JP2960704B2 - Method for synthesizing amines and diamines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently synthesizing amines and diamines by reacting in water without using a harmful organic solvent from the viewpoint of environmental protection.

[0002]

2. Description of the Related Art Conventionally, as a method for obtaining amines from imines, (a) a method by catalytic hydrogenation (CATALYTIC HYDROGE
NATION ORGANIC SYNTHESIS PROCEDURES AND COMMENTARY
Freifelder 65), (b) Metallic sodium, amalgam of metallic sodium, magnesium (THE CHEMISTRY OF THE
CARBON-NITROGEN DOBLE BOND Patai 276), a method using a metal such as yttrium (Chem. Lett., 203 (1990)),
(c) Method using lithium aluminum hydride or sodium borohydride (COMPREHENSIVE ORGANIC SYNTHESIS R
obertson Vol8,25), (d) Method using electrode reaction using lead, copper, mercury, etc. as cathode (Modern Synthetic Reacti
ons House 210), (e) Method using ruthenium complex (Chem.
Lett., 237 (1997)).

On the other hand, as a method for obtaining diamines from imines, (f) a method using sodium metal (J. Org. Chem., V.
ol37, 653 (1972)), (g) a method using titanium tetrachloride-mercury amalgam system (Synthesis, 255 (1988)), (h) a method using samarium iodide (Chem. Lett., 1141 (1990)), ( i) Indium method (Tetrahedoron Lett., Vol. 34, 1647 (199
3)), (j) Method using aluminum or bismuth (Tetrahe
dron Lett., Vol. 36, 6747 (1995)) and the like are well known.

[0004] However, the method (d) has various problems in practice on an industrial scale, and the amalgam of metallic sodium (b), the mercury electrode of (d) and the method of (g) require industrial use. There is a problem that requires mercury, which is not possible in the production method. The methods using metallic sodium of (b) and (f) involve risks in the reaction operation. (a), (b) yttrium,
Each of the methods (c), (e), (g), (h) and (i) has a problem that an expensive metal is required. In addition, any method except the method (d) has a problem that an organic solvent is required for the reaction. Recently, from the viewpoint of environmental protection, environmentally friendly organic synthesis in water without using an organic solvent has become increasingly important. Any of these methods is extremely unsatisfactory as a simple and environmentally friendly method for synthesizing amines and diamines.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel method for efficiently synthesizing amines and diamines in water without using an organic solvent by a short and easy operation under mild conditions. To provide.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, when zinc is used, the reduction reaction and the reductive coupling reaction of imines in an alkaline aqueous solution are performed. It was found that the process proceeded to obtain amines and diamines.

The present invention has been completed on the basis of the above-mentioned findings, and is described as follows: "Zinc was added to a mixed solution of an imine and an alkaline aqueous solution, and the mixture was reacted in water without using an organic solvent to form a mixture. A method for synthesizing amines and diamines, wherein the mixture is separated by distillation (first invention). "

[0008]

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[In the formula, R ₁ represents a phenyl group or a naphthyl group, R ₂ represents a hydrogen atom or a phenyl group, and R ₃ represents a hydrogen atom, a cyclic alkyl group, a phenyl group, a naphthyl group, a benzyl group or a phenethyl group. And represents a group, which may further have a substituent. Wherein the first compound is a compound represented by the formula
Method for synthesizing amines and diamines according to the invention (second method)
Invention)] "The resulting mixture is a mixture of an amine and a diamine, and the amine is represented by the following general formula (b):

[0010]

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Wherein R ₁ , R ₂ and R ₃ each independently have the same meaning as described above. Represented by the following general formula (c):

[0012]

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Wherein R ₁ , R ₂ and R ₃ each independently have the same meaning as described above. ] The method for synthesizing the amines and diamines according to the first or second invention, which is a compound represented by the formula:

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for synthesizing amines and diamines of the present invention (hereinafter, referred to as “method of the present invention”).
Will be described in detail.

The imines represented by the general formula (a) used in the present invention include benzylidene aniline,
(4-methylbenzylidene) aniline, (4-methoxybenzylidene) aniline, (4-fluorobenzylidene) aniline, benzylidene-4-methylaniline, 1
-Naphthylideneaniline, N-benzylidenebenzylamine, N-benzylidene-α-methylbenzylamine,
Examples thereof include N-benzylidenephenethylamine, N-benzylidenecyclohexylamine, N-benzylidene-1-naphthylamine, and benzophenone imine.

A base such as potassium hydroxide or sodium hydroxide is used.
The molar ratio is preferably 11 times, but is not particularly limited.

The amount of zinc used is 1 to 1 with respect to the starting imines.
It is preferably in the range of 5 times weight. Zinc is usually
A commercially available product is used as it is.

The reaction is carried out in an aqueous alkaline solution. At this time, no organic solvent is required. When the reaction is difficult to proceed only by stirring, the reaction may be performed under ultrasonic irradiation. The reaction temperature is generally selected in the range of 10 to 80C, preferably 20 to 60C. The progress of the reaction is followed by instrumental analysis, for example by gas chromatography.

[0019]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 A benzylideneaniline (5 mmol, 905
mg) and a 10% aqueous sodium hydroxide solution (20 ml), and zinc (5 g) was gradually added over 10 minutes with stirring at room temperature. After completion of the addition, the reaction was carried out at room temperature for 90 minutes. After completion of the reaction, insolubles were filtered off and the aqueous layer was extracted with dichloromethane. After the extract was dried over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure to obtain a mixture of amine and diamine. Kugelrohr distillation of this mixture (jacket temperature 140 ° C, vacuum 0.8 torr)
r) to give N-benzylaniline (732 mg, 80
%) And 1,2-dianilino-1,2-diphenylethane (102 mg, 12%).

Examples 2 to 4 The same procedures as in Example 1 were carried out except that the starting compounds, the reaction temperature and the like were varied, to obtain the results shown in Table 1.

Example 5 In Example 1, the reaction was carried out under ultrasonic irradiation.
Table 1 shows the results of the same treatment.

[0023]

[Table 1]

[0024]

According to the method of the present invention, amines and diamines can be synthesized from imines by an extremely simple operation and a reaction in water without using an organic solvent which is harmful to the environment.

Continuation of front page (72) Inventor Yoshiharu Mitoma 1-1-1, Chikushigaoka, Minami-ku, Fukuoka City School Corporation Fukuda Gakuen Towa University Central Science Research Institute (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 1/00-409/44

Claims (3)

(57) [Claims] 1. A method for preparing amines and diamines, wherein zinc is added to and mixed with a mixture of an imine and an aqueous alkali solution, the mixture is reacted in water without using an organic solvent, and the resulting mixture is separated by distillation. Synthesis method. 2. The imine is represented by the following general formula (a): [Wherein, R ₁ represents a phenyl group or a naphthyl group, R ₂ represents a hydrogen atom or a phenyl group, and R ₃ represents a hydrogen atom, a cyclic alkyl group, a phenyl group, a naphthyl group, a benzyl group or a phenethyl group. And these may further have a substituent. The method for synthesizing amines and diamines according to claim 1, which is a compound represented by the formula: 3. The resulting mixture is a mixture of an amine and a diamine, wherein the amine is represented by the following general formula (b): [Wherein, R ₁ , R ₂ and R ₃ each independently have the same meaning as described above. Wherein the diamine is represented by the following general formula (c): [Wherein, R ₁ , R ₂ and R ₃ each independently have the same meaning as described above. The method for synthesizing amines and diamines according to claim 1 or 2, which is a compound represented by the formula: