U.S. patent number 3,929,831 [Application Number 05/507,158] was granted by the patent office on 1975-12-30 for heterocyclic substituted fluorans.
This patent grant is currently assigned to Ciba-Geigy AG. Invention is credited to Robert Garner, Jean Claude Petitpierre.
United States Patent |
3,929,831 |
Garner , et al. |
December 30, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Heterocyclic substituted fluorans
Abstract
Heterocyclic substituted fluoran compounds of the formula
##SPC1## Wherein R.sub.1, r.sub.2 and R.sub.3 independently of the
other, represent hydrogen, alkyl with one to four carbon atoms,
nitro or halogen, or R.sub.2 and R.sub.3 together complete a
condensed carbocyclic ring, X.sub.1 and X.sub.2 independently of
the other, represent hydrogen, alkyl with one to 12 carbon atoms,
alkenyl with at most 12 carbon atoms, alkoxyalkyl with two to eight
carbon atoms, alkoxycarbonylalkyl with three to nine carbon atoms,
cycloalkyl with five or six carbon atoms, acyl having one to 12
carbon atoms, or optionally substituted benzyl, phenyl or naphthyl,
and The nitrogen ring A represents a heterocyclic radical which
optionally includes a further hetero atom as a ring member and the
benzene ring B may be further substituted by nitro or one to four
halogen atoms. These fluorans compounds are particularly useful as
colour formers which give intense dark green, grey black or red
colours when they are brought into contact with an
electron-accepting co-reactant.
Inventors: |
Garner; Robert (Ramsbottom
Bury, EN), Petitpierre; Jean Claude (Kaiseraugst,
CH) |
Assignee: |
Ciba-Geigy AG (Basel,
CH)
|
Family
ID: |
26265504 |
Appl.
No.: |
05/507,158 |
Filed: |
September 18, 1974 |
Foreign Application Priority Data
|
|
|
|
|
Sep 26, 1973 [UK] |
|
|
45048/73 |
Oct 23, 1973 [UK] |
|
|
49331/73 |
|
Current U.S.
Class: |
548/407;
250/396R; 503/222; 544/150; 544/172; 544/173; 544/174; 546/15;
546/197; 548/577 |
Current CPC
Class: |
C09B
11/24 (20130101); B41M 5/3275 (20130101); B41M
5/1455 (20130101) |
Current International
Class: |
B41M
5/145 (20060101); B41M 5/30 (20060101); B41M
5/132 (20060101); B41M 5/327 (20060101); C09B
11/00 (20060101); C09B 11/24 (20060101); C07D
207/14 (); C07D 207/24 (); C07D 207/26 () |
Field of
Search: |
;260/31R,326.34,326.5CA,326.85 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Moyer; Donald B.
Attorney, Agent or Firm: Kolodny; Joseph G. Almaula; Prabodh
I. Roberts; Edward McC.
Claims
We claim:
1. A fluoran compound of the formula ##SPC13##
wherein
R.sub.1, r.sub.2 and R.sub.3 independently of the other, represent
hydrogen, alkyl with one to four carbon atoms, nitro or halogen,
or
R.sub.2 and R.sub.3 together complete a condensed carbocyclic
ring,
X.sub.1 and X.sub.2 independently of the other, represent hydrogen,
alkyl with one to 12 carbon atoms, alkenyl with at most 12 carbon
atoms, alkoxyalkyl with two to eight carbon atoms,
alkoxycarbonylalkyl with three to nine carbon atoms, cycloalkyl
with five or six carbon atoms, acyl having one to 12 carbon atoms,
or an unsubstituted or substituted benzyl, phenyl or naphthyl
radical, and
the nitrogen ring A represents the pyrrolidinyl radical and the
benzene ring B is unsubstituted or substituted by nitro or one to
four halogen atoms.
