JPS6358812B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to p-prenylstyrene and a method for producing the same. p-Prenylstyrene [also known as 1-(3-methyl-2-butenyl)-4-ethenylbenzene] provided by the present invention is a new compound that has not been described in any known literature, and has excellent anti-inflammatory and analgesic effects. 2-(p-
It is useful as an intermediate for producing prenylphenyl)propionic acid and its salts. Conventionally, as a method for producing 2-(p-prenylstyrene)propionic acid, a method using a ketal of p-haloacetophenone as a starting material and going through a six-step process (see Japanese Patent Application Laid-Open No. 163545/1982) has been known. However, this method requires expensive raw materials and long steps, and is not necessarily suitable for industrial implementation. The present inventors produced 2-(p-prenylphenyl) in a short reaction process from industrially easily available raw materials.
As a result of intensive studies on methods for producing propionic acid, we found that p-prenylstyrene can be obtained from industrially easily available raw materials in a short reaction process, and that it can be easily converted to 2-(p-prenylphenyl)propionic acid. They discovered this and completed the present invention. That is, according to the present invention, the following methods (i) and (ii)
and (iii) p-prenylstyrene can be produced. Method (i): General formula (In the formula, Z ¹ represents a prenyl group or a vinyl group, and X ¹ represents a halogen atom.) A Grignard reagent obtained from the compound represented by the formula and magnesium metal is optionally used as a catalyst for a group metal compound of the periodic table. , and the general formula Z ² −X ² () (wherein, Z ² represents a vinyl group when the above Z ¹ is a prenyl group, and a prenyl group when the above Z ¹ is a vinyl group). , and X ² represents a halogen atom.) A method of reacting with a compound represented by Method (ii): General formula (In the formula, one of R ¹ and R ² represents a hydroxyl group,
The other represents a hydrogen atom. ) A method for dehydrating the compound shown in Method (iii): General formula (In the formula, one of X ³ and X ⁴ represents a halogen atom, an arylsulfonyloxy group or an alkylsulfonyloxy group, and the other represents a hydrogen atom.) A method of reacting a base with a compound represented by the following. Among the compounds represented by the general formula () used in method (i), p-halostyrene can be obtained by a method described in the literature, for example, by combining a Grignard reagent obtained from p-bromochlorobenzene and metallic magnesium with vinyl chloride as a nickel salt catalyst. [K. Tamao et al, Bulletin of the
Chemical Society of Japan, Vol.49(7), 1958−
1969 (1976)]. Furthermore, p-prenylhalobenzene is, for example,
It can be easily obtained by reacting a Grignard reagent obtained from p-dihalobenzene and magnesium metal with prenyl halide. The two halogen atoms of p-dihalobenzene used here may be the same or different and may be any of iodine, bromine, chlorine, and fluorine atoms, but from the viewpoint of industrial availability, , preferably a bromine atom or a chlorine atom. As the metallic magnesium, magnesium pieces for Grignard reaction are preferred, but powdered or granular magnesium, or activated magnesium prepared from magnesium chloride and metallic potassium can also be used. As the prenyl halide, prenyl chloride and prenyl bromide are preferred. In carrying out this reaction, it is preferable to use a solvent,
In particular, it is recommended to use ether solvents such as tetrahydrofuran, tetrahydropyran, diethyl ether, diisopropyl ether, and dimethoxyethane. The reaction temperature when preparing the Grignard reagent can generally be selected arbitrarily within the range of about -20°C to about 160°C, but it is operationally convenient to control the reaction temperature by refluxing the solvent. preferable. Metallic magnesium is usually preferably used in an amount of about 1 to 1.5 atomic equivalents to p-dihalobenzene. The reaction temperature in the reaction between Grignard reagent and prenyl halide is approximately −30°C.
