JPH051231A - Furan compound - Google Patents

Abstract

PURPOSE:To obtain a furan compound having photochromic properties and being stable in each isomeric form by reducing two specified nitro compounds. CONSTITUTION:A furan compound of formula III is obtained by reducing two nitro compounds of formulas I and II. In the formulas, R1 to R6 may be the same or different and are each a group having at least one carbon atom, H or X (wherein X is F, Cl, Br or I). The furan compound in the form of an isomer of formula II is converted into an isomer having a structure of formula IV by irradiation with light having a specified wavelength (lambda1). The isomer of the structure of formula IV is reconverted into an isomer of the initial structure by irradiation with light of a specified wavelength (lambda2). During this conversion, the compound does not undergo any change in molecular weight but undergoes a change in structure to cause a change in absorption wavelength. Namely, the furan compound of formula III has the so-called photochromic properties in which it reversibly changes its structure by irradiation with light, is thermally stable and is effective as a memory material.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to novel furan compounds. More specifically, the present invention relates to a so-called furan compound having a so-called photochromic property, which undergoes a reversible structural change upon 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 furan compound having photochromic properties and stable in any isomer.

[0004]

The furan 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 and R ₆ may be the same or different, at least one of which is a group containing carbon, —H, or —X (X = F, Cl, Br, I)) And
Desirably, R _{1 to} R ₆ are the same. A more desirable furan compound of the present invention is characterized in that the substituent is —CH ₃ or —Br.
Preferably, R ₃ and R ₆ are both -H, an acyl group, or -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 mixtures 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.

The compound of formula 1 can be obtained by reducing two kinds of nitro compounds as shown in formula 3.

[0012]

[Chemical 4]

(In the chemical formula 3, R ₁ , R ₂ , R ₃ ,
R ₄ , R ₅ and R ₆ are as defined in Chemical Formula 1. ) Zinc-sodium hydroxide, lithium aluminum hydroxide and the like are used for the reduction, and examples of the solvent include ethanol and ether.

[Production Example] In the chemical formula 1, R ₁ and R ₄ are acetyl groups, and R ₂ , R ₃ , R ₅ and R ₆ are methyl groups. It is shown in two stages. Method for producing 3,3'-azobis (4-acetyl-2,5-dimethylfuran) (1) 3-acetyl-2,5-dimethyl-4-nitrofuranacetic anhydride (24.5 ml) was added in an ice bath. Upon cooling, 60% nitric acid (4.1 ml) was added slowly, followed by sulfuric acid (1 drop). 3-Acetyl-2,5-dimethylfuran (3.0 g) is added dropwise in small portions with thorough stirring to the solution. During this period, the reaction temperature is maintained at 0 to 5 ° C. The reaction mixture is stirred at 0-5 ° C for 30 minutes, and a solution of sodium hydroxide (22.0 g) in 150 ml of water is cooled to 0 ° C to be neutralized. Then, it was extracted with chloroform, dried and the solvent was distilled off to obtain 1.575 g of 3-acetyl-2,5-dimethyl-4-nitrofuran (yield 39.
6).

Elemental analysis (as C H N) C ₈ H ₉ NO ₄ (183.16) (2) 3,3'-Azobis (4-acetyl-2,5-dimethylfuran) Ethanol (15.7 ml), 12M sodium hydroxide solution (2.6 ml) was added to 3-acetyl obtained in (1) above. -2,5-Dimethyl-4-nitrofuran (1.5 g) was added, and zinc powder (4.4 g) was slowly added little by little while heating under reflux. After the addition is complete, continue refluxing for 30 minutes. The hot reaction mixture is then filtered off, purified,
0.176 g of the title compound was obtained (yield 14.2%).

Elemental analysis (as C H N) C ₁₆ H ₁₈ N ₂ O ₄ (302.32) 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 furan compound having the photochromic property 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 the isomerization reaction formula 4 of the example of the present invention, in which the abscissa at 80 ° C. shows the time, and the ordinate shows the ratio of the maximum absorption wavelength.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location G03C 1/73 503 8910-2H G11B 7/24 516 7215-5D (72) Inventor Masamitsu Uehara Nagano Prefecture Seiko Epson Co., Ltd. 3-3-5 Yamato, Suwa-shi

Claims (6)

[Claims] 1. A furan-based compound represented by Chemical Formula 1. [Chemical 1] (Wherein the substituents R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , and R
₆ may be the same or different and at least one represents a carbon-containing group, -H, or -X (X = F, C
l, Br, I)) 2. The furan-based compound according to claim 1, wherein the substituent is an alkyl group or an acyl group. 3. The furan-based compound according to claim 1, wherein the substituents are the same. 4. The furan-based compound according to claim ₃ , wherein the substituent is —CH ₃ . 5. The furan-based compound according to claim 3, wherein the substituent is -Br. 6. The furan-based compound according to claim 1, wherein R ₃ and R ₆ are both —H, an acyl group or —X.