JP5397738B2 - Azomethine compound - Google Patents

Description

  The present invention relates to a novel azomethine compound, and more particularly to a novel azomethine compound that is excellent in light resistance and can be produced at low cost, and has excellent color tone when used as a magenta dye.

  The heat-sensitive sublimation transfer method uses a thermal transfer film that carries a dye layer in which a sublimable dye is dissolved or dispersed in a binder resin. The thermal transfer film is layered on the image-receiving film and is transferred to a heating device such as a thermal head. By applying energy according to the above, the sublimation dye contained in the dye layer on the thermal transfer film is transferred to the image receiving film to form an image.

This heat-sensitive sublimation transfer method can control the amount of dye transfer in dot units according to the amount of energy applied to the thermal transfer film, so that it is excellent in forming a gradation image and has advantages such as easy formation of characters, symbols, etc. have.
The image obtained by such a thermal transfer method can form a high-quality image similar to a silver salt photograph, and accordingly, there is an extremely high demand for prevention of image quality degradation due to factors such as light, heat, and humidity of the image. Development of various sublimation dyes for improving image storage stability has been made.

  For example, as a thermal transfer dye having excellent transferability and storage stability, Patent No. 3013137 (Patent Document 1) and Patent No. 3078308 (Patent Document 2) include 1H-pyrazolo [5,1-C] [1 , 2,4] An azomethine compound having a structure in which a triazole ring is a coupler and a pyridine ring group is bonded to the coupler via a nitrogen atom is disclosed. Japanese Patent No. 2840901 (Patent Document 3) uses a 1H-pyrazolo [1,5-b] [1,2,4] triazole ring as a coupler, and a phenylamino group is bonded to the coupler via a nitrogen atom. An azomethine compound of structure is disclosed. Further, JP-A-5-239367 (Patent Document 4) describes a 1H-pyrazolo [1,5-b] [1,2,4] triazole ring coupler, which is a combination of both, to a pyridine ring group. An azomethine compound having a structure in which is bonded to a coupler via a nitrogen atom is disclosed.

  Although the azomethine dyes disclosed in the above patents 3013137 and 3078308 are excellent in light resistance, the 1H-pyrazolo [5,1-C] [1,2,4] triazole ring is used as a coupler. There is a cost problem. The azomethine dye described in Japanese Patent No. 2840901 using a 1H-pyrazolo [1,5-b] [1,2,4] triazole ring compound as a raw material coupler has a merit that it can be produced at a relatively low cost. May be insufficient.

On the other hand, the dye described in JP-A-5-239367, which is a combination of 1H-pyrazolo [1,5-b] [1,2,4] triazole ring coupler and pyridine ring group, can be produced at low cost and is light resistant There is an advantage that it is excellent in performance. In particular, a phenyl group introduced as a substituent R ₆ of the 1H-pyrazolo [1,5-b] [1,2,4] triazole ring proposed in JP-A-5-239367 (9, (10, 11, 22, 112) is excellent in that the color tone of the pigment is close to the required color gamut.

Patent No. 3013137 Japanese Patent No. 3078308 Japanese Patent No. 2840901 JP-A-5-239367

However, the compounds described in JP-A-5-239367, in particular, compounds having a phenyl group introduced as the substituent R ₆ of the triazole ring are excellent in terms of production cost and light resistance, but have a low coupling reaction rate. As described in JP-A-5-239367, the yield is about 20%.

  The present inventors now perform a coupling reaction well in an azomethine compound in which a pyridine ring is bonded to a 1H-pyrazolo [1,5-b] [1,2,4] triazole ring through a nitrogen atom. And the production cost of the obtained azomethine compound can be greatly reduced. The present invention is based on this finding.

  Therefore, an object of the present invention is to provide a 1H-pyrazolo [1,5-b] [1,2,4] that can perform a coupling reaction satisfactorily and can greatly reduce the production cost of the obtained azomethine compound. An object is to provide an azomethine compound in which a pyridine ring is bonded to a triazole ring through a nitrogen atom.

  Another object of the present invention is to provide a method for producing the above azomethine compound.

（式中、
Ｒ_１は、フェニル基またはナフチル基であるが、該フェニル基またはナフチル基は、アルキル基もしくはハロゲンにより置換されていてもよく、
Ｒ_２およびＲ_３は、それぞれ独立して、炭素数Ｃ２〜４のアルキル基を示す。）。 The azomethine compound according to the present invention is represented by the following formula (I).

