JPH04305545A - 2-alkylalkanediol compounds and production thereof - Google Patents

Abstract

PURPOSE:To provide a novel 2-alkylalkanediol compound useful as an intermediate for polymer liquid crystals having low transition points and used in the fields such as an opto-electronics field and an optical filed. CONSTITUTION:A 2-alkylalkanediol compound of formula I (n is an integer of 7-16), especially an optically active alkanediol of formula II (C* is an optical activity-inducing symmetrical carbon), e.g. (S)-2-methyl-1,10-decanediol. The compound is obtained by reacting a compound of formula III (m is an integer of 2-14), especially an epoxy alkane of formula IV, with a trialkyl aluminum, subjecting the reaction product to a hydroboration reaction and subsequently oxidizing or ozone-oxidizing the reaction product. The method enables to readily produce 2-alkylalkanediol compounds having various main chains.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to novel 2-alkyl alkanediols that can be used as intermediates for producing polymeric liquid crystals used in the optoelectronics, optics, etc. fields, and a method for producing the same.

0002

2. Description of the Related Art Liquid crystals that can utilize or control molecular orientation are used in various fields such as display materials, recording materials, and optical materials. Most of these are low-molecular liquid crystals, but polymer liquid crystals are a material that exhibits the same electrochemical and thermo-optic effects as low-molecular liquid crystals, can fix its orientation structure, and is easy to handle over a large area. Development is desired.

On the other hand, 2-alkylalkanediols have a main chain of 8 or less carbon atoms [for example, Helv. C
Him. Acta. , 67 2 p434-440
(1984), Japanese Unexamined Patent Publication No. 58-157739], such polymers with a short number of carbon atoms in their main chains often have a high transition point when made into polymeric liquid crystals, which is unfavorable for processing. Furthermore, 2-alkylalkane diols with short main chains can be produced by oxidative decomposition of 1-methylindane and reducing the resulting ester, and by-products of the hydroformylation reaction of 7-octen-1-al. There are known methods for reducing (see the above-mentioned document), but these methods can only produce compounds with a specific chain length, and it is extremely difficult to obtain compounds with different chain lengths.

0004

SUMMARY OF THE INVENTION The present invention solves the above problems, and an object of the present invention is to provide novel 2-alkyl alkanediols and main chain molecules useful as intermediates for polymeric liquid crystals having a low transition point. An object of the present invention is to provide a simple method for producing 2-alkylalkanediols having various lengths.

[0005]

[Means for Solving the Problems] The present invention is based on the following general formula 5.

Novel 2-alkyl alkanediols represented by the formula (wherein n is an integer of 7 to 16 and R represents a lower alkyl group), in particular, carbon atoms to which a lower alkyl group R is attached as a side chain. Novel optically active 2-alkyl alkanediols in which optical activity is induced and the following general formula 6

Reacting an epoxy alkene represented by the formula (wherein m represents an integer of 2 to 14) with trialkylaluminum,
2 shown in the above general formula 5, which is then hydroborated and then oxidized or ozone oxidized.
- A method for producing alkyl alkanediols.

[0006] As the lower alkyl group in the compound represented by the above general formula 5, methyl, ethyl, propyl, butyl and the like are preferable because they stabilize the orientation structure. The compound represented by the general formula 5 includes 2-methyl-1
, 8-octanediol, 2-methyl-1,9-nonanediol, 2-methyl-1,10-decanediol, 2
-Methyl-1,11-undecanediol, 2-methyl-1,12-dodecanediol, 2-methyl-1,13
-tridecanediol, 2-methyl-1,14-tetradecanediol, 2-methyl-1,15-pentadecanediol, 2-methyl-1,16-hexadecanediol, 2-methyl-1,17-heptadecanediol, 2
-Methyl-1,18-octadecanediol, 2-ethyl-1,8-octanediol, 2-ethyl-1,9-
Nonanediol, 2-ethyl-1,10-decanediol, 2-ethyl-1,11-undecanediol, 2-
Ethyl-1,12-dodecanediol, 2-ethyl-1
, 13-tridecanediol, 2-ethyl-1,14-
Tetradecanediol, 2-ethyl-1,15-pentadecanediol, 2-ethyl-1,16-hexadecanediol, 2-ethyl-1,17-heptadecanediol, 2-ethyl-1,18-octadecanediol, 2
-Propyl-1,8-octanediol, 2-propyl-1,9-nonanediol, 2-propyl-1,10-
Decanediol, 2-propyl-1,11-undecanediol, 2-propyl-1,12-dodecanediol, 2-propyl-1,13-tridecanediol, 2-
Propyl-1,14-tetradecanediol, 2-propyl-1,15-pentadecanediol, 2-propyl-1,16-hexadecanediol, 2-propyl-1
, 17-heptadecanediol, 2-propyl-1,1
8-octadecanediol, 2-butyl-1,8-octanediol, 2-butyl-1,9-nonanediol,
2-butyl-1,10-decanediol, 2-butyl-
1,11-undecanediol, 2-butyl-1,12
-dodecanediol, 2-butyl-1,13-tridecanediol, 2-butyl-1,14-tetradecanediol, 2-butyl-1,15-pentadecanediol,
2-Butyl-1,16-hexadecanediol, 2-butyl-1,17-heptadecanediol, 2-butyl-
1,18-octadecanediol and these (S)-
, (R)-optically active substance. Among these, representative compounds include (S)-2-methyl-1,
9-nonanediol, (S)-2-methyl-1,10-
The physical and chemical properties of decanediol are shown below. (S)-2-methyl-1,9-nonanediol (1) 1
H-NMR (270 MHz, in CDCl3, TMS standard) δ (ppm) 0.92 (d, 3H, J = 6.8H
z), 1.0 to 1.7 (m, 13H), 1.82 (bs
, 2H), 3.40 (dd, 1H, J1=10.3Hz
, J2=6.8Hz), 3.49(dd,1H,J1=
10.3Hz, J2=5.9Hz) (2) Infrared absorption spectrum (neat) (cm-1) 3230, 2
840, 1450, 1370, 1025 (3) Mass spectrometry (FAB) (m/z) 175 ([M+H] ion, C10
H23O2,175) (S)-2-methyl-1,10-decanediol (1)
1H-NMR (270 MHz, in CDCl3, TMS standard) δ (ppm) 0.91 (d, 3H, J = 6.8
Hz), 1.0 to 1.7 (m, 17H), 3.41 (d
d, 1H, J1=10.3Hz, J2=5.9Hz),
3.50 (dd, 1H, J1=10.3Hz, J2=5
．． 9Hz), 3.63(t,2H,J=6.4Hz)(
2) Infrared absorption spectrum (neat) (cm-1)
3230, 2850, 1440, 1365, 102
5 (3) Mass spectrometry (FAB) (m/z) 189 ([M+H] ion, C11
H25O2,189)

The compound of the above general formula 5 is prepared by using the corresponding 1,2-epoxyalkene shown in the above general formula 6 as a starting material, and the following general formula 7 is obtained.

It can be produced via an alkenol represented by the following formula (wherein m is an integer of 2 to 14 and R represents a lower alkyl group).

The 1,2-epoxyalkenes represented by the general formula 6 include 1,2-epoxyoctene, 1,2-
Epoxynonene, 1,2-epoxydecene, 1,2-epoxyundecene, 1,2-epoxidedodecene, 1,2
-Epoxytridecene, 1,2-epoxytetradecene, 1,2-epoxypentadecene, 1,2-epoxyhexadecene, 1,2-epoxyheptadecene, 1,2-
Epoxy octadecene and these (S)-, (R)-
, an optically active substance can be exemplified. Such epoxy alkenes were prepared by preparing Nocardia corallina (Nocardia colarina) according to the method disclosed in Japanese Patent Publication No. 56-40.
ia corallina) B-276 (Microbial Technology Research Institute Deposit Number FERM P-4094), the following general formula CH2=CH-(CH2)m-CH=C
It can be easily obtained by oxidizing the alkanediene represented by H2 (wherein m represents an integer of 2 to 14) and separating and removing the diepoxyalkane produced at the same time. Incidentally, the epoxy alkene obtained by this method is an (R)-optically active form.

In the production method of the present invention, first, the epoxy alkene of the above general formula 6 is reacted with a trialkylaluminium to obtain the corresponding alkenol shown by the above general formula 7.

[0010] This reaction is usually carried out in a solvent, and examples of the solvent used in this reaction include organic solvents such as hexane, heptane, cyclohexane, toluene, and pentane.

[0011] In this reaction, trialkylaluminum is dissolved or suspended in a reaction solvent, and while stirring,
It is preferable to add the epoxy alkene directly or after dissolving it in the same solvent as the above reaction solvent.

[0012] The reaction temperature can be carried out in a wide range of -20 to 100°C, but a temperature of 0 to 50°C is preferable.
It is preferable to appropriately select the epoxy alkene and the type of solvent. The reaction time is 2 to 1 depending on the reaction temperature.
It is preferable to select an appropriate time within the range of 00 hours.

Trialkylaluminum includes trimethylaluminum, triethylaluminum, tri-i-propylaluminum, tri-n-propylaluminum,
It is selected from tri-n-butylaluminum, tri-i-butylaluminum, tri-t-butylaluminum, etc. depending on the purpose of the product. This trialkylaluminum is preferably used in an amount of 0.5 to 6 times in mole per mole of epoxy alkene.

Next, the alkenol represented by the general formula 7 obtained by the above method is oxidized after hydroboration, or directly oxidized with ozone.

For hydroboration, borohydride compounds such as borane, thexylborane, dicyamylborane, dicyclohexylborane, and 9-BBN can be used. The borohydride compound is preferably used in an amount of 0.4 to 10 times in mole per mole of alkenol. In this reaction, by oxidizing with alkaline hydrogen peroxide solution or air oxidation in post-treatment,
A 2-alkylalkanediol represented by the general formula 5 corresponding to the number of carbon atoms is obtained.

This reaction is preferably carried out in a solvent,
In this case, tetrahydrofuran, diglyme, etc. can be used as the solvent. The reaction temperature of this reaction is −
It can be carried out in a wide range of 50 to 50℃, but -20℃
It is preferable to conduct the reaction at a temperature of ~20°C, and it is preferable to select the temperature appropriately in consideration of the type of alkenol and the type of solvent. The reaction time may be appropriately selected in the range of 0.1 to 100 hours depending on the reaction temperature. Note that the target product can be isolated by known means such as distillation, recrystallization, and column chromatography.

On the other hand, as a method for directly oxidizing the alkenol represented by the general formula 7 with ozone, a method in which ozone gas is directly blown into the reaction solution is simple and preferable. In this case, the amount of ozone gas is 1 to 1 mole of alkenol.
It is preferable to set it as 10 times mole. By reacting the ozonide obtained by this reaction with a metal hydride such as sodium borohydride or lithium aluminum hydride, the 2-alkylalkanediol shown in the general formula 5 can be obtained. This reaction is usually carried out in a solvent, such as methanol, ethanol,
Chloroform, methylene chloride, tetrahydrofuran, diethyl ether, etc., and mixed solvents thereof can be used. The reaction temperature for this reaction can be carried out in a wide range of -100°C to 30°C, but preferably in the range of -78 to 0°C.

After the reaction is completed, the desired product may be isolated by known methods such as distillation, recrystallization, and column chromatography.

[0019] The 2-alkyl alkanediol obtained by ozone oxidation has one carbon shorter in the main chain than the 2-alkyl alkanediol obtained by hydroboration, so the number of carbon atoms can be adjusted depending on the purpose. can be adjusted.

The 2-alkyl alkanediols thus obtained have two functional groups in the molecule, and polymer compounds such as polyether, polyester, and polyurethane can be obtained by polymerization reaction. In particular, this optically active substance can be used as an optical material such as a polymeric liquid crystal having a low transition point.

[0021]

