JP3741466B2 - Chiral photochromic material - Google Patents

Description

【００１１】
（式中、Ｘは
【００１２】
【化５】

【００１３】
で表される基、ここでＲ7は水素原子、置換されていてもよいアルキル基又はアリール基、ＹおよびＺは酸素原子、イオウ原子又は置換されていてもよいＮＨ基、Ｒ¹およびＲ⁴はアルキル基、アルコキシ基又はアルコキシカルボニル基、Ｒ²，Ｒ³，Ｒ⁵およびＲ⁶はアルキル基、水素原子又はハロゲン原子を示し、Ｒ¹〜Ｒ⁶のいづれかが不斉炭素を有し、Ｒ²とＲ³および／またはＲ⁵とＲ⁶は互いに結合して環を形成してもよい）で表されるジアリールエテン化合物である。
【００１４】
上記一般式（１）中、Ｘは
【００１５】
【化６】

【００１６】
で表される基であり、ここでＲ⁷は水素原子、置換されていてもよいアルキル基、又はアリール基である。
【００１７】
具体的にＲ⁷を例示すると、置換されてもよいアルキル基としてはメチル基、プロピル基などの炭素数１〜６のアルキル基；フェニル基、トルイル基等の炭素数６〜１４のアリール基が挙げられ、置換基としてはフッ素、塩素、臭素等のハロゲン原子；メチル基、プロピル基などの炭素数１〜６のアルキル基；フェニル基、トルイル基等の炭素数６〜１４のアリール基；ベンジル基等の炭素数７〜１５のアラルキル基；メトキシ基、プロポキシ基などの炭素数１〜６のアルコキシ基；シアノメチル基；メトキシカルボニルメチレン基等のアルコキシカルボニルアルキレン基、メトキシエチレン基等のアルコキシアルキレン基；ニトロ基；アミノ基等が挙げられる。
【００１８】
前記一般式（１）中、ＹおよびＺは酸素原子、イオウ原子又はＮＨ基であり、ＮＨ基の水素は置換されていてもよい。当該置換基としてはメチル基等の炭素数１〜６のアルキル基；フェニル基等のアリール基が挙げられる。
【００１９】
前記一般式（１）中、Ｒ¹およびＲ⁴はアルキル基、アルコキシ基又はアルコキシカルボニル基であり、不斉炭素を持たない場合のアルキル基としては、メチル基、イソプロピル基等の炭素数１〜６のアルキル基；不斉炭素を持たない場合のアルコキシ基としてはエトキシ基、プロピル基等の炭素数１〜６のアルコキシ基；不斉炭素を持たない場合のアルコキシカルボニル基としてはメトキシカルボニル基、エトキシカルボニル基等の炭素数２〜７のアルコキシカルボニル基が挙げられる。
【００２０】
前記一般式（１）中、Ｒ²，Ｒ³，Ｒ⁵およびＲ⁶はアルキル基、水素原子又はハロゲン原子を示し、不斉炭素を持たない場合のアルキル基としては、メチル基、イソプロピル基等の炭素数１〜６のアルキル基；ハロゲン原子としてはフッ素原子、塩素原子、臭素原子が挙げられる。
【００２１】
また、Ｒ²とＲ³および／またはＲ⁵とＲ⁶は互いに結合して環を形成してもよく、この場合は前記ＹまたはＸを含む不飽和複素環と縮合してベンゾフラン環、ベンゾチオフェン環、インドール環を形成するのが好適である。
【００２２】
本発明のジアリールエテン化合物において、上記Ｒ¹〜Ｒ⁶のいづれかが不斉炭素を有することが必須である。Ｒ¹およびＲ²で不斉炭素を有する置換基をより具体的に例示すると２−ブチル基、２−ヘプチル基、２−ノニル基、メンチル基等の不斉炭素含有アルキル基；２−ブトキシ基、２−ヘプトキシ基、２−ノニルオキシ基、メンチルオキシ基等の不斉炭素含有アルコキシ基；２−ブトキシカルボニル基、２−ヘプトキシカルボニル基、２−ノニルオキシカルボニル基、メンチルオキシカルボニル基等の不斉炭素含有アルコキシカルボニル基が挙げられ、Ｒ²，Ｒ³，Ｒ⁵およびＲ⁶で不斉炭素を有する置換基をより具体的に例示すると２−ブチル基、２−ヘプチル基、２−ノニル基、メンチル基等の不斉炭素含有アルキル基が挙げられる。
【００２３】
本発明のジアリールエテン化合物は以下の方法により合成される。
【００２４】
Ｘが
【００２５】
【化７】

