JPS5844648B2 - Method for producing 1,1,1-trichloro-4-methylpentene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing 1,1,1-trichloro-4-mepentene as shown in general rule I).

More specifically, the present invention is directed to the general formula (il) thyl (wherein R1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group or an acyl group).

: The compound represented by: is subjected to a dehydration reaction, a dealcoholization reaction or a decarboxylation reaction in the presence of a solid acid selected from the group consisting of silica gel, silica alumina, diatomite, pumice, Fuller's earth and activated alumina. 1,1゜1-trichlor-4- represented by the general formula (I)
Method for producing methylpentene and general formula (wherein R1 has the same meaning as in general formula (n)).

] to dimethylvinyl carbinol or its derivatives under radical reaction conditions to obtain the compound represented by general 4 II), which is then added to silica gel, silica alumina, diatomaceous earth, pumice, Fuller's earth and activated alumina. 1, 1 represented by the general formula (1), which is subjected to a dehydration reaction, dealcoholization reaction or decarboxylation reaction in the presence of a solid acid selected from the group consisting of
,1-4! The present invention relates to a method for producing J chloro-4-methylpentene.

In general formula (II) and general formula (III), R1 is preferably a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or a C 1 to 20 aralkyl group. -10 acyl groups, particularly preferably a hydrogen atom, methyl group, ethyl group, propyl group, butyl group, acetyl group or butyryl group.

1 shown in the above general formula 1) obtained by the method of the present invention
, 1,1-trichloro-4-methylpentene can be used as a raw material for the synthesis of various useful compounds, especially 1,1,
1-Trichloro-4-methyl-3-pentene is an important synthetic intermediate for synthetic pyrethroids, which have recently attracted attention as insecticides.

Synthetic pyrethroids have the disadvantage of rapid photodegradation of natural pyrethroid insecticides, whereas synthetic pyrethroids are superior in terms of persistence and insecticidal efficacy. CM, Eliot et al., Nature, 244 + 456 (1973
Reference% Synthesis Recently, as a method for synthesizing cyclopropane carboxylic acid ester for herethroid, a method was reported in JP-A-49-47531 in which the corresponding aldehyde was obtained by ozonolysis of chrysanthemum acid and then subjected to Wittig reaction. Ta.

However, this method uses expensive raw material as a starting material and requires complicated operations such as an ozone oxidation reaction and a Wittig reaction, so it is considered difficult to adopt it as an industrial method.

Also, J. F'arkas et al. Col Iect, Cze
ch, Chem.

Commun, 24.2230 (1959) reported the diazoacetate method.

That is, I. After acetylating 1,1-trichloro-4-methyl-3-penten-2-ol, it was reduced with zinc acetic acid to obtain 1,1-dichloro-4,4-dimethylbutadiene, which was further converted into a known In this method, it is reacted with diazoacetate to form cyclopropanecarboxylic acid ester.

However, this method also uses the raw material 1,1-dichloro-4,
This method is not an industrial method due to drawbacks such as the long reaction steps required for 4-dimethylbutadiene synthesis, the complicated operation of reducing zinc acetate, and the low yield of addition reaction of diazoacetate at 37%. I can not say.

Furthermore, recently, prenol was used as a starting material, and after reacting with orthoacetic ester, tetrahalogenated methane was added, and then a reduction reaction was performed with an alkali.
A method for synthesizing cyclopropane carboxylic acid ester was announced.

This method is considered to be an industrially advantageous route compared to the above two methods because the reaction steps are short and the yield in each step is favorable, but there is no effective method for synthesizing the raw material prenol. Problems remain in that the price of orthoacetic ester is high.

As a result of intensive and detailed study of a new and effective synthetic route for the above-mentioned synthetic pyrethroids, the present inventors found that the above-mentioned pa
1,1-dichloro-4,4- used by rkas et al.
General 4 I) easily derivatized to dimethylbutadiene
We have discovered a new method for producing t,i,i-trichloro-4-methylpentene represented by the formula, and have completed the present invention.

Dimethylvinylcarbinol or its derivative represented by general formula (III) [hereinafter referred to as compound ■]
A compound represented by general formula (II) can be produced by reacting with chloroform radical reaction conditions.

Radical reaction conditions can be achieved by the presence of a radical reaction initiator or by irradiation with light.

As a radical reaction initiator, benzoyl peroxide (BPO
), azobisinbutyronitrile (AIBN), acetyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, etc. can be used.

The radical reaction initiator may be used in a so-called contact amount.

The reaction is preferably carried out under an atmosphere of an inert gas such as carbon dioxide, nitrogen, or helium.

In addition, when carrying out the above reaction, chloroform may be used in an equimolar amount to compound (II[);
It can also serve as a solvent by using 2 to 20 times the mole of I[I].

