JPS6127380B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to intermediates for the production of synthetic urushiol-like substances, and in particular to novel compounds 4-(9', 10', 12',
The present invention relates to 13'-tetrabromostearoyl)-veratrol and a method for producing the same. (Conventional technology) Lacquerware is a traditional craft specializing in the East, especially Japan, and is known worldwide as Japan.As is well known, the raw material for lacquerware is the natural lacquer secreted by the lacquer tree. I've been doing it. However, since the opening of the Meiji era, these resources have continued to deplete, and currently only 90
The country relies on imports from China for more than % of its total production. Due to these circumstances, lacquer is extremely expensive. Furthermore, research has been conducted on the synthesis of urushiol, a drying oil that makes up the majority of natural lacquer liquid, since the Meiji era, but this synthesis is extremely difficult and has not yet been solved, much less how to produce it industrially at low cost. is considered almost impossible. For this reason,
Since ancient times, the synthesis of urushiol-like substances, which are relatively easy to produce, has been devised and utilized. Natural urushiol has the general formula (R in the formula is the number of carbon atoms having 1 to 3 double bonds.
15 straight-chain hydrocarbon groups)
- A mixture of homologs of alkenylcatechols.
The average number of double bonds in the formula is two, but three compounds account for 50% of them. According to Professor Ichiro Miyagawa of Nagoya University, the conditions that synthetic urushiol-like substances should have, that is, the chemical structure, are generally: (a) The number of carbon atoms in the catechol side chain should be 15 or more (b) The number of carbon atoms in the side chain should be 15 or more. The higher the degree of saturation, the better the drying. (c) The chemical resistance is almost the same for those with 1 to 3 double bonds, but is not good for those with 0 double bonds. (d) Catechol It is known that there is almost no difference in the cured film due to the difference in the position of the side chain in the nucleus. (Problems to be Solved by the Invention) Synthetic urushiol-like substances are compounds in which the raw material catechol can be obtained at low cost, and the alkenyl group introduced into the side chain of catechol can also be obtained from natural unsaturated fats. You can obtain it relatively easily by using . However, in this method, in the step of introducing side chains to catechol, the addition reaction of carbon double bonds to catechol takes precedence, making it impossible to introduce alkenyl groups in a linear form, and it is not possible to introduce alkenyl groups in a branched form. Compounds are preferentially produced. As a result, many types of compounds were produced as by-products, which had to be used all at once as lacquer substitutes. Naturally, the quality was not good, and it was difficult to produce products that could be dried at room temperature. It has been used only as. Particularly in recent years, as a result of the abnormal rise in the price of lacquerware, the price of lacquerware has become extremely expensive, and it has become difficult to use conventional low-grade products such as urushiol-like substances. There is a demand for high-grade products consisting of unaccompanied compounds. Furthermore, in order to produce a compound with excellent performance as a urushiol analogue, it is necessary that the hydrocarbon side chain introduced into the catechol nucleus is in a completely linear form, as is the case with natural urushiol, and that the catechol Must be in position 3 or 4 of the nucleus. Moreover, the number of double bonds of the carbon unsaturated group contained must be 2 to 3. However, when long-chain hydrocarbons with carbon unsaturated bonds or their derivatives are directly reacted with catechol, the addition reaction of carbon double bonds takes precedence, resulting in the hydrocarbon group branching into the catechol nucleus. As a result of the addition reaction with the hydroxyl group of catechol, an ether bond was usually formed on the oxygen. This is extremely inconvenient for use as a lacquer paint that dries at room temperature. (Means for solving the problems) In order to solve these problems, the present invention
An intermediate for producing a synthetic urushiol-like substance that meets the demand for higher quality lacquer products as mentioned above.
In particular, the object of the present invention is to provide an intermediate for industrially synthesizing catechol having a linear unsaturated alkyl group without producing by-products. That is, in order to obtain such an intermediate, linoleic acid, which is naturally obtained at an extremely low cost, was sought as a raw material for the unsaturated hydrocarbon group in the side chain of the catechol nucleus.
Furthermore, in order to prevent these carbon unsaturated groups from directly adding to the catechol nucleus, it was decided to protect it with bromine. Furthermore, in order to prevent the formation of ether-like by-products, we have come to the conclusion that it is extremely appropriate to use veratrol in which the hydroxyl group of catechol is protected as a methoxy group. Specifically, the present invention relates to chemical structural formulas 4-(9', 10', 12', 13'-tetrabromostearoyl)-veratrol, represented by The present invention also provides a production method in which veratrol (2) is reacted with 9,10,12,13-tetrabromostearoyl chloride (3) in the presence of a Friedel-Crafts catalyst in order to obtain the above compound (1). be. This reaction generally uses a reaction belonging to the Friedel-Crafts reaction and is carried out in the presence of a Friedel-Crafts catalyst. As the catalyst, in addition to so-called Lewis acids such as anhydrous aluminum chloride, iron chloride, boron acid fluoride, and zinc chloride, protonic acids such as fluorinated water can be used. Also, suitable solvents include nitrobenzene, nitromethane, carbon disulfide, and ethylene dichloride. 9,10,12,13-tetrobromostearoyl chloride (3) used in this reaction can be obtained, for example, by saponifying soybean oil (4) containing a large amount of glycerin ester of linoleic acid, as shown in the following formula. Bromine is added to the extracted mixed fatty acid (5), the precipitated high-purity linoleic acid tetrabromide (9, 10, 12, 13-tetrabromostearic acid (6)) is melted, and excess thionyl chloride is added to this. can be synthesized by adding

