JPH0377871A - 2-(2-(3-hydroxyphenyl)vinyl)-pyrazine and its production - Google Patents

Abstract

NEW MATERIAL:2-[2-(3-Hydroxyphenyl)vinyl-pyrazine expressed by formula I. USE:The compound expressed by formula I is stable at ambient temperature and has a good crystallinity, large second high frequency-generating (SHG) activity and excellent transparency, having lambdamax at 336nm of short wave region, useful, especially as non-linear optical material and also as fluorescent brightener, laser dye, etc. PREPARATION:2-(Trimethylsilylmethyl)-pyrazine expressed by formula II is reacted with 3-(tert.-butyldimethylsiloxy)benzaldehyde expressed by formula III in a polar organic solvent such as tetrahydrofuran in the presence of an alkyl lithium such as n-BuLi dissolved in a hydrocarbon solvent such as n- hexane at a temperature from -78 deg.C to ambient temperature to provide the compound expressed by formula I.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a novel organic compound, 2-[2-(3-hydroxyphenyl)vinyl-1-pyrazine, and a method for producing the same. The novel compound of the present invention is particularly useful as a nonlinear optical material, and also has fluorescent properties. It can also be used as a whitening agent, laser dye, etc. [Prior Art] Nonlinear optical materials cause phenomena such as frequency conversion, amplification, oscillation, and switching of laser light, and generate second harmonics (
It can be applied to SHG), third harmonic generation (THG), high-speed shutters, optical memories, optical arithmetic elements, etc. In addition, nonlinear optical materials can be applied to optical switches and the like that take advantage of the property that their refractive index changes depending on an electric field. Conventionally, KHl PO, NH4 is used as a nonlinear optical material.
Inorganic single crystal materials such as HI PO4-L i NbO5 and KNbOs are known, but recently urea, p-nitroaniline, 2-methyl-4-nitroaniline (MNA), 4-(N,N -dimedylamino)-4'
- Development of nonlinear optical organic materials such as nitrostilbene (DANS) and stilbazolium salts is progressing. Nonlinear optical organic materials generally have nonlinearity originating from intramolecular −rr and electrons, so they do not involve lattice vibration in response to light, and therefore have a faster response than inorganic materials.
It is possible to synthesize a material with a large nonlinear optical constant or a material whose absorption region can be changed. Moreover, the method of making materials into devices is not limited to single crystallization, but also LB films,
Various methods can be considered, such as steaming, liquid crystallization, and polymerization. By the way, nonlinear optical materials are required to have the following characteristics. 1) Among nonlinear optical effects, especially second harmonic generation (S
HG) is positioned as a basic technology for wavelength conversion due to its high conversion efficiency, etc., and a high SHG efficiency (with urea as 1) is required. (2) For a material to exhibit optical nonlinearity, it is required that it has no spatial inversion symmetry, and in particular, that its crystal does not have a center of symmetry. (3) It is desired that the material be stable at room temperature and form a single crystal as large as possible. (4) Since the wavelength of current semiconductor lasers is about 800 nm, it is practically important that the maximum wavelength (λsax) or cut-off wavelength (λCutoff) be in the shortest wavelength region as possible. However, known nonlinear optical inorganic materials are expensive to produce single crystals with high purity, have deliquescent properties, and are generally SHG-based.
It has the disadvantage of low efficiency. On the other hand, although it is generally known that some nonlinear optical organic materials have high SHG efficiency, it is difficult to produce stable and large crystals at room temperature. For example, MN
Although A has high SHG efficiency, it is difficult to obtain large single crystals. Although urea is easy to obtain large single crystals, is white and transparent, and has a short cutoff wavelength of 200 nm, it has the disadvantage of poor moisture resistance. In addition, DAN S, a stilbene conductor, exhibits a very large second-order nonlinear polarizability β at the molecular level, but when it becomes a crystal, it exhibits nonlinear optical effects because the molecular arrangement has inversion symmetry. do not have. Furthermore, stilbazolium salt has a large nonlinear optical effect with an SHG efficiency of about 250, but the cutoff wavelength is 473 (λlax) ~
588nrn, which is on the long wavelength side, poses a practical problem. In general, nonlinear optical materials give crystals colored yellow to L-orange due to the structure of the Tr, [child conjugated system, and for this reason, the cutoff wavelength is usually 4
Many of them are located in the long wavelength region exceeding 00 nm. In this way, the S I4 G efficiency is high, it is stable and easy to grow into a large single crystal, it has excellent transparency, and λ
