JPH0112736B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol.

2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol provided by the present invention is a new compound that has not been described in any known literature, and is an effective 2, 2-dimethyl-3-methylenebicyclo[2.2.1]heptane-
It is useful as a synthetic intermediate for 5-ol or its lower aliphatic carboxylic acid ester. 2,2-dimethyl-3-methylenebicyclo[2.2.1]heptan-5-ol is a monoterpene alcohol isolated from the essential oil of Chrysanthemum japonense by Matsubara et al., and is called Nojigiku alcohol. Tetrahedron Letters
No. 48, 4219-4222 (1974)]. This Nojigiku alcohol has a slight camphor-like and mint-like top note and a floral note with a melancholy feeling, and the lower aliphatic carboxylic acid ester of Nojigiku alcohol also has a slight camphor-like and mint-like top note. and a floral note with a refreshing and unique fresh green and balsam-like feeling (Japanese Patent Application Laid-Open No. 59-155308
(see publication).

The present inventors first discovered that a lower aliphatic carboxylic acid ester of Nojigiku alcohol can be obtained by electrolytically oxidizing tricyclene and/or camphene in a lower fatty acid carboxylic acid, and that this lower aliphatic carboxylic acid ester of Nojigiku alcohol can be hydrolyzed. It was found that the alcohol was induced by Nojigiku alcohol (see JP-A-59-157290). Recently,
The present inventors found that when the above tricyclene was electrolytically oxidized in a lower aliphatic carboxylic acid, in addition to the lower aliphatic carboxylic acid ester of Nojigik alcohol being produced, 2,2,3-trimethylbicyclo[2.2.1]
The co-production of lower aliphatic carboxylic acid esters of heptane-3,5-diol;
-trimethylbicyclo[2.2.1]heptane-3,
Lower aliphatic carboxylic acid esters of 5-diol are easily converted to 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol by hydrolysis, and these 2,2,3 -Trimethylbicyclo[2.2.1]heptane-3,5-diol and its lower aliphatic carboxylic acid ester can be subjected to dehydration or decarboxylation under the same conditions as the elimination reaction of ordinary tertiary alcohols or their esters. The present inventors have discovered that Nojigiku alcohol or its lower aliphatic carboxylic acid ester can be easily derived by reaction, leading to the present invention.

According to the present invention, 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5- diol can be obtained.

Although tricyclene is used as a substrate in the method of the present invention, this tricyclene may be diluted with camphene. The electrolytic oxidation reaction is carried out in lower aliphatic carboxylic acids. Examples of the lower aliphatic carboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, and caprylic acid, with acetic acid being particularly preferred. In addition to being used as a solvent, these lower aliphatic carboxylic acids themselves act as reaction reagents. Therefore, according to the electrolytic oxidation reaction of the present invention, 2,2,3-trimethyl An ester of bicyclo[2.2.1]heptane-3,5-diol is obtained. The amount of lower aliphatic carboxylic acid used is 5 mol or more, preferably 20 to 50 mol, per 1 mol of substrate.
It is a mole. Note that a solvent such as methyl acetate or ethyl acetate that does not inhibit the electrolytic oxidation reaction may be present in the reaction system.

In the electrolytic oxidation reaction of the present invention, it is preferable to use a suitable supporting electrolyte. The supporting electrolyte is preferably one that is non-reactive with the substrate or reaction product and does not inhibit the electrolytic oxidation reaction, such as potassium chloride, magnesium sulfate, barium phosphate, lithium perchlorate, sodium perchlorate, potassium acetate, and strontium acetate. , halides and sulfates of alkali metals or alkaline earth metals such as sodium, potassium, barium, calcium, strontium, and magnesium, such as potassium propionate and sodium p-toluenesulfonate;
Phosphate, perchlorate, acetate, propionate or toluenesulfonate; ammonium salts such as ammonium sulfate, ammonium perchlorate, ammonium acetate, ammonium propionate, ammonium p-toluenesulfonate; n-butylammonium phosphate , di-n-butylammonium acetate, triethylammonium propionate, triethylammonium chloride, triethylammonium sulfate, trimethylammonium perchlorate, p-
Primary ~ having an alkyl group having 1 to 6 carbon atoms such as tetraethylammonium toluenesulfonate
Halides, sulfates, phosphates, perchlorates, acetates, propionates or toluenesulfonates of quaternary ammonium cations; trimethylamine, triethylamine, diisopropylamine,
Chain or cyclic amines such as butylamine, pyrrolidine, piperazine, pyridine, picoline, etc. can be used alone or in a mixture of two or more. In addition, among these supporting electrolytes, salts of lower aliphatic carboxylic acids include alkali metal hydroxides, alkaline earth metal hydroxides, and ammonia that can form salts with lower aliphatic carboxylic acids present in the system. It can also be prepared in-system by adding water, a primary to tertiary amine having an alkyl group having 1 to 6 carbon atoms, and the like. Particularly preferred supporting electrolytes include amines, lower aliphatic carboxylates, and ammonium salts. The amount of supporting electrolyte to be used varies depending on the type of supporting electrolyte and solvent used and the required current density. For example, when using triethylamine as the supporting electrolyte, it is necessary to use 1 mole of substrate and 70 moles of acetic acid.
0.3 to 3.0 mol is preferred.