(Where
R ₁ is a phenyl group or a naphthyl group, and the phenyl group or naphthyl group may be substituted with an alkyl group or a halogen,
R ₂ and R ₃ each independently represents an alkyl group having 2 to 4 carbon atoms. ).

In addition, a method for producing an azomethine compound according to another embodiment of the present invention includes reacting a compound represented by the following formula II with a compound represented by the following formula III with an oxidizing agent in the presence of a base. Become.

  According to the present invention, an azomethine compound in which a pyridine ring is bonded to a 1H-pyrazolo [1,5-b] [1,2,4] triazole ring represented by the formula I through a nitrogen atom is represented by the above formula II. And the formula III can be favorably carried out, and the production cost of the resulting azomethine compound can be greatly reduced. Moreover, since the compound of the said formula I is excellent in light resistance, it is not necessary to introduce | transduce various substituents for improving light resistance like the azomethine compound which combined the phenyl group.

Hereinafter, the azomethine compound according to the present invention will be described.
The azomethine compound according to the present invention is represented by the following formula I.

式中、Ｒ_１は、フェニル基またはナフチル基であるが、該フェニル基またはナフチル基は、アルキル基もしくはハロゲンにより置換されていてもよく、Ｒ_２およびＲ_３は、それぞれ独立して、炭素数Ｃ２〜４のアルキル基を示す。

In the formula, R ₁ is a phenyl group or a naphthyl group, and the phenyl group or naphthyl group may be substituted with an alkyl group or a halogen, and R ₂ and R ₃ each independently represent a carbon number A C2-4 alkyl group is shown.

  Like the compound represented by the formula I, an azomethine compound in which a 1H-pyrazolo [1,5-b] [1,2,4] triazole ring coupler and a pyridine ring group are bonded via a nitrogen atom has a light resistance. It has the advantage that it can be manufactured at low cost. However, a compound in which a pyridine ring group having no substituent is bonded to a coupler, such as the azomethine compound described in JP-A-5-239367, has a reaction yield of 1 between the coupler and the pyridine ring in the production process. It is as low as ˜20%. In the present invention, focusing on the pyridine ring and introducing a methyl group at the ortho position of the pyridine ring, the coupling reaction rate is remarkably improved, and the reaction yield is 40% or more.

からなる群から選択されるものであることが好ましい。このような置換基を有していてもよいフェニル基またはナフチル基等のアリール基を導入することにより、所望の色相に近似させることができるとともに、吸収スペクトルがシャープ化する。また、耐光性や溶解性も向上する。 In the present invention, in the above formula I, R ₁ is the following substituents (i) to (v):

It is preferably selected from the group consisting of By introducing an aryl group such as a phenyl group or a naphthyl group which may have such a substituent, it is possible to approximate a desired hue and sharpen an absorption spectrum. Moreover, light resistance and solubility are also improved.

Among these, R ₁ is more preferably substituents (ii) and (iv) from the viewpoint of sharpening the absorption spectrum and improving light resistance.

  As shown in the following synthesis scheme, the azomethine compound according to the present invention is represented by a 1H-pyrazolo [1,5-b] [1,2,4] triazole coupler represented by the following formula II, and a formula III. The pyridyldiamino derivative can be obtained by reacting with an oxidizing agent in the presence of a base.

  The 1H-pyrazolo [1,5-b] [1,2,4] triazole derivative represented by the formula II, which is a coupler, is synthesized using a method similar to the method described in JP-A-5-239367. be able to. For example, the compounds of formula II and formula III can be obtained as follows.

First, as shown in the following synthesis scheme, a benzoic acid ester compound as a starting material is reacted with acetonitrile in the presence of potassium t-butoxide to obtain compound a, and then compound a is reacted with hydrazine to obtain compound b. Prepare. Subsequently, imidate hydrochloride is allowed to act on compound b to obtain an amidine compound, and then hydroxylamine is allowed to act on compound b to obtain compound c.

Then, compound p is reacted with p-tolylsulfonic acid chloride as described below. The compound of formula II can be obtained by heating to reflux in the presence of pyridine.