2. A fluoran compound according to claim 1, of the formula
##SPC14##
wherein
R.sub.4, r.sub.5 and R.sub.6 independently of the other represent
hydrogen, halogen, methyl or ethyl,
X.sub.3 represents alkyl with one to 12 carbon atoms, alkoxyalkyl
with two to eight carbon atoms, cycloalkyl with five or six carbon
atoms, acyl with one to seven carbon atoms, phenyl or benzyl which
is unsubstituted or substituted in the ring by methyl or
halogen,
X.sub.4 represents hydrogen, alkyl with one to eight carbon atoms,
cycloalkyl with five or six carbon atoms, acyl with one to seven
carbon atoms, or benzyl unsubstituted or substituted in the ring by
methyl or halogen.
3. A fluoran compound according to claim 2, of the formula
##SPC15##
wherein
X.sub.5 represents alkyl with one to 12 carbon atoms, acyl with one
to seven carbon atoms, phenyl, benzyl or chlorobenzyl,
X.sub.6 represents hydrogen, alkyl with one to eight carbon atoms,
acyl with one to seven carbon atoms, benzyl or chlorobenzyl.
4. A fluoran compound according to claim 3, of the formula
##SPC16##
wherein
X.sub.7 and X.sub.8 represent, independently of the other, alkyl
with one to eight carbon atoms, benzyl or chlorobenzyl.
5. A fluoran compound according to claim 3, of the formula
##SPC17##
wherein
X.sub.9 represents alkyl with one to 12 carbon atoms, benzyl or
phenyl.
6. A fluoran compound according to claim 3, of the formula
##SPC18##
wherein
X.sub.9 represents alkyl with one to eight carbon atoms, benzyl or
phenyl and
X.sub.10 represents acyl having one to seven carbon atoms.
7. The 2-phenylamino-3-methyl-6-N-pyrrolidinylfluoran.
8. The 2-dibenzylamino-6-N-pyrrolidinyl fluoran.
Description
The 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 ##SPC2##
Wherein
R.sub.1, r.sub.2 and R.sub.3 independently of the other, represent
hydrogen, alkyl with one to 12 carbon atoms, nitro or halogen,
or
R.sub.2 and R.sub.3 together complete a condensed carbocyclic ring,
especially a condensed benzene or tetrahydro benzene ring,
X.sub.1 and X.sub.2 independently of the other, represent hydrogen,
alkyl with one to 12 carbon atoms, alkenyl with at most 12 carbon
atoms, alkoxyalkyl with two to eight carbon atoms,
alkoxycarbonylalkyl with three to nine carbon atoms, cycloalkyl
with five or six carbon atoms, acyl having one to 12 carbon atoms,
or optionally substituted phenyl, naphthyl or benzyl,
The nitrogen ring A represents a heterocyclic radical which
optionally includes a further hetero atom as ring member,
especially oxygen, sulphur or nitrogen, and the benzene ring B may
be substituted by nitro or one to four halogen atoms.
Halogen, in each occurrence in the definitions of the substituents,
preferably stands for fluorine, bromine or especially chlorine.
When R.sub.1, R.sub.2 and R.sub.3, as well as X.sub.1 and X.sub.2
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 dodecyl.
R.sub.1, R.sub.2 and R.sub.3 are preferably hydrogen, halogen or
alkyl having one to four carbon atoms such as methyl or ethyl.
Alkenyl in X.sub.1 and X.sub.2 stands e.g. for allyl, 2-methallyl,
2-ethylallyl, 2-butenyl or octenyl.
Alkoxyalkyl and Alkoxycarbonylalkyl in X.sub.1 and X.sub.2 may have
one to four carbon atoms in each alkyl part and stand preferably
for .beta.-methoxyethyl or .beta.-ethoxyethyl and
.beta.-methoxycarbonylethyl or .beta.-ethoxycarbonylethyl,
respectively.