【００２６】
の場合は、
【００２７】
【化８】

【００２８】
のように、３−オキサモイル置換不飽和複素環化合物と不飽和複素環の３−酢酸クロリドを縮合させて合成できる。
【００２９】
Ｘが
【００３０】
【化９】

【００３１】
の場合は、
【００３２】
【化１０】

【００３３】
のように３−シアノメチル置換の不飽和複素環基を縮合した後、加水分解し酸無水物化することにより合成できる。
【００３４】
Ｘが
【００３５】
【化１１】

【００３６】
の場合は、
【００３７】
【化１２】

【００３８】
のように３−リチオ不飽和複素環化合物とシクロパーフルオロアルケン誘導体を反応させることで合成できる。
【００３９】
【発明の効果】
本発明では、不斉分子をジアリールエテン分子へ導入することにより、ヘリセン類似構造をもつ閉環体の光不斉誘導を行い、ヘリセンの一方の不斉構造を光生成させることができ、誘起旋光度の場合と異なり高い旋光度を誘起させることができる。
【００４０】
【実施例】
以下、本発明を説明するために、実施例を挙げて説明するが、本発明はこれらの実施例に限定されるものではない。
【００４１】
実施例１
２−（２−メチル−３−ベンゾチエニル）−（２−（ｌ−メンチル）−３−ベンゾチエニル）−Ｎ−シアノメチルマレイミド（Ａ）の合成
【００４２】
【化１３】

