JP4224046B2 - Optical recording medium - Google Patents

Description

  The present invention relates to an optical recording medium having a recording layer for recording information as a pattern by a laser, and more specifically, a recording layer suitable for recording by a so-called blue laser, more specifically, a recording layer. It is characteristic of the dye compound.

  Currently, recording media such as CD-R / RW, DVD-R / RW, and MO can be recorded in a non-contact manner, and various recording media can record large amounts of data. In recent years, it has rapidly become widespread as an external recording device for data processing devices such as computers because random access is easier than tape streamers that record and store large volumes, and the unit price of media is low. is doing.

  In particular, in CD-R and DVD-R, the media is very inexpensive, and it has excellent compatibility regardless of the computer model, and it can be used in various DV devices, etc. It is widely used in institutions, schools and government offices, and is considered to have more and more advantages in the future.

  In recent years, data handled up to now has been recorded moving image data with a large amount of data such as movies from a relatively small amount of data such as character data or still image data, even with DVD-R. There is a growing demand for recording a large amount of data with a small recording capacity. Therefore, an optical recording medium capable of high-speed and high-density recording / reproduction using a short-wavelength laser such as a blue laser has been proposed and researched and developed by related companies.

  In order to develop an optical recording medium capable of recording and reproducing at such a high density, an organic dye material for recording on a high-speed and high-density optical recording medium using a laser beam having a short oscillation wavelength such as a blue laser is required. However, the present situation is that an organic dye material having a sufficient maximum absorption in the vicinity of 405 nm, which is 390 nm to 430 nm, particularly the most important wavelength region, has not been developed.

Examples of compounds having absorption in such a wavelength region include pyran compound derivatives, polyacene diimide dye derivatives, and cyanine organic dyes as the basic skeleton of organic dyes described in Patent Documents 1 to 5, for example. A mixture, a method using a benzene derivative having a specific amino group introduced at the para-position of the methine group, and the like have been proposed.
JP 2004-322564 A JP 2004-090372 A JP 2003-266554 A JP 2003-246142 A JP 2003-103935 A

  However, for example, as can be seen from the absorption curve chart of the synthetic compound described in Patent Document 3, λmax is 350 to 380 nm, the absorption intensity near 405 nm is small, and it is not necessarily adapted to so-called blue laser light. It can not be said.

  Further, in order to use the organic dye material as described above as an optical recording medium, it is necessary to include the organic dye material in a recording layer on one side or both sides of the optical recording medium. In order to form such a recording layer, the organic dye is generally dissolved in some organic solvent and then spin-coated. However, in order to spin coat the organic dye material, toluene, xylene or cellosolve organic solvent has to be used as a solvent. However, such an organic solvent may damage the material of the optical recording medium, The use is avoided because of problems.

Ｒ_１〜Ｒ_３は、水素原子、ハロゲン、シアノ基、ニトロ基、ヒドロキシル基、カルボキシル基、カルボキシアルキル基、炭素数１〜２０のアルコキシ基（１〜３位のいずれかで枝分かれしているものを含む）、炭素数１〜２０のアルキルオキシカルボニル基のうち、いずれかの官能基または原子であり、
Ｒ_４は、水素原子、炭素数１〜２０のアルキル基（１〜３位のいずれかで枝分かれしているものを含む）、炭素数１〜３のカルボキシアルキル基のうち、いずれかの官能基または原子である。 In the present invention, among the 5-benzylidene-2-thioxo-thiazolidin-4-one derivatives represented by the following general formula (A), R _{1 to} R ₄ in the formula (1) are respectively the following functional groups or atoms: The main solution is that the thiazolidine derivative compound of any of these is contained in the recording layer of the optical recording medium.

R _{1 to} R ₃ are each a hydrogen atom, a halogen, a cyano group, a nitro group, a hydroxyl group, a carboxyl group, a carboxyalkyl group, or an alkoxy group having 1 to 20 carbon atoms (branched at any one of 1 to 3 positions) A functional group or an atom among the alkyloxycarbonyl groups having 1 to 20 carbon atoms,
R ₄ is a functional group selected from a hydrogen atom, an alkyl group having 1 to 20 carbon atoms (including those branched at any one of positions 1 to 3), and a carboxyalkyl group having 1 to 3 carbon atoms. Or it is an atom.

  Since the optical recording medium of the present invention contains the above compound in the recording layer, the absorption region of the recording layer has a large absorption in the range of 390 to 430 nm, and further has a maximum absorption region in the wavelength region near 400 nm. A medium having an absorption band corresponding to the wavelength of a so-called blue laser having a wavelength near 405 nm can be obtained.