[Example] Synthesis of 2-methyl-9-decen-1-ol To 20 ml (20 mmol) of a 1M hexane solution of trimethylaluminum, 2.14 g (R)-1,2-epoxy-9-decene (13. 9 mmol) was added dropwise, and the mixture was reacted with stirring at room temperature for 1.5 hours, then at 50° C. for 2 hours, and finally under reflux for 1.5 hours. The reaction solution was cooled to room temperature, 5 g of sodium sulfate decahydrate was added thereto, stirred for 1 hour, filtered, and the filtrate was concentrated under reduced pressure. The residue was subjected to silica gel column chromatography (
(S)-2-methyl-9-decen-1-ol as a colorless oil having the following physical and chemical properties.1.
98 g (yield 83%) was obtained. (1) 1H-NMR (270MHz, CDCl3+D2
(in O, TMS standard) δ (ppm) 0.92 (d, 3
H, J=6.8Hz), 1.0-1.7 (m, 11H)
, 1.9-2.1 (m, 2H), 3.3-3.6 (m,
2H), 4.85-5.05 (m, 2H), 5.7-5
．． 9 (m, 1H) (2) Infrared absorption spectrum (nea
t) (cm-1) 3270, 2840, 1635
, 1450, 1370, 1025,
900(3) Specific optical rotation [α]D26 (c=1.
13, EtOH) -10.1°

Synthesis of 2-methyl-1,10-decanediol A solution of borane (50 mmol) in tetrahydrofuran (10 ml) containing 8.2 g (100 mmol) of cyclohexene at -10°C
ml was titrated over 8 minutes. After completion of the dropwise addition, the mixture was stirred at 0°C for 1 hour, further stirred at room temperature for 15 minutes, and then cooled to 0°C to give (S)-2-methyl-9- obtained by the above method.
A solution of 1.70 g (10.0 mmol) of decen-1-ol in 10 ml of tetrahydrofuran was added. 0 of this liquid
After stirring at ℃ for 2 hours and at room temperature for 12 hours, aqueous sodium hydroxide solution was added to stop the reaction, 20 ml of 34% by weight hydrogen peroxide solution was added, and the mixture was stirred and reacted for 1 hour. After the reaction was completed, extraction was performed with ethyl acetate, and the extract was dried over anhydrous sodium sulfate. Then, the solvent was distilled off under reduced pressure,
[
α]D26 (c=0.18, EtOH) is -12.0°
Thus, 1.54 g (yield: 81%) of colorless oily (S)-2-methyl-1,10-decanediol was obtained.

Synthesis of 2-methyl-1,9-nonanediol (S)-2-methyl-9- obtained by the above method
40 ml of an ethanol solution containing 1.02 g (6.0 mmol) of decen-1-ol was cooled to -78°C, and ozone gas was blown into the solution for 1 hour while stirring. Next, 1.14 g (30 mmol) of sodium borohydride was added thereto, the temperature was raised to room temperature over 2 hours, and then the mixture was stirred at room temperature for 1 hour. To this, 2N hydrochloric acid was added to stop the reaction, and the product was extracted with ethyl acetate and dried over anhydrous sodium sulfate. After distilling off the solvent, the residue was purified by silica gel column chromatography (eluent: 8 vol/1 vol mixture of hexane/ethyl acetate), and it had the above-mentioned physicochemical properties and specific optical rotation [α]D26. (c=1
．． 04, EtOH) at -10.2°, colorless oil (S
)-2-methyl-1,9-nonanediol 0.94g (
A yield of 90.4%) was obtained.

[0024]

Effects of the Invention The novel 2-alkyl alkanediols of the present invention are useful as intermediates for polymeric liquid crystals with low transition points, and the method of the present invention can be applied to The effect is that alkyl alkanediols can be easily produced at low cost.

Claims (4)

[Claims] Claims: 1. Novel 2-alkyl alkanediols represented by the following general formula 1: (wherein n is an integer of 7 to 16 and R represents a lower alkyl group). [Claim 2] It is represented by the following general formula 2 [Formula 2] (where n is an integer of 7 to 16, C* is an asymmetric carbon having induced optical activity, and R represents a lower alkyl group) Novel optically active 2-alkyl alkanediols. [Claim 3] Reacting an epoxy alkene represented by the following general formula 3 [Formula 3] (wherein m represents an integer from 2 to 14) with a trialkylaluminum,
2. A method for producing 2-alkyl alkanediols shown in formula 1 according to claim 1, characterized in that the hydroboration is then followed by oxidation or ozone oxidation. [Claim 4] An epoxy alkene represented by the following general formula 4 [Formula 4] (where m is an integer of 2 to 14 and C* represents an asymmetric carbon having induced optical activity) is converted into a trialkyl 3. A method for producing optically active 2-alkyl alkanediols represented by the general formula 2 according to claim 2, which comprises reacting with aluminum, followed by hydroboration and then oxidation or ozone oxidation.