Since the electrolytic oxidation reaction of the present invention is carried out in a lower aliphatic carboxylic acid, acid-resistant electrodes such as gold, platinum, titanium plated with gold or platinum, carbon, or lead peroxide are preferably used. Materials which give particularly good results in terms of reaction yield and selectivity are carbon, platinum or titanium plated with platinum. The current density is in the range of 5 to 100 mA/cm ² , preferably 10 to 50 mA/cm ² , and this value can be adjusted by adjusting the terminal voltage. Although the theoretical amount of electricity is 2F/mol, it is actually preferable to use 2.5 to 4.5F/mol to increase the reaction rate of tricyclene. Although the reaction is possible over a relatively wide range of temperatures, such as from 10 to 50°C, it is particularly practical to carry out the reaction in the temperature range from 25 to 45°C. Incidentally, if a reaction at a constant temperature is desired, the reaction system may be cooled or heated by conventional means.

The electrolytic oxidation reaction in the present invention can be carried out continuously or batchwise. After the electrolytic oxidation reaction, for example, the reaction mixture or the residue obtained by distilling off the solvent from it under reduced pressure is poured into water or a dilute alkaline aqueous solution, and this is extracted with a suitable solvent such as hexane to achieve the desired purpose. The oil containing the lower aliphatic carboxylic acid ester of 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol can be separated. In addition to the target product, this oil contains lower aliphatic carboxylic acid ester of Nojigikku alcohol, which is the main product.
A lower aliphatic carboxylic acid ester of 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol can be separated and obtained from this oil by a commonly used separation method such as distillation.

The lower aliphatic carboxylic acid ester of 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol obtained by the electrolytic oxidation reaction is purified according to a conventional method with or without isolation and purification. By hydrolysis, it can be converted into 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol.

The elimination reaction of water or carboxylic acid from 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol and its lower aliphatic carboxylic acid ester is a conventionally known general tertiary The dehydration or decarboxylation reaction from alcohol or its ester can be carried out under conditions, and typical examples of the dehydration or decarboxylation reaction are shown below.

(1) Acidic acids such as hydrochloric acid, phosphoric acid, boric acid, sulfuric acid, oxalic acid, acetic acid, trifluoroacetic acid, boron trifluoride/ether complex, p-toluenesulfonic acid, potassium hydrogen sulfate, silica, alumina, acidic ion exchange resin, etc. Dehydration or decarboxylation reaction in the presence of a catalyst at room temperature or under heat; (2) At room temperature or in the presence of a dehydrating agent such as iodine, anhydrous copper sulfate, dimethyl sulfoxide, hexamethylphosphoric triamide, phosphorus pentoxide, etc. Dehydration reaction under heating; (3) Halogenating reagents such as thionyl chloride, phosphorus tribromide, phosphorus trichloride, phosphorine chloride, phosphorus pentachloride, N-bromsuccinimide; p-toluenesulfonyl chloride, methanesulfonyl chloride, etc. sulfonating agent; or acetyl chloride;
In the presence of an esterifying agent such as acetic anhydride, preferably in the presence of a base such as pyridine, sodium ethoxide, potassium acetate, at a temperature of -70°C,
Dehydration reaction under heating; (4) Decarboxylic acid reaction under heating These dehydration or decarboxylic acid reactions can be carried out in the absence of a solvent, but can also be carried out in the presence of a solvent. Examples of solvents include benzene, n
-Hydrocarbons such as hexane; diethyl ether,
Ethers such as tetrahydrofuran and dimethoxyethane; alcohols such as methanol and ethanol; halogenated hydrocarbons such as chloroform and methylene chloride; or dimethylformamide, acetone, and water are used. Furthermore, by using excessive amounts of acetic acid and amines in the above reaction, they can also serve as a solvent.