【００４３】
１００ｍｌ３つ口フラスコに２−メチル−３−ベンゾチエニル酢酸０．９２２ｇ（４．４７ｍｍｏｌ）とオキサリルクロライド１．４２２ｇ（１１．２ｍｍｏｌ）と乾燥ベンゼン４０ｍｌを加え、室温で２時間、還流条件下で１時間攪拌した。溶媒を留去したのち、１，２−ジクロロエタン２５ｍｌを加えた。
【００４４】
この溶液を、あらかじめ用意しておいた２−（ｌ−メントキシ）−３−（シアノメチルオキサモイル）ベンゾチオフェン１．３６５ｇ（３．４２５ｍｍｏｌ）と、トリエチルアミン１５ｍｌとジクロロエタン２５ｍｌの混合溶液中へ室温で滴下した。そのまま４８時間攪拌後、希塩酸を加えてクロロホルムで抽出した。有機層を無水硫酸マグネシウム上で乾燥した。溶媒を留去し、得られた液体をカラムで分離し、２−（２−メチル−３−ベンゾチエニル）−３−（２−（ｌ−メンチル）−３−ベンゾチエニル）−Ｎ−シアノメチルマレイミド（Ａ）を得た。（１．３７８ｇ，収率７１％）この化合物は赤橙色液体（分解点８６℃を有する微少の滴）として得られた。
【００４５】
１Ｈ−ＮＭＲ（ＣＤＣｌ３溶液中）を測定したところ、δ＝０．５５から２．４１ｐｐｍ付近にメンチル基のメチルに基ずく９Ｈ、メチレンに基ずく６Ｈ、メチンに基ずく３Ｈ、チオフェンに結合したメチル基に基ずく３Ｈのピークがみられ、δ＝３．６２から３．７４ｐｐｍ付近にメンチルオキシ基の酸素に結合したメチンの１Ｈのピークがみられ、δ＝４．５１ｐｐｍ付近にシアノメチル基のメチレンの２Ｈのピークがみられ、δ＝６．８８から７．６３ｐｐｍ付近にベンゾチオフェン環の８Ｈのピークがみられた。質量分析をしたところ、４３０（Ｃ10Ｈ19+），４０１，２９０，８３にスペクトルが１８，１２，１８，１００の強度比で得られた。元素分析をしたところＣ：６９．８５％，Ｈ：６．０５％，Ｎ：４．９４％で計算値のＣ：９６．６９％，Ｎ：５．６７％，Ｎ：４．９３％と良く一致した。以上の分析より（Ａ）の化合物を同定した。
【００４６】
（Ａ）のヘキサン溶液へ４５０ｎｍの光を照射すると、２つのジアステレオマー（Ｂ１），（Ｂ２）が得られた。これらの化合物の１Ｈ−ＮＭＲを測定すると、ほぼ同一のδ＝０．５５から２．４１ｐｐｍ付近にメンチル基のメチルに基ずく９Ｈ、メチレンに基ずく６Ｈ、メチンに基ずく３Ｈ、閉環したチオフェンに結合したメチル基に基ずく３Ｈのピークがみられ、δ＝４．１７から４．２３ｐｐｍ付近にメンチルオキシ基の酸素に結合したメチンの１Ｈのピークがみられ、δ＝４．６０ｐｐｍ付近にシアノメチル基のメチレンの２Ｈのピークがみられ、δ＝７．１５から９．２５ｐｐｍ付近に閉環したベンゾチオフェン環の８Ｈのピークがみられた。
【００４７】
これにより（Ｂ１）、（Ｂ２）を下記の構造と同定した。
【００４８】
【化１４】

【００４９】
これらの、旋光度を測定すると６３３ｎｍでそれぞれ＋１３００゜，−１３００゜という大きい旋光度が得られた。
【００５０】
実施例２
実施例１のｌ−メントール基をｄ−メントール基に代え、同様の合成を行い下記の（Ｃ）の化合物を得た。
【００５１】
【化１５】

【００５２】
１Ｈ−ＮＭＲ（ＣＤＣｌ３溶液中）を測定したところ、δ＝０．５５から２．４１ｐｐｍ付近にメンチル基のメチルに基ずく９Ｈ、メチレンに基ずく６Ｈ、メチンに基ずく３Ｈ、チオフェンに結合したメチル基に基ずく３Ｈのピークがみられ、δ＝３．６２から３．７４ｐｐｍ付近にメンチルオキシ基の酸素に結合したメチンの１Ｈのピークがみられ、δ＝４．５１ｐｐｍ付近にシアノメチル基のメチレンの２Ｈのピークがみられ、δ＝６．８８から７．６３ｐｐｍ付近にベンゾチオフェン環の８Ｈのピークがみられた。
【００５３】
（Ｃ）へ４５０ｎｍの光を照射して得られたエナンチオマーはそれぞれ＋１３００゜，−１３００゜の旋光度を与えた。
【００５４】
実施例３
２−（２−メチル−３−ベンゾチエニル）−３−（２−（ｓｅｃ−ブトキシ）−３−ベンゾチエニル）−Ｎ−シアノメチルマレイミド（Ｄ）の合成。
【００５５】
【化１６】

