CH645112A5 - FUROPYRIDINONES AND SUBSTITUTED FUROPYRAZINONES AND THEIR USE IN THE FIELD OF IMAGE REPRODUCTION. - Google Patents

Description

This invention relates to furopyridinones and furo-pyrazinones useful as color formers in pressure-sensitive carbonless reproduction systems, pressure-sensitive reproduction products, and thermal labeling products containing them.

It is known that several categories of organic compounds with very diverse structural types are useful as color formers in reproduction systems without carbon paper. Among the best known categories are phenothiazines, for example, benzoylleucomethylene blue; fluoranes, for example 2'-anilino-6'-diethylaminofluorane; phthalides, for example crystalline violet lactone, and various other types of color formers commonly used in commercial carbonless reproduction systems. Typical examples of these many systems described in the prior art are those of the U.S. Patents. Nos 2712507,2800457 and 3041289. A large number of color formers of the prior art, however, have one or more drawbacks, such as low dye power, low light stability, low resistance to sublimation and low solubility in common organic solvents.

The U.S. Patent No. 3775424 and Belgian patent No. 412406 describe furopyridinones and furopyrazinones for pressure-sensitive recording materials, and Belgian patent 55 No. 862217 describes a series of phthalides usable as color formers in color systems. carbon-sensitive pressure-sensitive reproduction, thermal marking systems and hectographic reproduction systems.

The present invention relates to a series of 7- (and 5 -) (2-R3-4-60 NR4R5-phenyl) or (1-R6-2-R, -3-indolyl) -7- (and 5 -) [ (Y1-Y2-phenyl) - (Y3-Y4-phenyl) amino] furo- [3,4-b] -pyridine-5- (7H) - [and 7- (5H) -] ones, of 3- ( and l -) (2-R3-4-NR4Rs-phenyl) or (l-Rfi-2-R7-3-indolyl) -3- (and l -) [(Yi-Y2-phenyl) (Y3-Y4- phenyl) amino] furo- [3,4-c] -pyridme-l- (3H) - [and 3 (1H) -] ones and 7- (2-R3-4-NR4R5-phenyl) or (l- R6-2-R7-65 3-indolyl) -7 - [(Yt -Y2-phenyl) (Y3-Y4-phenyl) amino] furo- [3,4-b] -pyra-zine-5- (7H) -ones, which can be used as color-forming agents in carbon-free reproduction products sensitive to pressure and in thermal marking products. The ingredients

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they give colorful images with good to excellent tinctorial power; they have a high resistance to sublimation, improved solubility in common organic solvents, and have the particular advantage of having excellent light stability.

The compounds of the invention have the formula I:

4 (i)

-NOT

(at)

(b)

VX

(vs)

R7 is a hydrogen atom or a phenyl or non-tertiary lower alkyl group.

Preferably, A has the formula (a) or (d) and Z has the formula (f) above. The preferred compounds in this particular group of compounds are:

7- [4- (dimethylamino) phenyl] -7- (diphenylamino) furo- [3,4-b] -pyri-dine-5- (7H) -one;

5- [4- (dimethylamino) phenyl] -5- (diphenylamino) furo- [3,4-b] -pyri-dine-7- (5H) -one;

7- [4- (dimethylamino) phenyl] -7- [bis- (4-octylphenyl) amino] furo- [3,4] -pyridine-5- (7H) -one;

5- [4- (dimethylamino) phenyl] -5- [bis- (4-octylphenyl) amino] furo- [3,4-b] -pyridine-7- (5H) -one;

7- [4- (dimethylamino) -2-methylphenyl] -7- [bis- (4-octylphenyl) ami-no] furo- [3,4-b] -pyridine-5- (7H) -one;

5- [4- (dimethylamino) -2-methylphenyl] -5- [bis- (4-octylphenyl) ami-no] furo- [3,4-b] -pyridine-7- (5H) -one;

7- (1-ethyl-2-methyl-3-indolyl) -7- (diphenylamino) furo- [3,4-b] -pyridine-5- (7H) -one;

5- (1- (ethyl-2-methyl-3-indolyl) -5- (diphenylamino) furo- [3,4-b] -pyridine-7- (5H) -one;

7- (1-ethyl-2-methyl-3-indolyl) -7- [bis- (4-octylphenyl) amino] furo- [3,4-b] -pyridine-5- (7H) -one, and

5- (1-ethyl-2-methyl-3-indolyl) -5- [bis- (4-octylphenyl) amino] furo- [3,4-b] -pyridine-7- (5H) -one.

The compounds of formula I above can be prepared by a process which consists in reacting a pyridinecarboxylic acid of

30

(d) (e)

formulas in which

Yj, Y2, Y3 and Y4, identical or different, are hydrogen or halogen atoms, or lower alkoxy, alkyl having 1 to 9 carbon atoms, phenylalkyl lower or NRtR2. where Rt is a hydrogen atom or a lower alkyl group and R2 is a hydrogen atom or a lower alkyl, lower alkanoyl, phenylsulfonyl or (lower alkyl) phenylsulfonyl group;

Z is a monovalent radical of formula:

R.RCN-4 5

(he)

35 with a diarylamine of formula III:

T "" \

(III)

45

formulas in which

R3 is a hydrogen atom or a lower alkyl, lower alkoxy group, a halogen atom or a di (lower alkyl) amino group;

R4 is a lower alkyl group;

R5 is a lower alkyl or benzyl group;

R6 is a hydrogen atom or a non-tertiary alkyl group having from 1 to 18 carbon atoms, and

2 '"* 4

in the presence of an alkanoic acid anhydride having from 2 to 5 carbon atoms, A, Z, Yx, Y2, Y3 and Y4 in formulas II and III being as defined above.

The compounds of formula I can also be obtained by reacting a pyridinecarboxylic acid of formula II with thionyl chloride, phosphorus oxychloride, phosphorus trichloride or phosphorus pentachloride, then reacting the resulting product with a diarylamine of formula III in the presence of an organic base 50, the groups A, Z, Yj, Y2, Y3 and Y4 in formulas II and III being as defined above.

The invention also relates to a carbonless pressure sensitive duplicating product or a thermal marking product containing a color generating substance comprising a compound of formula I as described above. A particular embodiment is a pressure sensitive transfer sheet, designed for use with a receiving sheet having an electron accepting layer, comprising a backing sheet coated on one side with a layer of breakable microcapsules under pressure, said microcapsules containing a liquid solution of a color-generating substance comprising at least one compound of formula I. Another embodiment resides in a heat-reactive recording material, comprising a support sheet coated with a side of a layer containing a mixture containing at least one color generating compound of formula I and an acidic developer, so that application of heat will produce a marking reaction between the color generating compound and the acidic developer .

645,112

4

30

As used herein, the term halo refers to chlorine, fluorine, bromine or iodine. Chlorine is the preferred halogenated substituent because of its relatively low price and the ease of preparation of the necessary chlorine intermediates, and because the other halogens do not have any particular advantages over chlorine. However, the other halogens mentioned above are also satisfactory. The expressions lower alkyl, lower alkoxy and di (lower alkyl) amino designate saturated acyclic groups having from 1 to 4 carbon atoms, in straight or branched chain; by way of example, the methyl, ethyl, propyl, isopropyl, butyl, s-butyl, isobutyl, t-butyl, methoxy, ethoxy, propoxy, isopro-poxy, butoxy, s-butoxy, isobutoxy groups -butoxy, dimethylamino, diethylamino, ethylmethylamino, dipropylamino, dibutylamino, isobutylmethylamino, di-t-butylamino, etc.

The term lower alkanoyl denotes saturated acyclic acyl groups having from 1 to 5 carbon atoms, which may be straight or branched chain; for example, formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, 2-methylbutyryl, isovaleryl, pivalyl, etc. groups.

The term phenyl-lower alkyl includes benzyl, 2-phenylethyl, 2-phenylpropyl, 3-phenylpropyl, 1-phenylbutyl, 2,2-dimethyl-2-phenylethyl, etc. If desired, the phenyl group may have a lower alkyl or lower alkoxy substituent.

25

As used herein, the expression alkyl having from 1 to 9 carbon atoms denotes aliphatic straight or branched chain, monovalent and saturated hydrocarbon radicals, comprising methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t- butyl, amyl, 1-methylbutyl, 3-methylbutyl, hexyl, isohexyl, heptyl, isoheptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, 3-ethyl-heptyl, etc.

The term non-tertiary alkyl having from 1 to 18 carbon atoms includes, in addition to the above-mentioned alkyl groups having from 1 to 9 carbon atoms, obviously excluding any tertiary alkyl group, straight chain aliphatic hydrocarbon radicals or branched, monovalent and saturated, such as n-decyl, n-undecyl, n-tridecyl, n-dodecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, 1,3, 5-tri-methylhexyl, 1,5-dimethyl-4-ethylhexyl, 5-methyl-2-butylhexyl, 2-4Q propylnonyl, 2-butyloctyl, 2-pentylnonyl, 1,2-dimethyltetra-decyl, etc.

The anhydrides of C2-C5 alkanoic acids include acetic, propionic, butyric, isobutyric, valeric, isovaleric, a-methylbutyric, pivalic, etc. anhydrides. 45

Acetic anhydride is preferred because of its low price and high reactivity. However, the other aforementioned anhydrides are also satisfactory.

In common practice of the first process described above, approximately equimolar amounts of the pyridinecarboxylic acid of formula II and the diarylamine of formula III are reacted in the presence of an alkanoic acid anhydride having from 2 to 5 carbon atoms, such as acetic anhydride, with or without inert diluent, at a temperature of about 0 to 100 ° C, for about 10 min to 72 h. The reaction is generally carried out in the absence of an inert diluent, at about 20-50 ° C, for about 0.5 to 2 h. The product thus obtained can be separated by filtration if it is insoluble in the reaction medium, or by dilution of the reaction medium with a miscible solvent in which the product is insoluble, such as a lower alkanol or a hydrocarbon of molecular weight. o lower area, for example isopropyl alcohol or hexane, or a mixture of these, to effect the precipitation of the product. Alternatively, the reaction mixture can be poured into an aqueous base, such as ammonium hydroxide, sodium hydroxide, sodium carbonate or diluted sodium bicarbonate, and the product can be extracted with an organic solvent such as benzene or toluene, then the organic solvent is evaporated to obtain the product in the form of a residue. Once the product has been isolated, it can be purified by conventional means such as trituration or recrystallization from an appropriate solvent.

In the preceding reaction, the diarylamine of formula III serves as a basic catalyst. However, if desired, an additional organic base can be used such as pyridine, collidine, lower trialkylamines, urea, etc. Usually, pyridine and urea are preferred.

In current practice of the second process described above, a compound of formula I can be prepared in two stages which consist, firstly, in reacting a pyridinecarboxylic acid of formula II with an excess of a mineral acid chloride such as chloride thionyl, phosphorus oxychloride, phosphorus trichloride or phosphorus pentachloride, with or without an inert diluent such as benzene, toluene, chloroform, 1,2-dichloroethane or N, N-dimethylformamide, 20-80 ° C, for about 0.5 to 2 h, then reacting the resulting product which, although not having been isolated, is supposed to be a chloride of formula IV:

(IV)

in which A and Z are as defined above, with a diarylamine of formula III above, in an inert solvent, in the presence of an organic base such as pyridine, cholidine, a lower trialkylamine or urea, at a temperature from 0 to 80 ° C, for about 1 to 48 h. The product can be isolated and purified in a conventional manner.

The pyridinecarboxylic acids and pyrazinecarboxylic acids of formula II above which are required as starting materials in the preparation of the end products of formula I are generally known; see for example the description of the E.U.A. Nos 3936564 and 3775424, and Japanese patent publications Nos 73/8727, 73/3205 and 73/8729. The pyridinecarboxylic and pyrazinecarboxylic acids which are new can be prepared according to the procedures described for the preparation of the known compounds, that is to say by reaction of an anhydride of formula V:

(V)

with an appropriate aniline of formula VI or an indole of formula VII:

(VII)

NR4R5

in which A, R3, R4, Rs, R6 and R7 are as defined above, in the presence of a Lewis acid, for example aluminum or zinc chloride, and in the presence of a diluent such as benzene, chlorobenzene or o-dichlorobenzene, at a temperature of approximately 0 to 100 ° C. The reaction is conveniently carried out in benzene in the presence of aluminum chloride, at approximately 0.25 ° C. The more reactive indoles of formula VII can react with anhydrides of formula V in the absence of Lewis acid, by simple heating

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reagents together in an inert solvent at about 80-150 ° C.

It will obviously be seen that the reaction of asymmetric anhydrides of formula V, in which A is:

with an aniline of formula VI or an indole of formula VII can give isomers or a mixture of isomers of Z-CO-pyridinecarboxylic acids (formula II). For example, the reaction of 2,3-pyridinedicarboxylic anhydride (formula Va below) with an aniline or indole of formula VI or VII (ZH below) will produce either a 2- (Z-CO) acid - 3-pyridinecarboxylic of formula Ha, or i a 3- (Z-CO) -2-pyridinecarboxylic acid (formula IIb), or mixtures thereof. It will obviously be seen that the ratio of the isomers obtained will depend on the various reaction conditions such as the temperature, the solvent, the catalyst and the relative solubility of the isomers in the reaction medium. Usually, when carried out as described herein, the reaction gives a mixture of isomers, the 2- (Z-CO) -3-pyridinecarboxylic acid of formula Ha predominant in the isolated product. If desired, the mixture of isomeric Z-CO-pyridinecarboxylic acids can be separated by conventional means such as selective precipitation at different pHs, fractional crystallization or chromatography, and each can then be reacted isomers IIa and IIb separated with an appropriate diarylamine of formula III to obtain a furo- [3,4-b] -pyridine-5- (7H) -one of formula la and a furo- [3,4-b] - pyridine-7- (5H) -one of formula Ib, respectively. However, it is generally preferred simply to react the isolated mixture of Z-CO-pyridinecarboxylic acids isomers of formulas IIa and IIb with a diarylamine to obtain an isomeric mixture of furopyridinones of formulas la and Ib separate by conventional means, if desired. However, since the two isomers can be used as color-forming agents, it is economically advantageous to simply use the mixture in the practice of this invention.

