droplets oE
the colour former solution, the encapsulating material consisting of gelatine, as e.g. described in United States Patent Specifica-tion 2,800,457.
Alternatively, the capsules preerably may be made of aminoplast or modified aminoplasts by polycondensation as described in British Patent Specification 989,264 or 1,156,725.
A preferred arrangement is wherein the encapsulated colour former is coated on the back side of a transfer sheet and the electron accepting substance is coated on the ront side of a receiving sheet.
In another preferred material one or more of the new fluorans are co-encapsulated with one or more other known colour formers, such as crystal violet lactone, benzoyl leuco methylene blue, or a bis-indolyl phthalide such as 3,3-bis(l'-n-octyl-2'-methylindol-3'-yl)-phthalide.
The microcapsules containlng the colour formers of formula ~1) are used for making pressure-sensitive copying material of the various types known in the art, such as so called "Chemical Transfer" and "Chemical Self-contained"
papers. The various systems mainly are distinguished by the arrangement of the capsules 9 the colour reactants and ~ 5 the support material.

The mlcrocapsules may be in an undercoating of the upper sheet and the colour reactznts, that is the electron acceptor and coupler, may be in the overcoating o~ the lower sheets. However, Lhe components may also be used in the paper pulp. Such systems are called "Chemical '~ransfer" system, ~nother arrangement we have in the self-contained papers. There the microcapsules containing the colour former and and the colour reactants are in or on the same sheet as one or more individual coatings or in the paper p-llp.
Such pressure-sensitive copying materials are de scribed e.g. in US Patent Specifications 3,516,846, 2,730,457, 2,932,582, 3,427,180, 3,418~250 and 3~418,656. Further systems are disclosed in British Patent Specifications 1,042,597>
1,042,598, 1,042,596, 1,042,599, 1,053,935 and 1,517,650.
- Microca~sules containing the colour formers of formula (~) - are suitable for any of these and other sy3:tems.

The capsules are preferably fixed to the carrier by means of a suitable adhesive. Since paper is the preferred carried material, these adhesives are predominantly paper coating agents, such as e.g. gum arabic, polyvinyl alcohol, hydroxymethylcellulose, casein, metllylcell~lose or dextrin.
In the present application, the definition "paper"
not on]y includes normal papers from cellulose fibres, but also papers in which the cellulose fibres are replaced (partially or completely) by synthetic fibres o~ polymers.

The new fluoran compounds may also be used as colour ormer in thermoreactive recording material compris~
ing at least a support, a binder, a colour former and an electron acceptin~ substance. Thermoreactive recording systems comprise heat-sensitive recording and copying materials and papers. These systems are used e.g. ~or the recording of information, for example, in electronic com-puters, in teleprinters or telewriters, in measuring instru-ments. The mark-forming also can be made manually with a heated pen~ A further means for inducing heat-in:itiated marks are laser beams. The thermoreactive recording material may be arranged in such a manner that the colour former is LS dissolved or dispersed in a layer of the binder, and in a second layer the developer and the electron-accepting sub-stance are disso'.ve~ or dîspersed in the binder. Another possibility consists in dispersing both the colour former ancl the developer in one layer. By means of heat the binder is so~tened at specific areas imagewise and the dyestuff is formed at these points, since only at the points where heat is applled does the colour former come into contact with the electron accepting substance.
The developers are the same e]ectron-accepting substances as are used in pressure sensitive papers. For practical reasons the developer should be solid at room temperature ancl melt or evaporate above 50 C. Examples of such products are the already mentioned clays, phenolic resins, ph~nolic compounds such as 4-tert.-butylphenol,

4-phenylphenol, 4-hydroxydipllenyloxide; a-naphthol, 4-hydro-xybenzoic acid methyl ester, ~-naphthoL, 4-hydroxyacetophe-none,2,2'-dihydroxydiphenyl, 4,4'-isopropylidene diphenol, 4,4'-isopropyliden-bis-(2-methylphenol~, 4,4'-bis-(hydroxy-phenyl) valeric acid, hydroquinone, pyrogallol, phloroglu-cinol, p-, m-, o-hydroxybenzoic acid, gallic acld, l-hydro-xy-2-naphthoic acid, boric acid, and the aliphatic dicarbo-xylic acids e.g. tartaric acid, oxalic acid, maleic acid, citraconic acid or succinic acid.