Cycloalkyl in the meaning of these X-radicals may be cyclopentyl or
preferably cyclohexyl. The optional substituents in the benzyl,
phenyl or naphthyl group may be alkyl with one to four carbon
atoms, alkoxy with one to four carbon atoms, alkoxycarbonyl with
two to five carbon atoms, acyl having one to four carbon atoms,
nitro, halogen or an amino group optionally substituted by alkyl
with one to four carbon atoms or by benzyl. Examples of these
aromatic or araliphatic radicals are p-methylbenzyl,
p-chlorobenzyl, p-nitrobenzyl, p-tolyl, xylyl, p-chlorphenyl,
p-nitrophenyl, 1-methylnaphthyl-(2) or 2-methylnaphthyl-(1).
Among the acyl groups the alkanoyl groups containing one to 12
carbon atoms, such as formyl, acetyl or propionyl are especially
noteworthy. Further acyl substituents may be alkylsulphonyl having
one to 12 carbon atoms, such as methylsulphonyl, as well as benzoyl
or benzene-sulphonyl groups which may be substituted in benzene
ring by halogen, methyl or methoxy groups.
In the fluoran compounds falling under formula (1), the nitrogen
ring A denotes a heterocyclic radical which is attached to the
fluoran ring through the nitrogen atom. The heterocyclic radical
may have three to 12, preferably five or six ring members, wherein
one or two hetero atoms may be included as ring members. It is for
instance a pyrrolidinyl, piperidino, pipecolino, perhydroazepinyl,
heptamethyleneimino, octamethylenimino,
1,2,3,4-tetrahydroquinolinyl, indolinyl or hexahydrocarbazolyl
group, or in case the hetero ring includes a further hetero atom, a
morpholino, thiomorpholino, piperazino, N-alkyl piperazino with one
to four carbon atoms in the alkyl part, or a pyrazolinyl 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 four chlorine atoms.
Practically important groups of the compounds of formula (1) may be
defined by the following formula ##SPC3##
wherein
R.sub.4, r.sub.5 and R.sub.6 independently of the other, represent
hydrogen, halogen, methyl or ethyl,
X.sub.3 represents alkyl with one to eight carbon atoms,
alkoxyalkyl with two to eight carbon atoms, cycloalkyl with five or
six carbon atoms, acyl with one to seven carbon atoms, phenyl or
benzyl optionally substituted in the ring by methyl or halogen,
X.sub.4 represents hydrogen, alkyl with one to eight carbon atoms,
cycloalkyl with five or six carbon atoms, acyl with one to seven
carbon atoms or benzyl optionally substituted in the ring by methyl
or halogen, and
the nitrogen ring A and the benzene ring B have the given
meanings.
Particularly useful fluoran compounds of the formulae (1) and (2)
may be represented by the formula ##SPC4##
wherein R.sub.4, R.sub.5 and R.sub.6 have the meaning given under
formula (2),
X.sub.5 represents alkyl with one to eight carbon atoms, acyl with
one to seven carbon atoms, phenyl or benzyl,
X.sub.6 represents hydrogen, alkyl with one to eight carbon atoms,
acyl with one to seven carbon atoms or benzyl,
the nitrogen ring A.sub.1 represents a morpholino, piperazino or
especially a pyrrolidinyl or piperidino ring and the benzene ring
B.sub.1 may be further substituted by one to four halogen atoms,
especially chlorine atoms.
Of special interest are fluoran compounds falling under formulae
(1) to (3), which are listed under A, B and C, respectively.
A. compounds of the formula ##SPC5##
wherein
A.sub.1, b.sub.1, r.sub.4, r.sub.5 and R.sub.6 have the meaning
given under formula (3),
X.sub.7 and X.sub.8 independently of the other, represent alkyl
with one to eight carbon atoms or benzyl.
These fluoran compounds are distinguished as dark green colour
formers.
B. compounds of the formula ##SPC6##
wherein
A.sub.1, b.sub.1, r.sub.4, r.sub.5 and R.sub.6 have the meaning
given under formula (3) and
X.sub.9 represents alkyl with one to eight carbon atoms, benzyl or
phenyl.
These fluoran compounds are colour formers which give a grey or
black colour when contacted with an electron accepting
co-reactant.