The temperature can be arbitrarily selected within the range from 100°C to about 100°C, but preferably from about 0°C to about 30°C. The reaction can also be accelerated by adding a copper catalyst, a nickel catalyst, or the like. The amount of prenyl halide used is generally about the same mole to about twice the mole of p-dihalobenzene used in preparing the Grignard reagent. In method (i), p-halostyrene is used as the compound represented by the general formula (), and the compound represented by the general formula () is
When a prenyl halide is used as the compound represented by p-halostyrene and magnesium metal, the preparation of a Grignard reagent from p-halostyrene and magnesium metal and the reaction of the Grignard reagent with prenyl halide can be carried out using the above-mentioned process from p-dihalobenzene and magnesium metal. This can be carried out using the same operations and conditions as when preparing a Grignard reagent and reacting it with prenyl halide. As p-halostyrene, p-chlorostyrene and p-bromstyrene are preferred. In method (i), when p-prenylhalobenzene is used as the compound represented by general formula () and vinyl halide is used as the compound represented by general formula (), the reaction is preferably carried out in the presence of a solvent. In particular, it is preferable to use ether solvents such as tetrahydrofuran, tetrahydropyran, diethyl ether, diisopropyl ether, and dimethoxyethane. The reaction temperature during the preparation of Grignard reagent from p-prenylhalobenzene and metallic magnesium can be arbitrarily selected within the range of about 0°C to about 160°C, but it is convenient to control the reaction temperature by refluxing the solvent. is preferred because it is simple. When starting the reaction, it is more effective to activate magnesium by adding a small amount of iodine, ethyl bromide, ethylene dibromide, etc. The amount of metallic magnesium used is usually about 1 to 4 atomic equivalents relative to p-prenylhalobenzene. The reaction between the Grignard reagent and the vinyl halide is carried out in the presence of a group metal compound catalyst of the periodic table. As the vinyl halide, it is preferable to use vinyl chloride or vinyl bromide, and the amount used is generally about equimolar to about 3 times the molar amount of p-prenylhalobenzene used in preparing the Grignard reagent. . Effective examples of metal compounds of Group Group of the periodic table used as catalysts include nickel compounds, iron compounds, palladium compounds, and specific examples include NiCl ₂ ,
NiBr ₂ , Ni(acac) ₂ (acac represents an acetylacetonate group), Ni[(C ₆ H ₅ ) ₃ P] ₂ Cl ₂ , Ni
[(C ₆ H ₅ ) ₂ P (CH ₂ ) ₂ P (C ₆ H ₅ ) ₂ ] Cl ₂ , Ni
[(C ₆ H ₅ ) ₂ P (CH ₂ ) ₃ P (C ₆ H ₅ ) ₂ ] Cl ₂ , FeCl ₃ , Fe
(acac) ₃ , _PdCl2 , Pd( _OOCCH3 ) ₂ , _PdCl2
Examples include [(C ₆ H ₅ ) ₃ P] ₂ and Pd [(C ₆ H ₅ ) ₃ P] ₄ . Such group metal compound catalysts generally have about a
Used in amounts ranging from 0.001 mol% to about 10 mol%. The reaction temperature is about -60°C to about 60°C, preferably about -30°C to about 40°C, and the reaction pressure is from atmospheric pressure to about 20 atmospheres, preferably from atmospheric pressure to about 5 atmospheres. Among the compounds represented by the general formula () used in method (ii), 1-(p-prenylphenyl)ethanol was converted to p-prenylphenyl according to the method previously discovered by some of the present inventors and their co-researchers. By reacting a Grignard reagent obtained from prenylhalobenzene and metallic magnesium with acetaldehyde (Japanese Patent Application Nos. 56-134778 and 56-134779)
2-(p-prenylphenyl)ethanol can be easily obtained in good yields by reacting ethylene oxide with a Grignard reagent obtained from p-prenylhalobenzene and magnesium metal. These 1-(p-prenyl)
