JP3300139B2 - Pentamethine compound and optical recording material containing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pentamethine compound,
The present invention relates to a method for producing the compound and an optical recording material containing the compound.

[0002]

2. Description of the Related Art In recent years, in an optical recording material using a semiconductor laser for recording and reading of information, a cyanine-based compound, a squarylium-based compound, a phthalocyanine-based compound or the like is used instead of a metal-based material such as tellurium in a recording layer. It has been proposed to use organic dye compounds having absorption in the infrared region. Organic dye-based compounds have a melting point,
Since the decomposition temperature is low and the thermal conductivity is low, high sensitivity and high density can be achieved. Further, since it has low toxicity and can form a recording layer by a coating method, improvement in productivity and cost reduction can be expected. However, generally, organic dye compounds having absorption in the near infrared region have low solvent solubility, so that it is difficult to form a recording layer having a required film thickness. Further, an optical recording material using an organic dye-based compound has a defect that the reflectance is lower than that of an optical recording material using a metal substance such as tellurium, the light stability is poor, and the optical recording material is easily deteriorated by reproduction light. That is, it has good absorption and reflection in the semiconductor laser oscillation region,
At present, an optical recording material using an organic dye compound having high solvent solubility and good light stability has not been developed. In recent years, research on shortening the wavelength of a semiconductor laser oscillation region has been actively conducted to improve the recording density, and an optical recording material suitable for a semiconductor laser having a shorter wavelength has been demanded.

[0003]

An object of the present invention is to provide a pentamethine compound which has good absorption and reflection in the oscillation range of a semiconductor laser, has high solvent solubility and is excellent in photostability, and contains the compound. It is to provide an optical recording material.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found a novel pentamethine compound and have achieved the object of the present invention. That is, the present invention firstly relates to a novel pentamethine compound represented by the following general formula (1).

[0005]

Embedded image (Wherein, R ₁ and R ₅ each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms or a cycloalkyl group having 5 to 7 carbon atoms, and R ₂ and R ₆ Is
Each independently an alkyl group having 1 to 8 carbon atoms, 5 to 5 carbon atoms
7 represents a cycloalkyl group, an aryl group or a substituted aryl group, wherein R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; A cycloalkyl group having 5 to 7 carbon atoms, an aryl group or a substituted aryl group, and Z represents an acidic residue. )

[0006] The present invention also relates to a method for producing a novel pentamethine compound represented by the general formula (1).

Further, the present invention relates to an organic near-infrared absorbing dye of an optical recording material for a semiconductor laser, which has the general formula (1)
The present invention relates to an optical recording material containing a novel pentamethine compound represented by the following formula:

As a general cyanine dye having a light absorption characteristic (maximum absorption wavelength) close to that of the compound of the present invention, it has a structural formula completely different from that of the pentamethine compound of the present invention. NK-2421 (trade name, manufactured by Nippon Kogyo Dye) is known. However, equation (6)
The compound of the formula (1) has low solvent solubility, and the recording layer using the compound has low light stability and cannot be suitably used as an optical recording material for a semiconductor laser.

[0009]

Embedded image

Although the pentamethine compound of the present invention has a different structure and the recording layer using the pentamethine compound also has a different maximum absorption wavelength, a compound having a partially similar substituent is disclosed in JP-A-1-153755. Gazette and Japanese Patent Laid-Open Publication
JP-A-02478 discloses a heptamethine compound having a bis-indolyl group at both ends (for example, a compound of the formula (7)). ) Is disclosed.

[0011]

Embedded image

However, the compounds of the formulas (7) and (8) have low solvent solubility, and the recording layer using the formulas (7) and (8) has poor absorption and reflection balance. Therefore, the compounds of the formulas (7) and (8) cannot be suitably used as an optical recording material for a semiconductor laser.

Hereinafter, the present invention will be described in detail.

In the general formula (1), R ₁ and R ₅ are each an alkyl group having 1 to 8 carbon atoms.
To 6 linear or branched alkyl groups are preferred, and in particular, methyl, ethyl, n-propyl, isopropyl, n-
Butyl, isobutyl, sec-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl and isohexyl are preferred. As the alkoxyalkyl group having 2 to 8 carbon atoms, an alkoxyalkyl group having 3 to 6 carbon atoms is preferable, and particularly, a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, an ethoxymethyl group, an ethoxyethyl group, and an ethoxypropyl group are preferred. And an ethoxybutyl group are preferred. The cycloalkyl group having 5 to 7 carbon atoms is particularly preferably a cyclohexyl group.