„CC * QÇ

(Go) 0

jC0oH Y

0

(Ha) "(IIb)

Z

y) D-nh <1 * 3

2 4

It has been found, in general, that the reaction of 2,3-pyridinedicarboxylic anhydride with an indole of formula VII, as described here, gives a mixture of isomers of formulas IIa and IIb, where Z is:

in which the Ha isomer predominates in the isolated product by a factor greater than about 7. In addition, it has been observed that the most abundant isomer (ie IIa) is also the most reactive. Consequently, the subsequent reaction of the isomer mixture of IIa and IIb with a diarylamine of formula III will give almost exclusively the furo- [3,4-b] -pyridine-5- (7H) -one (formula la), the isomer Ib being observed only in traces.

The reaction of 2,3-pyridinedicarboxylic anhydride with an aniline of formula VI, according to the procedures described here, also gives a mixture of isomers of formulas IIa and IIb, Z being:

R, R_N '

4 5

and, although the Ha isomer again predominates in the isolated product, significant amounts of IIb isomers are also obtained. 55 Thus, although the Ha isomer is more reactive, a sufficient concentration of the less reactive isomer IIb is present in the mixture to give, after reaction with a diarylamine of formula III, a mixture of furo- [3,4- b] -pyridinones isomers of formulas la and Ib, in which the isomer predominates and the isomer Ib is present in a smaller but significant amount.

Similarly, the reaction of 3,4-pyridinedicarboxylic anhydride (formula Vb below) with an aniline of formula VI or an indole of formula VII (ZH below) gives a mixture of 3- (Z- CO) -4-pyridinecarboxylic acid (formula Ile) and 4- (Z-CO) -3-65 pyridinecarboxylic acid (formula Ild). Then the mixture is reacted with a diarylamine of formula III to obtain an isomeric mixture of furo- [3,4-c] -pyridine-1- (3H) -one (formula le) and furo- [3,4- c] -pyridine-3- (1H) -one (formula Id).

The diarylamines of formula III, which are also useful as starting materials in the methods of the invention, belong to a well-known category of compounds and are available commercially or readily obtained by procedures well known in the art.

The new compounds of formula I above are essentially colorless in the form described. When in contact with an acidic medium, for example silica gel or one of the products commonly used in carbon-free reproduction products sensitive to pressure, such as silty clay or phenolic resins, the compounds of formula I develop a colored image from yellow to black, having a good to excellent dye resistance and having a resistance to sublimation, a suitability for xerographic reproduction and a particularly good light stability. The compounds are therefore perfectly suitable for use as colorless precursors, that is to say as color-generating substances in carbon-free duplicators sensitive to pressure. Compounds which give a yellow to red color can be used as adjuvants (of toner type), in mixture with other color forming agents, to give images of a neutral shade which are preferably easily reproducible by xerographic means . The compounds of formula I in which one or more of the groups Y], Y2, Y3 and Y4 are alkyl groups of 1 to 9 carbon atoms have excellent solubility in common and inexpensive organic solvents, such as odorless mineral spirits , kerosene, vegetable oils, etc., which avoids the need for more expensive and specialized solvents such as polyhalogenated or alkylated biphenyls which were usually used to prepare the microencapsulated solutions of color forming agents of the prior art.

The compounds of this invention can be incorporated into any of the commercial products known in the field of carbon-free reproduction. A typical technique for such an application is as follows: one micro-encapsulates, according to well-known procedures, for example those described in the US patent. No. 3649649, solutions containing one or more colorless precursors of formula I, optionally in admixture with other color formers in suitable solvents. The microcapsules are coated on the back of a transfer sheet with

3

(id)

using a suitable binder, and the coated transfer sheet is then assembled in a bundle, the side coated with microcapsules being in contact with a receiving sheet coated with an electron-accepting substance, for example silty clay or a phenolic resin. Applying pressure to the package, such as that from a stylus, typewriter, or other form of writing or printing, causes the capsules to break on the back. The solution of color-forming agents released by the broken microcapsules flows onto the receiving sheet and comes into contact with the acid medium, forming a yellow to black image of good dye resistance and superior light stability. It is obvious that variants of this mode of application can be used. For example, the receiving sheet in a bundle may be coated with the subject compounds and the acidic developer may be contained in the microcapsules applied to the back of the top sheet of the bundle, or the receiving sheet may be coated with a mixture containing both the acidic revealing agent and the microencapsulated color-forming agent.

It has also been found that when the compounds of formula I are intimately mixed with an acid developer of the type generally used in thermal papers such as those described in the U.S. Patent. No. 3539375, i.e. papers which give a colored image when they are in contact with a heated stylus or a heated character, for example bisphenol A, heating the mixture gives a colored image having variable shades ranging from yellow to purple, depending on the particular compound of the invention that is used. The ability of the compounds of formula I to give a dark color when they are heated in admixture with an acid developer such as bisphenol A makes them usable in thermal paper marking products, whether an original or a double by bringing the thermal paper into contact with a heated stylus or a heated character according to one or other of the methods well known in the field.

The molecular structure of the compounds of this invention was determined by the mode of synthesis, elementary analysis and study of their infrared, nuclear magnetic resonance and mass spectra. The identity and relative abundance of isomers in mixtures of Z-CO-pyridinecarboxylic acids and furopyridinones were determined based on thin layer chromatography and nuclear magnetic resonance spectroscopy

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645,112

using the displacement reagent, tris (dipivalomethanato) -europium (III) [Eu (DPM) 3],

The following examples will illustrate the invention without, however, limiting it.

Example 1:

A. To a mixture containing 10 g of 2,3-pyridinedicarboxylic anhydride and 26 g of N, N-diethyl-m-phenetidine in 100 ml of benzene, 27 g of aluminum chloride are added. After 20 h of stirring at approximately 40 ° C., the reaction mixture is filtered and the solid obtained is added to 800 ml of ice and water. The resulting precipitate is collected, washed with water, then dissolved in 600 ml of 10% aqueous sodium hydroxide. After filtration to remove a small amount of insoluble substance, the basic aqueous solution is acidified with dilute hydrochloric acid, to pH 6. The resulting precipitate is collected, washed with water and dried, which gives 13.4 g of product. The filtrate is set aside for further processing, as described in part B below. The 13.4 g of solid substance are again dissolved in an aqueous base. The resulting solution is filtered and the filtrate is adjusted to pH 6 with dilute hydrochloric acid. The pale yellow solid which precipitates is collected, washed with water and dried. Then the dried material is diluted in a mixture of 100 ml of toluene and 10 ml of ethanol, and the pale yellow solid is collected and dried, which gives 2.6 g of 3- [4- (diethylamino) -2-ethoxybenzoyl] -2-pyri-dinecarboxylic, pf 264-270 ° C with decomposition.

B. The filtrate which has been set aside is acidified to pH 2. The resulting light yellow precipitate is collected, washed with water and dried to give 6.0 g of product. Recrystallization from a mixture of ethanol and toluene gives 4.0 g of 2- [4- (diethyl-amino) -2-ethoxybenzoyl] -3-pyridinecarboxylic acid, m.p. 209-210 ° C.

