JP2795501B2 - Method for producing alkyl diamines - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an alkyldiamine. Specifically, a method for producing an α- (aminophenyl) alkylamine and a mixture thereof, comprising catalytically reducing an α- (nitrophenyl) alkylamine mixture or a mineral acid salt thereof obtained by nitrating an α-phenylalkylamine. About.

[Conventional technology and its problems]

The present inventors have previously disclosed in Japanese Patent Application Laid-Open No.
A method for producing (aminophenyl) methylamine and a mixture thereof (also known as aminobenzylamine mixture) is described. An aminobenzylamine mixture is obtained by catalytic reduction of a mineral acid salt of a nitrobenzylamine mixture obtained by nitrating benzylamine. Combine. The yield by this method is between 58% and 75% based on benzylamine. R. Glyphs et al., NA Report 6439 (JR
Compared to the references described in Griffith et al, NRL Report 6439), the yield is considerably improved, but the yield is not satisfactory. In addition, since the nitrobenzylamine mixture precipitates in a crystalline state, a filtration and removal step is required, which poses a problem from the viewpoint of a continuous process. On the other hand, α- (aminophenyl) represented by the formula (III)
The alkylamine mixture can also be synthesized by nitrating the phenylalkylketone represented by the formula (IV) and then performing catalytic hydrogen reduction using a reducing catalyst in the presence of linear ammonia, preferably in an organic solvent. The present inventors have already presented in Japanese Patent Application Laid-Open No. 2-145548. However, when nitration is performed using phenylalkylketone, for example, acetophenone as a raw material, the resulting isomer of nitrophenylalkylketone represented by the formula (V) has an O-form of 15 to 25 mol% and an m-form of 75 to 85 mol%. % And the p-form is
Only 1 mol% or less is synthesized.

When an (aminophenyl) alkylamine represented by the formula (III) is synthesized from a nitrophenylalkylketone represented by the formula (V), a reaction between a carbonyl group and an amino group occurs, and a secondary amine or a tertiary amine is reacted. Since many high-boiling substances are generated, the yield of the target compound is significantly reduced.

In addition, the α- (aminophenyl) alkylamine represented by the formula (III) sometimes becomes a solid at room temperature, so that care must be taken when handling it.

[Means for solving the problem]

The present invention has earnestly studied a method for producing an α- (aminophenyl) alkylamine represented by the formula (III) in order to solve the above-mentioned problem. As a result, a novel production method of an α- (aminophenyl) alkylamine mixture different from the conventional production method was found. That is, the present invention provides a compound of the formula (I) (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms) by nitrating the α-phenylalkylamine represented by the formula (II) [Wherein, R is the same as described above, and the substitution position of the NO ₂ group is
A mixture of α-nitrophenylalkylamines represented by the following formula (III): [Wherein, R is the same as described above, and the substitution position of the NH ₂ group is
A 2,3- or 4-position of a phenyl group].

Here, in the present invention, the formula (IV) (Where R represents a lower alkyl group having 1 to 5 carbon atoms), acetophenone, propiophenone, propylphenyl ketone,
Butylphenylketone and pentylphenylketone.

Formula (I) obtained by reductive amination of these compounds Wherein R represents a lower alkyl group having 1 to 5 carbon atoms, α-phenylalkylamine, α-phenylethylamine, α-phenylpropylamine, α-phenylbutylamine, α-phenylpentylamine, α
-Phenylhexylamine.

Formula (III) obtained by the production method of the present invention (Wherein, R in the formula is the same as R in the formula (I), and the NH ₂ group of the phenyl group is located at ortho, meta or para). ) As alkylamines, α- (2-aminophenyl) ethylamine, α- (3-aminophenyl) enylamine, α- (4-aminophenyl) ethylamine, α
-(2-aminophenyl) propylamine, α- (3-
Aminophenyl) propylamine, α- (4-aminophenyl) propylamine, α- (2-aminophenyl)
Butylamine, α- (3-aminophenyl) butylamine, α- (4-aminophenyl) butylamine, α-
(2-aminophenyl) pentylamine, α- (3-aminophenyl) pentylamine, α- (4-aminophenyl) pentylamine, α- (2-aminophenyl) hexylamine, α- (3-aminophenyl) Hexylamine, α- (4-aminophenyl) hexylamine, and mixtures thereof.