As a solvent, a solvent that does not directly participate in the reaction, such as carbon disulfide, n-hexane, n-hebutane, etc., may be used, but
Use of these solvents is not mandatory.

The reaction temperature is preferably room temperature to 100°C when light is used as the radical reaction initiation method, and 70 to 180°C when a radical reaction initiator is used.

Radical addition reactions of olefin halides, esters, alcohols, active methylenes, etc. have been known for a long time, and can be broadly classified into the following two methods.

a) Heating in the presence of an organic amine and a transition metal compound.

b) heating in the presence of a radical initiator;

However, method a) cannot be applied to the present invention due to selectivity.

That is, under the conditions a) above, the reaction in which chloroform is added mainly with Ct type and .CHCt2 type radicals proceeds.

Furthermore, in the radical addition reaction of haloform to primary allylic alcohols, ethers, and esters that have been attempted in the method b), for example, Kharasch et al.
.

Am, Chem, Soc,, 69, l 105 (19
47), and Lewis et al. J., Am., Che.
As stated in M. Soc., 76°457 (1954), a large amount of telomer grows, and Tarran
t et al. J, Org.

Chem., 2nd Edition, 4646 (1961), the yield of the 1:1 adduct is extremely low at 20-30%.

Furthermore, it is known that tertiary allyl alcohol such as dimethylvinyl carbinol easily undergoes a dehydration reaction under heating.

However, when dimethylvinyl carbinol or its derivative represented by 4m) and chloroform are reacted under the radical reaction conditions f as described above, no dehydration reaction or telomer formation occurs.

For example, after adding a small amount of benzoyl peroxide (BPO) to 8.61 g of dimethylvinyl carbinol in 50 ml of chloroform and reacting at 140°C under a nitrogen atmosphere for 16 hours, the reaction solution was analyzed by gas chromatography. The conversion rate was 78.2 points, and the selectivity for the target 1,1,1-trichloro-4-methyl-4-pentanol was 94.5 points.

The compound represented by the general formula (II) is subjected to a dehydration reaction, dealcoholization reaction or depotarboxylic acid reaction in the presence of a solid acid selected from the group consisting of silica gel, silica alumina, diatomaceous earth, pumice, Fuller's earth and activated alumina. i represented by the general formula (I) which is the object of the present invention by adding
, i,i-trichloro-4-methylpentene.

This dehydration reaction, dealcoholization reaction or decarboxylation reaction is carried out under heating in a gas phase or liquid phase in a temperature range of 80 to 250°C.

Furthermore, in order to accelerate the reaction rate, it is also possible to use a solid acid in which vanadium pentoxide or the like is supported on diatomaceous earth.

Thus obtained t,i,ih dichloro-4-
The product composition of methylpentene varies depending on the reaction conditions, but the main products are 1,1,1-trichloro-4-methyl-3-pentene and 1゜1.1-1-lichloro-4-
It is methyl-4-pentene.

In addition to this, large amounts of 1, 1-cyc-o-4. By-products such as 4-dimethylbutadiene are also obtained.

1,1,1-trichloro-4-methyl- obtained here
4-Pentene can be heated directly or in the presence of a catalyst such as palladium, molybdenum, nickel, or cobalt to form 1゜1.1-1-lichloro-4-.
It can be isomerized to methyl-3-pentene.

l, l, l- easily obtained by the method of the present invention
As shown in the figure below, trichloro-4-methyl-3-pentene can be made into a cyclopropanecarboxylic acid ester for synthetic pyrethroid by reacting it with diazoacetic acid ester by a known method and then dehydrochlorinating it. can.

This method LEt'tjf, in the reaction of l,1-dichloro-4,4-dimethylbutadiene and diazoacetate as reported by Farkas et al., the cyclopropanecarboxylic acid ester contains two olefins. 3
This solves the problem that it can only be obtained with a yield of 7.5, and at the same time, the process can be greatly simplified because the raw material 1,1°1-trichloro-4-methyl-3-pentene can be easily obtained.

In addition, after reacting i, t, i-trichloro-4-methyl-3-pentene with haloacetic acid or its ester under radical reaction conditions or in a redox system as shown in the figure below,
It is possible to dehydrochloride it by alkali treatment and lead to a synthetic pyrethroid compound.

Furthermore, 1,1,1-trichloro-4-methyl-3-pentene can be converted to 1,1-dichloro-4゜4-dimethylbutadiene, which is used by Parkas et al., by dehydrochlorination. It is.

As described above, i,t,i-trichloro-4-methylpentene represented by general formula (I) is an important compound with a very wide range of uses, and the present invention provides an easy method for producing this compound. It is.

Hereinafter, the present invention will be explained in more detail with reference to examples.O Example 1 0.82 benzoyl peroxide was added to a solution of 7.2 f of dimethylvinyl carbinol in 5QmJ of chloroform, and the mixture was placed in an autoclave at 135°C under a nitrogen atmosphere. 18
A time reaction was performed.

