JP2885537B2 - Method for producing tolan derivatives - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a tolan derivative. More specifically, the present invention relates to a novel method for producing a corresponding tolan derivative and / or a tolan derivative further into which a hydroxyl group is introduced from a stilbene derivative.

As a conventional technique for producing a corresponding tolan derivative from a stilbene derivative, a method is generally employed in which the ethylene group of the stilbene derivative is brominated with bromine and then dehydrobrominated with a base. However, this method is complicated because it is a two-step reaction of "bromination" and "dehydrobromination", and is expensive because bromine used for bromination results in waste. Among the tolan derivatives, compounds having a nitro group and a hydroxyl group at the ortho position thereof are important substances as nonlinear optical materials, various dye intermediates, liquid crystal compound intermediates, etc. It is difficult to introduce hydroxyl groups and no such material has been produced.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to introduce a hydroxyl group at the ortho position of a corresponding tran derivative and / or a nitro group from a stilbene derivative in a one-step reaction under simple and mild reaction conditions. It is intended to provide a novel method for producing a tolan derivative.

[0004]

An object of the present invention is to provide a stilbene derivative represented by the general formula (I) in a polar solvent in the form of t-
It is achieved by treating with potassium butoxy, and at least one of the tolan derivatives represented by the general formula (II) can be obtained in a one-step reaction.

[0005]

[0006]

(In the formulas (I) and (II), R ₁ represents an amino group, a lower alkylamino group, a di-lower alkylamino group or a lower alkoxy group, and R ₂ represents a hydrogen atom or a hydroxyl group.) Stilbene The method of the present invention in which a tolan derivative represented by the formula (II) is obtained from a derivative in a one-step reaction can be achieved by using a polar solvent and a specific base.

Specific examples of the polar solvent used in the present invention include dimethylformamide, dimethylsulfoxide,
Quinoline, tetrahydroquinoline, methylpyrrolidone,
Dimethylimidazolidinone, hexamethylphosphoramide and the like. Preferably, dimethylformamide and dimethylsulfoxide are used, and dimethylformamide is particularly preferred. Furthermore, in the method of the present invention, a tran derivative represented by the formula (II) is specifically obtained by treating a stilbene derivative with potassium t-butoxide in the above-mentioned polar solvent. Therefore, when another metal alkoxide such as methoxysodium, methoxylithium or sodium ethoxy is used instead of potassium t-butoxide, the tolan derivative represented by the formula (II) cannot be obtained.

In the method of the present invention, the amount of potassium t-butoxide used affects the composition ratio of R ₂ of the compound of formula (II) formed. In order to convert the ethylene bond of the stilbene derivative into the acetylene bond of the tolane derivative, t-
The amount of potassium butoxide used must be at least 2 molar equivalents of the stilbene derivative. Therefore, in order to obtain a compound in which R ₂ is hydrogen among the tolan derivatives represented by the formula (II), potassium t-butoxy is used in an amount of 2 molar equivalents or more, preferably 3 molar equivalents or more of the stilbene derivative. t-
If the amount of potassium butoxy used is less than 2 molar equivalents of the stilbene derivative, the remaining amount of the unreacted stilbene compound will increase. When the amount of potassium t-butoxy used is at least 4 molar equivalents, preferably at least 5 molar equivalents of the stilbene compound, R ₂ of the tolan derivative of the formula (II) formed
Is a hydroxyl group and is mixed with a hydrogen atom. The larger the amount of potassium t-butoxy used, the more R
The production ratio of the compound in which ₂ is a hydroxyl group increases. In order to selectively obtain those in which R ₂ is a hydroxyl group, it is advantageous to use a large excess of potassium t-butoxide.

