JPS60218352A - 4-(9',10',12',13'-tetrabromostearoyl)-catechol - Google Patents

Abstract

NEW MATERIAL:A compound shown by the formula I . USE:An intermediate for preparing a synthetic urushiol analog. PREPARATION:4-(9',10',12',13'-Tetrabromostearoyl)-veratrol shown by the formula II is treated with boron tribromide at low temperature (e.g., -80 deg.C), to give a compound shown by the formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to intermediates for the production of synthetic urushiol analogues, particularly the novel compound 4-(9',10').

11.18/-tetrabromostearoyl)-catechol and its production method.

Conventional Techniques Lacquerware is a traditional craft produced in the East, especially Japan, and is known around the world under the name "Japan."As is well known, it relies on natural lacquer liquid, which is kept secret from the Minister of Justice. Ta.

However, after the opening of the Meiji period, these resources continued to be depleted.
Currently, more than 9° of that amount depends on imports from China. 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 these reasons, the synthesis of urushiol-like substances, which are relatively easy to produce, has been devised and utilized since ancient times.

Natural urushiol has the general formula:
It is a mixture of homologs of 〇-alkenylcatechol represented by

The average number of double bonds in the formula is two, but eight compounds account for 50% of them. According to some professors at Nagoya University's Forbidden City, the conditions that synthetic urushiol-like substances should meet, namely the chemical structure, are generally: (a) the number of carbon atoms in the catechol side chain is preferably 15 or more; (b) the side chain The higher the degree of unsaturation, the better the drying.(C) Chemical resistance:
It is known that (d) there is almost no difference in the cured film due to the difference in the position of the side chain in the catechol nucleus.

Problems to be Solved by the Invention Synthetic urushiol-like substances can be obtained from the raw material catechol at low cost, and the alkenyl group introduced into the side chain of Rikiteko/L/ can be obtained from natural unsaturated fats. By using the obtained compound, comparative fishing part 1 can be easily obtained. However, in this method, in the step of introducing a 411 chain into catechol, the addition reaction of carbon double bonds to catechol takes precedence, and as a result, the alkenyl group cannot be introduced in a linear form, and instead a branched form. Compounds are preferentially produced.

As a result, many kinds of compounds were produced as by-products, and they had to be used all at once as legal products. Naturally, the quality was not good, and it was difficult to make products that could be dried at room temperature, so baking paints were used exclusively. 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 conventional low-grade products such as urushiol-like substances are used as strings, so although they are simple substitutes for urushiol, they are simple and by-products. In addition, in order to produce a compound with excellent performance as a urushiol analogue, the hydrocarbon side chain introduced into the catechol nucleus must be It must be in a completely linear form, as in the case of No. Furthermore, the phenolic hydroxyl group must be of the 0-dihydroxybenzene type, that is, the catechol type.

However, when a long-chain hydrocarbon having a carbon unsaturated bond or its derivative is directly reacted with catechol, the addition reaction of the carbon double bond takes priority. As a result, the hydrocarbon group bonds to the catechol nucleus in a branched manner,
Furthermore, as a result of the addition reaction to the hydroxyl group of catechol, a knee-chill bond was also usually formed on the oxygen. It was also considered to protect the hydroxyl group with a methoxy group. However, there are many compounds that contain methoxy groups in naturally occurring essential oils, and it has been common knowledge that fairly harsh conditions must be used to convert these into 7-enols by hydrolysis. For example, in concentrated hydrobromic acid for a long time 150-2
Even if heating to 0.00"C or using expensive and unstable hydriodic acid, similarly harsh reaction conditions are required, so it is difficult to react with compounds that have delicate and easily changeable parts of the molecular structure. These methods could not be applied.

Means and Action for Solving the Problems In order to solve these problems, the present invention provides an intermediate for producing a synthetic urushiol-like substance that meets the above-mentioned demands for upgrading lacquer products. 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, is used as a raw material for the unsaturated hydrocarbon group in the side chain of the catechol nucleus, and a linear chain in which the carbon unsaturated group is previously protected with bromine is used. The compound was reacted with veratrole whose hydroxyl group of the catechol nucleus was protected with a methoxy group.

This reaction compound was used to perform demethylation to obtain the desired intermediate having a catechol nucleus.

Specifically, the present invention relates to chemical structural formulas %formula% Labrum Mostea IV) - Located in Peratrail.

Further, the present invention resides in a production method in which, in order to obtain the above-mentioned compound (1), veratrol (chemical structural formula % formula % lavromostearoyl)-veratrol is treated with boron tribromide.

According to this method, boron tribromide can be made to act at extremely low temperatures, and the veratrol compound 11
Product (8) is very easily demethylated, and the compound (8) of the present invention is
Compound (1) can be obtained. Moreover, the highly functional bromine moiety undergoes no structural change at all. It is more preferable that the reaction temperature is low in order to eliminate the risk of side reactions occurring as the reaction temperature increases. Even at extremely low temperatures such as -80°C, the demethylation reaction proceeds rapidly.

In addition to boron tribromide, hta
Although it is possible to use t8 or the like, by-products are likely to be produced, and it is necessary to remove the by-products with a solvent, which complicates the process. In contrast, boron tribromide, although expensive, can be easily removed by treatment with water.

4-(9', 10', 12) used in this reaction
', 18'-tetrabromostearyl)-veratrol (2) can be obtained, for example, by the process shown in the following formula.