C. A mixture containing 1.7 g of 2- [4- (diethylamino) -2-ethoxybenzoyl] -3-pyridine-carboxylic acid, 1.0 g of diphenylamine, 0.5 is stirred for 20 h at room temperature. g of urea and 20 ml of acetic anhydride. Almost immediately after the reagents are combined, the mixture turns dark red, which indicates a rapid reaction. The reaction mixture is poured into 300 ml of toluene and 200 ml of 5% aqueous ammonium hydroxide. The toluene layer is separated, washed successively with water and a saturated aqueous solution of sodium chloride, then passed over a short column of silica gel. The desired product is eluted from the silica gel column with acetone. Evaporation of acetone in vacuo and crystallization of the residue in a mixture of 2-propanol and hexane gives 1.7 g of 7- [4- (diethylamino) -2-ethoxyphenyl] -7- (diphenyl- amino) furo- [3,4-b] -pyridine-5- (7H) -one as a light yellow-brown solid, mp 183.5-185 ° C. This product gives a red image on acid clay and on phenolic resin.

D. Following a procedure similar to that described in part C above, but using 2.5 g of 3- [4- (diethyl-amino) -2-ethoxybenzoyl] -2-pyridinecarboxylic acid, 1 , 5 g of diphenylamine, 0.5 g of urea and 30 ml of acetic anhydride and leaving the reaction mixture under stirring at room temperature for 2 d (the absence of color change in the reaction medium after 5 h indicating a slow reaction), 0.2 g of 5- [4- (diethylamino) -2-ethoxyphenyl] -5- (diphenylamino) furo- [3,4-b] -pyridine-7- is obtained (5H ) -one in the form of a brown gummy substance. This product gives a red image on acid clay and on phenolic resin.

Example 2:

By following a procedure similar to that described in Example 1C above, but using 1.7 g of 2- [4- (diethyl-amino) -2-ethoxybenzoyl] -3-pyridinecarboxylic acid, 1, 1 g of 3-chloro-N-phenylaniline, 0.5 g of urea and 20 ml of acetic anhydride, 1.0 g of 7 - [(3-chlorophenyl) phenylamino] -7- [4- ( diethylamino) -2-ethoxyphenyl] furo- [3,4-b] -pyridine-5- (7H) -one as a light yellow-brown solid, mp DO-lSl ^ C. This product gives a red image on acid clay and on phenolic resin.

Example 3:

A mixture containing 2.0 g of a mixture of isomers containing 3- [4- (diethylamino) -2-methylbenzoyl] -2-pyridinecarboxylic acid and 2- [ 4- (diethylami-no) -2-methylbenzoyl] -3-pyridinecarboxylic, 0.81 g of 4.4'-bis- (dimethylamino) diphenylamine, 6 ml of acetic anhydride and 0.5 ml of pyridine, then poured in 200 ml of 5% aqueous ammonium hydroxide and 100 ml of toluene. The toluene layer is separated, washed with water and with a saturated aqueous solution of sodium chloride, and evaporated to dryness in vacuo. The residue is diluted in a minimum quantity of acetone and 0.5 g of a mixture of isomers containing 7- [4-diethylamino) -2-methyl-phenyl] -7- {bis- [ 4- (dimethylamino) phenyl] amino} furo- [3,4-b] -pyridine-5- (7H) -one and 5- [4- (diethylamino) -2-methylphenyl] -5- {bis- [ 4- (dimethylamino) phenyl] amino} furo- [3,4-b] -pyridine-7- (5H) -one, in the form of a light green solid, mp 184-186 'C. A chloroform solution of the product in contact with an acid clay or with a phenolic resin gives a black image.

Example 4:

A. A mixture containing 3.2 g of a mixture of isomers containing 2- [4- (diethyl-amino) -2-methylbenzoyl] -3-pyridinecarboxylic acid and the mixture is stirred for 45 min at room temperature. 3- [4- (diethylamino) -2-methylbenzoyl] -2-pyridinecarboxylic acid, 2.05 g of 4,4'-dioctyldiphenylamine, 6 ml of acetic anhydride and 1.1 ml of pyridine. After diluting the reaction mixture with 6 ml of 2-pro-panol and 3 ml of hexane, the product is collected, washed with 2-propanol and dried, giving 1.5 g of a mixture isomer containing 7- [4- (diethylamino) -2-methylphenyl] -7- [bis- (4-octyl-phenyl) amino] furo- [3,4-b] -pyridine-5- (7H) -one and 5- [4- (diethyl-amino) -2-methylphenyl] -5- [bis- (4-octylphenyl) amino] furo- [3,4-b] -pyridine-7- (5H) -one, as a solid light purple,

m.p. 194-195 ° C with decomposition.

The filtrate is poured into 5% aqueous ammonium hydroxide and the product is extracted with toluene. The organic extracts are washed with water and with a saturated aqueous solution of sodium chloride, then they are evaporated to dryness under vacuum. Crystallization of the residue in 2-propanol gives 1.0 g of additional product in the form of a white solid. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a reddish purple image.

B. To a mixture containing 1.4 g of isomers consisting of 2- [4- (diethylamino) -2-methylbenzoyl] -3-pyridinecarboxylic acid and 3- [4- (diethylamino) -2-methylbenzoyl] -2- acid pyridinecarboxylic, 1.0 ml of thionyl chloride and 60 ml of N, N-dimethylformamide, a solution containing 1.84 g of 4,4'-dioctyldiphenylamine and 0.5 ml of pyridine in 40 ml of N is added , N-dimethylformamide at room temperature. After 1 h of stirring, the reaction mixture is poured into 5% aqueous ammonium hydroxide. The precipitate is collected, washed with water and air dried. Then the solid is diluted in a mixture of 30 ml of hexane and

10 ml of 2-propanol and filtered, which gives 1.03 g of a product essentially identical to the product of part A above.

C. A mixture containing 3.13 g of a mixture of 2- [4- (diethyl-amino) -2-methylbenzoyl-3-pyridinecarboxylic acid and acid isomers is stirred for 2 h at room temperature. 3- [4- (diethylamino) -2-methylbenzoyl] -2-pyridinecarboxylic, 3.94 g of 4,4'-dioctyldiphenylamine, 6 ml of acetic anhydride, 6 ml of acetic acid and 0.75 g of urea, then poured onto 5% aqueous ammonium hydroxide and extracted with toluene. The organic extract is washed with water and with a saturated aqueous solution of sodium chloride, then evaporated to dryness. The residue was analyzed by thin layer chromatography and infrared spectroscopy, and was found to contain the desired product, identical to the product in part A above.

D. The reaction of part C above is carried out, in the absence of urea. The reaction mixture is poured into am5 hydroxide

10

15

20

25

30

35

40

45

50

55

60

65

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5% aqueous monium and extracted with toluene. The toluene extract is washed with water and with a saturated aqueous solution of sodium chloride, then evaporated to dryness. The residue was analyzed by thin layer chromatography and infrared spectroscopy, and was found to contain the desired product, identical to the product in part A above.

Example 5:

Following a procedure similar to that described in Example 4A, but using 1.6 g of a mixture of isomers comprising 2- [4- (diethylamino) -2-methylbenzoyl] -3-pyridine acid -carboxylic and 3- [4- (diethylamino) -2-methylbenzoyl] -2-pyri-dinecarboxylic acid, 0.6 g of 4-isopropoxy-N-phenylaniline, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.7 g of a mixture of isomers containing 7- [4- (diethylamino) -2-methylphenyl] -7- [4-isopropoxyphenyl) phenylamino] furo- [3,4-b] is obtained -pyridine-5- (7H) -one and 5- [4- (diethylamino) -2-methylphenyl] -5 - [(4-isopropoxyphenyl) -phenylamino] furo- [3,4-b] -pyridine-7 - (5H) -one in the form of a white solid, pf 180-181 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a reddish purple image.