化合物（ｂ）

化合物（ｃ）

化合物（ｄ）

化合物（ｅ）

Among them, R ₃ and R ₄ are 2-ethylhexyl groups such as compounds (a), (b), (c), (d) and (e) of the following (Chemical Formula 22 to Chemical Formula 25, Chemical Formula 29): A compound such as 2-ethylhexyl ester is excellent in solubility in isopropyl alcohol and other various solvents, and has excellent characteristics that it is difficult to crystallize after being coated on a substrate and dried. In the following compounds (a) to (e), the recording layer can be easily formed on the substrate.
Compound (a)

Compound (b)

Compound (c)

Compound (d)

Compound (e)

化合物（ｇ）

化合物（ｈ）

化合物（ｉ）

化合物（ｊ）

化合物（ｋ）

In addition to the above compounds (a) to (e), among the compounds of the present invention, the following compounds (f) to (k) are experimentally compounds having appropriate absorption bands for blue lasers. Also became clear.
Compound (f)

Compound (g)

Compound (h)

Compound (i)

Compound (j)

Compound (k)

  Furthermore, the above compound can be deposited on a substrate not only by a wet coating method but also by a vapor deposition method or a sputtering method, and a good optical recording medium can also be produced by these methods.

  The present invention will be described in detail below. The present invention relates to an optical recording medium having a recording layer that can be recorded by a laser on at least one side, wherein the recording layer contains an organic dye compound represented by the general formula (A). Is. The recording layer has absorption in a blue light region of 390 to 430 nm. The compound represented by the general formula (A) will be described below.

(A) In formula, R < ₁ > -R < ₄ > represents a hydrogen atom or arbitrary substituents each independently, and arbitrary substituents may be further substituted. Examples of the optional substituent include R _{1 to} R ₃ as halogens such as fluorine, chlorine and bromine; methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert- A linear or branched alkyl group having 1 to 20 carbon atoms which may be substituted such as butyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group; hydroxy group, methoxy group, ethoxy group, propoxy group, 1 to 1 carbon atoms which may be substituted such as isopropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, n-hexyloxy group, n-octyloxy group and 2-ethylhexyloxy group 20 linear or branched alkyloxy groups; carboxyl group, methoxycarbonyl group, ethoxycarbonyl group, isopropoxycarbonyl group, n-butoxycar 1 carbon atom which may be substituted such as nyl group, isobutoxycarbonyl group, sec-butoxycarbonyl group, tert-butoxycarbonyl group, n-hexyloxycarbonyl group, n-octyloxycarbonyl group, 2-ethylhexyloxycarbonyl group, etc. -20 linear or branched carboxylic acid ester group; cyano group; nitro group and the like.

Examples of the optional substituent include R _{4 as} a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-hexyl group, and an n-octyl group. A linear or branched alkyl group having 1 to 20 carbon atoms that may be substituted, such as 2-ethylhexyl group; an alkyl carboxyl group represented by —R ₅ COOH in the following (Chemical Formula 5 to Chemical Formula 6); The following alkyl carboxylic acid ester groups represented by —R ₅ COOR ₆ of 7 to 16) are mentioned.

Alkyl carboxyl group (—R ₅ COOH)

Alkylcarboxylic acid ester (—R ₅ COOR ₆ )

In the organic dye compound, in general formula (A), R _{1 to} R ₃ are a hydroxyl group, an alkyl group, an alkoxy group, a carboxyl group, and a carboxylate group, and R ₄ is an alkyl group, an alkylcarboxyl group, and an alkylcarboxylate ester. Crystallization can be made difficult by selecting a group in particular and chemically modifying it to make it bulky.

Among them, compounds in which R ₃ and R ₄ are 2-ethylhexyl group, 2-ethylhexyl ester and the like are excellent in solubility in various solvents, and are difficult to crystallize after being coated on a substrate and dried. It was found that it has excellent characteristics. This seems to be the effect of introducing a bulky 2-ethylhexyl group or the like as a substituent. Specific examples of the compound having such particularly good characteristics include the above-mentioned compounds (a), (b), (c), (d) and (e).

  In order to produce the optical recording medium of the present invention, as a method for containing the above compound in the recording layer, a vacuum deposition method, a sputtering method, a doctor blade method, a cast method, a spin coating method, a dipping method, etc. are common, In terms of cost, spin coating is desirable.

  The coating solvent in the case of coating by a doctor blade method, a casting method, a spin coating method, a dipping method, or the like is not particularly limited as long as it is a solvent that does not attack the substrate. In general, lower alcohols such as methanol, ethanol and isopropyl alcohol are preferred. Examples of other coating solvents include ketone alcohol solvents such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone; cellosolv solvents such as methyl cellosolve and ethyl cellosolve; n-hexane, n-heptane and the like. Chain hydrocarbon solvents; Cyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane; Fluoroalkyl alcohol solvents such as tetrafluoropropanol and octafluoropentanol; Methyl lactate, Ethyl lactate, Methyl 2-hydroxyisobutyrate And the like, and the like.

