JPH0720901B2 - (4S) -2-Chloro-4-methylhexanol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a novel optically active substance (4S) -2-chloro-
Regarding 4-methylhexanol.

Alcohol compounds having a methyl branch are useful as various industrial chemicals such as intermediate raw materials for cosmetics and pharmaceuticals, and in particular, optically active alcohol compounds have recently attracted particular attention as intermediates for liquid crystal chemical substances. For example, alkoxyphenylpyrimidine compounds, alkoxybenzoic acid derivatives and the like are known as ferroelectric smectic liquid crystal chemical substances.

Conventionally, as an optically active alcohol as an intermediate for synthesizing a functional material required for an optical element characterized by having optical activity, 2-methylbutanol, secondary octanol, secondary butanol, secondary phenethyl are used. Alcohol is known.

Among the optical elements characterized by having optical activity, in the method of using the electric field response optical effect in the liquid crystal state, introduction of a polar group has been performed in order to enhance the responsiveness. Alcohol was mostly of low polarity.

In particular, in a ferroelectric liquid crystal, the response speed is known to be proportional to the spontaneous polarization, and it is desired to increase the spontaneous polarization in order to increase the speed. From this point of view, it was also reported that introduction of chlorine into the asymmetric carbon can increase spontaneous polarization and increase the response speed.
However, the compounds reported hitherto have a drawback that the stability of the liquid crystal phase is lowered, and are not practically satisfactory.

In view of the above situation, the inventors of the present invention are keen to find an optically active alcohol which is not only useful as an optically active intermediate but also brings high stability and large spontaneous polarization when it is induced into a liquid crystal compound. As a result of repeated studies, a compound represented by the following formula was found.

(* Indicates an asymmetric carbon atom.) The optically active alcohol of the present invention is an important substance as an industrial chemical. For example, in addition to the above-mentioned intermediates for liquid crystal compounds, an optically resolving agent or an asymmetric synthesis agent is used. It is useful as an auxiliary agent and is expected to have various physiological activities.

The present invention will be described in more detail below.

The compound of the present invention is obtained by, for example, brominating (S) -2-methylbutanol to synthesize (S) -2-methylbutyl bromide, reacting it with crotonaldehyde (6S)- 4-Hydroxy-6-methyloctene-2 was prepared, and then the hydroxyl group at the 4-position was chlorinated (6
S) -4-Chloro-6-methyloctene-2 after oxidation,
It can be produced by reduction.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples.

Example Synthesis of (4S) -2-chloro-4-methylhexanol (1). Synthesis of (S) -2-methylbutyl bromide.

(S) -2-Methylbutanol 48.5 g, concentrated sulfuric acid 28.3 g and
143.0 g of 47% hydrobromic acid was slowly added dropwise at room temperature. After the addition, the mixture was stirred under reflux for 5 hours and the reaction product was steam distilled. Take the organic layer, concentrated sulfuric acid 20ml, methanol / water mixed solution (1/9) 40ml, saturated sodium carbonate aqueous solution 40ml
Then, the product was washed twice with 40 ml of water and 40 ml of water each time, and dried with calcium chloride to obtain 65.6 g of (S) -2-methylbutyl bromide.

(2). (6S) -4-Hydroxy-6-methyloctene-2
Synthesis of (S) -2-methylbutyl bromide obtained in (1) 11.9
A Grignard reagent was prepared from g, 2.3 g of magnesium metal and 50 ml of diethyl ether, and 6.8 g of crotonaldehyde was slowly added dropwise thereto at 0 to 5 ° C. After stirring at room temperature for 30 minutes, 15 ml of a saturated aqueous ammonium chloride solution was added at 10 ° C., the mixture was filtered and the solvent was distilled off to obtain 8.7 g of (6S) -4-hydroxy-6-methyloctene-2.

(3). Synthesis of (6S) -4-chloro-6-methyloctene-2 Dissolve 8.7 g of (6S) -4-hydroxy-6-methyloctene-2 obtained in (2) in 45 ml of carbon tetrachloride, 17.6 g of triphenylphosphine was added, and the mixture was stirred under reflux for 3 hours. After distilling off the solvent, the mixture was extracted with n-hexane, and n-hexane was distilled off to obtain 4.4 g of (6S) -4-chloro-6-methyloctene-2.

(4). Synthesis of (4S) -2-chloro-4-methylhexanol 50 ml of anhydrous methanol and 50 ml of anhydrous dichloromethane were taken, and 4.4 g of (6S) -4-chloro-obtained in (3) was taken.
6-Methyloctene-2 was dissolved. Cool to -40 ° C and
Oxygen containing 04 g / l ozone was bubbled in for 1 hour at a rate of 120 l / h. Nitrogen gas was blown in to remove excess ozone, 19.0 g of sodium borohydride was added at the same temperature, the temperature was raised to room temperature over 1 hour, and then 1 more at the same temperature.
Stir for hours.

After standing overnight, add 50 ml of n-hexane to the reaction mixture and add 5% hydrochloric acid.
It was poured into 100 ml and stirred at room temperature for 1 hour.

The n-hexane layer was taken, washed with saturated saline and then dried over sodium sulfate.

Purified with a silica gel column using diethyl ether / n-hexane (2/8) as a developing solvent, and 2.9 g of (4S) -2-chloro-
4-Methylhexanol was obtained.

The results of IR and NMR analysis of the obtained compound are as follows, and it was confirmed that the compound was the desired product.

IR (cm ^-1 ) 3320 (s), 2900 (s), 1455 (m), 1380 (m), 1075 (s), 680 (w), 610 (w) H-NMR (CCl ₄ ) δ 4.10 ~ 3.72 (m, 1H, CHCl) 3.53 (d, J = 5.0Hz, 2H, CH ₂ O) 2.45 (br.s, 1H, OH) 1.90 to 1.03 (m, 5H, CH ₂ and CH) 0.96 to 0.65 ( m, 6H, CH ₃ ) The specific rotation of the obtained compound is shown below.

[Α] _D = + 14.69 ° (26 ° C, C = 1, CHCl ₃ solution)

Claims (1)

[Claims] 1. (4S) -2-Chloro-4-methylhexanol represented by the following formula. (* Indicates an asymmetric carbon atom.)