Example 6:

Following a procedure similar to that described in Example 4A, but using 1.55 g of a mixture of isomers containing 2- [4- (diethylamino) benzoyl] -3-pyridinecarboxylic acid and 3- [4- (diethylamino) benzoyl] -2-pyridinecarboxylic acid, 1.2 g of 4-isopropoxy-N-phenylaniline, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.7 is obtained g of a mixture of isomers containing the 7- [4- (diethylamino) phenyl] -7 - [(4-isopropoxyphenylamino] furo- [3,4-b] -pyridine-5- (7H) -one and the 5- [4- (diethylamino) phenyl] 5 - [(4-isopropoxyphenyl) phenylamino] furo- [3,4-b] -pyridine-7- (5H) -one, in the form of a white solid, mp 173-175 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 7:

Following a procedure similar to that described in Example 3, but using 1.55 g of a mixture of isomers containing 2- [4- (diethylamino) benzoyl] -3-pyridinecarboxylic acid and the 3- [4- (diethylamino) benzoyl] -2-pyridinecarboxylic acid, 1.33 g of 4,4'-bis (dimethylamino) diphenylamine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0 is obtained, 83 g of a mixture of isomers containing 7- [4- (diethylamino) phenyl] -7- {bis- [4- (dimethylamino) -phenyl] -amino} furo- [3,4-b] -pyridine -5- (7H) -one and 5- [4- (diethyl-amino) phenyl] -5- {bis- [4- (dimethylamino) phenyl] amino} -furo- [3,4-b] -7 - (5H) -one in the form of a light brown-gray solid, pf 187 ° C with decomposition. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a dark brown image.

Example 8:

A mixture containing 0.2 g of a mixture of isomers containing 2- [4- (diethylamino) -benzoyl] -3-pyridinecarboxylic acid and 3- [4- (diethylamino) -benzoyl] -2-pyridinecarboxylic, 0.15 g of diphenylamine and 5 ml of acetic anhydride. The reaction mixture is poured into 100 ml of toluene and 100 ml of 5% aqueous ammonium hydroxide. The toluene layer is separated, washed successively with water and with a saturated aqueous solution of sodium chloride, then evaporated to dryness under vacuum. Crystallization of the residue in hexane gives 0.1 g of a mixture of isomers containing 7- [4- (diethyl-amino) phenyl] -7- (diphenylamino) furo- [3,4-b] - pyridine-5- (7H) -one and 5- [4- (diethylamino) phenyl] -5- (diphenylamino) furo- [3,4-b] -pyri-dine-7- (5H) -one under form of a yellow-brown solid, pf 168-169 ° C. This product gives a dark orange image on acid clay and on phenolic resin.

Example 9:

A mixture containing 2.7 g of a mixture of isomers containing 2- [4- (dimethylamino) benzoyl] -3-pyri-dinecarboxylic acid and 3- [4- ( dimethylamino) benzoyl] -2-pyridine-carboxylic acid, and 25 ml of acetic anhydride. After forming a solution, 1.7 g of diphenylamine are added. The mixture is stirred 2'A h at 25 ° C and 1% V h at 50 ° C, then cooled to 5 ° C. The resulting solid is filtered and washed with isopropanol to give 1.3 g of a mixture of isomers comprising 7- [4- (dimethylamino) -phenyl] -7- (diphenylamino) furo- [3,4-b] -pyridine-5- (7H) -one and 5- [4- (dimethylamino) phenyl] -5- (diphenylamino) furo- [3,4-b] -pyridine-7- ( 5H) -one in the form of a very light orange solid, pf 175-179 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 10:

By following a procedure similar to that described in Example 9, but using 2.7 g of a mixture of isomers comprising 2- [4- (dimethylamino) benzol] -3-pyridinecarboxylic acid and the 3- [4- (dimethylamino) benzoyl] -2-pyridinecarboxylic acid, 4.0 g of 4,4'-dioctyldiphenylamine and 25 ml of acetic anhydride, 2.7 g of a mixture of isomers comprising 7- [4- (dimethyl-amino) phenyl] -7- [bis- (4-octylphenyl) amino] furo- [3,4-b] -pyridine-5- (7H) -one and 5- [4 - (dimethylamino) phenyl] -5- [bis- (4-octylphenyl) -amino] furo- [3,4-b] -pyridine-7- (5H) -one in the form of a light peach solid, mp 203-208 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 11:

Following a procedure similar to that described in Example 3, but using 1.6 g of a mixture of isomers containing 3- [4- (diethylamino) -2-methylbenzoyl] -4-pyridinecarb acid -oxylic and 4- [4- (diethylammo) -2-methylbenzoyl] -3-pyridine-carboxylic acid, 1.3 g of 4,4'-bis (dimethylamino) diphenylamine and 6 ml of acetic anhydride, obtains 1.5 g of 3- [4- (diethylamino) -2-methylphenyl] -3 - {(bis- [4- (dimethylammo) phenyl] amino} furo- [3,4-c] -pyridine-l- (3H) -one and 1- [4- (dimethylamino) -2-methylphenyl] -1- {bis- [4- (dimethylamino) phenyl] amino} furo- [3,4-c] -pyridine-3- ( 1H) -one in the form of a semi-solid A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a black image.

Example 12:

Following a procedure similar to that described in Example 3, but using 1.6 g of a mixture of isomers containing nat-3- [4- (diethylamino) -2-methylbenzoyl] -4 acid -pyridinecarb-oxylic and 4- [4- (diethylammo) -2-methylbenzoyl] -3-pyridine-carboxylic acid, 0.9 g of diphenylamine and 6 ml of acetic anhydride, a mixture of isomers is obtained containing 3- [4- (diethylamino) -2-methylphenyl] -3- (diphenylamino) -furo- [3,4-c] -pyridine-1- (3H) -one and l- [4- (diethylamino) -2-methylphenyl] -1- (diphenylamino) -furo- [3,4-c] -pyridine-3- (1H) -one. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a grape red image.

Example 13:

Following a procedure similar to that described in Example 3, but using 1.55 g of a mixture of isomers containing 3- [4- (diethylamino) -benzoyl] -4-pyridinecarboxylic acid and l '4- [4- (diethylamino) benzoyl] -3-pyridinecarboxylic acid, 1.3 g of 4,4'-bis (dimethylamino) diphenylamine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 1 , 5 g of a mixture of isomers comprising 3- [4- (diethylamino) phenyl] -3- {bis- [4- (dimethyl-amino) phenyl] ammo} furo- [3,4-c] - pyridine-1- (3H) -one and 1- [4- (di-methylamino) phenyl] -1- {bis- [4- (dimethylamino) phenyl] amino} furo- [3,4-c] -pyridine -3- (1H) -one in the form of a viscous oil. A

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65

toluene solution of the product in contact with an acid clay or with a phenolic resin gives a brown image.