2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol and its lower aliphatic carboxylic acid ester to be subjected to the above dehydration or decarboxylation reaction are isolated from the reaction mixture containing them. It does not have to be purified. For example, the reaction mixture obtained by electrolytic oxidation of tricyclene is extracted with hexane, etc., the extract is washed with water, dried, the solvent is distilled off, and the residue is distilled to produce the lower aliphatic carbon of Nojigikku alcohol. After obtaining the acid ester, the remaining oil containing the lower aliphatic carboxylic acid ester of 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol can be used as it is for the decarboxylic acid reaction. can. In addition, 2,2,3-trimethylbicyclo[2.2.1]heptane-2,2,3-trimethylbicyclo[2.2.1]heptane obtained by hydrolyzing lower fatty acid carboxylic acid ester of 3,5-diol The reaction mixture containing 3,5-diol can also be used as it is in the dehydration reaction. Under these dehydration or decarboxylation reaction conditions, Nojigik alcohol or its lower aliphatic carboxylic acid ester is stable, and therefore the 2,2,3-trimethylbicyclo [2.2 .1] Even if Nojigikku alcohol or its lower aliphatic carboxylic acid ester is mixed in heptane-3,5-diol or its lower aliphatic carboxylic acid ester, the final target product will not be lost.

The present invention will be specifically explained below using examples.

Example 1 1.32 g of tricyclene (GLC purity 100%) and 1.56 g of triethylamine as a supporting electrolyte were mixed with 40% acetic acid.
This solution was placed in a beaker-type non-diaphragm cell, and constant current electrolysis was performed using a carbon electrode at a current density of 20 mA/cm ² , a current flow rate of 4 F/mol, and a temperature of 20 to 29°C. After the reaction was completed, a large amount of water was added to the reaction mixture, the remaining acetic acid was neutralized with an aqueous sodium carbonate solution, and the reaction mixture was diluted with 50% n-hexane.
Extraction was carried out using three ml portions, totaling 150 ml. The extract was washed with water, dried over anhydrous sodium sulfate, and then the hexane was distilled off to obtain an oily substance. Next, this oil was dissolved in 50 ml of methanol, 10 ml of 2N caustic soda was added thereto, and the resulting mixture was stirred at room temperature for 1.5 hours. Methanol was distilled off from the reaction mixture under reduced pressure, the residual oil was poured into water, and this was mixed with three 50 ml portions of n-hexane.
A total of 150 ml was used for extraction. The extract was washed with water, dried over anhydrous magnesium sulfate, and then the hexane was distilled off, resulting in a FID-GLC distribution ratio of 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol of 8. % and the FID-GLC distribution ratio of Nojigik alcohol was 57%. By subjecting this oil to silica gel column chromatography, 0.30 g of white crystals of Nojigikku alcohol and 2,2,3
-trimethylbicyclo[2.2.1]heptane-3,
0.05 g of colorless needle crystals of 5-diol were obtained. The physical properties of these products are shown below.

Nojigiku alcohol mp: 55-57.5℃ IR spectrum (cm ^-1 ): 3320, 2960, 1660,
1050, 1030, 880 NMR spectrum (90MHz) δ ^CDCl3 _ppn ; 0.95, 1.02 (each s, 6H); 2.61 (bs, 1H); 3.7-3.9 (m, 1H); 4.64, 4.85 (each s, 2H) 2 , 2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol IR spectrum (cm ^-1 ): 3320, 1045-1030 Mass spectrum (m/e): 155 [M-CH ₃ ] ⁺ 152 [ M- _H2O ] ⁺ 137 [M- _H2O - _CH3 ] ⁺ NMR spectrum (220MHz) δ ^CDCl3 _TMS : 0.82, 0.89, 0.97, 1.01 (each s, 6H); 1.13 (s, 3H); 1.70 (m, 1H); 3.9~4.2 (m,
1H) Reference example 1.7g of 2,2,3-trimethylbicyclo[2.2.1]heptane-3,5-diol and 5.0ml of pyridine
After 1.2 g of thionyl chloride was added dropwise to this solution at a temperature of -5°C to 0°C, the mixture was stirred for 2 hours.
The resulting reaction mixture was poured into water and extracted with n-hexane. The extract was washed successively with diluted hydrochloric acid and sodium bicarbonate, dried over anhydrous magnesium sulfate, and then hexane was distilled off. By subjecting the residue to silica gel column chromatography,
0.10 g of Nojigiku alcohol was obtained. The physical properties of this product were consistent with those of Nojigiku alcohol obtained in Example 1.

Claims (1)

[Claims] 1 2,2,3-trimethylbicyclo [2.2.1]
Heptane-3,5-diol.