C. compounds of the formula ##SPC7##
wherein
A.sub.1, b.sub.1, r.sub.4, r.sub.5, r.sub.6 and X.sub.9 have the
given meanings and
X.sub.10 represents acyl having one to seven carbon atoms, for
example, alkanoyl with one to four carbon atoms, such as formyl,
acetyl or propionyl, or benzoyl, methylsulphonyl or
p-tolylsulphonyl.
These fluoran compounds are scarlet-red colour formers.
The new fluoran compounds of the formulae (1) to (6) are obtained
by a method known in the art. The process of manufacturing the
fluoran compounds of formula (1) comprises reacting a benzophenone
compound of the formula ##SPC8##
with a compound of the formula ##SPC9##
wherein A, B, R.sub.1, R.sub.2, R.sub.3, X.sub.1 and X.sub.2 have
the given meanings and Z.sub.1 and Z.sub.2 represent hydrogen or
alkyl having one to four carbon atoms, such as methyl, ethyl or
butyl. Preferably, of Z.sub.1 and Z.sub.2 one is hydrogen, methyl
or ethyl and the other is hydrogen. Most preferably, Z.sub.1 is
hydrogen and Z.sub.2 is hydrogen or methyl.
The reaction is advantageously carried out at 10.degree. to
100.degree.C by allowing the reactants of formulae (7) and (8) to
react together in the presence of an acidic condensing agent.
Examples of suitable condensing agents are acetic anhydride,
sulphuric acid, zinc chloride or phosphorous oxychloride. This
reaction is preferably completed by the addition of a base. The
bases may be organic or inorganic and can include, for example,
alkali metal hydroxides, such as sodium hydroxide or potassium
hydroxide, as well as aliphatic amines, such as triethylamine or
trihydroxyethylamine.
The starting compounds of formula (7) are new and are generally
prepared by reacting a phthalic anhydride of the formula
##SPC10##
with a compound of the formula ##SPC11##
wherein Z.sub.1 represents hydrogen or alkyl having one to four
carbon atoms and A and B have the meaning described above. This
reaction is suitably carried out in an organic solvent, such as
acetone, benzene, toluene, xylene, or a chlorobenzene, 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 A NH, in which the cycle A has the meaning
described above, with resorcinol or a monoalkyl ether derivative
thereof at temperatures between 50.degree. and 250.degree.C and
optionally under pressure. This reaction may or may not be assisted
by the use of a condensing agent, 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
.alpha.,.omega.-dihalogenoalkanes in which the halogen is, for
example, bromine or chlorine but more usually bromine.
Compounds of formula (1), wherein X.sub.1 or X.sub.2 or both
represent acyl may be manufactured by reacting a compound of
formula (1), wherein at least one of X.sub.1 and X.sub.2 represents
hydrogen, with acylating agents having at most 12 carbon atoms,
e.g. reactive functional derivatives of aliphatic carboxylic or
sulphonic acids, particularly 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.
The acylation is generally carried out by known methods, e.g. in
the presence of acid binding agents such as alkali metal carbonates
or tertiary nitrogen bases such as pyridine and optionally in the
presence of inert organic solvents such as acetone, isopropanol,
chlorobenzene or nitrobenzene.
The new fluorans, 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 substance, that is
an electron-accepting substance. Typical coreactants are, for
example, attapulgus clay, silton clay, silica, bentonite,
halloysite, aluminium oxide, aluminium phosphate, kaolin or any
acidic clay, or an acid reacting polymeric material such as a
phenolic polymer, an alkylphenol acetylene polymer, a maleic
acid-rosin resin or a partially or wholly hydrolysed polymer of
maleic anhydride with styrene, ethylene, vinyl methylether or
carboxy polymethylenes.
The preferred 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 compounds of formula (5) behave as
grey or black colour formers. On the other side, the fluoran
compounds of the formula (6) behave as red or scarlet-red colour
formers.