  Moreover, the pyridyldiamine derivative which is a compound of Formula III can be obtained according to the method described in Japanese Patent No. 3078308, for example.

  The azomethine compound of the present invention can be obtained by reacting the compound of formula II obtained above and the compound of formula III with an oxidizing agent in the presence of a base. This reaction is performed, for example, within 40 ° C. under water cooling for about 1 hour.

  The azomethine compound according to the present invention is useful as a heat-sensitive thermal transfer material. For example, the azomethine compound represented by the above formula I can be used as a magenta dye for sublimation thermal transfer, and can be suitably used in combination with other known yellow dyes, cyan dyes, other dyes and the like.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples.

[Example 1]
500 ml of tetrahydrofuran was added to 164.2 ml of ethyl 2-toluate, 57.9 ml of acetonitrile was added at 0 ° C., and 123.4 g of potassium tert-butoxide was added over 30 minutes. After stirring for about 1 hour, 320 ml of water was added and the mixture was separated with hexane, and the aqueous layer was neutralized to about pH 2 with concentrated hydrochloric acid. After neutralization, the mixture was separated with toluene, and the oil layer was distilled off under reduced pressure to obtain 154.5 g of the following compound A as an acetonitrile derivative (yield 97%). Compound A was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Next, 130 ml of 3-propanol was added to 129.3 g of Compound A, and the mixture was stirred at 40 ° C. To this, 48.7 g of hydrazine monohydrate was added dropwise and reacted at reflux temperature for 3 hours. Thereafter, about 100 ml of the reaction system was distilled off under reduced pressure, and 100 ml of saturated brine and 200 ml of toluene were added to separate the layers. After removing the aqueous layer, the oil layer was dried over magnesium sulfate. This toluene solution was distilled off under reduced pressure, and 140 ml of methanol was added to the residue. The methanol solution was added dropwise to 2800 ml of a saturated aqueous NaHCO ₃ solution to precipitate crystals. The crystals were collected by filtration and dried to obtain 94.1 g of Compound B which is an aminopyrazole derivative (yield 67%). Compound B was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Further, 52 g of Compound B was stirred in 250 ml of N, N-dimethylacetamide (hereinafter referred to as DMAC), and 39.4 g of imidate hydrochloride obtained from acetonitrile and methanol was added. After stirring at room temperature for 3 hours, 41.69 g of hydroxylamine hydrochloride and 24.6 g of sodium acetate were added, and the mixture was heated and stirred at 60 ° C. After reacting for 6 hours, the reaction system was transferred into 1500 ml to precipitate crystals. The crystals were collected by filtration and dried to obtain 50.6 g of compound C which is an amide oxime derivative (yield 83%). A synthesis scheme is shown below.

Subsequently, 46 g of Compound C was stirred in 46 ml of DMAC and 46 ml of acetonitrile, 38 g of P-toluenesulfonic acid chloride was added under water cooling, and 16.1 ml of pyridine was added. After stirring for 30 minutes, 16.1 ml of pyridine was added and the mixture was heated and stirred at 70 ° C. After stirring for 5 hours, the mixture was transferred into 800 ml of water and the crystals were collected by filtration. This crystal was recrystallized in 40 ml of methanol to obtain 10.6 g of Compound D (yield 25%). Compound D was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Next, 2.12 g of Compound D was stirred in 21 ml of methanol, and 2.80 g of sodium hydroxide and 5.0 g of Compound E were added. Thereafter, an aqueous solution obtained by dissolving 5.95 g of sodium persulfate in 8.33 ml of water was added dropwise to the reaction solution. After stirring for 1 hour, the reaction solution was filtered, and the obtained residue was suspended in warm water at 40 ° C. for 1 hour. After filtering the suspension, the obtained solid was dissolved in toluene and purified by silica gel chromatography to obtain 2.05 g of azomethine compound 1 (yield 53%). A synthesis scheme is shown below. The compound was identified by HPLC and ESIMS. The analysis results were as follows.
¹ H NMR, δ (ppm) (multiplicity, integral) (CDCl ₃ ) 7.30 (d, 1H), 7.64 (d, 1H), 7.32 (m, 3H), 6.66 (d, 1H), 3.66 (q , 4H), 2.59 (s, 3H), 2.52 (s, 3H), 2.46 (s, 3H), 1.26 (t, 6H)