[Table] (Effect) Hydrocarbon compounds with bromine on carbon, such as linoleic acid tetrabromide (6), in which the unsaturated group is protected with bromine, have bromine bonded in the presence of a Hudel-Crafts catalyst. Conventional chemical knowledge has been that it reacts with aromatic compounds such as veratrol at this position, that is, the reaction proceeds in a direction other than the target, resulting in the formation of a branched compound. However, the present invention has solved this problem by reacting the carboxylic acid group of the fatty acid polybromine compound with the veratrol nucleus in the form of acid chloride (3) as described above. If you do this,
As a result, the expected compound (1) was obtained as the acid chloride group reacts with the veratrol nucleus more quickly than the bromine group, which is abundant in the molecule. Furthermore, the bromine group is preserved as is during the reaction process. In other words, the bromine group can be preserved even when the methoxy group of the veratrol nucleus is demethylated by further reaction using this compound (1), which has a bromine group, as an intermediate to obtain the catechol nucleus. .
In this way, it is finally possible to obtain a synthetic urushiol-like substance in which a hydrocarbon side chain having 18 carbon atoms and the same unsaturated bonds as linoleic acid is introduced in a linear manner. The present invention will be explained below based on Examples. (Example) 9, 10, 12, 13-tetrabromostearic acid (6)
Synthesis Dissolve 250g of soybean oil (4) in 1250g of ethanol,
750 g of potassium hydroxide was mixed with an aqueous solution in a small amount of water. After heating and stirring this mixture at 80°C for 3 hours, ethanol was distilled off under reduced pressure.
Dilute sulfuric acid was added to liberate mixed fatty acids (5). This was extracted with ligroin, washed with brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated to about 500 c.c. This was cooled to -7°C using a cryogen, and 70 c.c. of bromine was gradually added dropwise with stirring. After stirring for 1 hour, the mixture was heated to 90° C. or higher to completely dissolve the precipitate, and then filtered hot. When the filtrate is cooled, crystals precipitate. This was suction filtered, washed with an aqueous sodium sulfite solution, the crystals were air-dried, and recrystallized with ligroin. Yield 73.6g (yield 29.2%), melting point 113.5-115℃
(Literature value 115℃). From the infrared absorption spectrum, it was identified as 9,10,12,13-tetrabromostearic acid (6), a known substance. Synthesis of 9,10,12,13-tetrabromostearoyl chloride (3) 10 g (1.704×10 ^-2 mol) of the above 9,10,12,13-tetrabromostearic acid (6) was heated to 120°C and melted. Then, 3 g (1.704 x 10 ^-2 x 1.5 mol) of thionyl chloride was added over 1 hour. The mixture was heated at 120° C. for 1 hour, and then excess thionyl chloride was distilled off under reduced pressure to obtain 9,10,12,13-tetrabromostearoyl chloride (3). Yield over 98%. The infrared absorption spectrum matched that of a known substance. Synthesis of 4-(9', 10', 12', 13'-tetrabromostearoyl)-veratrol (1) of the present invention 21.7 g (0.033 mol) of the above 9, 10, 12, 13-tetrabromostearoyl chloride (3) ) was dissolved in 20 ml of carbon disulfide. Add this solution to veratrol (2)
4.5g (0.033mol), anhydrous aluminum chloride 5.3g
(0.033×2.2 mol) and carbon disulfide (40 ml) with stirring. Boil under reflux for 15
The reaction mixture is stirred for a period of time, and after cooling, the mixture is poured into ice water acidified with hydrochloric acid, extracted with benzene, washed with aqueous sodium bicarbonate, then with water, and then dried. Benzene is distilled off to obtain crystals. Yield 10.1g (yield 42.6%), melting point 76-78°C. Elemental analysis (C, 43.58%; H, 5.59%,
Calculated value for C ₂₆ H ₄₀ O ₃ Br ₄ , C, 43.36%; H,
5.59%). The infrared absorption spectrum is shown in Figure 1 (1660cm
^-1 , phenyl ketone; 1022 cm ^-1 , veratrol nucleus φOCH ₃ ; 870, 840 cm ^-1 , 4-substituted veratrol). The proton NMR spectrum is shown in Figure 2 (6.95, 6.79ppm (6-H, J = 9.18Hz),
7.52ppm (3-H), 7.52, 7.64, 7.67ppm (5-
H); 4-substituted veratrol). From these analysis results, the product is 4-(9′・
It was confirmed that it has the chemical structure of 10', 12', 13'-tetrabromostearoyl)-veratrol (1). (Effects of the Invention) According to the present invention, 4-(9', 10', 12',
The ability to obtain 13'-tetrabromostearoyl)-bertolol provides an extremely pure synthetic urushiol analog intermediate. This intermediate can be easily produced from known substances because it uses the known Friede-Craft reaction. Moreover, since a single compound can be produced without any by-products, the synthetic urushiol-like substance finally obtained using this as a raw material does not contain any impurities. In fact, when a conventional synthetic urushiol-like substance containing impurities is mixed with natural urushi and used for a lacquer-based paint that dries at room temperature, the mixing ratio is 1 to 1 for Japanese urushi.
Although only 0.5 was used, when the synthetic urushiol-like substance produced using the present invention as an intermediate was similarly mixed with natural urushi, it showed the ability to form a dry coating film even at a ratio of 1:1 or more. This has made it possible to provide high-quality lacquer products that can be dried at room temperature.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an infrared absorption spectrum according to an example of the present invention, and FIG. 2 is a diagram similarly showing an NMR spectrum.

Claims (1)

[Claims] 1. Chemical structural formula 4-(9′・10′・12′・13′・-tetrabromostearoyl)-veratrol represented by: 2 Chemical structural formula obtained by reacting veratrol with 9,10,12,13-tetrabromostearoyl chloride in the presence of a Friedel-Crafts catalyst A method for producing 4-(9', 10', 12', 13', -tetrabromostearoyl)-veratrol represented by