JPH0316954B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new process for the preparation of azaphthalide compounds which can find use as color image-forming in pressure- or heat-sensitive recording materials. In pressure-sensitive carbon-free copying systems, an oil-based dye precursor of a chromogenic material, such as crystalline violet lactone, benzoyl leucomethylene blue, phthalide or fluorene, is usually present in microcapsules that are destroyed by pressure. Since the solution is isolated and the capsules form mutually independent pairs of copy sheets, they can be present as layers on separate transfer sheets or can be self-reactive to sensitive aspects of the copy receiving sheet itself. Can be present to form paper sheets. In pressure-sensitive copying systems of the above type, crystal violet lactone [3,3-bis-(4'-dimethylaminophenyl)-6-dimethylaminophthalide] is usually used as the dye precursor for the chromogen. be done. Since prints made with crystalline lactones are known to discolor very quickly under the action of light, research is constantly being carried out to find suitable substitutes for said lactones. A good alternative product that produces satisfactory blue prints with improved lightfastness is azaphthalide with aminophenyl- and indolyl substituents in the 3-position. However, the preparation of this color image always results in an isomeric mixture of 4 and 7-azaphthalide. Even if this isomer mixture improves the lightfastness and at the same time reduces the reactivity (CB-Ab nahme)
Even though a reduction in chromogenic content is obtained, as a rule in the production of pressure-sensitive recording materials an undesirable discoloration of the microcapsules containing the chromogenic substance appears, which is caused by the presence of the 7-azaphthalide isomer in the isomer mixture. When the reaction of quinolinic anhydride with indole compounds is carried out in a special organic reaction medium and in the presence of metal salts of polyvalent metals for the production of keto acids free of the necessary isomers as intermediates. It has now been discovered that it is possible to obtain isomer-free 4-azaphthalide compounds. Therefore, the object of the invention is to provide the formula: (wherein Y is hydrogen, alkyl having at most 12 carbon atoms, unsubstituted or substituted by halogen, cyano, hydroxyl or lower alkoxy, acyl having 1 to 12 carbon atoms, benzyl or halogen, nitro, lower alkyl or benzyl substituted by lower alkoxy. Z is hydrogen, lower alkyl or phenyl. X is -OR ₁ or preferably

[Formula], R ₁ and R ₂ are each independently hydrogen, alkyl having at most 12 carbon atoms, cycloalkyl, phenyl, unsubstituted or substituted by halogen, cyano, hydroxyl or lower alkoxy; phenyl or benzyl substituted by benzyl or halogen, nitro, cyano, lower alkyl, lower alkoxy or lower alkoxycarbonyl, or R ₁ and R ₂ taken together with the nitrogen atom to which they are attached are 5- or 6-membered is a heterocyclic residue. V is hydrogen, halogen, hydroxy, nitro, lower alkyl or lower alkoxy. and Ring A is unsubstituted or substituted with halogen, nitro, cyano, lower alkyl, lower alkoxy, lower alkoxycarbonyl, amino, mono-lower alkylamino or di-lower alkylamino. ) in the method for producing a 4-azaphthalide compound. The method comprises converting quinolinic anhydride at a temperature of at most 65°C to the formula: (wherein A, Y, and Z are as defined above) in an organic reaction medium consisting of an indole compound and a lower aliphatic monocarboxylic acid in the presence of an inorganic or organic metal salt of a polyvalent metal. The reaction product obtained is further expressed by the formula: (wherein X and V are as defined above), and the PH value of the resulting reaction mixture is adjusted to at least 6. Lower alkyl and lower alkoxy in the definition of the radicals of the 4-azaphthalide compound typically have 1-5, especially 1-3 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-
A group or group component such as butyl, sek-butyl or amyl or methoxy, ethoxy, or isopropoxy. Acyl is especially formalyl, lower alkylcarbonyl, such as acetyl, or propionyl or benzoyl. Still other acyl residues are lower alkylsulfonyl, such as methylsulfonyl or ethylsulfonyl as well as phenylsulfonyl. Benzoyl and phenylsulfonyl can be substituted by halogen, methyl, methoxy or ethoxy. If substituents R ₁ , R ₂ and Y are alkyl groups,
They can be straight-chain or branched alkyl residues. Such alkyl residues are, for example,
Methyl, ethyl, n-propyl, isopropyl,
n-butyl, sek-butyl, amyl, n-hexyl, 2-ethyl-hexyl, n-peptyl, n-
Octyl, isooctyl, n-nonyl, isononyl, or n-dodecyl. When the alkyl residues in R ₁ , R ₂ and Y are substituted, preferably cyanoalkyl, halogenalkyl, hydroxyalkyl, alkoxyalkyl, each having a total of 2 to 4 carbon atoms, e.g. -cyanoethyl, β
Of importance are chloroethyl, β-hydroxyethyl, β-methoxyethyl or β-ethoxyethyl. Examples of cycloalkyl in the definition of R ₁ and R ₂ are cyclopentyl or preferably cyclohexyl. benzyl group of R ₁ , R ₂ and Y and R ₁ and
Suitable substituents in the phenyl group of R ₂ are, for example, halogen, nitro, methyl or methoxy. Examples of arylaliphatic or aromatic residues of this type are p-methylbenzyl, O
- or p-chlorobenzyl, O- or p-nitrobenzyl, O- or p-tolyl, xylyl, O, m, or p-chlorophenyl, O- or p-nitrophenyl or O- or p-methoxyphenyl . When the substituents R ₁ and R ₂ are heterocyclic residues taken together with a common nitrogen atom, these are e.g.