  Recently, however, toxic solvents and those solvents that may affect the global environment tend to be avoided, so that more safe compounds that are soluble in lower alcohols are required. It has become. Examples of lower alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, 1-butanol, 2-butanol and the like. Among these, methanol is relatively strong in toxicity, and 1-butanol and 2-butanol have problems such as high boiling point and poor volatility. Further, ethanol is disadvantageous in terms of cost, and therefore, the most desirable lower alcohol is isopropyl alcohol (IPA), which is low in cost, has low toxicity, and has good volatility.

  In particular, the compounds (a), (b), (c), (d) and (e) have relatively good solubility in isopropyl alcohol, and after being applied on a substrate and dried as described above. Also has an excellent property that it is difficult to crystallize.

  In addition, when the organic dye compound is applied, a known useful substance such as a binder and a fading preventing agent can also be contained in the solvent. In addition to the recording layer, a layer preferable as a recording medium, such as a light reflection layer and a protective layer, can be appropriately provided.

  Hereinafter, a method for synthesizing the dye compound used in the present invention and an example of producing an optical recording medium using the dye compound are shown. However, the method for synthesizing the compound and the method for producing the recording medium are not limited thereto.

(Example 1)
[Compound (f); Synthesis of methyl-4-((4-oxo-2-thioxothiazolidine-5-ylidene) methyl) benzoate]

  A 200 mL four-necked flask equipped with a condenser with a water meter, a thermometer, and a stirrer were attached, and 4.00 g (0.03 mol) of rhodanine and 4.92 g of methyl 4-formylbenzoate (0.03) Mol), 1.2 g (0.015 mol) of ammonium acetate, 4.5 mL (0.075 mol) of acetic acid, and 45 mL of toluene, and stirred for 1.5 hours while distilling off water at 110 ° C. After cooling, the crystals were filtered off, washed with water, and dried overnight in a dryer at 60 ° C. to obtain 7.83 g of yellow crystals (crude yield 93.4%). The crystals were recrystallized using 300 mL of methyl isobutyl ketone to obtain 5.99 g of a yellow target product. The yield of the obtained compound was 71.4%, and the melting point was 231.6-232.2 ° C.

This compound was quantified with high sensitivity C, H, and N.
<Measurement device>
Oxygen circulation combustion and TCD detection method NCH quantifier Sumigraph NCH-21 type (manufactured by Sumika Chemical Analysis Center)
<Measurement results>
Calculated value as C12H9NO3S2
C (%) 51.60; H (%) 3.25; N (%) 5.01
Measured value C (%) 51.5; H (%) 3.07; N (%) 5.03
In other examples, C, H, and N determinations were performed using the same measuring apparatus.

Moreover, purity was measured by HPLC analysis.
<Measurement conditions>
Apparatus: LC-6A (manufactured by Shimadzu Corporation)
Column used: SUMPAX ODSA-212 5 μm 6 mm × 15 cm
Column temperature: 40 ° C
Moving layer: methanol: 0.1 M citric acid solution = 8: 2
Flow rate: 1.0 mm / min
<Measurement results>
HPLC area percentage purity 99.0%
In other examples, the purity was measured by the same method except for the kind of the solution in the moving bed.

[Production of recording medium]
The compound (f) thus obtained was dissolved in methyl cellosolve to prepare 2.0 wt%. The solution after filtration was dropped onto a transparent polycarbonate disk (diameter: 12 cm, thickness: about 1.2 mm) rotating at a rotational speed of 500 to 600 rpm, and applied by a spinner method. After the coating, it was dried with a drier to obtain an optical recording medium containing compound (1) in the recording layer. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 388 nm.
<Measurement conditions>
Apparatus: UV-2450 (manufactured by Shimadzu Corporation)
Measurement wavelength: 250-500 nm
In other examples, the compound was changed and a recording medium was prepared in the same manner, and the ultraviolet to visible spectrum was measured under the same measurement conditions.

(Example 2)
[Compound (g); Synthesis of 5- (2,4dihydroxybenzylidene) -2-thioxothiazolidine-4-one]

  A 200 mL four-necked flask was equipped with a condenser with a ball, a thermometer, and a stirring device, and 4.00 g (0.03 mol) of rhodanine, 4.14 g (0.03 mol) of 2,4-dihydroxybenzaldehyde, ammonium acetate 1. 2 g (0.015 mol), 4.5 mL (0.075 mol) of acetic acid and 45 mL of IPA were added and stirred at 85 ° C. for 1.5 hours. After cooling, the crystals were filtered off, washed with water, and dried overnight in a dryer at 60 ° C. to obtain 4.55 g of vermilion crystals (crude yield 59.9%). The crystals were dissolved in 220 mL of IPA, filtered hot (75 ° C.), and 120 mL IPA was recovered to obtain 2.23 g of vermilion crystals. The yield of the obtained compound was 29.3%, and the melting point was 262.6 to 262.9 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C10H7NO3S2
C (%) 47.42; H (%) 2.79; N (%) 5.53
Found C (%) 47.2; H (%) 2.32; N (%) 5.45

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: 0.1 M citric acid solution = 8: 2
<Measurement results>
HPLC area percentage purity 98.1%

[Production of recording medium]
The compound (g) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 425 nm.