【００５６】
５０ｍｌ３つ口フラスコに２−メチル−３−ベンゾチエニル酢酸０．２２２ｇ（１．０８ｍｍｏｌ）とオキサリルクロライド０．３５５ｇ（２．２４ｍｍｏｌ）と乾燥ベンゼン１５ｍｌを加え、室温で２時間、還流条件下で１時間攪拌した。溶媒を留去したのち、１，２−ジクロロエタン２０ｍｌを加えた。
【００５７】
この溶液を、あらかじめ用意しておいた２−（ｓｅｃ−ブトキシ）−３−（シアノメチルオキサモイル）ベンゾチオフェン０．２５７ｇ（０．８１２ｍｍｏｌ）と、トリエチルアミン４．２ｍｌとジクロロエタン２０ｍｌの混合溶液中へ室温で滴下した。そのまま７２時間攪拌後、希塩酸を加えてクロロホルムで抽出した。有機層を無水硫酸マグネシウム上で乾燥した。溶媒を留去し、得られた液体をカラムで分離し、２−（２−メチル−３−ベンゾチエニル）−３−（２−（ｓｅｃ−ブトキシ）−３−ベンゾチエニル）−Ｎ−シアノメチルマレイミド（Ｄ）を得た。（０．２１２ｇ，収率６３％）
この化合物は赤橙色液体（分解点１０９−１１０℃を有する微少の滴）として得られた。^１Ｈ−ＮＭＲ（ＣＤＣｌ_３溶液中）を測定したところ、δ＝０．５３から２．５３ｐｐｍ付近にｓｅｃ−ブトキシ基のメチルに基ずく６Ｈ、メチレンに基ずく２Ｈ、チオフェンに結合したメチル基に基ずく３Ｈのピークがみられ、δ＝３．９８から４．０７ｐｐｍ付近にｓｅｃ−ブトキシ基の酸素に結合したメチンの１Ｈのピークがみられ、δ＝４．６１ｐｐｍ付近にシアノメチル基のメチレンの２Ｈのピークがみられ、δ＝７．０３から７．７０ｐｐｍ付近にベンゾチオフェン環の８Ｈのピークがみられた。
【００５８】
（Ｄ）に４５０ｎｍの光を照射して得られた２つのジアステレオマーのＣＤスペクトルを測定した。結果を図１に示す。
【００５９】
実施例４
化合物（Ａ）をトルエンに溶解（１．２×１０−４ｍｏｌ／ｌ）し、４５０ｎｍ光および波長５７０ｎｍ以上の光を交互に照射し、その際の６３３ｎｍでの旋光度変化を測定した。６３３ｎｍには化合物（Ａ）の閉環体は吸収を持たず、フォトクロミック反応は誘起されない。結果を図２に示す。旋光度が可逆に変化することが認められた。これは不斉メントール基の存在により閉環反応に不斉誘導が行われた結果である。６３３ｎｍ光を用いることにより、非破壊的に記録を読み出すことが可能となった。
【図面の簡単な説明】
【図１】 （Ｄ）へ光照射して得られた２つのジアステレオマーのＣＤスペクトルを表す図である。
【図２】 （Ａ）のトルエン溶液の光照射による旋光度変化を表す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photochromic compound that causes a change in optical rotation upon light irradiation, and is suitable for an optical recording medium, and particularly relates to a material for performing nondestructive reading of recording by optical rotation reading.
[0002]
[Prior art]
The photochromic material refers to a material containing a molecule or a molecular assembly that reversibly generates two isomers having different states by the action of light. Development research has been promoted with the aim of applying photochromic materials to optical recording media. The performance required for the recording medium is as follows.
[0003]
1) Repeatability 2) Thermal irreversibility 3) Semiconductor laser sensitivity 4) Non-destructive reading function 5) High speed and high sensitivity response 6) Aiming for a molecule that has all these features The development of thermally irreversible photochromic molecules (diarylethene, fulgide) has been promoted. Currently, diarylethene molecules have sufficient repetition durability and thermal irreversibility, and have high speed and high sensitivity response (M.Irie, Mol.Cryst.Liq.Cryst.227,263 (1993) ).
[0004]
The problem remaining in the optical recording material using the photochromic material is how to achieve the nondestructive reading function. Conventional photochromic materials have the drawback that the photoreaction proceeds in proportion to the amount of absorbed light, so that even if a weak reading light is used, the recording disappears when it is read many times.