R ₂ and R ₆ are preferably alkyl groups having 1 to 8 carbon atoms, preferably linear alkyl groups having 1 to 4 carbon atoms, particularly methyl, ethyl, n-propyl and n-propyl.
-Butyl groups are preferred. The cycloalkyl group having 5 to 7 carbon atoms is particularly preferably a cyclohexyl group. As the aryl group, a phenyl group and a naphthyl group are preferable, and a phenyl group is particularly preferable. As a substituted aryl group, the substituent has 1 to 1 carbon atoms.
A linear alkyl group of 4, a halogen atom, and an alkoxy group having 1 to 4 carbon atoms are preferable, and a methyl group, an ethyl group, a chlorine atom and a methoxy group are particularly preferable.

When R ₃ , R ₄ , R ₇ and R ₈ are an alkyl group having 1 to ₈ carbon atoms, an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group and an ethyl group are particularly preferable. The cycloalkyl group having 5 to 7 carbon atoms is particularly preferably a cyclohexyl group. As the alkoxy group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, and an n-butoxy group are particularly preferable.

[0017] Specific examples of acidic residues Z is, ^F -, C
^{l -, Br -, I -} , ClO 4 -, BF 4 -, PF 6 -, SbF 6
_{^{-, CH 3 COO -, CH}} 3 SO 4 -, CF 3 SO 4 -,

[0018]

Embedded image Etc., but preferably I ⁻ , ClO ₄ ⁻ , B
F ₄ ⁻ , PF ₆ ⁻ , and SbF ₆ ⁻ .

Table 1 shows specific examples of the compound represented by the general formula (1) of the present invention.

[0020]

[Table 1]

The method for producing the pentamethine compound represented by the general formula (1) according to the present invention includes, for example, a bisindolylethylene compound represented by the general formula (2).

[0022]

Embedded image (Wherein R _{1 to} R ₈ are the same as described above) and the orthoester represented by the general formula (3)

[0023]

Embedded image embedded image Condensed with CH (OR) ₃ (3) (wherein R represents a methyl group or an ethyl group) in the presence of an acidic substance in a dehydrating organic acid. Alternatively, it can be produced using malonaldehyde dianyl represented by the formula (4) instead of the orthoester represented by the formula (3).

[0024]

Embedded image

In the above condensation reaction, examples of the acidic substance include hydrochloric acid, sulfuric acid, perchloric acid, methanesulfonic acid, and toluenesulfonic acid. As dehydrating organic acids,
For example, acetic anhydride, propionic anhydride, butyric anhydride, γ-
Butyrolactone and the like. Such a dehydrating organic acid is generally used in an amount of 10 to 1 per mole of the compound of the general formula (2).
It is used in an amount of about 00 mol, preferably 20 to 50 mol. A compound of general formula (2) and a compound of general formula (3) or (4)
The use ratio of the compound to the former is usually 0.
The molar amount is about 2 to 1.5 times, preferably about 0.4 to 0.7 times. The above reaction is usually performed at 10 to 150 ° C.
The reaction proceeds appropriately at about 40 ° C. to 120 ° C., and is generally completed in 30 minutes to 6 hours.

Further, as another method for producing the pentamethine compound represented by the general formula (1) of the present invention, for example, the compound of the general formula (2) and the compound of the general formula (5)

[0027]

Embedded image (Wherein, R _{1 to} R ₈ are the same as described above) in the presence of an acidic substance in a dehydrating organic acid.

In the above condensation reaction, examples of the acidic substance include hydrochloric acid, sulfuric acid, perchloric acid, methanesulfonic acid, and toluenesulfonic acid. As dehydrating organic acids,
For example, acetic anhydride, propionic anhydride, butyric anhydride, γ-
Butyrolactone and the like. Such a dehydrating organic acid is generally used in an amount of 10 to 1 per mole of the compound of the general formula (2).
It is used in an amount of about 00 mol, preferably about 20 to 50 mol. The ratio of the compound of the general formula (2) to the compound of the general formula (5) is usually about 0.5 to 1.5 times, preferably 0.8 to 1.2 times, the molar amount of the former. It is good to be about. The above reaction proceeds suitably at generally about 10 to 150 ° C, preferably 40 to 120 ° C, and is generally completed in 30 minutes to 6 hours.