[Example 2]
To 442 ml of ethyl 2-chlorobenzoate, 1500 ml of tetrahydrofuran was added, 142 ml of acetonitrile was added at 0 ° C., and 304 g of potassium-t-butoxide was added over 30 minutes. After stirring for about 1 hour, 900 ml of water was added and the mixture was separated with hexane, and the aqueous layer was neutralized to about pH 2 with concentrated hydrochloric acid. After neutralization, the mixture was separated with toluene, and the oil layer was distilled off under reduced pressure to obtain 407 g of compound F as an acetonitrile derivative (yield 84%). Compound F was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Next, 400 ml of 3-propanol was added to 405 g of compound F, and the mixture was stirred at 40 ° C. To this, 136 g of hydrazine monohydrate was added dropwise and reacted at reflux temperature for 3 hours. Thereafter, about 300 ml of the reaction system was distilled off under reduced pressure, and 100 ml of saturated brine and 500 ml of toluene were added to separate the layers. After removing the aqueous layer, the oil layer was dried over magnesium sulfate. This toluene solution was distilled off under reduced pressure, and 450 ml of methanol was added to the residue. The methanol solution was added dropwise to 8000 ml of a saturated aqueous NaHCO ₃ solution to precipitate crystals. The crystals were collected by filtration and dried to obtain 368 g of compound G, which is an aminopyrazole derivative (yield 84%). Compound G was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Further, Compound G367g was stirred in 1800 ml of methanol, and 208.2 g of imidate hydrochloride obtained from acetonitrile and methanol was added. After stirring at room temperature for 3 hours, 132.1 g of hydroxylamine hydrochloride and 36 g of caustic soda were added, and the mixture was stirred at 40 ° C. with heating. After reacting for 3 hours, the reaction system was transferred to 9000 ml to precipitate crystals. The crystals were collected by filtration and dried to obtain 378 g of compound H which is an amide oxime derivative (yield 79%). Compound H was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Subsequently, 85 g of Compound H was stirred in 85 ml of DMAC and 85 ml of acetonitrile, 65 g of P-toluenesulfonic acid chloride was added under water cooling, and 27.4 ml of pyridine was added. After stirring for 30 minutes, 27.4 ml of pyridine and 280 ml of methanol were added and stirred while heating under reflux. After stirring for 5 hours, it was transferred to 1600 ml of water, and the crystals were collected by filtration. The crystals were recrystallized in 80 ml of methanol to obtain 52.2 g of Compound I (yield 66%). Compound I was identified by HPLC and ESIMS. A synthesis scheme is shown below.

Next, 1.4 g of Compound I was stirred in 9.8 ml of methanol, and 1.67 g of sodium hydroxide and 1.82 g of Compound E were added. Thereafter, an aqueous solution obtained by dissolving 3.57 g of sodium persulfate in 5.0 ml of water was added dropwise to the reaction solution. After stirring for 1 hour, the reaction solution was filtered, and the obtained residue was suspended in warm water at 40 ° C. for 1 hour. After filtering the suspension, the obtained solid was dissolved in toluene and purified by silica gel chromatography to obtain 1.17 g of azomethine compound 2 (yield 48%). A synthesis scheme is shown below. The compound was identified by HPLC and ESIMS. The analysis results were as follows.
¹ H NMR, δ (ppm) (multiplicity, integral) (CDCl ₃ ) 9.29 (d, 1H), 7.46 (m, 4H), 6.67 (d, 1H), 3.66 (q, 4H), 2,59 (s, 3H), 2.43 (s, 3H), 1.26 (t, 6H)

Claims (4)

An azomethine compound represented by the following formula (I):

(Where
R ₁ is a phenyl group or a naphthyl group, and the phenyl group or naphthyl group may be substituted with an alkyl group or a halogen,
R ₂ and R ₃ each independently represents an alkyl group having 2 to 4 carbon atoms. ). R ₁ is the following substituents (i) to (v):

The azomethine compound according to claim 1, which is selected from the group consisting of: The azomethine compound according to claim 1 or 2, wherein R ₂ and R ₃ are ethyl groups. A method for producing the azomethine compound according to any one of claims 1 to 3, wherein the compound represented by the following formula II and the compound represented by the following formula III are oxidized in the presence of a base. A method comprising reacting with.