[0010] In the method of the present invention, the detailed elucidation of the reaction mechanism is incomplete, but in the reaction of converting an ethylene bond into an acetylene bond and the reaction of introducing a hydroxyl group, the dissolved oxygen in the solvent is involved in the progress of the reaction. Has been obtained. Further, in the production of the tolan derivative of the formula (II) in which R ₂ is a hydroxyl group, even if the generated tolan derivative in which R ₂ is a hydrogen atom is further treated with dimethylformamide and t-butoxy potassium, R ₂ is a hydroxyl group. Therefore, it is considered that the introduction of the hydroxyl group proceeds in parallel with the conversion from the ethylene bond to the acetylene bond. In the present invention, the reaction is completed at room temperature in a reaction time of several minutes to 2 hours. The reaction may be carried out by heating if necessary.
In the method of the present invention, the simultaneous use of a crown ether has the effect of activating potassium t-butoxide by capturing potassium in potassium t-butoxide. The stilbene derivative represented by the formula (I) used in the present invention can be prepared by various known methods, for example, the method described in Bull. Ch
em. Soc. Jpn. , 46 , 2828 (1973).
Can be easily synthesized. Examples are shown below, but the present invention is not limited to these examples.

[0011]

Example 1 Preparation of 4-dimethylamino-4'-nitrotolan 0.20 g (0.740 mmol) of 4-dimethylamino-4'-nitrostilbene, 20 ml of dimethylformamide and 0.42 g (3.74 mmol) of The potassium t-butoxide was stirred at room temperature for 1 hour. 8 ml of the reaction solution
Of water, and after adding 20 ml of 2N hydrochloric acid,
Extracted with ml of benzene. Extract solution is 15ml 10%
The extract was washed with an aqueous solution of sodium hydroxide, further washed with water, and then dried over anhydrous magnesium sulfate. Next, the solvent was distilled off from the extract under reduced pressure, and the residue was recrystallized from benzene to give 0.077 g (yield 39%) of 4-dimethylamino-4′-nitrotran as red-brown scaly crystals (m. p.
207-211 ° C). The target compound was confirmed from the following analysis results. MS (m / z): 266 (M ⁺ ) IR (KBr): 2210 cm ^-1 (C≡C) ¹ H NMR (CDCl ₃ ): 3.02 (ppm) (s, 6H, Me _{2 N) 6.67 (d, 2H} , J = 7.0Hz) 7.43 (d, 2H, 7.0) 7.59 (d, 2H, 8.9) 8.18 (d, 2H, 8 .9) elemental analysis: C H N measurements 72.01 5.24 10.40 calculated _{(C 16 H 14 N 2 O} 2) 72.16 5.30 10.52

[0012]

Example 2 Preparation of 4-dimethylamino-3′-hydroxy-4′-nitrotolan 0.40 g (1.49 mmol) of 4-dimethylamino-4′-nitrostilbene, 50 ml of dimethylformamide and 2.57 g ( (22.9 mmol) potassium t-butoxide was stirred at room temperature for 110 minutes. Reaction solution 15
Drained into 0 ml of water and extracted with 425 ml of benzene. The extract was washed with 30 ml of 2N hydrochloric acid, and the washed extract was dried over anhydrous magnesium sulfate. Then, the solvent was distilled off from the extract under reduced pressure, and the residue was recrystallized from benzene to give 0.222 g (53% yield) of 4-dimethylamino-3′-hydroxy-4′-nitrotran in a purple-red color. Obtained as needle-like crystals (mp 197-200 ° C decomposition). The target compound was confirmed from the following analysis results. MS (m / z): 282 (M ⁺ ) IR (KBr): 2200 cm ^-1 (C≡C) ¹ H NMR (CDCl ₃ ): 3.02 (ppm) (s, 6H, Me _{2 N) 6.66 (d, 2H} , J = 8.8Hz) 7.04 (dd, 2H, 8.8,1.8) 7.21 (d, 1H, 1.8) 7.42 (d , 2H, 8.8) 8.03 (d, 1H, 8.8) 10.66 (s, 1H, OH) Elemental analysis value CHN measured value 68.06 5.21 9.86 Calculated value (C _{16 H 14 N 2 O 3)} 68.07 5.00 9.93

[0013]