p-prenylstyrene can be obtained by subjecting phenylethanol and 2-(p-prenylphenyl)ethanol to a dehydration reaction. This dehydration reaction can be carried out using dehydration methods and conditions known to be useful for converting primary or secondary alcohols to the corresponding olefinic compounds. For example, Chemical Review Vol. 45 No. 347
General dehydration reaction conditions such as those described on pages 383-383 (1949) can be used. However, in order to avoid undesirable side reactions such as migration of double bonds or polymerization reactions, it is preferable to carry out the dehydration reaction under as mild conditions as possible. Particularly preferred is a method in which the mixture is heated to a temperature of about 60° C. to about 200° C. in acidic potassium sulfate in an amount of about 0.1 to 50% by weight based on the alcohol without a solvent or in an inert solvent such as hexane, benzene, or toluene. The compound represented by the general formula () used in method (iii) is a compound represented by the general formula () combined with a halogenating agent such as phosphorus halide or thionyl chloride,
It is easily obtained by reacting with arylsulfonyl halide or alkanesulfonyl halide. In the general formula (), when X ³ or X ⁴ represents a halogen atom, the halogen atom is preferably a chlorine atom or a bromine atom. Also,
When X ³ or X ⁴ represents an arylsulfonyloxy group, the arylsulfonyloxy group is preferably a benzenesulfonyloxy group, a p-toluenesulfonyloxy group, an α- or β-naphthalenesulfonyloxy group, or the like. Additionally, X ³
Alternatively, when X ⁴ represents an alkanesulfonyloxy group, the alkanesulfonyloxy group is preferably a lower alkanesulfonyloxy group such as a methanesulfonyloxy group or an ethanesulfonyloxy group. p-prenylstyrene can be obtained by reacting a base with a compound represented by the above general formula (). Examples of bases include inorganic bases such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and calcium oxide, alkali metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium t-butoxide, pyridine, picoline, quinoline,
Triethylamine, tributylamine, 1,5-
Diazabicyclo[4.3.0]Nonene-5,1,8-
An organic base such as diazabicyclo[5.4.0]undecene-7 can be used, and the amount thereof to be used is preferably about equimolar to about twice the molar amount of the compound represented by the general formula (). This reaction involves benzene, toluene, xylene, hexane, diethyl ether, diisopropyl ether, ethanol,
In an inert solvent such as methanol, from about -30℃ to approx.
Preferably, the temperature is within a range of about 120°C.
Further, by using a phase transfer catalyst, the reaction can be carried out in a two-phase system of an aqueous phase and an organic phase. According to this method (iii), p
- There is an advantage that prenylstyrene can be obtained. p-prenylstyrene, which is a compound of the present invention that can be produced as described above, is, for example,
It is easily produced by reacting with carbon monoxide and hydrogen in the presence of a rhodium catalyst (hydroformylation reaction) to produce α-(p-prenylphenyl)propionaldehyde, and then oxidizing it with silver oxide or other suitable oxidizing agent. can lead to 2-(p-prenylphenyl)propionic acid. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 3.2 g of magnesium shavings, 15 ml of tetrahydrofuran, and several pieces of iodine (approximately 20 mg) were placed in a flask that was flushed with nitrogen gas, and when 0.5 ml of ethyl bromide was added while stirring, the coloring caused by iodine disappeared. While stirring, heat and maintain at 110-120℃.
- A solution of 20 g of prenylchlorobenzene in 7 ml of tetrahydrofuran was added dropwise. After finishing dropping, add 1 more
Stirred at 120° C. for an hour, then cooled to room temperature and added 70 ml of tetrahydrofuran. In another flask through which nitrogen gas was passed, 50 ml of tetrahydrofuran, 19.3 g of vinyl bromide, and Ni [(C ₆ H ₅ ) ₂ P (CH ₂ ) ₃ P (C ₆ H ₅ ) ₂ ] were added.