Pyrrolidino, piperidino, pipecorino, morpholino, thiomorpholino or piperazino, for example N-methylpiperazino. Suitable heterocyclic residues are pyrrolidino, piperidino or morpholino. X is preferably an amino group of the formula: -NR ₁ R ₃ . V is preferably present in the meta position relative to the substituent X. The substituents R ₁ and R ₂ can be different from each other or, preferably, the same. R ₁ and R ₂ are preferably benzyl or lower alkyl and especially methyl or ethyl. V is preferably hydrogen, methyl, methoxy or especially ethoxy. N-substituent Y is preferably benzyl, acetyl,
propionyl or especially alkyl having 1 to 8 carbon atoms, such as n-octyl, n-butyl,
Methyl or ethyl. A particularly preferred N-substituent Y is ethyl or n-octyl. Z is preferably phenyl or especially methyl. The benzole ring A is preferably further unsubstituted or substituted by halogen. Halogen is, for example, fluorine, bromine or preferably chlorine. In carrying out the invention, the substances participating in the reaction are preferably used in each case in molar amounts. The production of the azaphthalide compound of formula (1) is carried out continuously in two stages by the so-called Eintopfverfahren process. In the first step, quinolinic anhydride is reacted with an indole compound of formula (2) in an organic solvent as defined and in the presence of an organic or inorganic metal salt, preferably at a temperature between 0 and 50°C. is room temperature (17~30
C). The reaction time depends on the temperature, the metal salt used as catalyst and the solvent, and is usually between 1/2 and 10 hours, preferably between 2 and 6 hours. Among the lower aliphatic monocarboxylic acids used as reaction medium in the process according to the invention, carboxylic acids which are liquid under the reaction conditions and which can have 1 to 5 carbon atoms are important and preferred. Suitable aliphatic monocarboxylic acids forming the reaction medium are formic acid, acetic acid, dichloroacetic acid, propionic acid,
Butyric acid, valeric acid or a mixture of these acids. However, suitable solvents are aliphatic monocarboxylic acids having 2 to 4 carbon atoms, such as butyric acid, isobutyric acid, propionic acid or especially acetic acid or mixtures of these carboxylic acids. The metal salts used according to the invention advantageously have an atomic weight of 24 to 210, preferably 26 to 140 and especially 26 to
Derived from polyvalent metals with 120. For example, these metals include aluminum, barium, lead, cadmium, calcium, chromium, iron, gallium, cobalt, copper, magnesium, manganese, molybdenum, nickel, mercury, strontium, tantalum, titanium, vanadium, tungsten, zinc,
tin, and zirconium. Here, aluminum, calcium, cadmium, iron chromium,
Cobalt, copper, nickel, manganese, strontium, tin and zinc are preferred. The anionic component of these metal salts is conveniently derived from mineral or organic acids, such as sulphates, halides, nitrates, formates, acetates, propionates, citrates or stearates. As halides, fluorides, iodides, bromides or preferably chlorides as well as pseudohalides such as rhodanides come into consideration. Metal salts can be used alone or in mixtures. Preferred metal salts include aluminum, calcium,
Sulphates or halides of metals consisting of groups containing iron, cadmium, cobalt, copper, manganese, nickel, tin, and zinc, such as aluminum chloride, calcium chloride, nickel chloride, cobalt chloride, iron chloride, copper chloride, Zinc chloride, tin chloride, tin bromide, manganese chloride, nickel bromide, calcium fluoride, cadmium iodide, or a mixture thereof. Generally, the best results are obtained in the presence of aluminum, calcium, cobalt, iron, copper or zinc chlorides. Of particular importance are zinc chloride and aluminum chloride. Mixtures of calcium chloride and zinc chloride, preferably in a mixing ratio of 1:9 to 2:1, are likewise suitable. The proportion of metal salt in the first reaction stage is preferably from 10 to 100 mol %, based on the quinolinic anhydride used;
