JP2008069081A - Manufacturing method of cyclic compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for obtaining an aimed cyclic compound with high optical efficiency by a photocyclization addition reaction of an unsaturated compound bearing at least one carbon-carbon unsaturated bond. <P>SOLUTION: The manufacturing method of the cyclic compound comprises subjecting the unsaturated compound bearing at least one carbon-carbon unsaturated bond to a photocyclization addition reaction using a light-emitting diode as a light source. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a cyclic compound.

Conventionally, it is generally well known in the field of organic chemistry that unsaturated compounds having a double bond undergo a cycloaddition reaction with light. This is described in Non-Patent Document 1. However, the yield of the cyclic compound produced by this light was generally low.
Specifically, for example, with respect to the photodimerization reaction using maleic anhydride as a raw material, according to Patent Document 1, the light wavelength is 300 nm to 600 nm and the reaction temperature is −10 ° C. to 50 ° C. to perform dimerization with high light efficiency. It is said that the body can be obtained.

In this reaction, usually a high-pressure mercury lamp is often used. However, high-pressure mercury lamps have a wide range of wavelengths from 200 nm to 600 nm, of which wavelengths less than 300 nm and more than 500 nm are not involved in this reaction, or are involved in polymer formation and reverse reaction of raw materials to unsaturated compounds. Therefore, the light emitted from the light source was not effectively used as the energy of the target reaction.
In addition, since extra wavelengths that are not involved in the reaction become heat rays and generate a lot of heat, it is necessary to cool the light source and reaction solution using a large apparatus in the actual reaction, which greatly affects the production cost. Was given.
Japanese Patent Laid-Open No. 2003-192585 Huisgen, Intersci. Pub. 1964

An object of the present invention is to provide a production method capable of obtaining a target cyclic compound with high light utilization efficiency from an unsaturated compound having at least one carbon-carbon unsaturated bond by a photocycloaddition reaction. .
Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention are:
It is achieved by a method for producing a cyclic compound, which comprises subjecting an unsaturated compound having at least one carbon-carbon unsaturated bond to a photocycloaddition reaction using a light emitting diode as a light source.

  According to the production method of the present invention, in a photocycloaddition reaction of an unsaturated compound having at least one carbon-carbon unsaturated bond, a target cyclic compound can be obtained with high light utilization efficiency.

  Hereinafter, the present invention will be described in detail.

  The photocycloaddition reaction of the present invention is a coupling reaction by light of two unsaturated molecules having one or more (conjugated) carbon-carbon unsaturated bonds, as generally known in organic chemistry. Indicates. For example, 1,2-cycloaddition reaction, 1,3-cycloaddition reaction, 1,4-cycloaddition reaction and the like can be mentioned. Specifically, [2 + 2], [4 + 2], [4 + 4] and the like can be mentioned. Examples thereof include a cycloaddition reaction, an ene reaction, and a 1,3-dipolar cycloaddition reaction. In the present invention, it is preferably used in a [2 + 2] cycloaddition reaction that reacts with unsaturated compounds having one unsaturated bond, and further used in a [2 + 2] cycloaddition reaction that reacts with maleic anhydride compounds. Is more preferable.

[Unsaturated compound]
Preferred examples of the unsaturated compound include formula (1)

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a phenyl group and a halogen group, or R ₁ and R ₂ are carbon atoms to which they are bonded. And a maleic anhydride compound represented by a C 4-10 cycloalkene ring. Examples of maleic anhydride compounds include maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, 2-ethylmaleic anhydride, 2,3-diethylmaleic anhydride, 2-isopropylmaleic anhydride, 2 , 3-Diisopropylmaleic anhydride, 2-n-butylmaleic anhydride, 2,3-di (n-butyl) maleic anhydride, 2-t-butylmaleic anhydride, 2,3-di (t-butyl) Maleic anhydride, 2-phenylmaleic anhydride, 2,3-diphenylmaleic anhydride, 2-fluoromaleic anhydride, 2,3-difluoromaleic anhydride, 2-chloromaleic anhydride, 2,3-dichloromaleic anhydride Acid, 2-bromomaleic anhydride, 2,3-dibromomaleic anhydride, 2-iodomaleic anhydride, 2,3-diiodomaleic anhydride 1-cyclopentene-1,2-dicarboxylic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, and the like.

<Light source>
As the light-emitting diode (LED) light source in the present invention, those emitting near-ultraviolet light are preferably used. As a preferable wavelength of the LED light source, a wavelength of 300 to 500 nm can be mentioned.
By using the LED light source in the present invention, it is not necessary to use wavelengths other than those effective for reaction. For example, a 375 nm LED light source emits light only in the region of 350 nm to 400 nm. Therefore, the side reaction which is caused at less than 300 nm hardly occurs, and the selectivity of the reaction can be greatly improved.
Moreover, since there is no wavelength that becomes a heat ray not involved in the reaction, the amount of heat generated in the reaction can be reduced. That is, since the heat generated during the reaction is reduced, the reaction temperature can be easily controlled, and the light source and the cooling device for cooling the reaction liquid can be reduced, so that the production cost can be reduced.