The compound of the general formula (2) is prepared by converting the corresponding indole compound and acetyl chloride to 50
It is obtained by reacting at ６０60 ° C. for several hours.

The compound of the general formula (5) can be obtained by reacting the compound of the general formula (2) with a Vilsmeier reagent in DMF.

The pentamethine compound of the present invention is used for an optical recording material such as an electrophotographic photosensitive member, an optical disk, an optical card, a liquid crystal display, and a light absorption filter.

As an optical recording material containing the pentamethine compound of the present invention, for example, an optical disk can be produced by applying a solution of the pentamethine compound of the present invention in a solvent on a transparent substrate.

The transparent substrate may be any optically transparent material. For example, glass, acrylic resin, polyethylene resin, vinyl chloride resin, vinylidene chloride resin, polycarbonate resin, ethylene resin, polyolefin copolymer resin, vinyl chloride copolymer resin, vinylidene chloride copolymer resin, styrene copolymer resin, etc. are used. .

As the solvent, halogenated hydrocarbons (for example, dichloromethane, chloroform, carbon tetrachloride, tetrachloroethylene, dichlorodifluoromethane, etc.),
Ethers (eg, tetrahydrofuran, diethyl ether, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.), alcohols (eg, methanol, ethanol, propanol, diacetone alcohol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.) And hydrocarbons (hexane, cyclohexane, octane, benzene, toluene, xylene, etc.).

Examples of the coating method include a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, and a screen printing method. Is preferably applied by a spin coating method. The thickness of the dye recording layer for an optical disk is generally 200 to 3
000 °, preferably 500-2000 °
Range.

In the optical recording material of the present invention, for example, a reflective layer made of metal may be provided on the recording layer. By providing the reflective layer, the effect of improving the reflectance, the S / N at the time of reproducing information, and the effect of improving the sensitivity at the time of recording can be obtained.

In the optical recording material of the present invention, for example, a light stabilizer may be mixed in the recording layer in order to improve light resistance. If necessary, a binder can be mixed in consideration of film forming properties and coating film stability.

In the optical recording material of the present invention, for example, a protective layer transparent to the recording and reproducing laser light may be provided on the recording layer.

[0039]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, the compound number in the following Examples means the number of the compound in Table 1. In the chemical structural formula, Ph represents a phenyl group.

Example 1 (Synthesis of Compound 1)

[0041]

Embedded image Ethylene compound of the general formula (2) [R ₁ : n-butyl group,
R ₂ : methyl group, R ₃ : hydrogen atom, R ₄ : hydrogen atom, R ₅ :
n-butyl group, R ₆ : methyl group, R ₇ : hydrogen atom, R ₈ :
[Hydrogen atom] 7.96 g, methanesulfonic acid 0.96 g and sodium acetate 1.64 g were added to acetic anhydride 20 ml, and the temperature was raised to 90 ° C.
1.48 g of ethyl orthoformate was added at the same temperature, and the mixture was reacted at the same temperature for 4.5 hours. After cooling, the solution was added dropwise to 500 ml of an aqueous solution in which 10 g of sodium perchlorate was dissolved, and the precipitated solid was filtered and washed with water. The obtained solid was dissolved in 200 ml of acetone and then reprecipitated with water to obtain a solid. The obtained solid was recrystallized from 300 ml of an acetone-hexane mixed solution to obtain 2.30 g of Compound 1.

The maximum absorption wavelength (λmax), gram extinction coefficient (εg), and elemental analysis values of the crystals in methanol were as follows. Fig. 1 shows the infrared absorption spectrum of this crystal.
Shown in Maximum absorption wavelength (λmax): 708 nm (in MeOH) Gram extinction coefficient (εg): 8.59 × 10 ⁴ ml / g · cm (in M
EOH) Elemental _{analysis: (C 57 H 67 N 4} ClO 4)

Example 2 (Synthesis of Compound 2)

[0044]