[0005]
[Problems to be solved by the invention]
To achieve non-destructive reading,
(1) Construction of a reaction system having a threshold for photoreaction (2) It is required to use either a method of reading birefringence or optical rotation that changes by photochromic reaction with light having a wavelength that does not induce photoreaction. .
[0006]
One of the methods (1) is to synthesize a photochromic molecule that undergoes a two-photon reaction. It has been found that a naphthopyran derivative undergoes a two-photon photochromic reaction, and its investigation has begun (M. Uchida, M. Irie; J. Am. Chem. Soc., 115 (1993) 6442). As the method of (2), Hattori et al. Have proposed that birefringence is read and used as a physical quantity (Y. Hattori, J. Yoshitake, T. Yamanaka; "Chemistry of Functional Dyes", Z. Yoshida, T. Kitao eds. (1989) 326-329). The above two-photon system has a drawback that the absorption wavelength is too short, and the birefringence reading is uneasy about storage stability.
[0007]
The present invention relates to a material for optical rotation reading, which is one of methods (2). In the case of birefringence reading, the orientation of photochromic molecules is essential. For the orientation, a stretched polymer material or liquid crystal is used, but in either case, when stored for a long period of time, relaxation occurs and the degree of orientation changes, resulting in loss of recording. On the other hand, in the present invention, since the optical rotation of the molecule itself changes, the problem of storage stability does not occur, and the optical rotation can be read at a wavelength that does not induce a photoreaction. So far, attempts have been made to introduce asymmetric molecules into azobenzene or spirobenzopyran to change induced circular polarization (induced CD) or optical rotation by photochromic reaction (M. Gooman, A. Koosoy, J Am. Chem. Soc., 88 (1966) 7010), the amount of change was very small.
[0008]
[Means for Solving the Problems]
The present invention is more to introduce asymmetric molecules into diarylethene molecules performs light asymmetric induction of a closed ring body having a helicene similar structure, it can be photogenerated one asymmetric structure helicene, induced optical rotation has been accomplished by Heading Succoth that inducing case unlike high optical rotation of the.
[0009]
That is, the present invention has the following general formula:
[Formula 4]