(Example 3)
[Compound (h); Synthesis of 5- (4- (dimethylamino) benzylidene) -2-thioxothiazolidin-4-one]

  A 200 mL four-necked flask equipped with a condenser with a moisture meter, a thermometer, and a stirrer were attached, 2.66 g (0.02 mol) of rhodanine, 2.98 g (0.02 mol) of p-dimethylaminobenzaldehyde. ), 0.77 g (0.01 mol) of ammonium acetate, 30 mL of acetic acid 3 mL (0.05 mol), and toluene were stirred at 110 ° C. for 1.5 hours while distilling off water. After cooling, the crystals were filtered off, washed with water and dried overnight in a dryer at 60 ° C. to obtain 4.92 g of red crystals (crude yield 93.0%). The crystals were recrystallized using 45 mL of dimethylacetamide and 80 mL of water to obtain 4.53 g of a red target product. The yield of the obtained compound was 86.0%, and the melting point was 281.4 to 281.7 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C12H12N2OS2
C (%) 54.52; H (%) 4.58; N (%) 10.60
Found C (%) 52.5; H (%) 4.49; N (%) 10.2.

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: 0.1 M citric acid solution = 8: 2
<Measurement results>
HPLC area percentage purity 97.6%

[Production of recording medium]
The compound (h) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 451 nm.

(Example 4)
[Compound (a); Synthesis of 2-ethylhexyl-4-((4-oxo-2-thioxothiazolidine-5-ylidene) methyl) benzoate]

A 200 mL four-necked flask was equipped with a ball condenser, a thermometer, and a stirrer, and 5- (4-hydroxy-3-methoxybenzylidene) -2-thioxothiazolidine-4-one 5.59 g (0.02 mol) Then, 5.21 g (0.04 mol) of 2-ethylhexyl alcohol, 0.2 g of dibutyltin oxide and 50 mL of toluene were added and toluene was collected at normal pressure, and then stirred at 130 to 140 ° C. for 6 hours. After cooling to 90 ° C., 30 mL of toluene and 30 mL of water were added, stirred and allowed to stand, then separated (70 ° C.), washed twice with water (30 mL, 70 ° C.), and then toluene was collected under reduced pressure at 65 ° C. IPA (30 mL) was added, and after cooling, the crystals were collected by filtration and dried overnight in a dryer at 60 ° C. to obtain 6.05 g of yellow crystals. The yield of the obtained compound was 83.3%, and the melting point was 130.1-131.0 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C19H23NO3S2
C (%) 60.45; H (%) 6.14; N (%) 3.71
Found C (%) 59.8; H (%) 6.03; N (%) 3.70

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: water = 95: 5
<Measurement results>
HPLC area percentage purity 97.6%

[Production of recording medium]
The compound (a) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 375 nm.

２００ｍＬの４つ口フラスコに水分定量受器のついた玉付きコンデンサー、温度計、撹拌装置を取り付け、ローダニン２．６６ｇ（０．０２モル）、４−（２−エチルヘキシル）−オキシ−３−メトキシベンズアルデヒド５．２９ｇ（０．０２モル）、酢酸アンモニウム０．７７ｇ（０．０１モル）、酢酸３ｍＬ（０．０５モル）、トルエン３０ｍＬを入れ１１０℃にて水を留去しながら１．５時間撹拌した。トルエン２０ｍＬ回収し冷却後、結晶を濾過し取り、トルエン１０ｍＬ洗浄、水洗後６０℃の乾燥機にて一晩乾燥し、黄色の結晶４．０４ｇ（粗収率５３．２％）を得た。その結晶を、ＩＰＡ２５ｍＬを用いて再結晶して黄色の結晶３．７９ｇを得た。さらにＩＰＡ５０ｍＬを用いて再結晶（洗浄ＩＰＡ１０ｍＬ）により黄色結晶の３．０６ｇを得た。得られた化合物の収率は、４０．３％、融点は、１３４．２〜１３４．７℃であった。 (Example 5)
[Compound (b); Synthesis of 5- (4- (2-ethylhexyloxy) -3-methoxybenzylidene) -2-thioxothiazolidin-4-one]

A 200 mL four-necked flask equipped with a condenser with a ball, a thermometer, and a stirrer with a moisture quantification receiver attached thereto, 2.66 g (0.02 mol) of rhodanine, 4- (2-ethylhexyl) -oxy-3-methoxy Benzaldehyde (5.29 g, 0.02 mol), ammonium acetate (0.77 g, 0.01 mol), acetic acid (3 mL, 0.05 mol), and toluene (30 mL) were added, and water was distilled off at 110 ° C. for 1.5 hours. Stir. After 20 mL of toluene was recovered and cooled, the crystals were filtered off, washed with 10 mL of toluene, washed with water, and dried overnight at 60 ° C. to obtain 4.04 g of yellow crystals (crude yield 53.2%). The crystals were recrystallized using 25 mL of IPA to obtain 3.79 g of yellow crystals. Furthermore, 3.06 g of yellow crystals was obtained by recrystallization (washing IPA 10 mL) using 50 mL of IPA. The yield of the obtained compound was 40.3%, and the melting point was 134.2-134.7 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C19H25NO3S2
C (%) 60.13; H (%) 6.64; N (%) 3.69
Found C (%) 62.3; H (%) 5.45; N (%) 3.73

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: water = 95: 5
<Measurement results>
HPLC area percentage purity 98.2%

[Production of recording medium]
The compound (b) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 415 nm.

２００ｍＬの４つ口フラスコに玉付きコンデンサー、温度計、撹拌装置を取り付け、
メチル−４−（（４−オキソ−２−チオキソチアゾリジン−５−イリデン）メチルベンゾエート８．３８ｇ（０．０３モル）、２−エチルヘキシルブロミド５．７９ｇ（０．０３モル）、ＤＭＦ １．５ｇ、炭酸水素ナトリウム５．０４ｇ（０．０６モル）、ヨウ化カリウム０．３ｇ（１．８×１０−３モル）、メチルイソブチルケトン１００ｍＬを入れ１１５℃で８時間撹拌した。冷却後濾過し、濾液を減圧回収した。その残留物を、ｎ−ヘキサン２００ｍＬを用いて抽出し熱濾過（６０℃）し、溶媒を１５０ｍＬ減圧回収、濾過し取り７．６３ｇの結晶を得た。さらにその結晶を、ｎ−ヘキサン１５０ｍＬで２回抽出し、冷却後 黄色の結晶５．４ｇを得た。得られた化合物の収率は、４６．０％、融点は、７３．２〜７２．２℃であった。 (Example 6)
[Compound (c); Synthesis of methyl-4-((3- (2-ethylhexyl) -4-oxo-2-thioxothiazolidine-5-ylidene) methyl) benzoate]

Attach a condenser with a ball, a thermometer, and a stirring device to a 200 mL four-necked flask.
Methyl-4-((4-oxo-2-thioxothiazolidine-5-ylidene) methylbenzoate 8.38 g (0.03 mol), 2-ethylhexyl bromide 5.79 g (0.03 mol), DMF 1.5 g , 5.04 g (0.06 mol) of sodium bicarbonate, 0.3 g (1.8 × 10 −3 mol) of potassium iodide and 100 mL of methyl isobutyl ketone were stirred for 8 hours at 115 ° C. After cooling, the mixture was filtered, The filtrate was recovered under reduced pressure, and the residue was extracted with 200 mL of n-hexane, filtered hot (60 ° C.), recovered with 150 mL of solvent under reduced pressure, and filtered to obtain 7.63 g of crystals. The mixture was extracted twice with 150 mL of n-hexane and cooled to obtain 5.4 g of yellow crystals, and the yield of the obtained compound was 46.0% and the melting point was 73.2-72.2 ° C. It was.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C20H25NO3S2
C (%) 61.35; H (%) 6.44; N (%) 3.58
Found C (%) 63.3; H (%) 5.80; N (%) 3.55

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: water = 95: 5
<Measurement results>
HPLC area purity 90.0%

[Production of recording medium]
The compound (c) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured to obtain the maximum absorption wavelength, λmax was 366 nm.

２００ｍＬの４つ口フラスコに玉付きコンデンサー、温度計、撹拌装置を取り付け、５−（４−ヒドロキシ−３−メトキシベンジリデン）−２−チオキソチアゾリジン−４−オン５．３５ｇ（０．０２モル）、２−エチルヘキシルブロミド３．８６ｇ、炭酸水素ナトリウム３．３６ｇ（０．０４モル）、ヨウ化カリウム０．４ｇ（２．４×１０−３）、メチルイソブチルケトン
２００ｍＬを入れ、１１５℃で１０時間撹拌した。さらに、炭酸水素ナトリウム１．６８ｇ（０．０２モル）、ヨウ化カリウム０．２ｇ（１．２×１０−３モル）を加え１１５℃で６時間撹拌した。冷却後、濾過し、ろ液を減圧回収し、その残留物をｎ−ヘキサン２００ｍＬで２回抽出し、冷却後黄色の結晶２．４１ｇを得た。得られた化合物の収率は、３１．８％、融点は、８１．８〜８２．１℃であった。 (Example 7)
[Compound (d); Synthesis of 5- (4-hydroxy-3-methoxybenzylidene) -3- (2-ethylhexyl) -2-thioxothiazolidin-4-one]