In addition, high pressure mercury lamps and other light sources used for this reaction emit light in all directions. In order to effectively use these lights, a so-called internal irradiation type light source having a light source inside the reaction liquid has been mainly used in this reaction.
According to the present invention, light is directional as a feature of the LED light source, and light can be emitted only in one direction. Therefore, the reaction solution only needs to be in the direction of the light, so that the reaction can be performed without placing a light source inside, the light can be used effectively, and the amount of the reaction solution can be reduced. Further, since the amount of the reaction solution can be reduced, the above-described cooling equipment can be further reduced.

<Reaction temperature>
The reaction temperature is preferably from −20 ° C. to 80 ° C., since a polymer is by-produced when the temperature is high, and the solubility of the raw material is lowered and the production efficiency is reduced when the temperature is low. More preferably, it is -10 degreeC-50 degreeC, Most preferably, it is 0 degreeC-20 degreeC. By controlling the reaction within this temperature range, the formation of by-products is greatly suppressed, and a cyclic compound such as a derivative having a cyclobutane ring is obtained with high selectivity and yield.

<Reaction solvent>
The reaction solvent must be a carbonyl compound that can be expected to have a photosensitizing effect, and must satisfy requirements such as solubility of raw materials and stability to photoreaction. Ten aliphatic esters are preferred.
Specific examples thereof include, for example, methyl formate, ethyl formate, n-propyl formate, i-propyl formate, butyl formate, methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, butyl acetate, methyl propionate, Examples include ethyl propionate, n-propyl propionate, i-propyl propionate, ethylene glycol diformate, ethylene glycol diacetate, ethylene glycol dipropionate, methyl pyruvate, ethyl pyruvate, and methyl acetobutyrate. .

Among these, more preferable solvents are ethyl formate, methyl acetate, ethyl acetate, i-propyl acetate, butyl acetate, ethylene glycol diformate, ethylene glycol diacetate, methyl acetobutyrate and the like.
The said solvent may be used independently, or 2 or more types may be mixed and used for it.
The amount of the solvent used is preferably 3 to 50 times by mass, more preferably 5 to 20 times by mass with respect to the raw material compound.

<Reaction time>
The reaction time can be extended until the unsaturated compound as a raw material disappears.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In addition, the light utilization efficiency used here indicates a ratio in which irradiated light is involved in the generation of the target product, and is expressed by the weight of dimer (g) per unit (irradiation light output × irradiation time). The

Example 1
1.2 g of maleic anhydride and 10.8 g of ethyl acetate were charged into a glass reactor having an internal volume of 20 ml and dissolved, and at 5 ° C., an ultraviolet LED (manufactured by Nitride Semiconductor, 365 nm, output 10 mW) was used from inside the reactor. Irradiated with ultraviolet rays. After 630 hours, the crystals were filtered, washed with ethyl acetate and dried to give 1.0 g of 1,2,3,4-cyclobutanetetracarboxylic acid-1,2: 3,4-dianhydride. Moreover, as a result of analyzing the filtrate by HPLC, 0.1 g of the same compound was contained. The light utilization efficiency at this time was 170 g / (kW · h).
The structure of this white crystal was identified by DSC, ¹ H-NMR, and IR.
DSC: 406 ° C. (sublimation)
¹ H-NMR (DMSO-d6): 3.9 (s, 4H)
IR (KBr): 1850, 1790, 1400, 1270, 900 cm ⁻¹

Comparative Example 1
100 g of maleic anhydride and 900 g of ethyl acetate were charged in a 1 L internal volume Pyrex (registered trademark) glass photoreactor and dissolved at 5 ° C. from the inside of the reactor with a 100 W high pressure mercury lamp (manufactured by SEN Special Light Source, light output 15 W) ) Was irradiated with ultraviolet rays. After 48 hours, the crystals were filtered, washed with ethyl acetate and dried to give 38.4 g of 1,2,3,4-cyclobutanetetracarboxylic acid-1,2: 3,4-dianhydride. Moreover, as a result of analyzing the filtrate by HPLC, 1.2 g of the same compound was contained. The light utilization efficiency at this time was 55 g / (kW · h).

Claims (3)

A method for producing a cyclic compound, comprising subjecting an unsaturated compound having at least one carbon-carbon unsaturated bond to a photocycloaddition reaction using a light emitting diode as a light source. The method for producing a cyclic compound according to claim 1, wherein the unsaturated compound is a compound having one unsaturated bond. The method for producing a cyclic compound according to claim 2, wherein the unsaturated compound is a maleic anhydride compound represented by the following formula (1).

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a phenyl group and a halogen atom, or R ₁ and R ₂ are carbon atoms to which they are bonded. And represents a cycloalkene ring having 4 to 10 carbon atoms.)