[0011]
(Where X is
[Chemical formula 5]

[0013]
Wherein R 7 is a hydrogen atom, an optionally substituted alkyl group or an aryl group, Y and Z are oxygen atoms, sulfur atoms or an optionally substituted NH group, R ¹ and R ⁴ are alkyl group, alkoxy group or alkoxycarbonyl ^{group, R 2, R 3, R} 5 and R ⁶ represents an alkyl group, a hydrogen atom or a halogen atom, have Izure whether asymmetric carbon of R ¹ ~R ^6, R ² And R ³ and / or R ⁵ and R ⁶ may be bonded to each other to form a ring).
[0014]
In the general formula (1), X represents
[Chemical 6]

[0016]
Wherein R ⁷ is a hydrogen atom, an alkyl group which may be substituted, or an aryl group.
[0017]
Specific examples of R ⁷ include alkyl groups having 1 to 6 carbon atoms such as methyl and propyl groups, and aryl groups having 6 to 14 carbon atoms such as phenyl and toluyl groups. Examples of the substituent include halogen atoms such as fluorine, chlorine and bromine; alkyl groups having 1 to 6 carbon atoms such as methyl and propyl groups; aryl groups having 6 to 14 carbon atoms such as phenyl and toluyl groups; benzyl An aralkyl group having 7 to 15 carbon atoms such as a group; an alkoxy group having 1 to 6 carbon atoms such as a methoxy group and a propoxy group; a cyanomethyl group; an alkoxycarbonylalkylene group such as a methoxycarbonylmethylene group; and an alkoxyalkylene group such as a methoxyethylene group Nitro group; amino group and the like.
[0018]
In said general formula (1), Y and Z are an oxygen atom, a sulfur atom, or NH group, and hydrogen of NH group may be substituted. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms such as a methyl group; and an aryl group such as a phenyl group.
[0019]
In the general formula (1), R ¹ and R ⁴ are an alkyl group, an alkoxy group or an alkoxycarbonyl group, and the alkyl group in the case of having no asymmetric carbon has 1 to 1 carbon atoms such as a methyl group and an isopropyl group. An alkyl group having no asymmetric carbon; an alkoxy group having 1 to 6 carbon atoms such as an ethoxy group and a propyl group; an alkoxycarbonyl group having no asymmetric carbon; a methoxycarbonyl group; C2-C7 alkoxycarbonyl groups, such as an ethoxycarbonyl group, are mentioned.
[0020]
In the general formula (1), R ² , R ³ , R ⁵ and R ^{6 each} represents an alkyl group, a hydrogen atom or a halogen atom. Examples of the alkyl group having no asymmetric carbon include a methyl group and an isopropyl group. A halogen atom includes a fluorine atom, a chlorine atom and a bromine atom.
[0021]
R ² and R ³ and / or R ⁵ and R ⁶ may be bonded to each other to form a ring. In this case, it is condensed with the unsaturated heterocyclic ring containing Y or X to form a benzofuran ring or benzothiophene. It is preferable to form a ring or an indole ring.
[0022]
In the diarylethene compound of the present invention, it is essential that any one of R ^{1 to} R ⁶ has an asymmetric carbon. More specifically, examples of the substituent having an asymmetric carbon in R ¹ and R ² include an asymmetric carbon-containing alkyl group such as a 2-butyl group, a 2-heptyl group, a 2-nonyl group, and a menthyl group; a 2-butoxy group , 2-heptoxy group, 2-nonyloxy group, menthyloxy group and other asymmetric carbon-containing alkoxy groups; 2-butoxycarbonyl group, 2-heptoxycarbonyl group, 2-nonyloxycarbonyl group, menthyloxycarbonyl group and the like Examples of the substituent having an asymmetric carbon in R ² , R ³ , R ⁵ and R ⁶ include a 2-carbon group, 2-heptyl group, 2-nonyl group. And asymmetric carbon-containing alkyl groups such as menthyl groups.
[0023]
The diarylethene compound of the present invention is synthesized by the following method.
[0024]
X is [0025]
[Chemical 7]

[0026]
In the case of,
[0027]
[Chemical 8]

[0028]
As described above, it can be synthesized by condensing 3-oxamoyl-substituted unsaturated heterocyclic compound and unsaturated heterocyclic 3-acetic acid chloride.
[0029]
X is [0030]
[Chemical 9]

[0031]
In the case of,
[0032]
[Chemical Formula 10]