0.12 g of Cl ₂ was added, and the Grignard solution prepared from the above p-prenylchlorobenzene was added dropwise at 10 to 20°C. After the dropwise addition was completed, the mixture was further stirred at the same temperature for 1 hour. Then 10% by weight ammonium chloride aqueous solution
Add 130 ml of water, separate into an organic layer and an aqueous layer, extract the aqueous layer with 50 ml of diethyl ether, wash the diethyl ether layer with the organic layer, wash with water, dry, concentrate, and add 3,5-di-tert. -Add 0.5g of butyl-4-hydroxytoluene (BHT) and distill to produce p-prenylstyrene (bp68-70℃/0.2mmHg) 12.5
I got g. The nuclear magnetic resonance spectrum measured for this product was as follows. ¹ HNMR ( _CDCl3 ): δ1.57-1.73 (m, 6H), 3.25
(d, J=7Hz, 2H), 5.0-5.4 (m, 2H), 5.6
(d, J=18Hz, 1H), 6.62 (dd, 11Hz and 18
Hz, 1H), 7.0 to 7.35 (m, 4H), ppm. Example 2 70 ml of tetrahydrofuran and Ni [(C ₆ H ₅ ) ₂ P (CH ₂ ) ₃ P (C ₆ H ₅ ) ₂ ] into a flask through which nitrogen gas was passed.
0.12 g of Cl ₂ was added and cooled to −30° C., and vinyl chloride was fed into the tetrahydrofuran solution through a glass tube to collect about 15 g of vinyl chloride.
A Grignard solution prepared in the same manner as in Example 1 from 20 g of p-prenylchlorobenzene and 3.2 g of magnesium shavings was added dropwise to this solution at 20 to 30°C. After the dropwise addition was completed, the mixture was stirred at the same temperature for 1 hour. The mixture was then treated and distilled in the same manner as in Example 1 to obtain 10.1 g of p-prenylstyrene. Example 3 3.2 g of magnesium shavings, 50 ml of tetrahydrofuran and several pieces of iodine (approximately 20 mg) were placed in a flask that was flushed with nitrogen gas, and when 0.5 ml of ethyl bromide was added while stirring, the coloring caused by iodine disappeared. While stirring and refluxing the solvent, 25.9 g of p-prenylbromobenzene was added to 30 g of tetrahydrofuran.
ml solution was added dropwise. After the dropwise addition was completed, the mixture was further stirred at the same temperature for 1 hour, and then cooled to room temperature. 50% tetrahydrofuran into another flask through nitrogen gas
ml, vinyl bromide 19.3 g and Ni [(C ₆ H ₅ ) ₂ P
0.12 g of (CH ₂ ) ₃ P(C ₆ H ₅ ) ₂ ]Cl ₂ was added, and the Grignard solution prepared from the above p-prenylbromobenzene was added dropwise at 10 to 20°C. After the addition was completed, the mixture was further stirred at the same temperature for 1 hour, and then treated in the same manner as in Example 1 to obtain 13.1 g of p-prenylstyrene after distillation. Examples 4 _to 13 Ni [( _C6H5 ) _2P ( _CH2 ) _3P in Example 1
p-prenylchlor was prepared in the same manner as in Example 1, using the periodic table group metal compound listed in Table 1 in the amount listed in Table 1 instead of 0.12 g of (C ₆ H ₅ ) ₂ Cl ₂ . p-prenylstyrene was produced by reacting a Grignard reagent prepared from benzene and magnesium with vinyl bromide. The yield of p-prenylstyrene was as shown in Table 1.

[Table] represents each methyl group.
Example 14 Magnesium shavings into flask through nitrogen
1.9 g, 30 ml of tetrahydrofuran, and several pieces of iodine (approximately 10 mg) were added, and while stirring, 0.2 ml of ethyl bromide was added, and the coloring caused by iodine disappeared.