Although there is a need for a nonlinear optical material with a short 1x or λcl off, a material with sufficient performance has not yet been provided. [Problems to be Solved by the Invention] An object of the present invention is to provide a novel organic compound. Another object of the present invention is to provide a novel organic compound having a nonlinear optical effect, which overcomes the problems of the prior art, is stable at room temperature, and has a center of symmetry. Forms a #11 crystal with no
It is an object of the present invention to provide a nonlinear optical material with high activity and excellent transparency. As a result of intensive research, the present inventors found that 2-[2-(3-hydroxyphenyl)vinyl]pyrazine, a new organic compound, is a stable and crystalline compound, and S
It was found that transparent microcrystals with high HG activity were formed, and λ ax was also in the short wavelength region of 336 nm. Moreover, this compound is 2-(trimethylsilylmethyl)
It has been found that it can be synthesized by reacting pyrazine and 3-(t-butyldimethylsiloxy)benzaldehyde in the presence of alkyllithium. It has been discovered that this compound is useful as a nonlinear optical material, but also has the potential to be used as a fluorescent whitening agent, laser dye, etc. The present invention has been completed based on these findings. [Means for Solving the Problems] That is, according to the present invention, 2-
[2-(3-hydroxyphenyl)vinyl]pyrazine is provided. Further, according to the present invention, a 2-[2-(3-hydroxy) A method of making phenyl)vinyl]pyrazine is provided. This compound can be particularly suitably used as a nonlinear optical material. Hereinafter, the constituent elements of the present invention will be explained in detail. [2-[2-(3-hydroxyphenyl)vinyl]pyrazine] 2-[2-(3-hydroxyphenyl)vinyl]pyrazine of the present invention is a new chemical substance. The compound of the present invention is similar to the above-mentioned DANS and stilbene derivatives such as stilbazolium salts in that the two π electron systems are bonded via a carbon-carbon double bond and is a trans isomer. There is. However, whereas the DANS crystal has a center of symmetry and does not have a nonlinear optical effect, the compound of the present invention exhibits an excellent nonlinear optical effect because its crystal does not have a center of symmetry, and the SHG of microcrystalline powder The efficiency is 1.1 times that of urea. Furthermore, while the cutoff wavelength of the stilbazolium salt is on the long wavelength side, the λwax of the compound of the present invention is 3
It has a relatively short wavelength of 36 nm, and has practical performance as a nonlinear optical material that uses semiconductor laser light. The compound of the present invention has stable crystals at room temperature, good crystallinity, and excellent transparency. As is clear from its chemical structure, it is also suitable for applications such as fluorescent whitening agents and laser dyes that utilize fluorescence. (Production method) Generally, stilbene-like compounds can be synthesized by Knoevenagel condensation, by reacting a compound with an active methylene with an aromatic aldehyde, but the compound of the present invention can be synthesized by reacting a compound with an active methylene with an aromatic aldehyde. Even if an attempt is made to carry out the Knoeffenagel condensation reaction with m-hydroxybenzaldehyde in the presence of an organic base such as piperidine, the reaction does not proceed. Therefore, the inventors conducted further research and found that 2
- It has been found that [2-(3-hydroxyphenyl)vinyl]pyrazine can be produced by applying the Peterso reaction. The Peterson reaction is a reaction in which a lithio derivative of trialkylsilane is reacted with an aldehyde compound to synthesize β-hydroxysilane (J. Org, Chem, 33,780 (196 g)).
This β-hydroxysilane easily forms olefin bonds by treating with acid or alkali. This reaction can be shown, for example, as follows. R' -C8-CH-R In the present invention, 2-(trimethylsilylmethyl)pyrazine is substituted with approximately the same argyllithium compound, such as n
- After lithiation by treatment with butyllithium (n-BuLl), 3= (t=butyldimethylsiloxane)
React with benzaldehyde to obtain the target compound. The manufacturing method according to the present invention can be expressed by the following chemical reaction formula. As the alkyllithium, n-butyllithium, 11
Examples include ec-butyllithium and ethyllithium, but n-butyllithium is preferred in terms of reactivity. Alkyllithiums are typically used as solutions in hydrocarbon solvents such as n-hexane. The above reaction is carried out in a polar organic solvent such as tetrahydrofuran (THF) that does not affect the chemical reaction. The reaction temperature is usually carried out in the range of -78°C to room temperature.