Example 3 Preparation of 4-methoxy-4'-nitrotran 0.20 g (0.783 mmol) of 4-methoxy-
4′-Nitrostilbene, 30 ml of dimethylformamide and 0.26 g (2.32 mmol) of potassium t-butoxide were stirred at room temperature for 80 minutes. 80 ml of the reaction solution
Water, and 30 ml of 2N hydrochloric acid was added thereto.
Extracted with 100 ml of benzene. The extract was washed twice with 20 ml of a 10% aqueous sodium hydroxide solution, further washed with water, and dried over anhydrous magnesium sulfate. Next, the solvent was distilled off from the extract under reduced pressure, and the residue was recrystallized from a mixed solvent of benzene and hexane to give 0.061 g.
(31% yield) of 4-methoxy-4′-nitrotran was obtained as yellow crystals (mp 118-120 ° C.). The target compound was confirmed from the following analysis results. MS (m / z): 253 (M ⁺ ) IR (KBr): 2210 cm ^-1 (C≡C) ¹ H NMR (CDCl ₃ ): 3.85 (ppm) (s, 3H, MeO) 6.91 (d, 2H, J = 8.8 Hz) 7.50 (d, 2H, 8.8) 7.63 (d, 2H, 8.8) 8.20 (d, 2H, 8.8) ) elemental analysis: C H N measurements 71.31 4.30 5.57 calculated _{(C 15 H 11 NO 3)} 71.15 4.35 5.53

[0014]

Example 4 4-methoxy-3′-hydroxy-4 ′
0.20 g (0.783 mmol of nitrotolan)
l) 4-methoxy-4'-nitrostilbene and 50 m
l of dimethylformamide and 1.32 g (11.76 m
mol) of potassium t-butoxide was stirred at room temperature for 90 minutes. The reaction solution was discharged into 150 ml of water, and 30 m
After adding 1 L of 2N hydrochloric acid, the mixture was extracted with 175 ml of benzene. The extract was washed with water, and the washed extract was dried over anhydrous magnesium sulfate. Then, the solvent was distilled off under reduced pressure from the extract, and the residue was recrystallized from benzene to give
91 g (43% yield) of 4-methoxy-3' - hydroxy-4'-nitrotolan was converted to yellow crystals (mp.
166 ° C). The target compound was confirmed from the following analysis results. MS (m / z): 269 (M ⁺ ) IR (KBr): 2220 cm ^-1 (C≡C) ¹ H NMR (CDCl ₃ ): 3.85 (ppm) (s, 3H, MeO) 6.91 (d, 2H, J = 9.5 Hz) 7.07 (dd, 2H, 8.8, 1.8) 7.26 (d, 1H, 1.8) 7.49 (d, 2H) , 9.5) 8.07 (d, 1H , 8.8) 10.64 (s, 1H, OH) elemental analysis C H N measurements 66.92 4.38 5.21 calculated _{(C 15} H ₁₁ NO ₄ ) 66.91 4.12 5.20

[0015]

According to the production method of the present invention, a corresponding tran derivative and / or a tran derivative further introduced with a hydroxyl group can be converted from various stilbene derivatives in a one-step reaction.
And it can be manufactured by a simple method.

Claims (3)

(57) [Claims] 1. A process for producing a tolan derivative represented by the general formula (II), comprising treating a stilbene derivative represented by the general formula (I) with potassium t-butoxide in a polar solvent. (In the formulas (I) and (II), R ₁ represents an amino group, a lower alkylamino group, a di-lower alkylamino group or a lower alkoxy group, and R ₂ represents a hydrogen atom or a hydroxyl group.) 2. The method according to claim 1, wherein the stilbene derivative represented by the general formula (I) is treated with at least 4 molar equivalents of potassium t-butoxide of the stilbene derivative represented by the general formula (I) in a polar solvent. A method for producing a tolan derivative represented by the general formula (III). (In the formulas (I) and (III), R ₁ represents an amino group, a lower alkylamino group, a di-lower alkylamino group or a lower alkoxy group.) 3. The process according to claim 1, wherein the polar solvent is dimethylformamide.