Embedded image An ethylene compound represented by the general formula (2) [R ₁ : ethyl group, R ₂ :
Methyl group, R ₃ : hydrogen atom, R ₄ : hydrogen atom, R ₅ : ethyl group, R ₆ : methyl group, R ₇ : hydrogen atom, R ₈ : hydrogen atom] 3.40 g, aldehyde compound of general formula (5) [R ₁ : ethyl group, R ₂ : methyl group, R ₃ : hydrogen atom, R ₄ : hydrogen atom, R ₅ : ethyl group, R ₆ : methyl group, R ₇ : hydrogen atom,
[R ₈ : hydrogen atom] 3.70 g and methanesulfonic acid 0.96 g were added to acetic anhydride 20 ml, and the mixture was heated to 80 ° C. and reacted at the same temperature for 1.5 hours. After cooling, the solution was dropped into 300 ml of an aqueous solution in which 2.8 g of sodium perchlorate was dissolved, and the precipitated solid was filtered and washed with water.
The obtained solid was dissolved in 100 ml of acetone and then reprecipitated with water to obtain a solid. The obtained solid was recrystallized with 150 ml of an acetone-hexane mixed solution to obtain 5.30 g of Compound 2.

The maximum absorption wavelength (λmax), gram extinction coefficient (εg), and elemental analysis values of the crystals in methanol were as follows. Maximum absorption wavelength (λmax): 703 nm (in MeOH) Gram extinction coefficient (εg): 1.05 × 10 ⁵ ml / g · cm (in
(MeOH) Elemental analysis: (C ₄₉ H ₅₁ N ₄ ClO ₄ )

Example 3 (Synthesis of Compound 3)

[0047]

Embedded imageThe ethylene compound represented by the general formula (2) [R₁: Ethyl group, R_Two:
Methyl group, R_Three: Methoxy group, R_Four: Hydrogen atom, R_Five: D
Tyl group, R₆: Methyl group, R₇: Methoxy group, R ₈:hydrogen
Atom] 4.50 g, methanesulfonic acid 1.40 g and sodium acetate
Was added to 30 ml of acetic anhydride, and the temperature was raised to 90 ° C. Malo
Add 1.10 g of dialdehyde dianil at the same temperature and
Reacted for 2.0 hours. After cooling, dissolve 10 g of sodium perchlorate
Dropped into 500 ml of the dissolved aqueous solution, the precipitated solid was filtered,
Washed with water. After dissolving the obtained solid in 200 ml of acetone,
Reprecipitation with water gave a solid. The solid obtained is acetone
Recrystallization with 300 ml of a hexane-hexane mixture gave 1.30 g of compound 3.
Was.

The maximum absorption wavelength (λmax), gram extinction coefficient (εg), and elemental analysis values of the crystals in methanol were as follows. Maximum absorption wavelength (λmax): 713 nm (in MeOH) Gram extinction coefficient (εg): 3.54 × 10 ⁴ ml / g · cm (in M
OH) Elemental analysis: (C ₅₃ H ₅₉ N ₄ ClO ₈ )

Example 4 (Synthesis of Compound 4)

[0050]

Embedded image In Example 3, as the ethylene compound of the general formula (2), [R ₁ : ethyl group, R ₂ : methyl group, R ₃ : methyl group, R ₄ : hydrogen atom, R ₅ : ethyl group, R ₆ : methyl Group,
[R ₇ : methyl group, R ₈ : hydrogen atom] 1.35 g of compound 4 was obtained in the same manner as in Example 3 except that 4.24 g was used.

The maximum absorption wavelength (λmax), gram extinction coefficient (εg), and elemental analysis values of the crystals in methanol were as follows. Fig. 2 shows the infrared absorption spectrum of this crystal.
Shown in Maximum absorption wavelength (λmax): 711 nm (in MeOH) Gram extinction coefficient (εg): 6.34 × 10 ⁴ ml / g · cm (in M
OH) Elemental analysis: (C ₅₃ H ₅₉ N ₄ ClO ₄ )

Example 5 (Synthesis of Compound 5)

[0053]

Embedded image In Example 3, as the ethylene compound of the general formula (2), [R ₁ : ethyl group, R ₂ : phenyl group, R ₃ : hydrogen atom, R ₄ : hydrogen atom, R ₅ : ethyl group, R ₆ : phenyl Group, R ₇ : hydrogen atom, R ₈ : hydrogen atom], and 0.72 g of compound 5 was obtained in the same manner as in Example 3.