By varying the structure of this new range of fluorans certain
properties may be "built-in," for example, the colour as described
in the previous paragraph, fade stability for compatibility with
other colour formers in mixtures, and any solubility
characteristics 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 the use in so-called pressure-sensitive recording material.
Such a material e.g. includes at least one pair of sheets, which
comprises at least a colour former of formula (1) dissolved in an
organic solvent, preferably contained in pressure rupturable
microcapsules and an electron accepting substance.
The colour former, 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 becoming active by being
separated from the electron accepting substance. 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 colourless colour formers of formula (1) are dissolved
in an organic solvent, they may be subjected to a
microencapsulation process and subsequently used for making
pressure-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 from the thus produced dyestuff which
absorbs in the visible region of the electromagnetic spectrum.
The general art of making microcapsules of some character has long
been known. Well known methods e.g. are disclosed in U.S. Pat. Nos.
2,183,053, 2,800,457, 2,800,458, 3,265,630, 2,964,331, 3,418,656,
3,418,250, 3,016,308, 3,424,827, 3,427,250, 3,405,071, 3,171,878,
and 2,797,201. Further methods are disclosed in British Patent
Specification No. 989,264 and above all British Patent
Specification No. 1,156,725. Any of these and other methods are
suitable for encapsulating the present colour formers.
Preferably the present colour formers are encapsulated dissolved in
organic solvents. Suitable solvents are preferably non-volatile
e.g. polyhalogenated diphenyl such as trichlorodiphenyl and its
mixture with liquid paraffin, tricresyl phosphate, di-n-butyl
phthalate, dioctyl phthalate, trichlorobenzene, nitrobenzene,
trichloroethyl-phosphate, petroleumether, hydrocarbon oils, such as
paraffin, condensated derivatives of diphenyl or triphenyl,
chlorinated or hydrogenated condensed aromatic hydrocarbons. The
capsule walls preferably have been obtained by coacervation forces
evenly around the droplets of the colour former solution, the
encapsulating material consisting of gelatine, as e.g. described in
U.S. Pat. No. 2,800,457.
Alternatively, the capsules preferably may be made of aminoplast or
modified aminoplasts by polycondensation as described in British
Patent Specification Nos. 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 front 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(1'-noctyl-2'-methylindol-3'-yl)-phthalide.
The microcapsules containing 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, the colour
reactants and the support material.
The microcapsules may be in an undercoating of the upper sheet and
the colour reactants, that is the electron acceptor and coupler,
may be in the overcoating of the lower sheets. However, the
components may also be used in the paper pulp. Such systems are
called "Chemical Transfer" system.
Another 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 pulp.
Such pressure-sensitive copying materials are described e.g. in
U.S. Pat. Nos. 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 Specification Nos. 1,042,597, 1,042,598, 1,042,596,
1,042,599, 1,053,935 and 1,517,650. Microcapsules containing the
colour formers of formula (1) are suitable for any of these and
other systems.
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,
methylcellulose or dextrin.
In the present application, the definition "paper" not only
includes normal papers from cellulose fibres, but also papers in
which the cellulose fibres are replaced (partially or completely)
by synthetic fibres of polymers.
The new fluoran compounds may also be used as colour former in
thermoreactive recording material comprising at least a support, a
binder, a colour former and an electron accepting substance.
Thermoreactive recording systems comprise heat-sensitive recording
and copying materials and papers. These systems are used e.g. for
the recording of information, for example, in electronic computers,
in teleprinters or telewriters, in measuring instruments. The
mark-forming also can be made manually with a heated pen. A further
means for inducing heat-initiated marks are laser beams. The
thermoreactive recording material may be arranged in such a manner
that the colour former is dissolved or dispersed in a layer of the
binder, and in a second layer the developer and the
electron-accepting substance are dissolved or dispersed in the
binder. Another possibility consists in dispersing both the colour
former and the developer in one layer. By means of heat the binder
is softened at specific areas imagewise and the dyestuff is formed
at these points, since only at the points where heat is applied
does the colour former come into contact with the
electron-accepting substance.