 The reaction according to the method of the present invention will be described.

1) Synthesis of Formula (I) as a Raw Material The raw material α-phenylalkylamine used in the present invention is described in, for example, Japanese Patent Application No. 53-95369, Chemical and Pharmaceutical Blutein (Chem. Pharm. BULL. Vol.
11 3 277 (1963)), and can be synthesized according to these synthesis methods. That is, equation (IV)
Amination of the carbonyl group of the alkyl phenyl ketone compound represented by the formula (1) gives an α-phenylalkylamine represented by the formula (I).

2) Object Method for Synthesizing Formula (I) When nitrating α-phenylalkylamine represented by formula (I) to synthesize formula (II), the solubility of α-phenylalkylamine in sulfuric acid is benzylamine. Since the solubility of the raw material used for nitration is considerably high compared to the solubility of nitric acid, problems such as an increase in the viscosity of the reaction solution and a delay in the reaction time even at a molar ratio of nitric acid of 1.1 and sulfuric acid of 2.1 per mole of the raw material amine. Did not occur.

Preferably, α-phenylalkylamine dissolved in a halogenated hydrocarbon solvent is subjected to a nitration reaction with a nitrating agent. Crystals do not precipitate even when the reaction solution is discharged into ice water. Therefore, after the neutralization treatment is performed, the reaction solution is dissolved in a halogenated hydrocarbon solvent and the oil is taken out. The extracted one is
Ortho, meta and para isomers are mixed. This is abbreviated as a mixture of α- (nitrophenyl) alkylamine. The nitro group of the extracted mixture of α- (nitrophenyl) alkylamine is hydrogen reduced.

That is, when a mixture of α- (nitrophenyl) alkylalkylamine is dissolved in methyl alcohol, a palladium-carbon catalyst is added as a catalyst to the mixture, and the hydrogenation reaction is carried out at normal pressure and normal temperature. Α-
A mixture of (aminophenyl) alkylamines can be obtained.

In order to separate and purify the obtained mixture of α- (aminophenyl) alkylamines, a distillation purification method is generally used. In the distillation purification, α- (2-aminophenyl) alkylamine is fractionated as an initial fraction, and then α- (3-aminophenyl) alkylamine and α- (4-aminophenyl) alkylamine are fractionated and taken out. Can be.

More specifically, the method of nitrating an α-phenylalkylamine to produce a mixture of intermediate α- (nitrophenyl) alkylamines may use a conventional nitrating agent. Mixed nitric acid, concentrated nitric acid,
Nitric acid-acetic acid and other known nitrating agents can be used. Usually, mixed acid or concentrated nitric acid is frequently used.

The reaction is carried out as follows using these nitrating agents. That is, when nitrating with concentrated acetic acid, 80-98% nitric acid is converted to α.
Used in an amount of 1.0 to 10 mol based on phenylalkylamine. When nitrating with a mixed acid, a mixed acid composed of a combination of nitric acid and sulfuric acid is used, and the molar ratio of α-phenylalkylamine, nitric acid, and sulfuric acid is used in the range of 1.0: 1.1 to 2.0: 1.0 to 5.0.

In this nitration reaction, halogenated hydrocarbon 1,
Use of solvents such as 2-dichloroethane, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chloroform, carbon tetrachloride, 1,1,2,2-tetrachloroethane, and trichloroethylene reduces the viscosity of the reaction solution. And it is easy to control the nitration reaction temperature. These solvents may be used alone or as a mixture of two or more.

As the reaction conditions of the present invention, it is desirable that the reaction is carried out at a reaction temperature of 25 ° C. or lower, in the range of −10 to 25 ° C., preferably,
It is in the range of -5 to 20C. If the reaction temperature is too low, the progress of the nitration reaction is slow, and it is difficult to complete nitro completely. Further, the viscosity of the reaction solution increases greatly. Conversely, if the reaction temperature is too high, by-products such as dinitro compounds tend to be produced.

In addition, it is a liquid-liquid reaction, in which α-phenylalkylamine is dropped into the nitrating agent, or α-phenylalkylamine is dissolved in a halogenated hydrocarbon and the nitrating agent is dropped. either will do.