The maximum absorption wavelength (λmax), gram extinction coefficient (εg), and elemental analysis values of the crystals in methanol were as follows. The infrared absorption spectrum of this crystal is shown in FIG.
Shown in Maximum absorption wavelength (λmax): 752 nm (in MeOH) Gram extinction coefficient (εg): 7.94 × 10 ⁴ ml / g · cm (in M
EOH) Elemental _{analysis: (C 69 H 59 N 4} ClO 4)

Example 6 (Synthesis of Compound 6)

[0056]

Embedded image In Example 1, instead of the ethylene compound of the general formula (2), [R ₁ : ethyl group, R ₂ : methyl group, R ₃ : hydrogen atom, R ₄ : phenyl group, R ₅ : ethyl group, R ₆ : Methyl group, R ₇ : hydrogen atom, R ₈ : phenyl group] 3.00 g of compound 6 was obtained in the same manner as in Example 1 except that 9.89 g was used.

The maximum absorption wavelength (λmax), gram extinction coefficient (εg), and elemental analysis values of the crystals in methanol were as follows. The infrared absorption spectrum of this crystal is shown in FIG.
Shown in Maximum absorption wavelength (λmax): 718 nm (in MeOH) Gram extinction coefficient (εg): 6.40 × 10 ⁴ ml / g · cm (in M
EOH) Elemental _{analysis: (C 73 H 67 N 4} ClO 4)

Example 7 (Synthesis of Compound 7)

[0059]

Embedded image In Example 1, as the ethylene compound of the general formula (2), [R ₁ : ethyl group, R ₂ : phenyl group, R ₃ : hydrogen atom, R ₄ : hydrogen atom, R ₅ : ethyl group, R ₆ : methyl group ,
[R ₇ : hydrogen atom, R ₈ : hydrogen atom] 2.80 g of compound 7 was obtained in the same manner as in Example 1 except for using 8.09 g.

The maximum absorption wavelength (λmax), gram extinction coefficient (εg), and elemental analysis value of the crystals in methanol were as follows. The infrared absorption spectrum of this crystal is shown in FIG.
Shown in Maximum absorption wavelength (λmax): 725 nm (in MeOH) Gram extinction coefficient (εg): 7.64 × 10 ⁴ ml / g · cm (in M
EOH) Elemental _{analysis: (C 69 H 59 N 4} ClO 4)

Example 8 (Synthesis of Compound 8)

[0062]

Embedded image In Example 3, as the ethylene compound of the general formula (2), [R ₁ : methoxyethyl group, R ₂ : methyl group, R ₃ :
A methoxy group, R ₄ : hydrogen atom, R ₅ : methoxyethyl group,
R ₆ : methoxy group, R ₇ : methoxy group, R ₈ : hydrogen atom]
In the same manner as in Example 3 except that 4.24 g was replaced with 10 g of sodium borofluoride instead of 10 g of sodium perchlorate,
0.72 g of compound 5 was obtained.

The maximum absorption wavelength (λmax) in methanol and the elemental analysis value of the crystals were as follows. Maximum absorption wavelength (λmax): 715 nm (in MeOH) Elemental analysis: (C ₅₃ H ₆₇ N ₄ O ₄ BF ₄ )

Example 9 (Synthesis of Compound 9)

[0065]

Embedded imageIn Example 3, an ethylene compound of the general formula (2) was used.
And [R₁: Methoxyethyl group, R_Two: Methyl group, R_Three:
Methyl group, R_Four: Hydrogen atom, R_Five: Ethyl group, R ₆: Met
Xyethyl group, R₇: Methyl group, R₈: Hydrogen atom] 4.24g
With sodium iodide instead of 10g of sodium perchlorate
Compound 9 was prepared in the same manner as in Example 3 except that 10 g of Compound 9 was used.
1.35 g was obtained.

The maximum absorption wavelength (λmax) and the elemental analysis value of the crystals in methanol were as follows. Maximum absorption wavelength (λmax): 713 nm (in MeOH) Elemental analysis: (C ₅₇ H ₆₇ N ₄ IO ₄ )

Example 10 (Synthesis of Compound 10)

[0068]

Embedded image Instead of the ethylene compound of the general formula (2) in Example 1, [R ₁ : methoxyethyl group, R ₂ : methyl group, R ₃ : cyclohexyl group, R ₄ : hydrogen atom, R ₅ : methoxyethyl group, R ₆ : Methyl group, R ₇ : cyclohexyl group, R ₈ : hydrogen atom] 9.89 g, the same as Example 1 except that 15 g of a 60% aqueous solution of hexafluorophosphoric acid (HPF ₆ ) was used instead of 10 g of sodium perchlorate. As a result, 1.05 g of Compound 10 was obtained.