It is preferably 12 to 50 mol%. After completion of the first reaction step, the reaction product (unisolated keto acid) is directly condensed with the compound of formula (3). This second reaction step is preferably carried out by reacting the reactants in the presence of an acidic dehydrating agent at a temperature of 20°C to 80°C. Examples for condensing agents of this type are sulfuric acid, phosphoric acid, phosphorus oxychloride, especially acetic anhydride. Temperatures of 20°C to 60°C are preferred in the use of acetic anhydride. The reaction time of the second stage is usually 1~
4 hours, preferably 11/2 to 3 hours. The reaction mixture is finally adjusted to a pH value of at least 6. In contrast, alkalis such as alkali metal hydroxides, for example sodium or potassium hydroxide, ammonia or alkali metal carbonates or monocarbonates, as well as mixtures of these compounds, are suitable and advantageous. Preferably 7 to 11
Adjusted to PH value. The desired product of formula (1) is generally isolated by separation, washing and drying of the precipitate formed in a known manner or by treatment with a suitable organic solvent, such as methanol or isopropanol, and optionally by recrystallization of the product. It will be done. If OR ₁ and/or V in the reaction product of formula (1) is in each case hydroxyl, the hydroxyl group can be late alkylated or aralkylated in accordance with the definitions of R ₁ and V. . When V and/or OR ₁ are hydroxyl, the alkylation or aralkylation of the reaction product is usually carried out by known methods. As an example,
In the presence of an acid binder, for example an alkali carbonate or a tertiary nitrogen base such as triethylamine,
The reaction is optionally carried out in the presence of an inert organic solvent, such as acetone, isopropyl alcohol, chlorobenzole or nitrobenzole. Suitable alkylating agents are alkyl halides,
For example, methyl or ethyl iodide, or methyl or ethyl chloride, or dialkyl sulfates such as dimethyl or diethyl sulfate. Suitable aralkylating agents are in particular benzyl chloride and the corresponding substitution products, such as p-chlorobenzyl chloride or 2,4-
Dimethylbenzyl chloride, preferably used in a non-polar organic solvent such as benzol, triol or xylol, is suitable. A particularly advantageous embodiment of the new process is that saturated aliphatic
Quinolinic anhydride is dissolved or suspended in a C ₂ -C ₄ -monocarboxylic acid, especially acetic acid, reacted with an indole compound of formula (2) and the mixture has an atomic weight of 26 to 66
in the presence of inorganic metal salts of polyvalent metals, especially metal halides, such as zinc chloride, calcium chloride, aluminum chloride, iron chloride, cobalt chloride or copper chloride, at room temperature, preferably for 2 to 6 hours. be. Then, the compound of formula (3) is added and after the addition of acetic anhydride, the reaction mixture is heated to 30°C to 60°C.
It is preferably heated for 1 to 3 hours. Subsequently, a pH of 7.5 to 9 is adjusted, for example with alkali metal hydroxide or aqueous ammonia. 4 of the precipitated formula (1)
- The azaphthalide compound is separated and recrystallized if desired. Eintopfverfahren method of the invention
Preferred 4-azaphthalide compounds of formula (1) which are continuously produced by V
is hydrogen, methyl, hydroxyl, methoxy or especially ethoxy, and X is a group of the formula -NR ₁ R ₂ where R ₁ and R ₂ are methyl or ethyl,
or -NR ₁ R ₂ is pyrrolidino or piperidino. ). Y is preferably alkyl having 1 to 8 carbon atoms.
Z is especially methyl and ring A is preferably unsubstituted. Most suitable azaphthalide compounds of formula (1) include the group is 2-ethoxy-4-dimethylaminophenyl or 2-ethoxy-4-diethylaminophenyl, Y is ethyl or octyl, Z is methyl, and ring A is unsubstituted. The great advantage of the process of the invention is that it is easily industrially applicable and that pure products are obtained in very good yields without isolation of intermediately formed keto acids. . In particular, the expression A 4-azaphthalide compound is obtained which is completely free of the 7-azaphthalide isomer corresponding to . The 4-azaphthalide compounds of formula (1) prepared by the process of the invention are usually colorless or at most weakly colored. It is particularly suitable as a rapidly developing color image former for use in heat-sensitive or especially pressure-sensitive recording materials which can be copying and bookkeeping materials. When this color image former is brought into contact with a preferably acidic color developer, i.e. an electron acceptor, the color tone and strong green - blue, blue or violet - which is sublimation-resistant and light-fast, especially for phenolic bases, changes. Produces a blue tone. Until now, German Publication No. 2842263 (DE-OS)
4 known by No. 3116815 or DE-OS3116815
- and 7-azaphthalide isomer mixture (DE
- According to OS3116815, the amount of the interfering 7-azaphthalide compound has been reduced to 2%. ), the isomer-free 4-azaphthalide prepared by the process of the invention is distinguished by the advantage that it does not lead to any undesired premature discoloration (self-coloration) during the production or storage of the recording material. In the following examples, the percentages listed are by weight unless otherwise stated. Example 1 20.0 g of quinolinic anhydride, 80 ml of acetic acid, 20.3 g of N-ethyl-2-methylindole and zinc chloride
Stir 2.74g at 20°C for 5 hours. Then 3-
(N,N-diethylamino)-phenetol 23.6g
and 30 ml of acetic anhydride are added and the reaction mixture is further heated to 50°C to 60°C and stirred at this temperature for 2 hours. After adding 170 ml of 30% aqueous ammonia and 100 ml of water, the product precipitates in the form of a porridge, which is separated.
This porridge is converted with 160 ml of isopropanol and refluxed for 1 hour. After cooling, the recrystallized product is separated, washed with isopropanol and dried. formula: 46.9 g of isomer-free 4-azaphthalide compound with a melting point of 156 DEG to 158 DEG C. are obtained. Example 2 6.0 g of quinolinic anhydride, 9.5 g of N-octyl-2-methylindole and 0.56 g of zinc chloride are stirred with 30 ml of glacial acetic acid at 20 DEG C. for 5 hours. Then 3-
6.6 g diethylaminophenetol and 8 ml acetic anhydride were added and the mixture was heated at 50°C for a further 2 1/2 hours.
Stir with The product precipitates after addition of 30% aqueous ammonia. This is separated and recrystallized from isopropanol. formula: 16.5 g of isomer-free 4-azaphthalide compound having a melting point of 113 DEG to 118 DEG C. are obtained. Copper dichloride () 0.30g instead of zinc chloride 0.56g
Alternatively, using 0.53 g of aluminum trichloride and otherwise proceeding as described in the examples, 15.9 g or 16.8 g of the 4-azaphthalide compound of formula (12), melting point 113
Obtain ℃~116℃ or 115℃~119℃. Example 3 A mixture of 1.5 g of quinolinic anhydride, 2.3 g of N-octyl-2-methylindole, 10 ml of glacial acetic acid, and 0.11 g of calcium chloride and 0.14 g of zinc chloride was
Stir at 20 °C for an hour. Then 1.6 g of 3-diethylaminophenetol and 2 ml of acetic anhydride are added and the reaction mixture is stirred for 21/2 hours at 50 DEG C. The product precipitates after adding 30% aqueous ammonia. This is separated from the aqueous phase and recrystallized from isopropanol. 4- without isomers of formula (12)
3.8 g of azaphthalide compound, melting point 114 DEG -117 DEG C. are obtained. If 0.19 g of iron trichloride or 0.14 g of cobalt dichloride is used in place of the metal salt mixture described above, and otherwise the procedure is as described in the examples, 3.3 g or 3.8 g of the 4-azaphthalide compound of formula (12), melting point 113 °C to 117 °C or 113 °C to 116 °C are obtained. Example 4 Quinolinic anhydride 8g, zinc chloride 1.1g, acetic acid 40g
ml, 9.95 g of N-butyl-2-methylindole are stirred for 5 hours at 20°C to 23°C. Here 3-(N,
9.3 g of N-diethylamino)-phenetol and 7.5 ml of acetic anhydride are added. The reaction mixture is then stirred for 2 hours at 50-60°C. After the reaction is complete, the acetic acid solution is neutralized with 30% aqueous ammonia to precipitate the reaction product. After separation of the aqueous phase, the crude product is dissolved in acetic acid and precipitated again with 30% aqueous ammonia. Formula after recrystallization from ethanol: 16.8 g of isomer-free 4-azaphthalide compound having a melting point of 152 DEG to 1540 DEG C. are obtained. Example 5 A solution of 3 g of the 4-azaphthalide compound of formula (11) in 80 g of diisopropylnaphthalene and 17 g of kerosene is coacervationed with gelatin and gum arabic in a manner known per se.
microencapsulation. Thereafter, no discoloration or fading of the microcapsules occurs. The resulting microcapsules are mixed with a starch solution and applied to paper sheets. A layer of phenolic resin is formed on the front side of the second sheet as a color developer. The sheet of paper containing the first microcapsules and the paper laminated with the developer are superimposed on each other adjacent to the layer. Pressure-sensitive copying paper is also obtained that does not discolor or fade during storage. Pressure is applied by hand or typewriter writing to the first leaf, immediately resulting in a dark blue copy with excellent lightfastness on the laminated paper sheet with a developer. Furthermore, upon use of each of the other color image formers obtained in Preparation Examples 2, 3 and 4, corresponding non-fading pressure-sensitive copying papers and deep light-fast blue copies are obtained by writing. .

Claims (1)

[Claims] 1. Quinolinic anhydride at a temperature of 0-65°C with the formula: (wherein Y is hydrogen, alkyl having 1 to 12 carbon atoms, unsubstituted or substituted by halogen, cyano, hydroxyl or lower alkoxy, acyl having 1 to 12 carbon atoms, benzyl or halogen, nitro, Benzyl substituted with lower alkyl or lower alkoxy.
Z is hydrogen, lower alkyl or phenyl.
Ring A is unsubstituted or substituted by halogen, nitro, cyano, lower alkyl, lower alkoxy, lower alkoxycarbonyl, amino, mono-lower alkylamino or di-lower alkylamino. ) is converted in an organic reaction catalyst consisting of a lower aliphatic monocarboxylic acid in the presence of an organic or inorganic metal salt of a polyvalent metal, and the resulting conversion product is further converted to the formula: ( _wherein , X is _{-OR 1} or −12
alkyl, cycloalkyl, phenyl, benzyl, or phenyl or benzyl substituted by halogen, nitro, cyano, lower alkyl, lower alkoxy, or lower alkoxycarbonyl, or R ₁ and R ₂ are the nitrogens to which they are attached. It is a 5- or 6-membered heterocyclic residue combined with atoms. V is hydrogen, halogen, hydroxy,
nitro, lower alkyl or lower alkoxy) and adjusting the resulting reaction mixture to a pH value of at least 6: A method for producing a 4-azaphthalide compound (wherein Y, Z, X, V and A are as defined above). 2. A method according to claim 1, characterized in that _2X is an amino group of the formula _-NR1R2 . 3 R ₁ and R ₂ are each independently lower alkyl or benzyl, or R ₁ and R ₂ together with the nitrogen atom to which they are bonded are pyrrolidino,
The method according to claim 1 or 2, characterized in that it is piperidino or morpholino. 4. A method according to any one of claims 1 to 3, characterized in that V is hydrogen, methyl, methoxy or ethoxy. 5. Process according to any one of claims 1 to 4, characterized in that Y is alkyl having 1 to 8 carbon atoms, acetyl, propionyl, or benzyl. 6. The method according to any one of claims 1 to 5, characterized in that Z is methyl or phenyl. 7. The method according to any one of claims 1 to 6, wherein ring A is unsubstituted. 8. Claims 1-7, characterized in that the reaction of quinolinic anhydride with an indole compound of formula (2) is carried out at a temperature of 0-50°C, preferably at room temperature.
The method described in any of the paragraphs. 9. Claims 1-8, characterized in that aliphatic monocarboxylic acids having 2-4 carbon atoms and preferably acetic acid are used as organic reaction medium.
The method described in any of the paragraphs. 10 The metal salt has an atomic weight of 24-240, preferably 26-
10. Process according to any one of claims 1 to 9, characterized in that it is derived from a polyvalent metal having a valence of 140, in particular 26-120. 11 Metal salts such as metal aluminum, calcium, iron, cadmium, cobalt, copper, manganese,
11. Process according to any of claims 1 to 10, characterized in that nickel, tin or zinc is used. 12 The condensation of the reaction product obtained from quinolinic anhydride and the indole compound of formula (2) with the compound of formula (3) is carried out at a temperature of 20°C to 80°C in the presence of an acidic dehydrating agent. A method according to any one of claims 1-11. 13 Claim 1-12, characterized in that the PH value of the reaction mixture is finally adjusted to 7-11.
The method described in any of the paragraphs. 14 Quinolinic anhydride is dissolved or suspended in a saturated aliphatic _C2 - _C4 -monocarboxylic acid, reacted with an indole compound of formula (2), and the mixture is dissolved or suspended at room temperature in a polyhydric acid having an atomic weight of 26-66. Stir in the presence of an inorganic metal salt of a valent metal, to which the compound of formula (3) is added, and the reaction mixture is heated for 30−60 min after addition of acetic anhydride.
The method according to claim 1, characterized in that the pH value is adjusted to 7.5-9 by heating to .degree.