Then, a solution of 10.9 g of p-prenylstyrene in 20 ml of tetrahydrofuran was added dropwise at a rate that maintained the reaction temperature at 45-55°C. After the dropwise addition was completed, the mixture was further stirred at the same temperature for 1 hour, and then cooled to room temperature (approximately 20°C). Next, a solution of 8.2 g of prenyl chloride in 10 ml of tetrahydrofuran was added dropwise at 20 to 25°C, and after the addition was completed,
It was left at room temperature overnight. Add 60 ml of 10% by weight ammonium chloride aqueous solution, separate into an organic layer and an aqueous layer, extract the aqueous layer with 40 ml of diethyl ether, wash the diethyl ether layer with the above organic layer with water, dry,
After concentration, 8.6 g of p-prenylstyrene was obtained by distillation. Example 15 A Grignard solution of p-bromstyrene was prepared in the same manner as in Example 14 using 14.4 g of p-bromstyrene and 1.9 g of turned magnesium, and then reacted with 8.2 g of prenyl chloride in the same manner as in Example 14. . The mixture was then treated in the same manner as in Example 14 to obtain 8.9 g of p-prenylstyrene. Example 16 1-(p-prenylphenyl)ethanol 5.7g
1.0 g of potassium hydrogen sulfate in 50 ml of benzene solution
was added and refluxed for 2 hours. The mixture was washed with a 10% aqueous sodium hydroxide solution, washed with water, dried, concentrated, and then distilled under reduced pressure to obtain 2.5 g of p-prenylstyrene. Example 17 A solution of 3.9 g of 1-chloro-1-(p-prenylphenyl)ethane in 10 ml of t-butanol was added dropwise to a solution of 2.2 g of potassium t-butoxide in 20 ml of t-butanol at room temperature, and the mixture was refluxed for 1.5 hours. Concentrate the reaction solution, add 50 ml of n-hexane, wash with water, dry,
The solvent was distilled off and distilled under reduced pressure to obtain 2.4 g of p-prenylstyrene. Example 18 Add 8.0g of potassium hydroxide to 30ml of toluene,
After heating and dissolving, a solution of 4.8 g of 1-chloro-1-(p-prenylphenyl)ethane in 10 ml of toluene was added dropwise, and the mixture was refluxed for 6 hours. After washing the reaction solution with water and drying, the solvent was distilled off and distilled under reduced pressure to obtain p-prenylstyrene.
2.8g was obtained. Example 19 Add 5.0 g of ethylene oxide to a Grignard solution prepared in the same manner as in Example 1 from 20 g of p-prenylchlorobenzene and 3.2 g of magnesium shavings at room temperature.
30 ml of tetrahydrofuran solution was added dropwise. After the dropwise addition was completed, the mixture was heated under reflux for 1 hour, then cooled to room temperature, an aqueous ammonium chloride solution was added, and the mixture was extracted with diethyl ether. After washing the extract with water, drying, and concentrating, it was purified by silica gel column chromatography to obtain 2-
(p-prenylphenyl)-1-ethanol 13.4
I got g. 5 g of potassium hydroxide was added to 5 g of 2-(p-prenylphenyl)-1-ethanol obtained by the above method, heated to 200° C., and then distilled under reduced pressure.
The obtained distillate was redistilled to obtain 2.3 g of p-prenylstyrene. Example 20 5.0 g of 2-(p-prenylphenyl)-1-ethanol obtained by the method of Example 19 was added to acetone.
After dissolving in 27 ml and adding 1.05 g of pyridine, -10
1.80 g of phosphorus trichloride was added dropwise at 0°C to 0°C. After the dropwise addition, the mixture was stirred for 1 hour, concentrated, and n-hexane and water were added to separate the layers. The organic layer was washed successively with water, 2% aqueous sodium hydroxide solution, and saturated brine, dried, and concentrated to obtain 5.25 g of 2-(p-prenylphenyl)-1-chloroethane. When 4.8 g of 2-(p-prenylphenyl)-1-chloromethane obtained by the above method was dehydrochlorinated in the same manner as in Example 18, 2.4 g of p-prenylstyrene was obtained. Reference example 1 Put 58.3 g of magnesium shavings, 800 ml of tetrahydrofuran, and several pieces of iodine (approximately 0.1 g) into a flask that is flushed with nitrogen gas, and add 2 ml of ethyl bromide while stirring. The coloring caused by iodine disappears and the temperature of the contents decreases. Rose. While refluxing the tetrahydrofuran, a solution of p-dichlorobenzene (294 g) in tetrahydrofuran (2) was added dropwise over about 4 hours. After the dropwise addition was completed, the mixture was further stirred for 2 hours and then cooled to room temperature. Then prenyl chloride (271.7g) in tetrahydrofuran (800ml)
The solution was added dropwise at 15-20°C over about 4 hours. After completion of the dropwise addition, the mixture was left at room temperature overnight. Next, 10% by weight ammonium chloride aqueous solution 2 was added to separate the organic and aqueous layers, the aqueous layer was extracted with 300 ml of diethyl ether, the diethyl ether layer was combined with the organic layer, washed with water, dried, concentrated and distilled. and p-prenylchlorobenzene (bp64-65.5℃/0.38mmHg)
222.3g was obtained. The nuclear magnetic resonance spectrum measured for this product was as follows. ¹ HNMR (CDCl ₃ ): δ1.66 (6H, s), 3.23 (2H,
d, J = 7.5Hz), 5.21 (1H, t, J = 7.5Hz),
6.94-7.26 (4H, m) ppm. Put 9.6 g of magnesium shavings, 30 ml of tetrahydrofuran, and a few pieces of iodine (approximately 50 Hz) into a flask that is flushed with nitrogen gas, and add 2 ml of ethyl bromide while stirring to color the mixture with iodine. disappeared.