The maximum absorption wavelength (λmax) in methanol and the elemental analysis value of the crystals were as follows. Maximum absorption wavelength (λmax): 711 nm (in MeOH) Elemental analysis: (C ₇₇ H ₇₅ N ₄ F ₆ O ₄ P)

[Measurement of Solubility] Each of the pentamethine compounds synthesized in Examples 1 to 7, the compounds of formulas (6), (7) and (8) and methanol were added to 50 ml sample tubes at 1%, 3% and 5%, respectively. % (W / v) of a methanol mixture, and the mixture was sealed and subjected to ultrasonic shaking at 50 ° C. for 10 minutes. Next, the mixture was allowed to stand at room temperature for 30 minutes and then filtered to confirm the presence or absence of insolubles. 1% (w / v) mixed solution containing insolubles was adjusted to 1% (w / v) solubilities of 1% (w / v) and 3% (w / v) without insolubles. Insoluble matter in the mixed solution of 1% or more to less than 3%, 3
5% with no insolubles in the mixture of% concentration (w / v) adjustment
(W / v) Adjustable mixed solution with insolubles is 3% or more to less than 5%, and 5% (w / v) adjusted mixed solution without insolubles is 5% or more. did. Table 2 shows the results
Shown in

[0071]

[Table 2]

Example 11 (Preparation of Optical Recording Material) A solution prepared by dissolving 1 part of the compound 1 (synthesized in Example 1) in 50 parts of diacetone alcohol was filtered through a 0.5 μm millipore filter, and then subjected to spin coating. Using spinner 1-H-III-A manufactured by Kyoei Semiconductor Co., Ltd., 15
An optical recording material was prepared by coating and drying on a 1 mm thick polycarbonate substrate at a rotation speed of 00 rpm.

Examples 12 to 17 (Preparation of Optical Recording Material) In Example 11, compounds 2 to 7 were used instead of compound 1.
Was used in the same manner as in Example 11 except that 1 part of each was used to produce an optical recording material.

Comparative Example 1 (Preparation of Optical Recording Material) In Example 11, the compound of the above formula (6) was used in place of compound 1.
An optical recording material was produced in the same manner as in Example 11, except that 1 part of the compound was used.

Comparative Example 2 (Preparation of Optical Recording Material) In Example 11, the compound of the above formula (7) was used in place of compound 1.
An optical recording material was produced in the same manner as in Example 11, except that 1 part of the compound was used.

Comparative Example 3 (Preparation of Optical Recording Material) In Example 11, the compound of the above formula (8) was used in place of compound 1.
An optical recording material was produced in the same manner as in Example 11, except that 1 part of the compound was used.

[Measurement of Reflectivity and Absorptance]
17 and 78 of the optical recording materials produced in Comparative Examples 1, 2, and 3
The reflectance and the absorptance from the substrate surface side at 0 nm were measured using a spectrophotometer UV-365 manufactured by Shimadzu Corporation. Table 3 shows the results.

[Recording Characteristics] A semiconductor laser head (laser diode LTO24MD; manufactured by Sharp, oscillation wavelength 780 nm, output 30 mW) and a photodiode were applied to the optical recording materials produced in Examples 11 to 17 and Comparative Examples 1, 2, and 3. The recording layer is irradiated with laser at a recording power of 6 mW and a pulse width of 0.2 ms from the substrate surface side using a device combined with a pulse generator, and the presence / absence of recording and the pit shape are measured with an optical microscope BHT manufactured by Olympus Corporation. And observed.

Table 3 shows the results. Pit shape is good
Clear pits were formed, and the pit shape was slightly good, in which pit formation was recognized or slightly unclear, and a pit shape defect was that pit formation was hardly confirmed. Is shown.

[Light Resistance Test] The optical recording materials prepared in Examples 11 to 17 and Comparative Examples 1, 2, and 3 were irradiated with a carbon arc fade meter at 40 ° C. for 6 hours and then absorbed at 780 nm on the substrate surface. Was measured to determine a change in absorptance, and the light resistance was compared. Absorption rate change (%) = {(absorption rate before test−absorption rate after test) / absorption rate before test} × 100 The results are shown in Table 3.