First, Rino/LL1! ! ? Bromine is added to mixed fatty acid (4) extracted by saponifying soybean oil (3) containing a large amount of glycerin ester. Excess thionyl chloride was added to the obtained high-purity linoleic acid tetrabromide (9,10,1't, 18-tetrabromostearic acid f51) to produce 's lOs 12 ml l'cl-tetrabromostear. The target compound (2) is obtained by reacting pyl chloride (6) with veratrol (7) in the presence of a 7-Riedel-Crafts catalyst.

(3) (4) In this way, it is possible to finally obtain a synthetic urushiol-like substance in which a hydrocarbon side chain having 18 carbon atoms and having the same unsaturated bonds as linoleic acid is introduced in a linear manner. .

The present invention will be explained below based on Examples.

Example 9.10,12,18-tetrabromostearic acid (6
) Synthetic soybean oil (8) 2509 was dissolved in 125 g of ethanol and mixed with an aqueous solution of 75 g of potassium hydroxide dissolved in a small amount of water. After heating and stirring the mixture at 80° C. for 8 hours, ethanol was distilled off under reduced pressure, and dilute sulfuric acid was added to liberate the mixed fatty acid (4).

This was extracted with ligroin, washed with brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated to about 5ooaa. This was cooled to -7℃ using a cryogen, and 700% of bromine was added.
C was gradually added dropwise while stirring. After stirring for 1 hour,
After heating to 90°C or higher to completely dissolve the precipitate, it was 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 78.69 (yield Q9.2%), melting point 118.5~
115°C (literature value 115°C). From infrared absorption spectroscopy, 9 + 10 t 12 s l 8- of known substances
It was identified as tetrabromostearic acid (5).

10 g of the above 9,10,12,18-tetrabromostearic acid (5) (1,704
Heat to 0°C to melt and add 3 g of thionyl chloride (1,7,0
4X 10""" Chloride (6) was obtained with an O yield of 98% or more.The infrared absorption spectrum matched a known substance.

・4- (9', 10', 12', 18/
-Tetrapromos, the above 9,10,12.18-tetrabromostearoyl chloride (6) 21.79 (
0,088 mol) was dissolved in 201 nl of carbon disulfide.

This solution was mixed with 4.5 g of veratrol (7) (0,0
88 mol), anhydrous aluminum chloride 5.39 (0,0
88X (2.2 mol) and carbon disulfide (40-mol) with stirring. The reaction mixture was stirred for 15 hours under boiling reflux, and after cooling, the mixture was poured into ice water containing hydrochloric acid.
Extract with benzene 1, sodium bicarbonate water, then
After washing with water, dry. Benzene is distilled off to obtain crystals.

Yield 10.12 (yield 42.6%), melting point 76-78°C
.

Elemental analysis (as 48-58%; ) I, 5.5
9%.

Calculated value as C16H4008Br4 0, 48.8
6%; H.

5.59%). Infrared absorption spectrum (1660cm.

Phenylketone; 10g2cm''1. Heratrol core group OOH: 870.840 cm'', 4-substituted veratrol). Proton NMR spectrum ('6.95°6
,? 9 pI)m (6-H, J -9,18Hz
), 7.52ppm (a-H), 7.52, 7.
64, 7.67 ppm (5”H; 4-substituted veratrol).

From these analysis results, the product is 4-(9'y10'
It was confirmed that it had the chemical structure of t 12' , 18/-tetrabromostearoyl)-veratrail (2).

'−(9' r 1o' obtained as above)
.

ml, 18'-tetrapromostearoyluberate p
- 1.858 g (2,57 x 10 moles) of 6
It was dissolved in 0-dichloro-U methane and cooled to -60°C.

To this, boron tribromide 2.609 (2,57XIOX4
mol) was added with stirring, kept at the same temperature for 1 hour, and then set aside overnight. This was poured into ice water acidified with hydrochloric acid, extracted with benzene, washed with water and brine, dried, and then the solvent was distilled off to obtain a solid product.

Yield 0.879 (yield 48.7%), melting point llo~1
1g℃.

Elemental analysis (0, 41, 64%; H, 5, 2a%.

Calculated value as 'g4H81508Br4 0, 41.
65%: H, 5,25%).

The infrared absorption spectrum is shown in Figure 1 (8200e
1m-11OH(7) absorption; 1650cm-1, force A
#;=existence of absorption of l group; absorption of methoxy group of l 02ocm-'' disappeared).

The p-pton NMR spectrum is shown in Figure g (8.9
Disappearance of 4 ppm (S, 6 H, 0CR8), 6
．． Presence of 58 ppm (broad, 2H, OH). In other words, the absorption of two methoxy groups disappears, and OH
A new fundamental individual absorption has occurred).

From these analysis results, the product is 4-(9').

It was confirmed that it had a chemical structure of 10', 12', 18'-tetrabromostearoyl)-catechol (1).

Effects of the Invention According to the present invention, the methyl group of the veratorel nucleus can be easily demethylated, and the unsaturated carbon and hydrogen group of the side chain of the catechol nucleus can be preserved with bromine to form 4-(9', 10'1g',18'
-tetrabromostearoyl)-catechol, an extremely pure synthetic urushiol analog intermediate is obtained.

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 was mixed with natural lacquer and used in a room-temperature-drying paint, the mixing ratio was only 0.5 of the Japanese method l. When a synthetic urushiol-like substance produced using the present invention as an intermediate is similarly mixed with natural urushi I・"""-E
-"c"b dry coating film (.

demonstrated the ability to produce 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 showing the same NMR spectrum. Patent applicant Junkichi Nagaiue, Kyushu Institute of Technology

Claims (1)

[Claims] 1. Chemical structural formula (% formula % tetrabromostearoyl)-tecol. A method for producing tetrabromostearoylcine-catechol, which comprises treating tetrabromostearoyl I)-veratrol with boron tribromide.