JPH051056A - Benzothiophene compound - Google Patents

Abstract

PURPOSE:To provide a new compound having photochromic property and thermal stability and useful as a memory material. CONSTITUTION:The compound of formula I (R1 to R10 are same or different groups, preferably CH3 or Br; both of R5 and R6 are preferably CH3, H, acyl or X; X is F, Cl, Br or I), e.g. 3,3'-azobis (2-methylbenzothiophene). The compound can be produced by putting 2-methyl-3-nitrobenzothiophene of formula II in an ethanol solution of sodium hydroxide and slowly adding zinc powder to the solution under thermal refluxing to effect the reaction.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel benzothiophene compound. More specifically, the present invention relates to a benzothiophene compound having a so-called photochromic property in which a reversible structural change occurs with light irradiation, and a memory material using the same.

[0002]

2. Description of the Related Art Conventional memory media include magnetic memory and magneto-optical memory.
The photochromic material can be a memory material having a memory density several tens of times that of a magnetic memory, several times that of a magneto-optical memory, and data transfer rates of 10 to 30 times and 30 to 50 times, respectively. However, in the photochromic materials that have been studied so far, one of the isomers thereof is thermally unstable, and it is easy to convert into a stable isomer. The storability and the stability at the time of reproduction (stability against reading light) were poor in reliability.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel benzothiophene compound having photochromic properties and stable in any isomer.

[0004]

The benzothiophene compound of the present invention has the chemical formula 1

[0005]

[Chemical 2]

(Wherein the substituents R ₁ , R ₂ , R ₃ , R ₄ ,
R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , and R ₁₀ may be the same or different and at least one group contains carbon;
Represents -H or -X (X = F, Cl, Br, I))
And preferably R _{1 to} R ₁₀ are the same. A more desirable benzothiophene compound of the present invention is characterized in that the substituent is -CH ₃ or -Br, and preferably R ₅ and R ₆ are both -CH ₃ , -H, an acyl group or-. It is characterized by being X.

[0007]

According to the constitution of the present invention, as shown in the chemical formula 2, the isomer of the structure A is converted to the structure B by irradiating the isomer of the structure A with the light of the specific wavelength (λ ₁ ). When another specific wavelength (λ ₂ ) is applied to the isomer of structure B, the structure returns to the original structure A.
During this period, there is no change in the molecular weight between the two substances, a structural change occurs, and the absorption wavelength changes.

[0008]

[Chemical 3]

(Any isomer of Chemical Formula 2 and a mixture thereof are included in the present invention.) These compounds are structurally stable and thermally stable in each state.

[0010]

EXAMPLE A compound represented by Formula 1 according to the present invention is
It is a novel substance and can be produced by the following method.

As the substance represented by the chemical formula 1, 3,3 '
-Azobis (2-methylbenzothiophene) can be mentioned, and a production example thereof is shown as Chemical Formula 3.

[0012]

[Chemical 4]

[Production Example] Production method of 3,3'-azobis (2-methylbenzothiophene) (reaction 1) 3-nitrobenzothiophene acetic anhydride (17 ml) was cooled in an ice bath to obtain 90% nitric acid ( 2.0 ml) was added slowly, and sulfuric acid (1 drop) was added.
Was added. A solution of benzothiophene (2.0 g) in DMSO is added dropwise in small portions with thorough stirring. During this period, the reaction temperature is maintained at 0 to 5 ° C. The reaction mixture is 0
Stir at ~ 5 ° C for 30 minutes and add sodium hydroxide (14.
A solution of 9 g) in 130 ml of water is cooled to 0 ° C. and neutralized. Then, it was extracted with benzene, dried and the solvent was distilled off to obtain 0.65 g of 3-nitrobenzothiophene (yield 24.4%).

[0014] (Reaction 2) 2-Methyl-3-nitrobenzothiophene 60% Na in DMSO (10 ml) cooled to 0 to 5 ° C.
Add 0.8 g of H (in oil) and stir at room temperature until no foaming occurs. 3-nitrobenzothiophene (1.8g)
Is dissolved and MeI (2.9 g) is slowly added dropwise while the solution is cooled. Then, the mixture was stirred for 1 hour, poured into 100 ml of water, stirred, extracted with benzene, dried, and dried with 2-methyl-
0.58 g of 3-nitrobenzothiophene was obtained (yield 3
0.0%).

[0015] (Reaction 3) 3,3′-azobis (2-methylbenzothiophene) Ethanol (39 ml), 12M sodium hydroxide solution (6.4 ml) was added with 2-methyl-3-nitrobenzothiophene (3.8 g). ), While heating under reflux,
Add zinc dust (10.6 g) slowly in small portions.
After the addition is complete, continue refluxing for 30 minutes. The hot reaction mixture is then filtered off and purified to give 0.16 g of the title compound.
Obtained (yield 5.1%).

[0016] Next, the photoisomerization reaction formula of the title compound is shown in Chemical Formula 4, and FIG. 1 shows the absorption spectrum of each structure.

[0017]

[Chemical 5]

Further, the results of measuring the thermal stability of the title compound in structure D are shown in FIG.

[0019]

Industrial Applicability As described above, the benzothiophene compound having photochromic properties according to the present invention is thermally stable and effective as a memory material.

[Brief description of drawings]

FIG. 1 shows structures C and D of isomerization reaction formula 4 according to an embodiment of the present invention.
FIG. 3 is an absorption spectrum diagram in FIG.

FIG. 2 shows the structure D of isomerization reaction formula 4 according to the example of the present invention, in which the horizontal axis represents time and the vertical axis represents the ratio of the maximum absorption wavelength.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masamitsu Uehara             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation

Claims (6)

[Claims] 1. A benzothiophene-based compound represented by Chemical Formula 1. [Chemical 1] (In the formula, substituents R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ ,
R ₈ , R ₉ and R ₁₀ may be the same or different, and at least one group containing carbon, —H, or —X.
Represents (X = F, Cl, Br, I)) 2. The benzothiophene-based compound according to claim 1, wherein the substituent is an alkyl group or an acyl group. 3. The benzothiophene-based compound according to claim 1, wherein the substituents are the same. 4. The benzothiophene-based compound according to claim ₃ , wherein the substituent is —CH ₃ . 5. The benzothiophene-based compound according to claim 3, wherein the substituent is —Br. 6. R ₅ and R ₆ are both —CH ₃ , —
The benzothiophene-based compound according to claim 1, which is H, an acyl group, or -X.