A 200 mL four-necked flask was equipped with a ball condenser, a thermometer, and a stirring device, and 5- (4-hydroxy-3-methoxybenzylidene) -2-thioxothiazolidine-4-one 5.35 g (0.02 mol) 2-ethylhexyl bromide 3.86 g, sodium hydrogen carbonate 3.36 g (0.04 mol), potassium iodide 0.4 g (2.4 × 10 −3) and methyl isobutyl ketone 200 mL were added and the mixture was stirred at 115 ° C. for 10 hours. Stir. Further, 1.68 g (0.02 mol) of sodium hydrogen carbonate and 0.2 g (1.2 × 10 −3 mol) of potassium iodide were added and stirred at 115 ° C. for 6 hours. After cooling, the mixture was filtered, and the filtrate was collected under reduced pressure. The residue was extracted twice with 200 mL of n-hexane to obtain 2.41 g of yellow crystals after cooling. The yield of the obtained compound was 31.8%, and the melting point was 81.8-82.1 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C18H22NO2S2
C (%) 62.03; H (%) 6.36; N (%) 4.02
Found C (%) 62.5; H (%) 5.51; N (%) 3.71

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: water = 95: 5
<Measurement results>
HPLC area percentage purity 99.0%

[Production of recording medium]
The compound (d) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 428 nm. FIG. 1 shows the measured ultraviolet to visible spectrum.

２００ｍＬの４つ口フラスコに水分定量受器のついた玉付きコンデンサー、温度計、撹拌装置を取り付け、ローダニンN−アセチックアシッド３．８２ｇ（０．０２モル）、２，４−ジヒドロキシベンズアルデヒド２．７６ｇ（０．０２モル）、酢酸アンモニウム０．７７ｇ（０．０１モル）、酢酸３ｍＬ（０．０５モル）トルエン３０ｍＬを入れ１１０℃にて水を留去しながら１．５時間撹拌した。冷却後、結晶を濾過し取り、水洗後６０℃の乾燥機にて一晩乾燥し、朱色の結晶３．１３ｇ（粗収率１００．５％）を得た。その結晶とメチルイソブチルケトン５０ｍＬを３０分間還流させ冷却後、結晶を濾過し取りして朱色の結晶２．２５ｇを得た。得られた化合物の収率は、７２．３％、融点を測定したところ、２１６℃で分解した。 (Example 8)
[Compound (i); Synthesis of 2- (5- (2,4-dihydroxybenzylidene) -4-oxo-2-thioxothiazolidin-3-yl) acetic acid]

A 200 mL four-necked flask equipped with a condenser with a water meter, a thermometer, and a stirrer were attached, 3.82 g (0.02 mol) of rhodanine N-acetic acid, and 2,4-dihydroxybenzaldehyde. 76 g (0.02 mol), 0.77 g (0.01 mol) of ammonium acetate, 30 mL of acetic acid 3 mL (0.05 mol) and 30 mL of toluene were added and stirred at 110 ° C. for 1.5 hours while distilling off water. After cooling, the crystals were filtered off, washed with water, and dried overnight in a dryer at 60 ° C. to obtain 3.13 g of vermilion crystals (crude yield 100.5%). The crystals and 50 mL of methyl isobutyl ketone were refluxed for 30 minutes and cooled, and the crystals were filtered off to obtain 2.25 g of vermilion crystals. The yield of the obtained compound was 72.3%, and when the melting point was measured, it was decomposed at 216 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C12H9NO5S2
C (%) 46.29; H (%) 2.91; N (%) 4.50
Found C (%) 43.9; H (%) 3.25; N (%) 6.51

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: 0.1 M citric acid solution = 8: 2
<Measurement results>
HPLC area purity 92.0%

[Production of recording medium]
The compound (i) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 426 nm.

Example 9
[Compound (j); Synthesis of 2- (5- (4- (methoxycarbonyl) benzylidene) -4-oxo-2-thioxothiazolidin-3-yl) acetic acid]

  A 200 mL four-necked flask equipped with a condenser with a water meter, a thermometer and a stirrer were attached, 9.56 g (0.05 mol) of rhodanine N-acetic acid, methyl 4-formylbenzoate, and 8. 21 g (0.05 mol), 1.93 g (0.025 mol) of ammonium acetate, 7.5 mL (0.125 mol) of acetic acid and 75 mL of toluene were added and stirred for 1.5 hours while distilling off water at 110 ° C. did. After cooling, the crystals were collected by filtration, washed with water and dried overnight in a dryer at 60 ° C. to obtain 16.1 g of yellow crystals (crude yield 95.2%). The crystals (5.0 g) and methyl isobutyl ketone (100 mL) were refluxed for 30 minutes and cooled, and then the crystals were filtered to obtain yellow crystals (4.3 g). The yield of the obtained compound was 81.9%, and the melting point was measured.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C14H11NO5S2
C (%) 49.84; H (%) 3.29; N (%) 4.15
Found C (%) 47.4; H (%) 3.13; N (%) 4.71

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: 0.1 M citric acid solution = 8: 2
<Measurement results>
HPLC area percentage purity 95.5%

[Production of recording medium]
The compound (j) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 377 nm.