Preerably ~usible, film-forming binders are ~isedO
These binders should be water-solub7e, since the nitrophthal-ides and the developer are water-insoluble. The binder should be able to disperse and fix the colour former and the developer at room temperature. In this way the two reactive components are present in the material in a non-associated~
form. After applying heat, the binder softens or melts, which enables the colour former to come into contact with the developer and to form a dyestufE.

I~ater-soluble or at least water swellable bind-ers are e.g. hydrophilic polymers such as polyvinyl alcohol, polyacrylic acid, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, polyacrylamide, polyvinylpyrrolidone gelatine or starch.

~ 18 -In so ar as the colour ~ormer and the developer are coated in two separate layers, binclers which are water-insoluble may be usecl, i.e. binders soluble in non-polai or only we~L~ olar solvents, e.g. natuL-al rubber, sylltlletic rubber, chlo~inated rubber, alkyd resins, polystyrene, styrene~butadienecopolymers, polymethylmethacrylates, ethyl-cellulose, nitrocellulose or polyvinylcarbazole.
The pre~erred arrangement, l~owever, is colo~tr former and developer in a water-soluble binder in one layer.
The coatings of the thermoreactive material may contain further additives. To improve the degree of whiteness, to ease the printing of the papers and to prevent the stick-ing o~ the heated pen, tllese materials may contain etg. talc, TiO2, ZnO or CaC03. In order to produce the dyestuf~ only within a limited temperature range there may be added sub~
stances such as urea, thiourea, acetanilide; phthalic acid anhydride or other corresponding m.eltable products which in-duce the simultaneous melting o colour former and developer.
Typical thermoreactive recording materials wherein the present colour formers may be used e.g. are described ~n German Patent Application 2,228,581, French Patent 1,524,826, Swiss Patent 407,185, German Patent Application 2,110,854, S~iss Patents 164,976, 444,196 and 444,197.
- The ~ollowing non-limitative examples illustrate the present invention. Percentages are expressed by welght, unless otherwise stated.

~L~5;~

2-(~T,N-dibenzylamino)~6~ pyrroliclin~lfluoran __A mixture of 77.75 g 2'-carboxy-2-hydroxy~4--N-pyrrolid;nylbenzophenoLle, 75.6 g N,N-clibenzyl~p-anisidine and 250 ml 98% sulplluric acid is stirred at 60 C for 5 hours and then quenched into 2750 ml ice water to precipitate a solid. The solid is filtered off, washed with water and added to a mixture of ,00 ml water, 250 ml methanol and 26.8 g sodium hydroxide a~ 70 C. The mixl-ure is boiled for 2 hours and then cooled to 85 C. The solid product is:~ltered off, l~ashed ~lith hot water then recrystallized from methan-ol~acetone and dried to yield 86 g white plates m.p. 180 C.
max. in 95 % acetic acid 435, 462 and 607 nm.
A solution of the 2-(N,N-dibenzylamino)-6-N-pyrrolidinyl-fluoran in a hydrogenated terphenyl solvent gives a dark green print when applied to silton clay coated paper.
Absorption maxima are observed ~t ~ 444 and 602 nm.

The benzophenone compound used in this example as starting material may be produced as follows:
A mixture of 74 g phthalic anhydride, 81.5 g 1-(3'-hydroxy-phenyl)pyrrolidine and 335 ml xylene is heated at 125 C
for 6 hours, then cooled to 25 C. The precipitate is filtered off, washed with methanol and dried to yield 110~5 g yellow solid having m.p. 194 C after crystallis-ation from ethanol~

~i9~3~
Example 2 2-Ethylamino-6-N-pyrrolid~y~
A mixture of 9033 g 2'-carboxy-2-hydroxy-4--N-pyrrolidinylb~nzophenone, 4.54 g N-ethyl-p-anisidine

5 and 30 ml 98 vlO sulphuric acid is s~irred at 60 C
or 5 hours and then quenched into 330 ml ice-water -to pre-cipitate a solid. The solid is filtered of, washed with water and aclded to 75 ml methanol and 16.5 ml trieth~71amine.
The mixture i~5 boiled with stirring for 12 hours, then cool-ed to 0 C. The precipitate is ~iltered off, washed with methanol and dried to yield 8,32 g of 2-ethylamino-6-N-pyrrolidinylfluoran as a white solid.
max. in 95 % acetic acid 434, 457 and 602 nm.

A solution of this compound in benzene is colourless and gi~es a black colour on contact with silica9 greenish black on attapulgus or silton clay and green on phenolic resin.

