JP3030447B2 - Method for producing 1,1-diphenylethylene derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a 1,1-diphenylethylene derivative useful as a raw material for a near-infrared absorbing leuco dye.

[0002]

2. Description of the Related Art A number of near-infrared absorptive leuco dyes have been disclosed to date for thermal paper compatible with scanning by a semiconductor laser. For example, JP-A-51-121
No. 035, JP-A-60-27589, JP-A-62-2
No. 4,365,533 discloses phthalide compounds having two vinyl groups, and JP-A-51-121037, JP-A-57-167979, and JP-A-63-165379 disclose phthalide compounds having one vinyl group. Compounds are disclosed. These leuco dyes, as raw materials,
It utilizes a 1,1-diphenylethylene derivative, and this compound is important in synthesizing a near-infrared absorbing leuco dye.

[0003] Conventionally, to synthesize this 1,1-diphenylethylene derivative, Grig is prepared by reacting a corresponding benzophenone derivative with methylmagnesium bromide or the like.
It is common to use the nard reaction. Meanwhile, Grigna
A method not utilizing the rd reaction is disclosed in JP-A-63-836.
No. 0 discloses a method of synthesizing an ethane compound by reacting with lead peroxide in nitric acid or formic acid.

However, in the case of the above two synthetic methods, the former method utilizing the Grignard reaction is firstly a method of dehydration and dehydration.
It is well known that strict control of the reaction conditions such as operation is required, and it is very difficult to produce the product industrially. On the other hand, the latter method also has difficulty in the case of industrial production because it uses a lead compound.

[0005]

An object of the present invention is to provide a novel method for producing a 1,1-diphenylethylene derivative useful as a raw material for a near-infrared absorbing leuco dye, which has solved the drawbacks of the conventional method. Aim.

[0006]

According to the present invention, an acetophenone derivative and an N, N-dialkylaniline are converted to Vils
A method for producing a 1,1-diphenylethylene derivative represented by the following formula 1, characterized in that the reaction is carried out in the presence of a meier reagent, in particular, using phosphoryl chloride as the Vilsmeier reagent, and using P as the acetophenone derivative.
1, characterized in that a substituted acetophenone is used,
A method for producing a 1-diphenylethylene derivative is provided.

Embedded image (R ₁ is hydrogen atom, lower alkyl group, lower alkoxy group, halogen atom, dialkylamino group R ₂ is lower alkyl group)

The present inventors have conducted intensive studies aiming at achieving the above object, and as a result, the acetophenone derivative and N, N-dialkylaniline are reacted in the presence of a Vilsmeier reagent to give 1- (4'-dialkylamino- Phenyl)
A method for synthesizing -1- (substituted or unsubstituted phenyl) ethylene has been found.

The Vilsmeier reagent used in the present invention includes, for example, phosphoryl chloride, phosgene, oxalyl chloride-benzoyl chloride, alkanesulfonyl chloride, arenesulfonyl chloride, alkyl chloroformate, aryl chloroformate and the like. In particular, phosphoryl chloride is superior in terms of cost and ease of use.

The acetophenone derivative used in the present invention depends on the intended ethylene derivative. For example, acetophenone, 4-methylacetophenone,
Methoxyacetophenone, 4-chloroacetophenone,
Acetophenones mainly having a substituent at the P-position, such as 4-dimethylaminoacetophenone, are suitable.

The N, N-dialkylaniline, which is the other raw material used in the present invention, includes N, N-dimethylaniline, N, N-diethylaniline, N, N-dipropylaniline, N, N-dianiline. Dibutylaniline and the like can be used.

Further, the method of the present invention can be carried out under any conditions without solvent or in the presence of a solvent. When a solvent is used, various solvents can be used.
More preferably, 2-dichloroethane is used.

The production method of the present invention is carried out, for example, by the following specific method. First, the acetophenone derivative is kept at or below room temperature in a solvent-free or dissolved state in a solvent, and the Vilsmeier reagent is added. Vilsmeier at this time
The amount of the reagent is equimolar to 10 with respect to the acetophenone derivative.
Use about twice the molar amount. Next, N, N-dialkylaniline is added and reacted. The reaction temperature is preferably in the range of room temperature to about 100 ° C., and the reaction time requires about 10 to 20 hours. After completion of the reaction, the target ethylene compound can be easily collected by performing a purification treatment in a conventional manner.

[0013]

The present invention will be described in more detail with reference to the following examples. Example 1 3.13 g of 4-methoxyacetophenone and 20 ml of 1,2-dichloroethane were placed in a three-necked flask equipped with a stirrer and uniformly dissolved. While maintaining the temperature at room temperature, 4.0 g of phosphoryl chloride is slowly added dropwise. After completion of the dropwise addition, the mixture is stirred at room temperature for 1 hour. Next, 2.6 g of N, N-dimethylaniline is added dropwise and stirred for 1 hour. Thereafter, the mixture is heated and refluxed for 20 hours. After cooling, the mixture is poured into 50 ml of a 10% aqueous NaOH solution and stirred. The organic layer is separated, dried over anhydrous sodium sulfate, and concentrated to collect a brown oil. To this is added 30 ml of toluene, and the mixture is refluxed for 2 hours. After cooling, toluene was distilled off, and 100 ml of hexane was removed.
After removing insolubles, the supernatant is concentrated to obtain a red-orange oil. Then, the resulting mixture was silica gel (Wakogel C2)
00), column chromatography purification was performed using toluene as a developing solution to isolate an ethylene compound. The isolated compound was pale purple crystals, mp 129-131 ° C. FIG. 1 shows the ¹ H-NMR measurement results of this compound.
Thereby, 1- (4'-dimethylaminophenyl)-
It was confirmed that 1- (4′-methoxyphenyl) ethylene was produced.

[0014]

According to the present invention, it is possible to produce a 1,1-diphenylethylene derivative under relatively mild conditions, and this is a method with little difficulty even in consideration of industrial production.

[Brief description of the drawings]

[1] according to the present invention 1- [4'-dimethylaminophenyl] -1 of (4'-methoxyphenyl) ethylene ¹
It is an H-NMR spectrum figure.

──────────────────────────────────────────────────続 き Continuing the front page (72) Inventor Nobuo Akagi 1-2-2 Dojima, Kita-ku, Osaka, Osaka Prefecture Inside Showa Chemical Industry Co., Ltd. (72) Yoshimi Hirata 1-2-2, Dojima, Kita-ku, Osaka, Osaka (56) References JP-A-63-150251 (JP, A) JP-A-63-8360 (JP, A) JP-A-63-258836 (JP, A) (58) Int.Cl. ⁷ , DB name) C07C 209/68 C07C 211/48 C07C 211/54 C07C 217/80

Claims (3)

(57) [Claims] 1. A method for producing a 1,1-diphenylethylene derivative represented by the following formula 1, characterized by reacting an acetophenone derivative with an N, N-dialkylaniline in the presence of a Vilsmeier reagent. Embedded image (R ₁ is hydrogen atom, lower alkyl group, lower alkoxy group, halogen atom, dialkylamino group R ₂ is lower alkyl group) 2. The method according to claim 1, wherein phosphoryl chloride is used as the Vilsmeier reagent. 3. The method according to claim 1, wherein a P-substituted acetophenone is used as the acetophenone derivative.