JPH04128281A - Photochromic compound - Google Patents

Abstract

NEW MATERIAL:The photochromic compound of formula I [R1 to R4 are H, halogen, alkyl, aryl, alkoxy, etc.; R5 is styryl; (n) is 1 or 2; X is O or N-R6 (R6 is H, alkyl, aryl, etc.); Y is O, S or N-R6]. EXAMPLE:(E)-alpha-2-methyl-5-styryl-3-thienylethylidene-(isopropyliden e)succinic acid anhydride. USE:An optical recording and optical memory material, a copying material, a photo-sensitizer for printing, an optical filter and a display material. PREPARATION:The compound of formula I can be produced e.g. by reacting 3-acetyl-2-methyl-5-styrylthiophene of formula II with diethylisopropylidenesuccinic acid diethyl ester of formula III in the presence of potassium tert. butoxide and tert. butanol, hydrolyzing the ester group of the reaction product and dehydrating with acetic anhydride.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to a novel photochromic compound used for optical recording, optical storage, copying media, etc.

[Prior Art and its Problems] One of the widely known photochromic compounds is a fulgide compound in which an alkylidene group is bonded to each of the two methylene carbons of succinic anhydride or a derivative thereof. (Tokuko Showa 60-5215
(No. 0, U.S. Patent No. 4,220,708, etc.) These fulgide-based photochromic compounds have the property of changing their structure when irradiated with light of a certain wavelength, and returning to their original structure when they are further irradiated with light of a specific wavelength. . Utilizing these properties, it becomes possible to optically read and write, and it can be used as various optical recording, optical storage, copying media, etc.

By the way, when used as such an optical recording medium, the following properties are required of the photochromic compound.

■Good repeat durability. (Repeatability of recording and erasing) - Good thermal stability in the dark. (Storability of color development/decoloration state) ■Sensitivity to long wavelength region. (Compatibility with semiconductor lasers) However, although all conventional fulgide compounds exhibit excellent performance in terms of conditions (■) and (■) above, there is no known compound that fully satisfies condition (■). . That is, there is no chromophoric material that exhibits high absorbance in the long wavelength region, resulting in the inconvenience that sufficient readout sensitivity cannot be obtained.

This invention was made to solve the above problems, and an object thereof is to provide a photochromic compound that exhibits high absorbance in a long wavelength region.

[Means for Solving the Problems] In the present invention, by introducing a styryl group into a specific site of a fulgide compound having a heterocycle, it is possible to lengthen the absorption wavelength of the color former and increase its absorption intensity.

That is, the photochromic compound of the present invention is represented by the following general formula (1).

In formula 1, R1-R4 are each a hydrogen atom, a norogen atom, an alkyl group, an aryl group, an allyl group, an aralkyl group, an aryloxy group, an allyloxy group, an aralkyl group,
It represents an amino group, a pyrrolyl group, a furyl group, a thienyl group, a thiazolyl group, an oxacylyl group, a cyano group, a nitro group, an ester group, or a trifluoromethyl group, %R8 represents a styryl group, and n represents 1 or 2. X represents an oxygen atom or N Re (R6 represents a hydrogen atom, an alkyl group, an allyl group, an aryl group, or an aralkyl group), and Y
does not represent an oxygen atom, a sulfur atom or N-n. ) The photochromic compound of the present invention can be synthesized by stop-condensing heterocycles of thiophene derivatives, furan derivatives, virol derivatives, etc., as shown in the synthesis scheme below. and further, if necessary, Rs N
An R6 group can be introduced into the fulgide ring by reaction with Ht and acid chloride or acetic anhydride. In addition, R I-R*, Y in the following synthesis scheme
and n are the same as the substituents in general formula (1).

Fulgir The thus obtained compounds of the present invention represented by the general formula (1) each have a styryl group introduced into a specific site of fulgide having a heterocycle, and the absorption wavelength of the chromophore is increased to a longer wavelength. This makes it possible to increase the absorption intensity.

The compound of this invention exhibits photochromic properties, for example, as shown below,
When irradiated with visible light of wavelength 500 nm, the colorless open ring form changes to a colored closed ring form, and when this closed ring form is further irradiated with visible light with a wavelength of 500 nm or more, it returns to the colorless open ring form.

Colorless body (open ring body) Colored body (
(R in the formula is the same as the substituent in general formula (I).) Because of these properties, these compounds are suitable for optical reading and writing using semiconductor lasers. It can be suitably used as an optical recording material, an optical storage material, a copying material, a photoreceptor for printing, an optical filter display material, etc.

[Example] (Example) (E) - Synthesis of α-2-methyl-5-styry-3-thienylethylidene (isopropylidene) succinic anhydride ■Synthesis of intermediate raw material 3-acetyl-2-methyl-5-styrylthiophene Sodium etquinde 15.0 g (0.22 mo12
) and dimethylformamide 90+aff, add 35 g of benzyl diethyl phosphonate (0°15 II
A mixture of 19 g (0,1 5 mo12) of 2-methyl-thiophene-5-aldehyde and 40 alt of dimethylformamide was slowly added dropwise while cooling with water.

After the dropwise addition was completed, the mixture was stirred at room temperature for 2.5 hours. The reaction solution was then poured into ice water, extracted with ether, and the organic layer was washed with water, dried, and the solvent was distilled off. The resulting solid was recrystallized from ethyl alcohol to yield 16 g of 2-methyl-5
-Styrylthiophene was obtained.