~ 21 Example 3 2-N-~ce~ l-N-e~h lamino-6-N-~ rroL ~ fluoran -Y . Y _ .. Y _ ~ .
A mixture o:E 4,0 g 2-ethylamino-6-N~-pyrrolidinyl fluoran, 12 ml acetic anhydride and 0,~ ml pyridinels stirred S at 120 C for 4 hours. The solution is then evaporated to dryness, the residue taken up in 20 ml 10% sodium carbonate solution and extracted with e-ther, Ater drying and evaporating of the ether, 3,2 g of 2-N-acetyl-N~ethylamino-6-N-pyrrolidinyl 1uoran are obtained.

~ max. in 95 ~/0 acetic acid 374~496 and 528 nm.
This compouncl Eorms a red coLour when brought in contact with electron acceptin~ substances such as silica.

3~

~ )-6-N- rrolidln lfluoran ~ _ _ Y_ . ~
A mixture of 15,5 g 2'-carboxy-2 ~ ethoxy-4-N-pyrrolidinylbenzophenone and 14,45 g p-dibenzylam no-phenol is stirred in 50 ml 98% sulphuric acid at 60C for 5 hours, cooled to 25C and ~ wned into a mixture of 100 ml water and 450 g ice. The pH of the quenched mass is adjust2d to 8.5 with 120 ml 35% to ammonia solution. The precipitate is filtered off, washed with water and dried at 70C in vacuo to yield 19,7 g of 2-dibenzylamino-6-N-pyrrolidinyl-fluoran. The product is recrystallized from a mixture of methanol and acetone to yield colourless plates having a melting point of 180C. This product is identical with the colour former obtained according to Example 1.
The 2'-carboxy-2-ethoxy-4~N-pyrrolidiny'-benzo-phenone compound used in this example as starting material may be produced as follows:
To a mixture o 31.1 g 2'-carboxy-4-N-pyrroli~inyl-2-hydroxy-benzophenone, 39.6 ml diethyl sulphate and 240 ml acetone at 35C, is added a solution of 16.8 g potassium hydroxide in 50 ml water, drop-wise over 4 hours. The reaction mixture is then stirred for a further 20 hours at 35-40C. A solu-tion o~ 11.2 g potassium hydroxide in 50 ml water is then added and the reaction mixture is heated to boiling and re-fluxed for 2 hours. The solvent is distilled of:E until the temperature of the residual solution is 96C. The residue is held at 96C for 30 minutes then cooled down to 0C
by the addition of ice. Approximately 25 ml 28~/o HCl is added to bring the pH between 3 - 4 when the product pre-cipitates as a white suspension. After filtering off and washing with water 32.0 g 2'-carboxy-4 ~-pyrrolidinyl-2-ethoxybenzophenone, melting point 184 - 5C, is obtained.

- 24 ~
.

~3~ ~3 Example 5 2-Anilino-3-methyl-6-N-~rrol dinyl :Eluoran 15 g 2'-carboxy-2-hydroxy-4-N-~pyrrolidinyl-benzophenone and 9,9 g 4-anilino-m-cresol are dissolved S in 50 ml o~ 96C sulphuric acid and stirred for 2 hours at 60C. The product is washed up in a manner analogous to Example 2 ancl recrystallised from ethyl aceta~hexane7 m.p. > 260C. ~max.in 95 % acetic acid 380,450 and 585 nm. When applied to paper coated with silton clay as described in Example 1 a grey print is obtained which gives absorption maxima a~ ~ 453 and 575 nm, By using procedures similar to those described in Examples 1 to 5 the fluoran compounds of the fonmula (11) listed in the following Table have been manufactured.

(11) ~ ~ X12 ~CO

- 2~ -3~

_ ~
~ . 1, ~ ~ l o ~ o O u~ O
,~ ~o o o o U~ `;t ~ ~ I ~ ;I' ~ `;t I ~
. _ . .

o o o U~ ~ o .,, ~ o o o o ~ ~ ~ ~ o o u~ ~ ~ ~O ~ ~ ~ `D ~O ~ ~O
~ c) r` r' r~ c~l `* c5~ o o ~
~C ~:d .f~ .1~ u) ~ ~D i-- 1~ ~ 1~ ~ \~1:) 1 c~ ~ ~ ~ ~ ~ ~ ~ ;I' 1~ i~ u) 11~ ~ ' a~ ~ ~ .-1 o c~
~. Ir~
_ 0~ ', ~
,~
o 1~ O U~
~i ' ~ 1 o ,~