The developers are the same electron-accepting substances as are
used in pressure sensitive papers. For practical reasons the
developer should be solid at room temperature and melt or evaporate
above 50.degree. C. Examples of such products are the already
mentioned clays, phenolic resins, phenolic compounds such as
4-tert.-butylphenol, 4-phenylphenol, 4-hydroxydiphenyloxide,
.alpha.-naphthol, 4-hydroxybenzoic acid methyl ester,
.beta.-naphthol, 4-hydroxyacetophenone, 2,2'-dihydroxydiphenyl,
4,4'-isopropylidene-diphenol,
4,4'-isopropyliden-bis-(2-methylphenol), 4,4'-bis-(hydroxyphenyl)
valeric acid, hydroquinone, pyrogallol, phloroglucinol, p-, m-,
o-hydroxybenzoic acid, gallic acid, 1-hydroxy-2-naphthoic acid,
boric acid, and the aliphatic dicarboxylic acids e.g. tartaric
acid, oxalic acid, maleic acid, citraconic acid or succinic
acid.
Preferably fusible, film-forming binders are used. These binders
should be water-soluble, since the nitrophthalides 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 dyestuff.
Water-soluble or at least water swellable binders are e.g.
hydrophilic polymers such as polyvinyl alcohol, polyacrylic acid,
hydroxyethylcellulose, methylcellulose, carboxymethylcellulose,
polyacrylamide, polyvinylpyrrolidone gelatine or starch.
In so far as the colour former and the developer are coated in two
separate layers, binders which are water-insoluble may be used,
i.e. binders soluble in non-polar or only weakly polar solvents,
e.g. natural rubber, synthetic rubber, chlorinated rubber, alkyd
resins, polystyrene, styrene-butadienecopolymers,
polymethylmethacrylates, ethylcellulose, nitrocellulose or
polyvinylcarbazole.
The preferred arrangement, however, is colour 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 sticking of the heated pen, these
materials may contain e.g. talc, TiO.sub.2, ZnO or CaCO.sub.3. In
order to produce the dyestuff only within a limited temperature
range there may be added substances such as urea, thiourea,
acetanilide, phthalic acid anhydride or other corresponding
meltable products which induce the simultaneous melting of colour
former and developer.
Typical thermoreactive recording materials wherein the present
colour formers may be used e.g. are described in German Pat.
Application No. 2,228,581, French Pat. No. 1,524,826, Swiss Pat.
No. 407,185, German Pat. Application No. 2,110,854, Swiss Pat. Nos.
164,976, 444,196 and 444,197.
The following non-limitative examples illustrate the present
invention. Percentages are expressed by weight, unless otherwise
stated.
EXAMPLE 1
2-(N,N-dibenzylamino)-6-N-pyrrolidinylfluoran
A mixture of 77.75 g
2'-carboxy-2-hydroxy-4-N-pyrrolidinylbenzophenone, 75.6 g
N,N-dibenzyl-p-anisidine and 250 ml 98% sulphuric acid is stirred
at 60.degree. C for 5 hours and then quenched into 2,750 ml ice
water to precipitate a solid. The solid is filtered off, washed
with water and added to a mixture of 500 ml water, 250 ml methanol
and 26.8 g sodium hydroxide at 70.degree. C. The mixture is boiled
for 2 hours and then cooled to 85.degree. C. The solid product is
filtered off, washed with hot water then recrystallized from
methanol/acetone and dried to yield 86 g white plates m.p.
180.degree. C. .lambda. 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
at .lambda. 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'-hydroxyphenyl) pyrrolidine and 335 ml xylene is heated
at 125.degree. C for 6 hours, then cooled to 25.degree. C. The
precipitate is filtered off, washed with methanol and dried to
yield 110.5 g yellow solid having m.p. 194.degree. C after
crystallisation from ethanol.