２００ｍＬの４つ口フラスコに水分定量受器のついた玉付きコンデンサー、温度計、撹拌装置を取り付け、ローダニンN−アセチックアシッド９．５６ｇ（０．０５モル）、バニリン７．６１ｇ（０．０５モル）、酢酸アンモニウム１．９３ｇ（０．０２５モル）、酢酸７．５ｍＬ（０．１２５モル）、トルエン７５ｍＬを入れ１１０℃にて水を留去しながら１．５時間撹拌した。冷却後、結晶を濾過し取り、水洗後６０℃の乾燥機にて一晩乾燥し、黄色の結晶１５．４ｇ（粗収率９４．８％）を得た。その結晶５．０ｇとメチルイソブチルケトン１００ｍＬを３０分間還流させ冷却後、結晶を濾過し取り、黄色の結晶４．５ｇを得た。得られた化合物の収率は、収率８５．３％、融点を測定したところ、２４７℃で分解した。 (Example 10)
[Compound (k); Synthesis of 2- (5- (4-hydroxy-3-methoxybenzylidene) -4-oxo-2-thioxothiaziridin-3-yl) acetic acid]

A 200 mL four-necked flask equipped with a condenser with a water meter, a thermometer, and a stirrer were attached, and 9.56 g (0.05 mol) of rhodanine N-acetic acid and 7.61 g of vanillin (0.05) Mol), 1.93 g (0.025 mol) of ammonium acetate, 7.5 mL (0.125 mol) of acetic acid, and 75 mL of toluene, and stirred for 1.5 hours while distilling off water at 110 ° C. After cooling, the crystals were filtered off, washed with water and dried overnight in a dryer at 60 ° C. to obtain 15.4 g of yellow crystals (crude yield 94.8%). The crystals (5.0 g) and methyl isobutyl ketone (100 mL) were refluxed for 30 minutes and cooled, and then the crystals were filtered to obtain yellow crystals (4.5 g). The yield of the obtained compound was 85.3%, and when the melting point was measured, it decomposed at 247 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C13H11NO5S2
C (%) 47.99; H (%) 3.41; N (%) 4.30
Found C (%) 45.0; H (%) 3.00; N (%) 5.49

The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: 0.1 M citric acid solution = 8: 2
<Measurement results>
HPLC area percentage purity 97.0%

[Production of recording medium]
The compound (k) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 412 nm.

２００ｍＬの４つ口フラスコに水分定量受器のついた玉付きコンデンサー、温度計、撹拌装置を取り付け、２−（５−（４−ヒドロキシ−３−メトキシベンジリデン）−４−オキソ−２−チオキソチアジリジン−３−イル）アセチックアシド３．２５ｇ（０．０
１モル）、２−ヘキシルアルコ−ル６．５ｇ（０．０５モル）、９８％硫酸０．１ｇを入れ１５０〜１６０℃で８時間撹拌した。９０℃まで冷却後、トルエン３０ｍＬ、水３０ｍＬを入れて撹拌、静置後、分液（７０℃）し、水洗２回（３０ｍＬ、７０℃）を行った。その後トルエンを減圧回収し、６５℃にてＩＰＡ３０ｍＬを加え、冷却後結晶を濾過し取り、６０℃の乾燥機にて一晩乾燥し、黄色の結晶１．７３ｇを得た。得られた化合物の収率は、３９．６％、融点は、１２２．０〜１２２．６℃であった。 (Example 11)
[Compound (e); Synthesis of 2-ethylhexyl 2- (5- (4-hydroxy-3-methoxybenzylidene) -4-oxo-2-thioxothiazolidin-3-yl) acetate]

A 200 mL four-necked flask equipped with a condenser with a water meter, a thermometer, and a stirring device were attached, and 2- (5- (4-hydroxy-3-methoxybenzylidene) -4-oxo-2-thioxo was attached. Thiaziridin-3-yl) acetic acid 3.25 g (0.0
1 mol), 6.5 g (0.05 mol) of 2-hexyl alcohol and 0.1 g of 98% sulfuric acid were added and stirred at 150 to 160 ° C. for 8 hours. After cooling to 90 ° C., 30 mL of toluene and 30 mL of water were added, stirred, allowed to stand, then separated (70 ° C.), and washed twice with water (30 mL, 70 ° C.). Thereafter, toluene was recovered under reduced pressure, and 30 mL of IPA was added at 65 ° C. After cooling, the crystals were filtered and dried overnight in a dryer at 60 ° C. to obtain 1.73 g of yellow crystals. The yield of the obtained compound was 39.6%, and the melting point was 122.0-122.6 ° C.