Example 14:

Following a procedure similar to that described in Example 3, but using 1.55 g of a mixture of isomers comprising 3- [4- (diethylamino) benzoyl] -4-pyridinecarboxylic acid and 4- [4- (diethylamino) benzoyl] -3-pyridinecarboxylic acid, 1.2 g of 4-acetamido-N-phenylaniline, 0.5 ml of pyridine and 6 ml of acetic anhydride, 1.5 g of d 'a mixture of isomers comprising 3- [4- (diethylamino) phenyl] -3 - [(4-acetamidophenyl) phenyl-amino] furo- [3,4-c] -pyridine-1- (3H) -one and 1- [4- (diethylamino) -phenyl] -1- [(4-acetamidophenyl) phenylamino] furo- [3,4-c] -pyridine-3- (1H) -one as a solid red-brown, pf 102-116 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange-red image.

Example 15:

3.0 g of a mixture of isomers containing 3- [4- (diethylamino) benzoyl] -4-pyridinecarboxylic acid and 4- [4- (diethylamino) benzoyl] acid are heated to 40 ° C. 3-pyridinecarboxylic acid in 30 ml of acetic anhydride. After forming a solution, 4.0 g of 4,4'-dioctyldiphenylamine are added, the mixture is stirred for 7 h, then left to stand for 40 h. The resulting solution is poured into 100 ml of ice water containing 76 ml of concentrated ammonium hydroxide. The product is extracted into 75 ml of toluene which is separated, which is dried over anhydrous calcium chloride and which is evaporated to obtain an oil. Crystallization from hexane gives 2.8 g of a mixture of isomers containing 3- [4- (diethyl-amino) pheny] -3- [bis- (4-octylphenyl) amino] furo- [3, 4-c] -pyridine-l- (3H) -one and l- [4- (diethylamino) phenyl] -l- [bis- (4-octylphenyl) -amino] furo- [3,4-c] - pyridine-3- (1H) -one as a yellow-brown solid, mp 114-117 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 16:

Following a procedure similar to that described in Example 3, but using 3.0 g of a mixture of isomers containing 3- [4- (diethylamino) benzoyl] -4-pyridinecarboxylic acid and 4- [4- (diethylamino) benzoyl] -3-pyridinecarboxylic acid, 1.7 g of diphenylamine and 30 ml of acetic anhydride, 1.4 g of a mixture of isomers containing 3- [4- (diethylamino) phenyl] -3- (diphenylamino) furo- [3,4-c] -pyridine-l- (3H) -one and l- [4- (diethyl-amino) phenyl] -1 - (diphenylamino) furo- [3,4-c] -pyridine-3- (1 H) -one in the form of a light orange solid, mp 135-14TC. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 17:

2.6 g of a mixture of isomers containing 3- [4- (diethylamino) -2-methylbenzoyl] -4-pyridinecarboxylic acid and 4- [4- (diethylamino) acid are heated to 40 ° C. -2-methylbenzoyl] -3-pyridine-carboxylic acid in 30 ml of acetic anhydride, then 4.0 g of 4,4'-dioctyldiphenylamine are added. The mixture is stirred for 3 h at room temperature, then it is poured into 100 ml of ice water and 76 ml of concentrated ammonium hydroxide, and 5.7 g of a mixture of isomers are obtained. containing 3- [4- (diethylamino) -2-methyl-phenyl] -3- [bis- (4-octylphenyl) amino] furo- [3,4-c] -pyridine-1- (3H) -one and 1 - [4- (diethylamino) -2-methylphenyl] -1 - [bis- (4-octylphenyl) -amino] furo- [3,4-c] -pyridine-3- (1H) -one in the form of a solid red, pf 58-105 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a purple image.

Example 18:

Following a procedure similar to that described in Example 3, but using 1.63 g of 3- [4- (diethylamino) -2- acid

645,112

methylbenzoyl] -2-pyrazinecarboxylic, 1.3 g of 4,4'-bis (dimethyl-amino) diphenylamine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.9 g of 7- [4] is obtained - (diethylamino) -2-methylphenyl] -7- {bis- [4- (dimethylamino) phenyl] amino} furo- [3,4-c] -pyrazine-5- (7H) -one in the form of a solid light orange, pf 193.5-195 ° C with decomposition. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a black image.

Example 19:

By following a procedure similar to that described in Example 3, but using 1.6 g of 3- [4- (diethylamino) -2-methylbenzoyl] -2-pyrazinecarboxylic acid, 0.9 g of diphenylamine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.1 g of 7- [4- (diethylamino) -2-methylphenyl] -7- (diphenylamino) -furo- [3,4-c] is obtained -pyrazine-5- (7H) -one, pf 189.5-191 ° C with decomposition. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a grape red image.

Example 20:

Following a procedure similar to that described in Example 3, but using 0.43 g of 3- [4- (diethylamino) -benzoyl] -2-pyrazinecarboxylic acid, 0.34 g of 4.4 ′ -bis (dimethylamino) -diphenylamine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.59 g of 7- [4- (diethylamino) phenyl] -7- {bis- [4- (dimethyl are obtained) -amino) phenyl] amino} furo- [3,4-b] -pyrazine-5- (7H) -one, pf 61-74 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a brown-red image.

Example 21:

Following a procedure similar to that described in Example 3, but using 0.5 g of 3- [4- (diethylamino) -benzoyl] -2-pyrazinecarboxylic acid, 0.38 g of 4-isopropoxy- N-phenyl-aniline, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.6 g of 7- [4- (diethylamino) phenyl] -7 - [- (4-isopropoxyphenyl) phenyl-amino] is obtained furo- [3,4-b] -pyrazine-5- (7H) -one, pf 75-82 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange-brown image.

Example 22:

Stirred and moderately heated in a hot water bath, for 1 h, a mixture containing 0.7 g of 3- [4- (dimethyl-amino) benzoyl] -2-pyrazinecarboxylic acid, 1.0 g of 4 , 4'-dioctyl-diphenylamine and 7 ml of acetic anhydride. The product, 7- [4- (dimethylamino) phenyl] -7- [bis- (4-octylphenyl) amino] furo- [3,4-b] -pyrazine-5- (7H) -one, is isolated by Column chromatography, in the form of a solid rust, mp 158-168 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a reddish brown image.

Example 23:

A mixture of 0.1 g of 3- [4- (diethylamino) benzoyl] -2-pyrazinecarboxylic acid, 0.1 g of diphenylamine and 2 ml of acetic anhydride is heated for several hours. stand for 3 d. The product, 7- [4- (diethylamino) -phenyl] -7- (diphenylamino) furo- [3,4-b] -pyrazine-5- (7H) -one, is isolated by column chromatography under the shape of a light orange solid, pf 140-142.6 ° C. A toluene solution of this product in contact with an acid clay or with a phenolic resin gives a red image.

Example 24:

It is gently heated for 5 h, then left to stand overnight a mixture containing 0.15 g of 3- [4- (diethyl-amino) benzoyl] -2-pyrazinecarboxylic acid, 0.18 g of 4.4 ' -dioctyl-diphenylamine and 3 ml of acetic anhydride. The product, 7- [4- (diethylamino) phenyl] -7- [bis- (4-octylphenyl) amino] furo- [3,4-b] -pyrazine-5- (7H) -one, is isolated by Column chromatography then crystallization from hexane, and a solid peach is obtained, mp 180-181 ° C.

9

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65

645112

10

A toluene solution of this product in contact with an acid clay or with a phenolic resin gives a red image.