When a mixed acid is used, either a previously prepared mixed acid may be used, or a raw material and one acid may be mixed, and then the other acid may be added dropwise.

After the reaction is completed, if the reaction solution is discharged into ice water, it is dissolved as an aqueous solution of sulfate. The mixture is neutralized with aqueous ammonia to separate a mixture of α- (nitrophenyl) alkylamine, extracted with a solvent and concentrated. This gives a mixture of intermediate α- (nitrophenyl) alkylamines.

When a nitration reaction is carried out using a solvent, if the mixture is discharged into ice water and neutralized in the same manner, it is separated into two layers. This may be separated and the oil layer may be concentrated.

The mol% of the isomer of the mixture of α- (nitrophenyl) alkylamine synthesized in this manner is such that the meta-form: para-form: ortho-form is in the range of 30-70: 30-70: 0.2-10. is there.

Α- (Nitrophenyl) obtained by this nitration reaction
The method of reducing the mixture of alkylamines is not particularly limited, and a method of reducing a nitro group to an amino group can be generally applied. However, catalytic reduction is preferred from an industrial viewpoint.

In the case of catalytic reduction, a metal catalyst generally used for catalytic reduction, for example, nickel, palladium, platinum, rhodium, ruthenium, cobalt, copper, or the like can be used as a reduction catalyst to be used. Industrially, it is preferable to use a palladium catalyst.

These catalysts can be used in the form of a metal, but are usually used by being supported on a carrier surface such as carbon, barium sulfate, silica gel, alumina, and celite, or are Raney catalysts such as nickel, cobalt, and copper. Also used as The amount of catalyst used is not particularly limited,
The metal is in the range of 0.01 to 10% by weight based on the raw material α-nitrophenylalkylamine, usually 2 to 8% by weight when used in a metal state, and 0.1 to 10% by weight when supported on a carrier. It is in the range of 5% by weight. The reaction solvent is not particularly limited as long as it is inert to the reaction. For example, methanol, ethanol, alcohols such as isopropyl alcohol, ethylene glycol,
Glycols such as propylene glycol, ethers, dioxane, tetrahydrofuran, ethers such as methylcelloylrub are preferably used, and in some cases, aliphatic hydrocarbons such as hexane and cyclohexane, benzene,
Aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,2-
Halogenated hydrocarbons such as trichloroethane and tetrachloroethane, and N, N-dimethylformamide can also be used. When a reaction solvent that is immiscible with water is used, if the progress of the reaction is slow, it can be accelerated by adding a commonly used phase transfer catalyst such as a quaternary ammonium salt or a quaternary phosphonium salt. . The amount of the catalyst used is not particularly limited as long as the raw material is turbid or completely dissolved, and is not particularly limited. Usually, 0.5 to 10 times the weight of the raw material is sufficient.

The reaction temperature is not particularly limited. Generally, it is preferably in the range of 5 to 200 ° C, particularly preferably 20 to 100 ° C. The reaction pressure is
Usually, the pressure is from normal pressure to about 100 atm.

In the reaction, a catalyst is usually added in a state where the raw materials are dissolved or suspended in a solvent, and then hydrogen is introduced at a predetermined temperature under stirring to perform a reduction reaction. The end point of the reaction can be determined by the amount of hydrogen absorbed or by gas chromatography or high performance liquid chromatography. After the completion of the reaction, the desired product can be obtained by removing the catalyst and the like used for reduction, concentrating the solvent, and then isolating the solvent by distillation.

The α- (aminophenyl) alkylamine mixture that can be produced in this manner has an isomer ratio of ortho: meta:
It is a liquid at room temperature in the composition range of 0.2 to 10 mol%: 30 to 70 mol%: 30 to 70 mol% in para form.

〔Example〕

Hereinafter, examples for specifically explaining the present invention will be described.