EXAMPLE 2
2-Ethylamino-6-N-pyrrolidinylfluoran
A mixture of 9.33 g
2'-carboxy-2-hydroxy-4-N-pyrrolidinylbenzophenone, 4.54 g
N-ethyl-p-anisidine and 30 ml 98% sulphuric acid is stirred at
60.degree.C for 5 hours and then quenched into 330 ml ice-water to
precipitate a solid. The solid is filtered off, washed with water
and added to 75 ml methanol and 16.5 ml triethylamine. The mixture
is boiled with stirring for 12 hours, then cooled to 0.degree. C.
The precipitate is filtered off, washed with methanol and dried to
yield 8,32 g of 2-ethylamino-6-N-pyrrolidinylfluoran as a white
solid. .lambda. max. in 95% acetic acid 434, 457 and 602 nm.
A solution of this compound in benzene is colourless and gives a
black colour on contact with silica, greenish black on attapulgus
or silton clay and green on phenolic resin.
EXAMPLE 3
2-N-Acetyl-N-ethylamino-6-N-pyrrolidinyl fluoran
A mixture of 4.0 g 2-ethylamino-6-N-pyrrolidinyl fluoran, 12 ml
acetic anhydride and 0,4 ml pyridine is stirred at 120.degree. 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 ether. After drying and evaporating of the ether,
3,2 g of 2-N-acetyl-N-ethylamino-6-N-pyrrolidinyl fluoran are
obtained. .lambda. max. in 95 % acetic acid 374,496 and 528 nm.
This compound forms a red colour when brought in contact with
electron accepting substances such as silica.
EXAMPLE 4
2-(N,N-dibenzylamino)-6-N-pyrrolidinylfluoran
A mixture of 15,5 g
2'-carboxy-2-ethoxy-4-N-pyrrolidinylbenzophenone and 14,45 g
p-dibenzylamino-phenol is stirred in 50 ml 98% sulphuric acid at
60.degree.C for 5 hours, cooled to 25.degree.C and drowned into a
mixture of 100 ml water and 450 g ice. The pH of the quenched mass
is adjusted to 8.5 with 120 ml 35% to ammonia solution. The
precipitate is filtered off, washed with water and dried at
70.degree.C in vacuo to yield 19,7 g of
2-dibenzylamino-6-N-pyrrolidinylfluoran. The product is
recrystallized from a mixture of methanol and acetone to yield
colourless plates having a melting point of 180.degree.C. This
product is identical with the colour former obtained according to
Example 1.
The 2'-carboxy-2-ethoxy-4-N-pyrrolidinyl-benzophenone compound used
in this example as starting material may be produced as
follows:
To a mixture of 31.1 g
2'-carboxy-4-N-pyrrolidinyl-2-hydroxybenzophenone, 39.6 ml diethyl
sulphate and 240 ml acetone at 35.degree.C, 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.degree.-40.degree.C. A solution of 11.2 g potassium hydroxide in
50 ml water is then added and the reaction mixture is heated to
boiling and refluxed for 2 hours. The solvent is distilled off
until the temperature of the residual solution is 96.degree.C. The
residue is held at 96.degree.C for 30 minutes then cooled down to
0.degree.C by the addition of ice. Approximately 25 ml 28% HCl is
added to bring the pH between 3 - 4 when the product precipitates
as a white suspension. After filtering off and washing with water
32.0 g 2'-carboxy-4-N-pyrrolidinyl-2-ethoxybenzophenone, melting
point 184.degree.- 185.degree.C, is obtained.
EXAMPLE 5
2-Anilino-3-methyl-6-N-pyrrolidinyl fluoran
15 g 2'-carboxy-2-hydroxy-4-N-pyrrolidinylbenzophenone and 9,9 g
4-anilino-m-cresol are dissolved in 50 ml of 96.degree.C sulphuric
acid and stirred for 2 hours at 60.degree.C. The product is washed
up in a manner analogous to Example 2 and recrystallised from ethyl
acetate/hexane, m.p. > 260.degree.C. .lambda. 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 at .lambda. 453 and 575 nm.