While stirring and heating and keeping at 110-120℃,
Add 60 g of prenylchlorobenzene, add 20 ml of tetrahydrofuran during the reaction, and after reacting for 4.5 hours, cool to room temperature, add 200 ml of tetrahydrofuran, and add a solution of acetaldehyde (22.0 g) in tetrahydrofuran (30 ml) at 5 to 10°C for about 2 hours. It dripped over time. After the addition was completed, the mixture was stirred for 1 hour. Then add 400ml of 10% by weight ammonium chloride aqueous solution,
Separate the organic layer and aqueous layer, extract the aqueous layer with 30 ml of diethyl ether, wash the diethyl ether layer with the organic layer, wash with water, dry, concentrate and distill.
-(p-prenylphenyl)ethanol (bp108
~110°C/0.5mmHg) 47.3g was obtained. The nuclear magnetic resonance spectrum measured for this product was as follows. ¹ HNMR (CDCl ₃ ): δ1.36 (3H, d, J = 6.5Hz),
1.67 (6H, s) 2.26 (1H, s) 3.25 (2H,
d, J = 7.5Hz) 4.73 (1H, q, J = 6.5Hz)
5.25 (1H, t, J=7.5Hz) 7.0~7.3 (4H,
m) ppm. Reference example 2 Put 55.1 g of magnesium shavings, 800 ml of tetrahydrofuran, and several pieces of iodine (approximately 0.1 g) into a flask that is flushed with nitrogen gas, and add 2 ml of ethyl bromide while stirring. The coloring caused by iodine disappears and the temperature of the contents decreases. Rose. Then, a solution of p-dibromobenzene (446 g) in tetrahydrofuran (2) was added dropwise at a rate that maintained the reaction temperature between about 25 and 30°C. After the addition was completed, the mixture was further stirred for 1 hour and then cooled to room temperature. Then, prenyl chloride (256.8g) was added to tetrahydrofuran (800g).
ml) solution was added dropwise at 15 to 20°C, and after the addition was completed, the solution was left overnight at room temperature (approximately 20°C). Add 10% by weight ammonium chloride aqueous solution 2, separate into an organic layer and an aqueous layer, extract the aqueous layer with 300 ml of diethyl ether, wash the diethyl ether layer with the previous organic layer,
After drying and concentration, it was distilled to obtain 270 g of p-prenylbromobenzene (bp 79-83°C/0.3 mmHg). The nuclear magnetic resonance spectrum measured for this product was as follows. ¹ HNMR (CDCl ₃ ): δ1.66 (6H, s) 3.22 (2H,
d, J = 7.5Hz) 5.22 (1H, t, J = 7.5Hz)
6.98 (2H, d, J=8.0Hz) 7.33 (2H, d,
J=8.0Hz) ppm. Reference example 3 Dissolve 0.25 mmol of RhH(CO) [P(C ₆ H ₅ ) ₃ ] _{3 and} 5.0 mmol of triphenylphosphine in a 500 ml stainless steel autoclave equipped with a thermometer, magnetic stirrer, gas inlet and sampling port. After charging 200 ml of the benzene solution, the inside of the autoclave was sufficiently replaced with nitrogen gas and then an equimolar mixed gas of hydrogen and carbon monoxide, and then maintained at 40 atmospheres (absolute pressure) with an equimolar mixed gas of hydrogen and carbon monoxide. The autoclave was heated until the internal temperature reached 80°C. After that, 45 g (0.262 mol) of p-prenylstyrene was added using a metering pump while stirring vigorously.