Example 1 Synthesis of α- (nitrophenyl) ethylamine mixture 45.5 g (0.375 g-mol) of α-phenylethylamine
Dissolved in 170 g of 1,2-dichloroethane, temperature -5 ° C to 0 ° C
With 110% (1.078 g-mol) of 96% sulfuric acid and 28.4 g (0.4%) of 94% nitric acid
(23 g-mol) was added dropwise over 1.5 hours. After the completion of the dropwise addition, the mixture was stirred at a temperature of 0 ° C to 20 ° C for 2.5 hours to complete the reaction. Next, the reaction solution was discharged into 550 g of ice water, neutralized with aqueous ammonia, separated from an α- (nitrophenyl) ethylamine mixture, and the desired product was extracted with 1,2-dichloroethane. The desolvent was analyzed by gas chromatography to find that the o-form was 7.0%, the m-form was 50.5%, and the p-form was 42.5%.
Met. Desolvation and simple distillation to α- (nitrophenyl)
58.4 g (yield 93.6%) of an ethylamine mixture was obtained. It was liquid after storage at 5 ° C. for 1 week. When analyzed by gas chromatography, the o-isomer 6.4 was obtained.
%, The m-form was 51.0%, and the p-form was 42.6%. The results of the elemental analysis are as follows.

Example 2 Method for synthesizing α- (aminophenyl) ethylamine mixture In a stainless steel autoclave having an internal volume of 400 ml, 24.9 g (0.15 g-mol) of the α- (nitrophenyl) ethylamine mixture obtained in Example 1 and methanol 74.8
g, 5% Pd-C catalyst 0.25 g, and after purging with nitrogen, introducing hydrogen and stirring vigorously at a pressure of 5-1 kg / cm ² ,
The reaction was completed at a reaction temperature of 30 to 60 ° C. for 100 minutes to complete the reaction. After the completion of the reaction, the mixture was filtered at 25 to 30 ° C. to remove the catalyst. This was concentrated under reduced pressure to remove most of the methanol, followed by simple distillation.
19.8 g of a mixture of α- (aminophenyl) ethylamine in a fraction at 110 to 120 ° C./1 to 2 mmHg were obtained. (Yield 97%) It was liquid even when stored at 5 ° C. Analysis by gas chromatography revealed that the o-form was 8.5% and the m-form was 48.
8% and p-isomer 42.7%. The results of the elemental analysis are as follows.

Fig. 1 shows the IR spectrum (rock salt plate, liquid film method) of the main fraction.
FIG. 2 shows the ¹ H-NMR spectrum (100 MHz, CDCL ₃ ).

Example 3 Synthesis method of α- (nitrophenyl) ethylamine mixture 96% sulfuric acid 76.5 g (0.75 g-mol) and 94% nitric acid 20.1 g (0.3
g-mol) was cooled to -10 ° C, and then 30.3 g (0.25 g-mol) of α-phenylethylamine was heated to a temperature of -10 to -5.
The mixture was added dropwise at about 3 hours over about 3 hours. After dropping, temperature -5 ° C
The reaction was completed by stirring at ０0 ° C. for 1 hour. Next, the reaction solution
The mixture was discharged into 500 g of ice water, neutralized with aqueous ammonia, and the α- (nitrophenyl) ethylamine mixture was separated.
The desired product was extracted with 1,2 dichloroethane. When the desolvated solution was analyzed by gas chromatography, the o-isomer 6.6 was obtained.
%, The m-form was 50.7%, and the p-form was 42.6%. After desolvation,
Simple distillation and α- (nitrophenyl) ethylamine mixture
37.7 (90.8% yield) was obtained. It was liquid after storage at 5 ° C. for 1 week. When analyzed by gas chromatography, the o-form was 6.9%, the m-form was 50.9%, and the p-form was 50.9%.
Body was 42.2%. The results of the elemental analysis are as follows.

Example 4 Method for synthesizing α- (aminophenyl) ethylamine mixture In a stainless steel autoclave having an internal volume of 400 ml, 24.9 g (0.15-mol) of the α- (nitrophenyl) ethylamine mixture obtained in Example 3 and methanol 74.8 were used.
g, 5% Pd-C catalyst 0.08 g, and after purging with nitrogen, introducing hydrogen, pressure 5-1 kg / cm ² , reaction temperature 20-32.
The reaction was terminated by stirring at 5.5 ° C. for about 5.5 hours. After the completion of the reaction, the mixture was filtered to remove the catalyst. This was concentrated under reduced pressure to remove most of the methanol, and then simple distillation was performed at 110 to 120 ° C / 1 to 2 mmH.
g-fraction α- (aminophenyl) ethylamine mixture 20.
0 g was obtained. (Yield 98%) This was liquid even after storage at 5 ° C for 1 week. When analyzed by gas chromatography, the o-form was 8.3%, the m-form was 47.8%, and the p-form was 43.
9%. The results of the elemental analysis are as follows.