[0033]
As shown in the above, it can be synthesized by condensing an unsaturated heterocyclic group substituted with 3-cyanomethyl and then hydrolyzing to acid anhydride.
[0034]
X is [0035]
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[0036]
In the case of,
[0037]
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[0038]
As described above, it can be synthesized by reacting a 3-lithio unsaturated heterocyclic compound with a cycloperfluoroalkene derivative.
[0039]
【The invention's effect】
In the present invention, more to introduce asymmetric molecules into diarylethene molecules performs light asymmetric induction of a closed ring body having a helicene similar structure, it can be photogenerated one asymmetric structure helicene, induced optical rotation Unlike the case, a high optical rotation can be induced.
[0040]
【Example】
Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples.
[0041]
Example 1
Synthesis of 2- (2-methyl-3-benzothienyl)-(2- (l-menthyl) -3-benzothienyl) -N-cyanomethylmaleimide (A)
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[0043]
To a 100 ml three-necked flask were added 0.922 g (4.47 mmol) of 2-methyl-3-benzothienylacetic acid, 1.422 g (11.2 mmol) of oxalyl chloride and 40 ml of dry benzene, and the mixture was refluxed at room temperature for 2 hours. Stir for hours. After the solvent was distilled off, 25 ml of 1,2-dichloroethane was added.
[0044]
This solution was poured into a prepared solution of 1.365 g (3.425 mmol) of 2- (l-mentoxy) -3- (cyanomethyloxamoyl) benzothiophene, 15 ml of triethylamine and 25 ml of dichloroethane at room temperature. It was dripped. After stirring for 48 hours, diluted hydrochloric acid was added and the mixture was extracted with chloroform. The organic layer was dried over anhydrous magnesium sulfate. The solvent was distilled off, and the resulting liquid was separated on a column, and 2- (2-methyl-3-benzothienyl) -3- (2- (1-menthyl) -3-benzothienyl) -N-cyanomethyl. Maleimide (A) was obtained. (1.378 g, 71% yield) This compound was obtained as a red-orange liquid (small drops having a decomposition point of 86 ° C.).
[0045]
1H-NMR (in CDCl3 solution) was measured, and it was found that δ = 0.55 to 2.41 ppm around 9H based on methyl methyl, 6H based on methylene, 3H based on methine, and methyl bonded to thiophene. A peak of 3H is observed based on the group, a peak of 1H of methine bonded to oxygen of the menthyloxy group is observed near δ = 3.62 to 3.74 ppm, and methylene of the cyanomethyl group is observed near δ = 4.51 ppm. The peak of 2H was observed, and the peak of 8H of the benzothiophene ring was observed in the vicinity of δ = 6.88 to 7.63 ppm. As a result of mass spectrometry, spectra of 430 (C10H19 +), 401, 290, 83 were obtained with an intensity ratio of 18, 12, 18, 100. When elemental analysis was performed, C: 69.85%, H: 6.05%, N: 4.94%, and calculated values C: 96.69%, N: 5.67%, N: 4.93%. Matched well. From the above analysis, the compound (A) was identified.
[0046]
When the hexane solution of (A) was irradiated with light of 450 nm, two diastereomers (B1) and (B2) were obtained. When 1H-NMR of these compounds was measured, it was found that about the same δ = 0.55 to 2.41 ppm, 9H based on methyl in the menthyl group, 6H based on methylene, 3H based on methine, and thiophene ring-closed. A peak of 3H based on the bound methyl group is observed, a peak of 1H of methine bound to oxygen of the menthyloxy group is observed near δ = 4.17 to 4.23 ppm, and cyanomethyl is observed near δ = 4.60 ppm. A 2H peak of methylene group was observed, and an 8H peak of a closed benzothiophene ring was observed near δ = 7.15 to 9.25 ppm.
[0047]
Thereby, (B1) and (B2) were identified as the following structures.
[0048]
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[0049]
When these optical rotations were measured, large optical rotations of + 1300 ° and -1300 ° were obtained at 633 nm, respectively.
[0050]
Example 2
The l-menthol group in Example 1 was replaced with a d-menthol group, and the same synthesis was performed to obtain the following compound (C).
[0051]
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[0052]