was installed over an hour. In addition, the autoclave is connected to an external gas stop (filled with gas of the same composition as the inside of the autoclave) through a pressure control valve to replenish the gas consumed during the reaction and keep the pressure inside the autoclave constant during the reaction. I did it like that. After the addition of p-prenylstyrene was completed, stirring was continued for an additional hour. After a total of 2 hours of reaction, the autoclave was allowed to cool and the pressure was released, and the reaction mixture was analyzed by gas chromatography.
- The remaining amount of prenylstyrene is 0.0052 mol (conversion rate of p-prenylstyrene 98%),
The amount of -prenylphenyl)propionaldehyde produced was 0.226 mol (selectivity 88%). other,
0.0257 mol of β-(p-prenylphenyl)propionaldehyde was produced (selectivity 10%). After removing benzene from the above reaction mixture, simple distillation is performed under reduced pressure to obtain a mixture of α-(p-prenylphenyl)propionaldehyde and β-(p-prenylphenyl)propionaldehyde, which is further purified by distillation. Possibly boiling point 85
42.0 g of α-(p-prenylphenyl)propionaldehyde was obtained as a fraction at ~86°C/0.22 mmHg. in CDCl ₃ solution measured for this
The ¹ H-NMR spectrum was as follows. (δ value using hexamethyldisiloxane as standard)

[Formula] H ^a : 9.56 (1H, d) H ^b : 1.28 (3H, d) H ^c : 3.45 (1H, q) H ^d : 6.90 to 7.20 (4H, m) H ^e : 3.23 (2H, d) H ^f : 5.23 (1H, t) H ^g : 1.63 (6H, s) A solution of 3.70 g of silver nitrate in 15 ml of water was added to a 400 ml solution of ethanol containing 2.0 g of α-(p-prenylphenyl)propionaldehyde obtained as above. Then, while stirring at room temperature, 88 ml of 0.5N-NaOH aqueous solution was slowly added dropwise over 2 hours.
Stirring was continued for an additional approximately 10 hours. After filtering out the formed black precipitate, the liquid was concentrated, extracted with isopropyl ether, and the aqueous layer was acidified with hydrochloric acid.
An oily substance precipitated out. This was extracted with isopropyl ether, washed with water, and the isopropyl ether was removed to obtain 1.77 g of 2-(p-prenylphenyl)propionic acid. of this
The NMR spectrum completely matched that of a separately synthesized standard.

Claims (1)

[Claims] 1 p-prenylstyrene. 2 General formula (In the formula, Z ¹ represents a prenyl group or a vinyl group, and X ¹ represents a halogen atom.) A Grignard reagent obtained from the compound represented by the formula and magnesium metal is optionally used as a catalyst for a group metal compound of the periodic table. exists, and the general formula Z ² −X ² (wherein Z ² represents a vinyl group when the above Z ¹ is a prenyl group, and represents a prenyl group when the above Z ¹ is a vinyl group) , ^X2 represents a halogen atom. 3 General formula (In the formula, one of R ¹ and R ² represents a hydroxyl group,
The other represents a hydrogen atom. ) A method for producing p-prenylstyrene, which comprises subjecting a compound represented by the following formula to a dehydration reaction. 4 General formula (In the formula, one of X ³ and X ⁴ represents a halogen atom, an arylsulfonyloxy group, or an alkylsulfonyloxy group, and the other represents a hydrogen atom.) It is characterized by allowing a base to act on the compound represented by Method for producing p-prenylstyrene.