Next, 8 g of this 2-methyl-5-styrylthiophene (
0,04mol12), acetic anhydride 4.6g (0,045mol12)
moI2) and benzene 60+l112, anhydrous tin chloride log and benzene IO+e at room temperature.
ff was added to perform Friedel-Crafu acetylation.

After stirring at room temperature for 1 hour, the mixture was acidified with hydrochloric acid, extracted with benzene, washed, dried, and the solvent was distilled off.

The resulting oil was eluted with column chromatography (developing solvent benzene) and 3-acetyl-2-methyl-
0.5 g of 5-styrylthiophene was obtained.

■Synthesis of intermediate raw material diethyl isopropylidene succinate 100g of potassium t-butoxide and 80g of t-butanol
Diethyl succinate 174 in a solution dissolved in 0ml
A mixed solution of 46.5 g of acetone and 46.5 g of acetone was added thereto, and the mixture was heated under reflux for 30 minutes. The half ester extracted with diethyl ether was added to a mixture of ethanol 112 and concentrated sulfuric acid 10II112, and the mixture was heated under reflux for 8 hours. After evaporating the solvent, extraction was performed with diethyl ether, and after washing, the solvent was evaporated, and the resulting crude product was purified by distillation under reduced pressure to obtain 120 g of diethyl isopropylidene succinate. (boiling point 74-75℃7
2 mI@l-1g) ■Synthesis of the title fulgide compound While refluxing a mixture of 0.22g of potassium-t-butoxide and 311Q of t-butanol, 3-acetyl-2-
0.5 g of methyl-5-styrylthiophene and 0.53 g of diethylisopropylidene succinate were added. After continuing to heat under reflux for 1 hour, the solvent was distilled off, and the resulting half ester was acidified with hydrochloric acid and extracted with ether. After washing and drying, the solvent was distilled off to obtain a yellow oily half ester. Then 5 w/v% ethanolic potassium hydroxide 50
+s (!) was added and heated under reflux for 10 hours. Then, after acidifying with hydrochloric acid, extraction with ether was performed to obtain a double product. This was dissolved in 10 ml of acetic anhydride and heated at 50°C for 1 hour. After distilling off the solvent, chloroform The solid containing the title fulgide was obtained by dissolving it in water, washing with water, drying, and evaporating the solvent.This solid was recrystallized from chloroform-hexane to obtain the title fulgide compound 24B (Z isomer, melting point 222-224°C). I got it.

Upon irradiation with ultraviolet rays, this compound rapidly changed into the E isomer and further into a colored substance. The identification results by NMR are shown in Table 1.

(Test Example) The fulgide compound obtained in the above example was dissolved in toluene to prepare a solution of 1, OX 1 O-'poQ/Q.

Add a 250W ultra-high pressure mercury lamp (manufactured by Ushio Inc.) to this solution.
A glass filter (UV-3 manufactured by Toshiba Glass Co., Ltd.) was used as the light source.
5 and UV-D36C) were irradiated with ultraviolet light with a wavelength of 365 nm, the solution was colored and
It changed to a closed ring form having maximum absorption at 58 nm. The absorption spectrum of this colored body is shown in FIG. 1 by a broken line.

Next, when visible light with a wavelength of 500n+e or more was irradiated using a 300W xenon lamp (manufactured by Ushio Inc.) as a light source, it quickly returned to an open ring form.

This change could be repeated.

For comparison, (E)-α-2,5-dimethyl 3-thienylethylidene (isopropylidene) succinic anhydride (
Hereinafter, it will be abbreviated as comparative example compound. ) under the same conditions.

This result is shown in FIG. 1 by a solid line. The maximum absorption wavelength of this comparative example compound was 520 nm.

As is clear from FIG. 1, it was confirmed that the introduction of styryl groups not only makes it possible to lengthen the wavelength of the absorption region, but also has an excellent effect on increasing the absorption intensity.

In particular, compared to the comparative example compound having a methyl group, the present example compound into which a styryl group has been introduced exhibits about twice the absorption intensity, and the introduction of the styryl group greatly contributes to the increase in the absorption intensity, indicating that the recording medium It was confirmed that this method has a significant effect on improving readout sensitivity.

[Effects of the Invention] As explained above, the photochromic compound of the present invention has a styryl group introduced into a specific site of a fulgide compound having a heterocycle, so it has a higher ring closure rate than conventional photochromic compounds. This not only makes it possible to extend the wavelength of the absorption region of the body to a longer wavelength, but also makes it possible to increase the absorption intensity.

Therefore, compatibility with semiconductor lasers is improved, and read sensitivity can be improved when used as a recording medium.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the absorption spectra of the photochromic compound of the present invention and a conventional photochromic compound.

Claims (1)

[Claims] A photochromic compound represented by the following general formula (I)▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(I
) {In the formula, R_1 to R_4 are each a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an allyl group, an alkoxyl group, an aryloxy group, an allyloxy group, an aralkyl group, an amino group, a pyrrolyl group, a furyl group, a thienyl group, It represents a thiazolyl group, an oxazolyl group, a cyano group, a nitro group, an ester group, or a trifluoromethyl group, R_5 represents a styryl group, and n represents 1 or 2. X is an oxygen atom or N-R_6 (R_6 is a hydrogen atom, an alkyl group,
Represents an allyl group, an aryl group, or an aralkyl group. ), and Y represents an oxygen atom, a sulfur atom, or NR_6. }