1H-NMR (in CDCl3 solution) was measured, and it was found that δ = 0.55 to 2.41 ppm around 9H based on methyl methyl, 6H based on methylene, 3H based on methine, and methyl bonded to thiophene. A peak of 3H is observed based on the group, a peak of 1H of methine bonded to oxygen of the menthyloxy group is observed near δ = 3.62 to 3.74 ppm, and methylene of the cyanomethyl group is observed near δ = 4.51 ppm. The peak of 2H was observed, and the peak of 8H of the benzothiophene ring was observed in the vicinity of δ = 6.88 to 7.63 ppm.
[0053]
The enantiomers obtained by irradiating (C) with 450 nm light gave optical rotations of + 1300 ° and -1300 °, respectively.
[0054]
Example 3
Synthesis of 2- (2-methyl-3-benzothienyl) -3- (2- (sec-butoxy) -3-benzothienyl) -N-cyanomethylmaleimide (D).
[0055]
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[0056]
To a 50 ml three-necked flask were added 0.222 g (1.08 mmol) of 2-methyl-3-benzothienylacetic acid, 0.355 g (2.24 mmol) of oxalyl chloride and 15 ml of dry benzene, and 1 hour under reflux conditions at room temperature. Stir for hours. After distilling off the solvent, 20 ml of 1,2-dichloroethane was added.
[0057]
This solution was added to a previously prepared mixed solution of 0.257 g (0.812 mmol) of 2- (sec-butoxy) -3- (cyanomethyloxamoyl) benzothiophene, 4.2 ml of triethylamine and 20 ml of dichloroethane. Added dropwise at room temperature. After stirring for 72 hours, dilute hydrochloric acid was added and the mixture was extracted with chloroform. The organic layer was dried over anhydrous magnesium sulfate. The solvent was distilled off, and the resulting liquid was separated on a column to give 2- (2-methyl-3-benzothienyl) -3- (2- (sec-butoxy) -3-benzothienyl) -N-cyanomethyl. Maleimide (D) was obtained. (0.212 g, 63% yield)
This compound was obtained as a red-orange liquid (small drops having a decomposition point of 109-110 ° C.). ^{When 1} H-NMR (in CDCl ₃ solution) was measured, it was found that δ = 0.53 to 2.53 ppm around 6H based on methyl of sec-butoxy group, 2H based on methylene, and methyl group bonded to thiophene. A peak of 3H is observed, a peak of 1H of methine bonded to oxygen of sec-butoxy group is observed near δ = 3.98 to 4.07 ppm, and methylene of cyanomethyl group is observed near δ = 4.61 ppm. A 2H peak was observed, and an 8H peak of the benzothiophene ring was observed in the vicinity of δ = 7.03 to 7.70 ppm.
[0058]
CD spectra of two diastereomers obtained by irradiating (D) with 450 nm light were measured. The results are shown in FIG.
[0059]
Example 4
The compound (A) was dissolved in toluene (1.2 × 10 −4 mol / l), 450 nm light and light having a wavelength of 570 nm or more were alternately applied, and the optical rotation change at 633 nm was measured. The ring-closed compound (A) has no absorption at 633 nm, and no photochromic reaction is induced. The results are shown in FIG. It was observed that the optical rotation changed reversibly. This is the result of asymmetric induction in the ring closure reaction due to the presence of the asymmetric menthol group. By using 633 nm light, it was possible to read the record nondestructively.
[Brief description of the drawings]
FIG. 1 is a diagram showing CD spectra of two diastereomers obtained by irradiating light to (D).
FIG. 2 is a diagram showing a change in optical rotation by light irradiation of the toluene solution of (A).

Claims (3)

The following general formula

(Where X is

Wherein R ⁷ is a hydrogen atom, an optionally substituted alkyl group or an aryl group, Y and Z are an oxygen atom, a sulfur atom or an optionally substituted NH group, R ¹ and R ⁴ Represents an alkyl group, an alkoxy group or an alkoxycarbonyl group, R ² , R ³ , R ⁵ and R ⁶ represent an alkyl group, a hydrogen atom or a halogen atom, and any one of R ^{1 to} R ⁶ has an asymmetric carbon; ² and R ³ and / or R ⁵ and R ⁶ may combine with each other to form a ring)
The diarylethene compound represented by these. X is

Y and Z are sulfur atoms, R ² and R ³ and R ⁵ and R ⁶ are bonded to each other to form an aromatic carbocycle, R ¹ is an alkyl group, and R ⁴ is an asymmetric carbon. The diarylethene compound according to claim 1, which is an alkoxy group having A photochromic material comprising the diarylethene compound according to claim 1.

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