By using procedures similar to those described in Examples 1 to 5
the fluoran compounds of the formula (11) listed in the following
Table have been manufactured. ##SPC12##
Ex. A.sub.2 X.sub.11 X.sub.12 m.p. .degree.C .lambda.maxima in nm
No. 95 % acetic acid Silton clay
__________________________________________________________________________
6 N--Pyrrolidinyl H n--C.sub.4 H.sub.9 202-203 435 459 599 446 582
7 do. H n--C.sub.8 H.sub.17 172-173 435 459 600 450 588 8 do. H
n--C.sub.10 H.sub.21 128-130 433 457 600 450 582 9 do. H 221-223
447 600 -- 10 do. CH.sub.3 CH.sub.3 247-248 439 467 605 460 580 11
do. C.sub.2 H.sub.5 C.sub.2 H.sub.5 210-211 444 472 633 474 636 12
do. n--C.sub.6 H.sub.13 n--C.sub.6 H.sub.13 65-66 444 474 640 472
642 13 do. --CH.sub.2 n--C.sub.8 H.sub.17 88-90 441 469 623 452 624
14 do. --CH.sub.2 n--C.sub.12 H.sub.25 oil 440 470 622 -- 15 do.
--CH.sub.2 112-115 440 460 605 452 602 16 do. --CH.sub.2 Cl
--CH.sub.2 Cl 128-130 435 463 608 -- 17 N--Pyrrolidinyl CH.sub.3
206-208 444 456 605 458 576 18 do. --CHO n--C.sub.4 H.sub.9 158-160
501 532 504 19 do. --CHO n--C.sub.8 H.sub.17 120-121 501 532 504 20
do. --COCH.sub.3 n--C.sub.4 H.sub.9 112-115 498 529 500 21 do.
--COCH.sub.3 n--C.sub.8 H.sub.17 77-79 498 529 500 22 do. --CO
n--C.sub.4 H.sub.9 177-178 501 535 500 23 do. --CO n--C.sub.8
H.sub.17 199-200 503 535 504 24 N--Piperidino H n--C.sub.8 H.sub.17
143-144 439 467 605 450 584
__________________________________________________________________________
APPLICATION EXAMPLES
EXAMPLE 25
Preparation of Pressure-sensitive Copying Paper
A solution containing 3 g of
2-dibenzylamino-6-N-pyrrolidinylfluoran in 100 g of hydrogenated
terphenyl is emulsified at 50.degree. C in 100 g of 12% pigskin
gelatin solution. 100 g of 12% gum arabic solution is added
followed by 200 ml of water at 50.degree. C. The emulsion is poured
into 600 g ice-water and stirred for 3 hours to complete the
coacervation. The resulting capsule slurry is coated onto paper and
dried. When the coated side is placed in 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 24.
EXAMPLE 26
Preparation of Pressure-sensitive Copying Paper
A solution containing 1.6 g of
2-dibenzylamino-6-N-pyrrolidinylfluoran, 0.6 g of
3,3-bis(1'-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 50.degree. C in 100 g of
12% pigskin gelatin solution. 100 g of 12% gum arabic solution is
added followed by 200 ml of water at 50.degree. C. The emulsion is
poured into 600 g ice-water and stirred for 3 hours to complete the
coacervation. The resulting 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.
EXAMPLE 27
Preparation of Thermoreactive Paper
6 g of an aqueous dispersion containing 1.6% of
2-dibenzylamino-6-N-pyrrolidinylfluoran, 0.8% of
3,3-bis(1'-n-octyl-2'-methylindol-3'-yl)phthalide, 0.1% of Crystale
violet lactone and 6.7% polyvinyl alcohol are mixted 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 contacted with a heated stylus a grey-black mark is
obtained which has excellent light fastness.
EXAMPLE 28
Preparation of Thermoreactive Paper
When the colour formers in Example 27 are replaced by
2-dibenzylamino-6-N-pyrrolidinylfluoran and
3,3-bis(1'-n-octyl-2'-methylindol-3'-yl)phthalide in the ratio 6:4
the resulting system gives an intense black image.
* * * * *