Example 25:

A mixture containing 3.1 g of 3- [4- (diethylamino) -2-methylbenzoyl] -2-pyrazine-carboxylic acid, 3.1 g of 4.4 is stirred in a hot water bath for 3 h. '-dioctyldiphenylamine and 25 ml of acetic anhydride. The reaction mixture is poured into water and the resulting solid is collected which is recrystallized from hexane, which gives la7- [4- (diethylamino) -2-methylphenyl] -7- [bis- (4 -octylphenyl) -amino] furo- [3,4-b] -pyrazine-5- (7H) -one as a light yellow-brown solid, mp 180-187 ° C. A toluene solution of this product in contact with an acid clay or with a phenolic resin gives a purple image.

Example 26:

Following a procedure similar to that described in Example 3, but using 4.5 g of a mixture of isomers containing 2 - [(1-ethyl-2-methyl-3-indolyl) carbonyl acid ] -3-pyridine-carboxylic acid and 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyridinecarboxylic acid, 3.6 g of 4-ethoxy-N-phenylaniline, 1 ml of pyridine and 8 ml of acetic anhydride, 5.5 g of 7- (1-ethyl-2-methyl-3-indolyl) -7 - [- (4-ethoxyphenyl) phenylamino] furo- [3,4-b are obtained ] -pyridine-5- (7H) -one as a yellow-brown solid, mp 122-129 ° C with decomposition. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 27:

Following a procedure similar to that described in Example 3, but using 1.6 g of a mixture of isomers containing 2 - [(1-ethyl-2-methyl-3-indolyl) carbonyl acid ] -3-pyridine-carboxylic acid and 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyridinecarboxylic acid, 2.0 g of 4,4'-dioctyldiphenylamine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.9 g of 7- (1-ethyl-2-methyl-3-indolyl) -7- [bis- (4-octylphenyl) amino] furo- [3, 4-b] -pyri-dine-5- (7H) -one as a light yellow-brown solid, mp 187 ° C with decomposition. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 28:

Following a procedure similar to that described in Example 3, but using 1.6 g of a mixture of isomers containing 2 - [(1-ethyl-2-methyl-3-indolyl) carbonyl acid ] -3-pyridine-carboxylic acid and 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyridinecarboxylic acid, 1.1 g of 4- (dimethylamino) -N-phenylaniline, 0 , 5 ml of pyridine and 6 ml of acetic anhydride, 1.3 g of 7- (1-ethyl-2-methyl-3-indolyl) -7 - {[4- (dimethylamino) phenyl] phenyl-amino are obtained } furo- [3,4-b] -pyridine-5- (7H) -one as a gray solid, mp 191-192 ° C with decomposition. A chloroform solution of the product in contact with an acid clay or with a phenolic resin gives a brown image.

Example 29:

Following a procedure similar to that described in Example 3, but using 1.6 g of a mixture of isomers containing 2 - [(1-ethyl-2-methyl-3-indolyl) carbonyl acid ] -3-pyridine-carboxylic and 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyridinecarboxylic acid, 1.3 g of 4,4'-bis (dimethylamino) diphenyl- amine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 0.35 g of 7- (1-ethyl-2-methyl-3-indolyl) -7- {bis- [4- (dimethylamino) - is obtained - phenyl] amino} furo- [3,4-b] -pyridine-5- (7H) -one as a white solid, mp 205-206 ° C with decomposition. A chloroform solution of the product in contact with an acid clay or with a phenolic resin gives a brown image.

Example 30:

Following a procedure similar to that described in Example 3, but using 1.6 g of a mixture of isomers containing 2 - [(1-ethyl-2-methyl-3-indolyl) carbonyl acid ] -3-pyridine-carboxylic acid and 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyridinecarboxylic acid, 0.95 g of N-phenyl-m-toluidine, 0.5 ml of pyridine and 6 ml of acetic anhydride, 7- (1-ethyl-2-methyl-3-indolyl) -7- (m-tolylphenylamino) furo- [3,4-b] -pyridine-5 is obtained - (7H) -one in the form of a yellow solid, pf 178-190 ° C with decomposition. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 31:

A mixture containing 4.5 g of a mixture of isomers containing 2 - [(1-ethyl-2-methyl-3-indolyl) -carbonyl] -3-pyridinecarboxylic acid and l 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyridinecarboxylic acid, 2.5 g of diphenylamine and 30 ml of acetic anhydride, then treated with 1 ml of pyridine and let sit overnight. The reaction mixture is poured into 750 ml of water and the resulting solid product is purified by column chromatography to give 7- (1-ethyl-2-methyl-3-indolyl) -7- (diphenylamino) furo- [3,4-b] -pyridine-5- (7H) -one in the form of a light orange solid, mp 132.5-136 ° C. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 32:

By following a procedure similar to that described in Example 3, but using 1.6 g of a mixture of isomers containing 3 - [(1-ethyl-2-methyl-3-indolylcarbonyl] - acid. 4-pyridine-carboxylic acid and 4 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -3-pyridinecarboxylic acid, 0.9 g of diphenylamine, 0.5 ml of pyridine and 6 ml of acetic anhydride, l- (l-ethyl-2-methyl-3-indolyl) -l- (diphenylamino) furo- [3,4-c] -pyridine-3- (1H) -one is obtained in the form of a viscous oil. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 33:

By following a procedure similar to that described in Example 3, but using 3.1 g of 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyrazinecarboxylic acid, 2, 2 g of 4-ethoxy-N-phenylaniline, 2 ml of pyridine and 10 ml of acetic anhydride, 1.1 g of 7- (1-ethyl-2-methyl-3-indolyl) -7 are obtained - [( 4-ethoxyphenyl) -phenylamino] furo- [3,4-b] -pyrazine-5- (7H) -one as a light brown solid, mp 120-135 ° C with decomposition. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives a reddish orange image.

Example 34:

By following a procedure similar to that described in Example 3, but using 0.8 g of 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyrazinecarboxylic acid, 1, 0 g of 4,4'-dioctyl-diphenylamine, 0.25 ml of pyridine and 3 ml of acetic anhydride, we obtain 7- (1-ethyl-2-methyl-3-indolyl) -7- [bis- (4-octylphenyl) -amino] furo- [3,4-b] -pyrazine-5- (7H) -one in the form of a semi-solid. A toluene solution of the product in contact with an acid clay or with a phenolic resin gives an orange image.

Example 35:

The mixture is stirred for 1 h at room temperature, then for 30 min, with moderate heating, a mixture containing 4 g of 3 - [(1-ethyl-2-methyl-3-indolyl) carbonyl] -2-pyrazinecarboxylic acid, 1 , 7 g of diphenylamine and 15 ml of acetic anhydride. The product, 7- (1-ethyl-2-methyl-3-indolyl) -7- (diphenylamino) furo- [3,4-b] -pyrazine-5- (7H) -one, is isolated by chromatography on column, in the form of a red solid, pf 98-100 ° C. A toluene solution

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65

11

645,112

of this product in contact with an acid clay or a phenolic resin gives an orange image.

It will be seen that by following procedures similar to those described in the previous examples, but using the Z- acids

Suitable CO-pyridinecarboxylates of formula II and the appropriately substituted diarylamines of formula III, there will be obtained the compounds of formula I of Examples 35 to 65 indicated in the table.