This compound was quantified with high sensitivity C, H, and N in the same apparatus as in Example 1.
<Measurement results>
Calculated value as C21H27NO5S2
C (%) 57.64; H (%) 6.22; N (%) 3.20
Found C (%) 57.2; H (%) 5.91; N (%) 3.14

Moreover, purity was measured by HPLC analysis.
The purity was measured by the same HPLC analysis as in Example 1.
<Measurement conditions>
Moving layer: methanol: water = 95: 5
<Measurement results>
HPLC area percentage purity 96.3%

[Production of recording medium]
The compound (e) thus obtained was contained in the recording layer of the optical recording medium in the same manner as in Example 1. When the ultraviolet to visible spectrum of this recording layer was measured and the maximum absorption wavelength was determined, λmax was 374 nm.

[Other evaluations]
The infrared absorption spectrum was measured about compound (a)-(k) obtained in Examples 1-11. Further, the maximum absorption wavelength λmax in the visible to ultraviolet region in the solution when the compounds (a) to (k) are dissolved in a solvent (chloroform or methanol) is measured, and the maximum absorption when this is used as the recording layer. The difference in wavelength was examined. Note that, as the measuring apparatus, the apparatus: UV-2450 (manufactured by Shimadzu Corporation) was used as in the case of the visible to ultraviolet absorption measurement of the recording layer when used as a recording medium.
Furthermore, the solubility in isopropyl alcohol (IPA) was measured. At this time, the crystallinity when the compounds (a) to (k) were contained in the recording layer of the optical recording medium was also visually determined. The above evaluations are summarized in Tables 1 and 2. Moreover, about the compound (f) (g) (h) (a) (b) (c) (d) of Examples 1-7, an infrared absorption spectrum is shown to FIGS. In addition, the measurement conditions of an infrared absorption spectrum are as follows.
Apparatus: FTIR-8400S (manufactured by Shimadzu Corporation)
Sample: 1/200 (KBr)

  The optical recording medium of the present invention contains a compound having a maximum absorption wavelength of about 410 nm, which is the wavelength of a so-called blue laser, in the recording layer, and thus can be industrially used as the recording medium for the blue laser.

It is an ultraviolet-visible absorption spectrum of the recording layer containing a compound (d). It is an infrared absorption spectrum of a compound (f). It is an infrared absorption spectrum of a compound (g). It is an infrared absorption spectrum of a compound (h). It is an infrared absorption spectrum of a compound (a). It is an infrared absorption spectrum of a compound (b). It is an infrared absorption spectrum of a compound (c). It is an infrared absorption spectrum of a compound (d).

Claims (3)

An optical recording medium having a recording layer recordable by a laser on at least one side,
Among the 5-benzylidene-2-thioxo-thiazolidin-4-one derivatives represented by the following general formula (A), R _{1 to} R ₄ in the formula (1) are any of the following functional groups or atoms, respectively. An optical recording medium comprising the thiazolidine derivative compound as described above in the recording layer.

R _{1 to} R ₃ = hydrogen atom, halogen, cyano group, nitro group, hydroxyl group, carboxyl group, carboxyalkyl group, alkoxy group having 1 to 20 carbon atoms (one branched at any of positions 1 to 3) C 1-20 alkyloxycarbonyl group R ₄ = hydrogen atom, C 1-20 alkyl group (including those branched at any one of positions 1 to 3), C 1-3 Carboxyalkyl group The optical recording medium according to claim 1, wherein R _{1 to} R ₄ in the general formula (A) are any combination among the combinations described in the following (a) to (e).
(a) R ₁ , R ₂ , R ₄ = H,

(b) R ₁ , R ₄ = H, R ₂ = OCH ₃ ,

(c) R ₁ , R ₂ = H, R ₃ = COOCH ₃ ,

(d) R ₁ = H, R ₂ = OCH ₃ , R ₃ = OH,

(e) R ₁ = H, R ₂ = OCH ₃ , R ₃ = OH,

2. The optical recording according to claim 1, wherein R _{1 to} R ₄ in the general formula (A) are any combination of the following combinations (f), (g), and (i) to (k). Medium.
(f) R ₁ , R ₂ , R ₄ = H, R ₃ = COOCH _{3
(g) R 1, R 3} = OH, R 2, R 4 = H
(i) R ₁ , R ₃ = OH, R ₂ = H, R ₄ = CH ₂ COOH
(j) R ₁ , R ₂ = H, R ₃ = COOCH ₃ , R ₄ = CH ₂ COOH
(k) R ₁ = H, R ₂ = OCH ₃ , R ₃ = OH, R ₄ = CH ₂ COOH

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