[0081]

[Table 3] Absorption Yield changes: smaller value indicates a higher light fastness of the recording layer.

[0082]

The pentamethine compound of the present invention has high solvent solubility, and an optical recording material using the pentamethine compound has good absorption and reflection in a semiconductor laser region and is excellent in light stability.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of Compound 1 synthesized in Example 1.

FIG. 2 is an infrared absorption spectrum of Compound 4 synthesized in Example 4.

FIG. 3 is an infrared absorption spectrum of Compound 5 synthesized in Example 5.

FIG. 4 is an infrared absorption spectrum of Compound 6 synthesized in Example 6.

FIG. 5 is an infrared absorption spectrum of compound 7 synthesized in Example 7.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinzo Nawamoto 1-43, Minami, Yuge-cho, Yao-shi, Osaka Yamamoto Kasei Co., Ltd. JP-A-60-83892 (JP, A) JP-A-60-159087 (JP, A) JP-A-6-9890 (JP, A) JP-A-1-1533753 (JP) (A) JP-A-6-51420 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09B 23/00 CA (STN) REGISTRY (STN)

Claims (10)

(57) [Claims] 1. A pentamethine compound represented by the following general formula (1). Embedded image (Wherein, R ₁ and R ₅ each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms or a cycloalkyl group having 5 to 7 carbon atoms, and R ₂ and R ₆ Is
Each independently an alkyl group having 1 to 8 carbon atoms, 5 to 5 carbon atoms
7 represents a cycloalkyl group, an aryl group or a substituted aryl group, wherein R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; A cycloalkyl group having 5 to 7 carbon atoms, an aryl group or a substituted aryl group, and Z represents an acidic residue. ) 2. The pentamethine compound according to claim ₁ , wherein R ₁ and R ₅ are an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 3 to 6 carbon atoms. 3. The pentamethine compound according to claim 1, wherein R ₂ and R ₆ are a methyl group, an ethyl group or a phenyl group. 4. The method according to claim 1, wherein R ₃ , R ₄ , R ₇ and R ₈ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. Items 1-3
The pentamethine compound according to any one of the above. 5. The method according to claim 1, wherein the acidic residue Z is I^-, ClO_Four ^-, BF_Four ^-,
PF₆ ^-Or SbF₆ ^-5. The method according to claim 1, wherein
The pentamethine compound according to the above item. 6. An indolylethylene compound represented by the following general formula (2): (Wherein, R ₁ and R ₅ each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms or a cycloalkyl group having 5 to 7 carbon atoms, and R ₂ and R ₆ Is
Each independently an alkyl group having 1 to 8 carbon atoms, 5 to 5 carbon atoms
7 represents a cycloalkyl group, an aryl group or a substituted aryl group, wherein R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; A cycloalkyl group having 5 to 7 carbon atoms, an aryl group or a substituted aryl group. ) And an orthoester represented by the following general formula (3): CH (OR) ₃ (3) (wherein R represents a methyl group or an ethyl group) in the presence of an acidic substance. The method for producing a pentamethine compound according to claim 1, wherein the pentamethine compound is condensed in a neutral organic acid. 7. An indolylethylene compound represented by the following general formula (2): (Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ are the same as those described in claim 6) and the following formula (4) Malonaldehyde dianyl represented by Is condensed in a dehydrating organic acid in the presence of an acidic substance, and the pentamethine compound according to claim 1. 8. An indolyl ethylene compound represented by the following general formula (2): (Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₈ are the same as those described in claim 6) and the following general formula (5) A compound represented by the formula (Wherein, R ₁ and R ₅ each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms or a cycloalkyl group having 5 to 7 carbon atoms, and R ₂ and R ₆ Is
Each independently an alkyl group having 1 to 8 carbon atoms, 5 to 5 carbon atoms
7 represents a cycloalkyl group, an aryl group or a substituted aryl group, wherein R ₃ , R ₄ , R ₇ and R ₈ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; A cycloalkyl group having 5 to 7 carbon atoms, an aryl group or a substituted aryl group. 2) is condensed in a dehydrating organic acid in the presence of an acidic substance. 9. An optical recording material comprising a recording layer containing the pentamethine compound according to claim 1. 10. An optical recording material comprising a recording layer provided on a substrate, wherein the pentamethine compound according to claim 1 is contained in the recording layer.