Z — Di

3 O

-o s

oC

at

S

a> x W

X

00

u

1

X

CO

u 'to *

x se

CJ

X

fS

U

o

X

"S u

M

X U

X

X

U

X U

X U

<>

X u

E u x u

<N

O

C / 3

se z u

3 X

at

"not

E

U

x n "Ti o 2

00

E ^

Z 3

at

NOT-'

x x

00

u

1

Tf *

s

X

S

m u

i

X

X

X

neck

■ if *

x

X

X

u

X "

u

X

u

X a

X o

X X

X u

X u

I

VS

X

co

U

I

VS

X

u

X

"

u x

NOT

U

X u

X

rj

U

X

M

U

I I

X

are u

o o

x "

M

u

-3-

M cd i

X

X

00

u

1

X u

X

u

X u

4)

Table (continued)

Example

AT

r3

r4

rs ro r7

Y,

y2

y3

y4

47

H

c2h5

c6h5ch2

-

-

H

H

H

3-CH3

48

cl c2h5

c2hs

-

-

H

H

H

4-NHS02C6H4CH3-p

49

__

-

-

H

ch3

H

H

H

H

50

-

-

-

H

c6h5

H

4-C8H17

H

4-arylalkyl *

51

-

-

-

ch3

ch3

H

H

H

3-C1

52

-

-

-

n-C4Hg ch3

H

H

h

4-NHS02C6H5

53

__

-

n-CgH17

ch3

H

H

H

H

54

_

-

H

ch3

H

H

H

H

55

n-C4H9

EYELASH,

ch3

-

-

H

H

H

4-Br

56

(CH3) 2CHCH20

ch3

ch3

-

-

2-C1

4-C1

2-C1

4-C1

57

N ^.

(see-C4H9) 2N

sec-C4H9

-

-

-

H

H

H

H

58

Br ch3

ch3

-

-

H

3-C4H90

H

3-C4H90

59

-

-

-

n-CI8H37

ch3

3-C2H5

5-C9H19

3-C2H5

5-C9H, 9

60

/ \

-

-

-

(CH3) 2CH (CH2) 8

H

H

H

3- (CH3) 3C

-

Table (continued)

Example a

r3

r4

rs r6

r,

y,

y2

y3

y4

61

-

-

-

n "C6H13

ch3

H

H

4-n-C6H13

H

62

-

-

-

c2h5

ch3

H

H

H

4-NHCOC4H9

63

-

-

-

c2h5

ch3

h h

h

4-NH2

64

h ch3

ch3

-

-

h h

h

4-CHCH2C6Hs 1

ch3

65

C2Hs c2h5

c2hs

-

-

h

2-c1

h

4-f

* Derived from arylalkylated and oetylated diphenylamine sold by B.F. Goodrich Chemical Co. under the brand name Good-rite anti-oxidant 3190.

Example 66:

A solution containing 1.46 g of the color-forming agent of Example 28 is mixed in 60 ml of isopropylbiphenyl and a solution containing 5 g of carboxymethylcellulose in 200 ml of water, and they are emulsified by rapid stirring. The desired particle size (5 µm) is checked under the microscope. To the emulsion, a solution containing 15 g of pigskin gelatin in 120 ml of water is added. The pH is adjusted to 6.5 with 10% aqueous sodium hydroxide with rapid stirring and, after the gradual addition of 670 ml of water at 50 ° C., the pH is adjusted to 4.5 with 10% aqueous acetic acid while continuing to stir rapidly. After 5 min, the mixture is cooled to 15 ° C, treated with 10 g of 25% aqueous glutaraldehyde and stirred rapidly for 15 min. The resulting dispersion of microcapsules is stirred more slowly overnight, diluted with water to obtain 1120 g and coated on sheets of white typewriter paper (film thickness 0.04 mm). The leaves are air dried. Double typed images are prepared on receiving sheets coated with phenolic resin or acid clay. The color forming agent of example 28 gives a brown image on the two types of receiving sheets.

Example 67:

A dispersion of the color-forming agent of Example 28 in polyvinyl alcohol is prepared by stirring for 1 h, in a paint stirrer, a mixture containing 2.0 g of the color-forming agent, 3, 7 g of water, 8.6 g of 10% aqueous polyvinyl alcohol and 10 g of zirconium grinding beads. A dispersion of bis-phenol A in polyvinyl alcohol is prepared by stirring a mixture containing 9.8 g of bis-phenol A, 18.2 g of water, 42 g of 10% aqueous polyvinyl alcohol and 70 ml of zirconium grinding balls. The coating mixture is prepared by combining and thoroughly mixing 2.1 g of the dispersion of the color former in polyvinyl alcohol with 47.9 g of the dispersion of bis-phenol A in polyvinyl alcohol. The coating mixture is applied (at thicknesses of 0.075 and 0.04 mm) to sheets of white reproduction paper, then the sheets are dried at room temperature. Contact of the coated sheets with a stylus heated to 110-150 ° C gives a purple image.

Claims (8)

645,112 1. Compound of formula (I): (I) 1 "2 in which A is a divalent radical of formula (a), (b), (c), (d) or (e): (at) (vs) .NOT ^ X (d) (e) formulas in which Yj, Y2, Y3 and Y4, identical or different, are hydrogen or halogen atoms, or lower alkoxy, alkyl having from 1 to 9 carbon atoms, phenyl lower alkyl or NRjR2, where Ri is a d atom hydrogen or a lower alkyl group and R2 is a hydrogen atom or a lower alkyl, lower alkanoyl, phenylsulfonyl or (lower alkyl) phenylsulfonyl group; Z is a monovalent radical of formula (f) or (g): formulas in which R3 is a hydrogen atom, a lower alkyl or lower alkoxy group, a halogen atom or a di (lower alkyl) amino group; R4 is a lower alkyl group; R5 is a lower alkyl or benzyl group; Re is a hydrogen atom or a non-tertiary alkyl group having from 1 to 18 carbon atoms, and R7 is a hydrogen atom or a non-tertiary phenyl or lower alkyl group. 2. Compound according to claim 1, characterized in that A has the formula (a) or (d). 5 3. Compound according to claim 2, characterized in that Z has the formula (0, R3 is a hydrogen atom or a lower alkyl group, R4 and R5 are each a lower alkyl group and Y i and Y3 are each a hydrogen atom. 4. Compound according to claim 2, characterized in that Z has the formula io (g) and Y, and Y3 are each a hydrogen atom. 5. Compound according to claim 3, characterized in that Y2 and Y4, identical or different, are hydrogen atoms or alkyl groups having from 1 to 9 carbon atoms. 6. 7- [4- (Dimethylamino) phenyl] -7- [bis- (4-octylphenyl) amino] -15 furo- [3,4-b] -pyridine-5- (7H) -one according to claim 1 . 7. 5- [4- (Dimethylamino) phenyl] -5- [bis (4-octylphenyl) amino] -furo- [3,4-b] -pyridine-7- (5H) -one according to claim 1. 8. 7- (1-Ethyl-2-methyl-3-indolyl) -7- (diphenylamino) furo- [3,4-b] -pyridine-5- (7H) -one according to claim 1. 9. 5- (1-Ethyl-2-methyl-3-indolyl) -5- (diphenylamino) furo- [3,4-b] -pyridine-7- (5H) -one according to claim 1. 10. Carbon-free duplication product sensitive to pressure or thermal marking product, characterized in that it contains a color-generating substance containing a compound according to one of claims 1 to 9. 30