After the reaction, unreacted dimethylvinyl carbinol and chloroform were recovered by distillation under reduced pressure to obtain a dark red viscous liquid 30.1S' as a residue.

By vacuum distilling this material, bp60-61.5
1,1,1-trichloro-4-methyl-4-pentanol as a fraction of 0.3 mm
(yield 690; b).

This product was analyzed by gas chromatography (Silico
As a result of neDC-550, 160℃), the purity was 95.4φ
It turned out to be.

The impurity was estimated to be the isomer 1,1,3-trichloro-4-methyl-4-pentanol from the mass spectrum.

The structure of 1゜i,i-trichloro-4-methyl-4-pentanol was confirmed by the following method.

Infrared absorption spectrum 3340.1380, 1368, 1280°1220.
1150,1073,1035゜942.910,79
5,745,695cz-1 mass spectrum Then, silica gel 1.0'? was added, heated, and refluxed for 4.0 hours.

After the reaction, the solvent was distilled off under reduced pressure, and the residue was distilled under vacuum to obtain 1,1,1-dichloro-4-mether-4-pentene and 1,1,1-dichloro-4-mether-4-pentene and , 1,1-)-lichloro-4-methyl-3-pentene mixture 3.81 was obtained (yield 84%).

As a result of gas chromatography analysis of this material, t,
i, i-trichloro-4-methyl-4-pentene vs. 1,
1.1-t! The ratio of J chloro-4-methyl-3-pentene was found to be 40:60.

After separating each compound by precision distillation of the above mixture, the structures of these compounds were confirmed by the following method.

Infrared absorption spectrum (neat) Examples 2 to 8 Similarly to Example 1, various dimethylvinyl carbinol or its derivatives were reacted with chloroform under various radical reaction conditions in an inert gas atmosphere.

The results are summarized in Table 1. *Yield was determined by gas chromatography analysis of the residue obtained by concentrating the reaction solution.

Example 9 A glass tube with an inner diameter of 1.5 cm and a length of 30 CrrL was filled with a carrier in which 2% of vanadium pentoxide was supported on a diatomer.
Heat the outside with a ribbon heater to bring the internal temperature to 130-135.
℃.

To this, 501 toluene of i,i,t-trichloro-4-methyl-4-pentanol obtained by the method of Example 1
0ml solution is fed at 30ml/111 and the distillate is cooled and trapped in a condenser.

After drying the distillate over magnesium sulfate, the solvent is distilled off under reduced pressure.

Gas chromatography analysis of the residue revealed 1,1. l
The conversion rate of -trichloro-4-methyl-4-pentanol was 93.6%, and the target 1,1.1-1-lichloro-4-
Methyl-4-pentene and 1,1.1-trichlor-
The selectivity of 4-methyl-3-pentene was 98.7%, and the respective ratio was 53:57.

Example 10 A reaction tube with an inner diameter of 3 CrIL and a length of 30 cm was filled with 150 ml of silica-alumina catalyst and heated to 140°C.

In addition to this, t, i, i-tri'7 obtained by the method of Example 1
0-4-methyl-4-pentanol 606z 202
L? Feed at a rate of /hr.

After the distillate leaving the reactor is trapped through a cooling pipe,
Ether is added to this, and the ether layer is washed with water and dried.

The ether was distilled off under reduced pressure and the residue was analyzed by gas chromatography, which revealed that 1,1゜1-trichloro-4-methyl-4-pentene vs. The ratio of raw materials 1,
The conversion rate of 1,1-todichloro-4-methyl-4-pentanol was 97.1%.

By precision distilling the residue, 1,1,1-4-lichloro-4-methyl-4-pentene 11.11' and 1,1-trichloro-4-methyl-3-pentene 325z were obtained.

Claims (1)

[Claims] 1. A compound represented by the general formula (II) (wherein R1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, or an acyl group) can be used as a compound represented by silica gel, silica alumina, quartzite, or pumice. 1, 1, 1 represented by the general formula (I), which is subjected to a dehydration reaction, dealcoholization reaction or decarboxylation reaction in the presence of a solid acid selected from the group consisting of , Fuller's earth and activated alumina. - Method for producing trichloro-4-methylpentene. 2 General formula (1) (wherein R1 represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group or an acyl group.) Chloroform is added to dimethylvinyl carbinol or a derivative thereof under radical reaction conditions. and general formula (I) [wherein R1 has the same meaning as in general formula (1)]. ] is obtained, which is subjected to a dehydration reaction in the presence of a solid acid selected from the group consisting of silica gel, silica alumina, diatomite, pumice, Fuller's earth and activated alumina,
i, t, 1 represented by general formula (I) characterized by being subjected to dealcoholization reaction or decarboxylation reaction
-A method for producing t-lichloro-4-methylpentene.