Example 5 Synthesis of α- (nitrophenyl) propylamine mixture 33.5 g (0.25 g-mol) of α-phenylpropylamine
A mixed acid consisting of 75 g (0.75 g-mol) of 98% sulfuric acid and 17.7 g (0.275 mol) of 98% nitric acid dissolved in 125 g of 1,2-dichloroethane at a temperature of 0 ° C. or less was added dropwise over 2 hours. Temperature after dropping is 0 to 25
The reaction was completed by stirring at 2 ° C. for 2 hours. Next, the reaction solution was discharged into 370 g of ice water, neutralized with aqueous ammonia, separated from an α- (nitrophenyl) propylamine mixture, and extracted with 1,2 dichloroethane. The desolvent was analyzed by gas chromatography to find that the O-form was 6.4% and the m-form was 51.0%.
%, P-form was 42.5. After removing the solvent, simple distillation
40.9 g of (nitrophenyl) propylamine mixture (yield 9
1%). The results of the elemental analysis are as follows.

Example 6 Method for synthesizing α- (aminophenyl) propylamine mixture In a SUS autoclave having an internal volume of 500 ml, the α- (nitrophenyl) propylamine mixture 27.0 obtained in Example 5 was added.
g (0.15 mol), 81 g of methanol and 0.1 g of a 5% Pd-C catalyst, and after purging with nitrogen, introducing hydrogen and introducing a pressure of 2 to 2.
The reaction was completed by stirring at 4 atm at a reaction temperature of 25 to 37 ° C for about 6 hours. After the reaction, the catalyst was removed by filtration. This was concentrated under reduced pressure to remove most of the methanol, followed by simple distillation to 135-1.
21.9 g (95.0% yield) of a mixture of α- (aminophenyl) propylamine at 40 ° C./1 to 2 mmHg was obtained. It was liquid when stored at 5 ° C. Further, when the valve seat was obtained by gas chromatography, the O-form was 7.9% and the m-form was 49.
3% and p-form was 42.0%.

 The results of the elemental analysis are as follows.

Example 7 Method for synthesizing α- (nitrophenyl) butylamine mixture The same operation as in Example 5 was carried out using 37.3 g (0.25 mol) of α-phenylbitylamine to obtain α- (nitrophenyl) butylamine.
45.1 g (93% yield) of a butylamine mixture was obtained. When stored at 5 ° C., it remained liquid without precipitation. Analysis by gas chromatography revealed that the O-form was 6.1%, the m-form was 53.3%, and the p-form was 40.6%. Subsequently, the same operation as in Example 6 was performed to obtain 39 g of an α- (aminophenyl) butylamine mixture (95% yield). When stored at 5 ° C., it remained liquid without precipitation. When analyzed by gas chromatography, the O-form was 7.1%, the m-form was 53.9%, and the p-form was 3%.
9.0%.

Example 8 Method for synthesizing α- (aminophenyl) pentylamine mixture Using 40.8 g (0.25 g-mol) of α-phenylpentylamine, the same operation as in Example 7 was performed to obtain an α- (aminophenyl) pentylamine mixture. 39.6 g (89% yield) was obtained. It remained liquid without precipitation when stored at 5 ° C.

Comparative Example 1 At a reaction temperature of 0 ° C. or less, 107 g (1 mol) of benzylamine was added.
It was dropped into a mixed acid of 77 g (1.2 mol) of 98% nitric acid and 300 g (3 mol) of 98% sulfuric acid over 5 hours. After dropping, 3h at 20-25 ° C
The reaction was completed by stirring. Next, the reaction solution was discharged into 750 g of ice water, and the precipitated crystals were filtered and washed with saturated saline to obtain 218 g of wet crystals (solid content: 60%). The results for the elemental molecules are as follows, which is the sulfate of nitrobenzylamine (60% yield).