1$.~ U~ X~

_ ~ . . __ C~

$~
~o C~
,, ~ m~ m . ~
_ _ _ .
. ...
.. ~ . .
.
¢
. _ , . _ . _ x æ ~ ~1 J ~) ~ U'7 ~
_ _ __ _ _ _ _ _ _ _ - 2~ -__ P~ .
~D ~ ~ O O O
~ u~ u~ 2 ~ 2 ~
.,1 o ~ _ .
~ .
) ~ C~l 'C~l ~ ~ U~ ,l. U~
.,1 o ~ ~ ~ ~ ~ ~ o ~ a~ ~ LO ~ o .~1 ~ ~o ~ ~ oo oo ,1 ~ r~
X ~ U~ o o ~ ~ o o ~D
r~ ~ u~
~i ~ ~ a~
U~
~ _ _ . .
C~ oo o ~ U~ ~o o o O ~o c~ o C~l ~ ~ ~ ,` ~ C~l . , , , , , ' ~ ~
~o oo o ~ I` ~`
. O u~ ~ ,~ I~ r~ ~ ~
C~l ~ ~ ~ ~ ~ -~.
_ _ ~ .
i~ I~ r~ r~
o~
C~3 ~ ) V V C.) ~_ _ __~_ _ _ _ ., . Cj ~~ ~ ~ O O O O
~_3 _j, c~ ~ C~ C,) C.) C.) ~C I I1.
__ ~

r~l ~-3 ~1 ~
.~ , ~p~
C~ I OS) O O O 0 3 ~ æ ra ~ z __ o r_ a~ ~ o ~ C~l æ ~

5~
APPL~CATION EXAMP _ xample 25 Preparation of Pressure-sensitive Copying Paper A solution contain;ng 3 g of 2-dibenzylamino-6-N-pyrrolidinylfluoran in 100 g of hydrogenated terphenyl is emulsified at 50C in 100 g of 12% pig-skin gelatin solution 100 g of 12% gum arabic solution is added followed by 200 ml of water at 50C. The emulsion is poured into 600 g ice-water and stirred for three hours to complete the Goacervation. The resulting capsule slurry is coated onto paper and dried. When the coated side is placed in lQ contact with a second sheet coated with silton clay, attapulgite clay or phenolic resin a dark green image is obtained after application of pressure by writing. Similar effect can be obtained by using any other colour former of the Examples 2 to 2~.
Exam~ 6 Pr aration of Pressure-sensitive Co ying Pa er ep P P
A solution containing 1.6 g of 2-dibenzylamino-6-N-pyrrolidinyl-fluoran,`0.6 g of 3,3-bis(l'-n-octyl-2'-methylindol-3'-yl)phthalide, 0.1 g of Crystal violet lactone and 0.6 g of benzoyl leuco methylene blue in 100 g of hydrogenated terphenyl is emulsified at 50C in 100 g of 12% pigskin gelatin solution. 100 g of 12% gum arabic solution is added followed by 200 ml of water at 50C. The emulsion is poured into 600 g ice-water and stirred for three hours to complete the coacervation. The resul~ing capsule slurry is coated into paper and dried. When the coated side is placed in contact with a second sheet coated with silton clay or attapulgite clay a grey-black image is obtained after application of pressure by writing.
~x le 27 amp Pre aration of Thermoreactive Pa er P p

6 g of an aqueous dispersion containing 1.6% of 2-dibenzylamino-6-N-pyrrolidinylfluoran, 0.8% of 3,3-bis(l'-n-octyl-2'-methylindol-3'-yl)phthal-ide, 0.1% of Crystal violet lactone and 6.7% polyvinyl alcohol are mixed with 134 g of an aqueous dispersion containing 14% 4,4'-isopropylidenediphenol and 6% polyvinylalcohol, the mixture is then coated on paper and dried. When 1~5;~3~ ~

contacted with a heated stylus a gr0y-black mark is obtained which has ex-cellent light fastness.
Example 28 Preparation of Thermoreactive Pa~er When the colour formers in Example 27 are replaced by 2-dibenzyl-amino-6-N-pyrrolidinylfluoran and 3,3-bis(l'-n-octyl-2'-methylindol-3'-yl) phthalide in the ratio 6:4 the resulting system gives an intense black image.

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Claims

The embodiments of the invention in which an exclusive pro-perty or privilege is claimed are defined as follows:

1. A fluoran compound ot the formula (1) wherein R1, R2 and R3 independently of the other, represent hydro-gen, alkyl with 1 to 12 carbon atoms, nitro or halogen or R2 and R3 together complete a condensed carbocyclic ring, X1 and X2 independently of the other, represent hydro-gen, alkyl with 1 to 12 carbon atoms, alkenyl with at most 12 carbon atoms, alkoxyalkyl with 2 to 8 carbon atoms, alkoxycarbonylal-kyl with 3 to 9 carbon atoms, cycloalkyl with 5 or 6 carbon atoms, acyl having L to 12 carbon atoms, or a benzyl, phenyl or naphtyl radical which is unsubstituted or substituted by alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms 3 alkoxycarbonyl of 2 to S carbon atoms, acyl of 1 to 4 carbon atoms, nitro, halo-gen or by an amino group which is unsubstituted or substituted by alkyl of 1 to 4 carbon atoms or benzyl, and the nitrogen ring A represents a pyrrolidino or a piperidino ring and the benezene ring B may be substituted by nitro or 1 to 4 halogen atoms.

2 A fluoran compound according to claim 1 of the formula wherein R4, R5 and R6 independently of the other represent hydrogen, halogan, methyl or ethyl, X3 represents aklyl with 1 to 8 carbon atoms, alkoxyalkyl with

2 to 8 carbon atoms, cycloalkyl with 5 or 6 carbon atoms, acyl with 1 to 7 carbon atoms, phenyl or benzyl unsubstituted or substituted in the ring by methyl or halogen.
X4 represents hydrogen, alkyl with 1 to 8 carbon atoms, cycloalkyl with 5 or 6 carbon atoms, acyl with l to 7 carbon atoms or benzyl unsubstituted or substituted in the ring by methyl or halogen, and the nitrogen ring A and the benzene ring B have the meaning given in claim 1.

3. A fluoran compound according to claim 2 of the formula wherein R4, R5 and R6 have the meaning given in claim 2, X5 represents alkyl with 1 to 8 carbon atoms, acyl with 1 to 7 carbon atoms, phenyl or benzyl, X6 represents hydrogen, alkyl with 1 to 8 carbon atoms, acyl with 1 to 7 carbon atoms or benzyl and the nitrogen ring Al represents a pyrrolidino or a piperidino ring and the benzene ring B1 may be further substituted by 1 to 4 halogen atoms.

4. A fluoran compound according to claim 3 of the formula wherein A1, B1, R4, R5 und R6 have the meaning given in Claim 3 X7 and X8 represent, independently of the other, alkyl with 1 to 8 carbon atoms or benzyl.

5. A fluoran compound according to Claim 3 of the formula wherein A1, B1, R4, R5 and R6 have the meanings given in Claim 3, and X9 represents alkyl with 1 to 8 carbon atoms, benzyl or phenyl.

6. A fluoran compound according to Claim 3 of the formula wherein A1, B1, R4, R5 and R6 have the meanings given in Claim 3, and X9 the meaning given in Claim 5, and X10 represents acyl having 1 to 7 carbon atoms.

7. A process for the manufacture of fluoran compounds as defined in Claim 1, which comprises reacting a benzophenone compound of the formula with a compound of the formula wherein A, B, R1, R2, R3, X1 and X2 have the meanings given in Claim 1, and Z1 and Z2 represent hydrogen or alkyl having 1 to 4 carbon atoms.

8. A pressure-sensitive recording material which comprises at least a colour former dissolved in an organic solvent and an electron accepting substance, said colour former, upon coming into contact with the electron substance being able to produce a coloured marking at the points where the pressure is applied, wherein the colour former is a flu-oran compound of formula (1) as defined in Claim 1.

9. A pressure-sensitive recording material according to Claim 8, wherein the solid accepting substance is atta-pulgus clay, silton clay, silica or a phenolic resin or com-pound.

10. A pressure-sensitive recording material according to Claim 8, wherein the encapsulated colour former is coated on the back side of a transfer sheet and the electron accept-ing substance is coated on the front side of a receiving sheet.

11. A thermoreactive recording material comprising at least a support, a binder, a colour former and an elec-tron accepting substance wherein the colour former is a fluoran compound of the formula (1) given in Claim 1.

12. A thermoreactive composition comprising a colour former, an electron accepting substance and a binder wherein the colour former is a fluoran compound of the formula (1) given in Claim 1.