【Example〕

The present invention will be specifically described below with reference to Examples and Reference Examples, but the present invention is not limited to these Examples. [Reference Example 1] 1.2 g (111 mrri) of diisopropylamine made from 2-1
ol) in 200rnρTHF solution at O'C.
A solution of n-butyllithium in n-hexane (1,50 mo
i/C) 70 mA (105 mmol) was added dropwise, and the mixture was kept at this temperature and stirred for 20 minutes. Then, it was cooled to -78°C and 2-methylpyrazine (9.42g, 100rny
After stirring at -78°C for 30 minutes and at 0°C for 30 minutes, the mixture was cooled again to -78°C, and trimedelsilyl chloride (12.4 g, 114 mmol) was added dropwise. Stirring was continued for about 19 hours while slowly raising the temperature of the reaction system to room temperature. Next, a saturated aqueous sodium bicarbonate solution was added, and the precipitate was filtered through Celite, followed by extraction with ethyl acetate, and the combined organic layers were washed with saturated sodium chloride water, dried over potassium carbonate, and concentrated. By gel filtration of the product through silica gel and further distillation, 11.0 g (66.1 mmol, e rate 6G%) of pure 2-(trimethylsilylmethyl)pyrazine was obtained.
was obtained as a colorless oil. The boiling point of the product is 100
-102°C (30mmHg). [Reference Example 2] 5.3 g (35 mgn
ol) and m-hydroxybenzaldehyde 3.60
To a dimethylformamide (DMF) 25rnA solution of g (29,5 mrrnol) was added imidazole 5°Og (73 rriinol), and after adding #5% sodium carbonate aqueous solution stirred at room temperature for 4 hours, n
- Extracted with hexane and washed the combined organic layers with water. This crude product was purified by distillation to obtain the desired product. The boiling point of the product was 124=126° C. (3 mmHg) and the yield was 78%. [Example 1] THF (2
A solution of n-butyl lithium in n-hexane (1,44 nyrnol, /l2) was added to the solution at -78°C.
)7.1m12 (LO, 2mmol) was added dropwise to -78
The mixture was stirred at 0°C for 30 minutes and at 0°C for 15 minutes. The reaction system was cooled again to -78°C, and 2.36 g of 3-(t-butyldimethylsiloxy)benzaldehyde (9,9
8 mmol) of THF (15 mj2) solution was added dropwise,
The mixture was stirred at −78° C. for 2 hours and in a greenhouse for 25 minutes. Water 30mA to the reaction mixture! and then acetic acid 100
m1. After adding 3 ml of concentrated hydrochloric acid, the mixture was heated under reflux for 12 hours. Most of the solvent was distilled off under reduced pressure, and the 0 reaction product neutralized with an aqueous potassium carbonate solution was extracted with dichloromethane and purified by silica gel column chromatography to obtain 2-[2-(3-hydroxyphenyl)vinyl ] 1.63 g (8.22 mmol) of pyrazine was obtained. The yield was 82% and the melting point of the product recrystallized from benzene was 129.0-130.5°C. About 'H-NMR spectrum and attribution of the product, Part 1
In addition, the IR spectrum is shown in FIG. Note that the peak value of the IR spectrum, the δ value of the NMR spectrum, and the measured Uv value are shown below. I R (K B r ): 1640, 1580,
1400,960,860°780 [c--'1'H-NMR (DMSO): 9.45 (IH
), 8.80 (IH). 8, 60 (IH), 8.50 (IH), 7
．． 67 (IH). 7.3-6.6 (5H) [pp■lUV (EI
Oh): λmax=336 nm The compound (product) obtained from the analysis of these measurement results is 2-[2
-(3-hydroxyphenyl)vinyl-1-pyrazine was confirmed.

[Example 2] Nd: YAG was added to the fine powder crystals of 2-[2-(3-hydroxyphenyl)vinyl 1-pyrazine obtained in Example 1 of
When irradiated with a laser (wavelength = 1.064 μm, output 10 mJ/pulse), second harmonics are generated (SHG) L, 1/2 wavelength of the incident light (532 nm).
m) green light was observed. Furthermore, it was confirmed that the SHG efficiency was 1.1 times that of urea. Furthermore, this crystal is stable at room temperature and has good crystallinity.
It has been found that transparency is excellent. These measurement results demonstrate that this compound is useful as a nonlinear optical material.

【Effect of the invention】

According to the present invention, a novel organic compound 2-[2-(
3-Hydroxyphenyl)vinyl-1 pyrazine and methods for making the same are provided. The compound of the present invention is stable at room temperature and has good crystallinity, and S
It has high HG activity and excellent transparency, especially
It is useful as a nonlinear optical material and has important practical significance, such as being able to be used as a wavelength conversion element for lasers. (Margin below)

[Brief explanation of drawings]

Figure 1 is a diagram showing the +H-NMR spectrum and attribution of the compound produced in Example 1, and Figure 2 is a diagram showing the I of the compound.
It is a figure showing an R spectrum.

Claims (3)

[Claims] (1) 2-[2-(3-hydroxyphenyl)vinyl]pyrazine represented by the following formula ▲ Numerical formulas, chemical formulas, tables, etc. are available▼. (2) A nonlinear optical material comprising the compound according to claim 1. (3) 2-(trimethylsilylmethyl)pyrazine and 3-
A method for producing 2-[2-(3-hydroxyphenyl)vinyl]pyrazine, which comprises reacting (t-butyldimethylsiloxy)benzaldehyde in the presence of an alkyllithium.