Next, 21.8 g of nitrobenzylamine sulfate wet crystals were charged into a glass sealed container together with 0.5 g of a 5% Pd-C catalyst and 45 g of water, and the mixture was vigorously stirred while introducing hydrogen. Reaction temperature 25 ~
The reaction was completed by hydrogenation at 30 ° C. for 7 hours. After completion of the reaction, the mixture was heated to 50 to 60 ° C., and then filtered to remove the catalyst.
To this, 22.5 g of a 45% sodium hydroxide solution and 14.0 g of sodium sulfate (decahydrate) were added, neutralized, and allowed to stand to separate into two layers. Remove the lower layer and distill the upper layer to 130-140
C./5 to 7 mmHg of a colorless transparent oily fraction of 7.1 g was obtained. (Total yield from benzylamine: 58.6%). This is a mixture of aminobenzylamines and, by gas chromatography analysis, m-aminobenzylamine 48.5%,
The composition was p-aminobenzylamine 50.2% and o-aminobenzylamine 1.3%.

Comparative Example 2 At a reaction temperature of 0 ° C. or less, 107 g (1 mol) of benzylamine was added.
The mixture was added dropwise over 5 hours to a mixed acid of 257 g (4.0 mol) of 98% nitric acid and 200 g (2 mol) of 98% sulfuric acid. After dropping, 3h at 20-25 ° C
The reaction was completed by stirring. Next, the reaction solution was discharged into 750 g of ice water, and the precipitated crystals were filtered and washed with saturated saline to obtain 284 g of wet crystals (solid content 64.3 g). The results of the elemental analysis are as follows, which is the nitrate of nitrobenzylamine. (Yield: 85%) Next, nitrobenzylamine nitrate wet crystals were reduced and post-treated in a glass sealed container in the same manner as in Comparative Example 1 to obtain a mixture of aminobenzylamines. (Total yield from benzylamine: 74.5%).

This is a mixture of aminobenzylamines, and analysis by gas chromatography shows m-aminobenzylamine 47.4%, p-aminobenzylamine 51.1%, o
-A composition of 1.5% aminobenzylamine.

〔The invention's effect〕

According to the present invention, α-phenylalkylamine is used as a starting material and has a property of being liquid at normal temperature.
(Aminophenyl) alkylamines and mixtures thereof can be obtained. The α-phenylalkylamine is nitrated with nitric acid or a mixed acid to form an o-, m-, p-substituted α-
(Nitrophenyl) alkylamines and mixtures thereof are obtained. This mixture has the property of being liquid at room temperature. Further, it has a feature that decomposition and side reactions during hydrogen reduction are extremely small, so that the target α- (aminophenyl) alkylamine and a mixture thereof can be obtained in high yield. Also, among the two amino groups of α- (aminophenyl) alkylamine, one is directly connected to the benzene ring, and the other amino group is hindered by the alkyl group on the secondary carbon. Have different reactivities. From this, it is expected that this substance and the diisocyanate derived therefrom will have characteristic properties.

Further, α- (aminophenyl) represented by the formula (III)
Alkylamines and mixtures thereof are compounds useful as raw materials for epoxy resins, polyurethanes or polyurea resins. In particular, a diisocyanate in which an amino group is converted to an isocyanate group by phosgenation can be provided. Further, α- (aminophenyl) alkylamine represented by the formula (III) has an asymmetric carbon and is useful as an optical resolving agent.

[Brief description of the drawings]

FIG. 1 shows the α- (aminophenyl) ethylamine mixture.
FIG. 2 is a diagram showing an IR spectrum, and FIG. 2 is a diagram showing an NMR spectrum.

Continuation of the front page (56) References JP-A-61-10538 (JP, A) Chem. Abstr. , Vol. 59 (1963) No. 9846e J.C. Prakt. Chem. , 324 (5) (1982) p. 832-840J. Chem, Soc. Chem. Commun. , (22) (1984) P. 1485-1486 Chem, Abstr. , Vol. 61 (1965) No. 2607f (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 1/00-409/44 C08G 18/32 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (1) Formula (I) (Wherein, R represents a lower alkyl group having 1 to 5 carbon atoms) by nitrating the α-phenylalkylamine represented by the formula (II) [Wherein, R is the same as described above, and the substitution position of the NO ₂ group is
A mixture of α-nitrophenylalkylamines represented by the following formula (III): [Wherein, R is the same as described above, and the substitution position of the NH ₂ group is
The α- (aminophenyl) alkylamine mixture represented by the following formula: