TITLE OF INVENTION:
NOVEL PROCESS FOR PRODUCING BISAMINOPHENYLALKYLUREA
TECHNICAL FIELD
The present invention relates to a novel process for producing bisaminophenylalkylureas which are diamine compounds useful as e.g. a material of a polymer for preparation of a liquid crystal alignment film. Some of bisaminophenylalkylureas produced by the present invention are novel compounds, and accordingly, the present invention also relates to a process for producing such novel diamine compounds.
BACKGROUND ART
At present, a polyimide film has been used for a liquid crystal alignment film to be used for a liquid crystal display element in many cases, and such a liquid crystal alignment film of the polyimide film is prepared by applying a solution of a polyamic acid which is a precursor of the polyimide or a solution of a solvent-soluble polyimide to a substrate, followed by firing, and subjecting the obtainable film to an alignment treatment such as rubbing treatment (Patent Documents 1 and 2). This polyamic acid or the solvent-soluble polyimide is commonly produced by a polycondensation reaction of a tetracarboxylic acid derivative such as a tetracarboxylic acid dihydrate and a diamine compound.
The diamine compound as a material of such a polyamic acid, polyimide or the like influences properties of a liquid crystal alignment film obtainable from it and thus properties of a liquid crystal display element and is thereby important, and heretofore, various amine compounds have been proposed and used.
PRIOR ART DOCUMENTS PATENT DOCUMENTS
Patent Document 1: JP-A-7-120769
Patent Document 2: JP-A-9-146100

DISCLOSURE OF INVENTION TECHNICAL PROBLEM
The applicant has proposed in WO2010/053128 a bisaminophenylalkylurea represented by the following formula (1) as a material of a polyamic acid or a polyimide to obtain a liquid crystal alignment film having favorable liquid crystal alignment properties and having high mechanical strength with little scars or scrape on the film surface at the time of rubbing treatment:
H2N H H NNH2
wherein each of R11 and R21 which are independent of each other, is a C1-3 alkylene group.
Some of such bisaminophenylalkylureas are novel compounds not disclosed in any document before filing of the present application.
Further, as a process for producing such a bisaminophenylalkylurea, production of the desired product by subjecting a nitrophenylalkylamine hydrohalide and a carbonyl compound such as bis(4-nitro-substituted or non-substituted phenyl) carbonate to a condensation reaction in a reaction solvent to produce a nitro compound, and reducing the nitro compound in a reaction solvent may be considered.
However, in such a case, if the bisaminophenylalkylurea is to be produced in a commonly used solvent such as tetrahydrofuran, a ketone or an alcohol, a large apparatus will be required since the reaction rate tends to be low and the volume efficiency tends to be low, and in some cases, by-products may form due to a reaction with the solvent, or the product may be colored, and thus no high purity product will be obtained.
The object of the present invention to provide a process for producing the bisaminophenylalkylurea by the above reaction, capable of obtaining the desired product with high purity in high yield, with a high reaction rate and a high volume efficiency, and with a small amount of by-products.
Another object of the present invention is to provide a process for producing a novel substance which has not been known yet among bisaminophenylalkylureas, with

SOLUTION TO PROBLEM
The present inventors have conducted extensive studies to achieve the above objects and as a result, they have found that the above objects can be achieved by using specific organic solvents respectively as a reaction solvent when a nitrophenylalkylamine hydrohalide and a specific carbonyl compound as starting materials to a condensation reaction to produce a nitro compound, and as a reaction solvent when the obtained nitro compound is reduced to produce the desired bisaminophenylurea, and by using, when the above nitro compound is crystallized and then the reaction is allowed to proceed, a specific solvent as a solvent to be used for crystallization.
The present invention provides the following. [1] A process for producing a bisaminophenylalkylurea represented by the following formula (4), which comprises subjecting a (nitrophenyl)alkylamine hydrohalide represented by the following formula (1) and a carbonyl compound represented by the following formula (2) to a condensation reaction in an amide solvent in the presence of a base to produce a nitro compound represented by the following formula (3), and reducing the obtained nitro compound in a lower alcohol solvent;

wherein R is a C1-3 alkylene group, and Y is a phenoxy group which may have a nitro group as a substituent on an optional carbon atom, or a 1-imidazolyl group. [2] The process for producing a bisaminophenylalkylurea according to the above [1], wherein a lower alcohol is added to a reaction mixture containing the nitro compound

obtained by the condensation reaction, and the nitro compound is crystallized and isolated.
[3] The process for producing a bisaminophenylalkylurea according to the above [1], wherein a lower alcohol is added to a reaction mixture containing the nitro compound obtained by the condensation reaction, and the nitro compound is reduced without being isolated.
[4] The process for producing a bisaminophenylalkylurea according to any one of the above [1] to [3], wherein the bisaminophenylalkylurea obtained by the reduction reaction is subjected to hydrazine treatment.
[5] The process for producing a bisaminophenylalkylurea according to any one of the above [1] to [4], wherein the (nitrophenyl)alkylamine hydrohalide is 2-(4-nitrophenyl)ethylamine hydrochloride or (4-nitrophenyl)methylamine hydrochloride. [6] The process for producing a bisaminophenylalkylurea according to any one of the above [1] to [5], wherein the carbonyl compound is bis(4-nitro-substituted or non-substituted phenyl) carbonate or carbonyldiimidazole.
[7] The process for producing a bisaminophenylalkylurea according to any one of the above [1] to [6], wherein the bisaminophenylalkylurea is bis(4-aminophenylmethyl)urea. [8] The process for producing a bisaminophenylalkylurea according to any one of the above [1] to [6], wherein the bisaminophenylalkylurea is bis(4-aminophenylethyl)urea. [9] A process for producing a nitro compound represented by the above formula (3), which comprises subjecting a (nitrophenyl)alkylamine hydrohalide represented by the above formula (1) and a carbonyl compound represented by the above formula (2) to a condensation reaction in an amide solvent in the presence of a base, and adding a lower alcohol to a reaction mixture containing the nitro compound represented by the above formula (3) and crystallizing the nitro compound.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, as evident from Examples as compared with the after-mentioned Comparative Examples, a bisaminophenylalkylurea as the desired product can be produced with high purity in high yield, with a high reaction rate and a high volume efficiency and with a small amount of by-products.
According to the production process of the present invention, bis(4-

aminophenylethyI)urea which is a novel compound among the bisaminophenylalkylureas can be obtained with high purity in high yield.
DESCRIPTION OF EMBODIMENTS
A: Step of subjecting nitrophenylalkylamine hydrohalide and carbonyl compound to
condensation reaction to produce nitro compound

The nitrophenylalkylamine hydrohalide as the starting material is a compound represented by the above formula (1). In the formula (1), R is a C1-3 alkylene group, preferably a methylene group or an ethylene group. X is a halogen atom, preferably a chlorine atom or a bromine atom.
As preferred specific examples of the nitrophenylalkylamine hydrohalide, hydrochloride or bromate of 2-(4-nitrophenyl)ethylamine (also called 4-nitrophenethylamine) and hydrochloride or bromated of (4-nitrophenyl)methylamine may be mentioned.
The carbonyl compound represented by the above formula (2) may, for example, be bis(4-nitro-substituted or non-substituted phenyl) carbonate (also called bis(4-nitro-substituted or non-substituted phenyl) carbonate), or carbonyl diimidazole. The bis(4-nitro-substituted or non-substituted phenyl) carbonate may be preferably bis(4-nitrophenyl) carbonate or bis(4-phenyl) carbonate.
The above condensation reaction is carried out in an organic solvent, and according to findings by the present inventors, this reaction solvent significantly influences the condensation reaction rate and as a result, significantly influences the volume efficiency of the reaction. That is, they have found that when an amide solvent is used as the reaction solvent, the condensation reaction rate is high and thus the volume efficiency is very high, as compared with a solvent such as tetrahydrofuran, a ketone or an alcohol. As a result, for example, the volume efficiency in Example 1 reaches so high as from 3.5 to 4 times the volume deficiency in Comparative Example 1

in which tetrahydrofuran is used as the reaction solvent.
In the present invention, the amide solvent may, for example, be dimethylformamide (DMF), N,N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone or hexamethylphosphoric triamide, and is particularly preferably dimethylformamide.
The carbonyl compound is used in an amount of preferably from 0.4 to 0.6 mol,. Particularly preferably from 0.45 to 0.5 mol per 1 mol of the nitrophenylalkylamine hydrohalide.
The amide solvent is used in an amount of preferably from 0.5 to 10 times by mass, more preferably from 5.5 to 6.5 times by mass, to the nitrophenylalkylamine hydrohalide.
In the condensation reaction, preferably, a base is used as a catalyst. Such a base may, for example, be preferably a trialkylamine such as triethylamine, trimethylamine or tripropylamine; or 4-NN-dimethylaminopyridine. Such a base is used in an amount of preferably from 1.5 to 6 mol, particularly preferably from 1.8 to 2.2 mol per 1 mol of the nitrophenylalkylamine hydrohalide.
The reaction temperature in the condensation reaction is preferably within a range of from 30 to 100°C, more preferably from 55 to 65°C.
A specific condensation reaction is preferably as follows.
That is, in an inert atmosphere of e.g. nitrogen, the nitrophenylalkylamine hydrohalide and the carbonyl compound are dissolved in dimethylformamide as the reaction solvent to obtain a solution, and to the solution, triethylamine is gradually added preferably at from 30 to 100°C, particularly preferably at from 55 to 65°C, preferably with stirring, preferably for from 5 minutes to 10 hours. As the case requires, stirring is further continued while the above temperature is maintained. In such a manner, the condensation reaction proceeds, whereby the desired product nitro compound represented by the above formula (3) is produced.
To a reaction mixture containing the nitro compound, a lower alcohol which is a poor solvent for the nitro compound is added. The lower alcohol is an alcohol having preferably from 1 to 3 carbon atoms, more preferably methanol or ethanol. The lower alcohol is gradually added preferably at from 30 to 100°C, particularly preferably at from 55 to 65°C preferably for 5 minutes to 10 hours.

Then, the obtained lower alcohol solution of the nitro compound is cooled preferably to from 0 to 10°C for crystallization. The nitro compound obtained by crystallization is, as the case requires, washed preferably with a lower alcohol and dried.
When the bisaminoalkylphenylurea is to be produced from the obtained nitro
compound, as a lower alcohol is used as the reaction solvent in the present invention,
the nitro compound may be used as it is for the subsequent step without being
crystallized and isolated from the lower alcohol solution of the nitro compound.
B; Step of reducing nitro compound to produce bisaminophenylurea This step is represented by the following reaction formula:
AS mentionea aoove, xne nitro compound represeniea oy me Tormuia ^; is reduced to produce the bisaminoalkylphenylurea represented by the formula (4) as the desired product. This reduction reaction is also carried out in a solvent, and the reaction solvent in this reaction also significantly influences the reduction reaction rate and thus significantly influences the volume efficiency of the reaction. At the same time, depending on the solvent to be used, reaction by-products with the solvent may form.
In the present invention, a lower alcohol is used as the reaction solvent and as a result, a high volume efficiency will be obtained and in addition, reaction by-products with the solvent will not form. For example, if tetrahydrofuran or the like which is an organic solvent commonly used as the reaction solvent is used, the volume efficiency tends to be low and in addition, by-products as adducts will form.
In the above reduction reaction, preferably a catalyst is used. Such a catalyst may be a metal catalyst commonly used for catalytic reduction, such as nickel, palladium, platinum, rhodium, ruthenium, cobalt or copper. Industrially, a palladium catalyst is preferred. Such a metal may be used in a metal state, but is usually used as supported on the surface of a carrier such as carbon, barium sulfate, silica gel, alumina or celite, or nickel, cobalt, copper or the like may be used also as a Raney catalyst.
The amount of use of the catalyst is not particularly limited, and is preferably from 0.01 to 10 mass% to the nitro compound represented by the formula (3), and usually,

preferably from 2 to 8 mass% in a case where it is used in a metal state, and preferably from 0.1 to 5 mass% in a case where it is supported on a carrier.
The reducing agent is particularly preferably hydrogen. The reducing agent is used in an amount of preferably from 1 to 15 mol, more preferably from 2 to 10 mol per 1 mol of the nitro compound represented by the formula (3).
The amount of use of the reaction solvent is preferably from 4 to 30 times by mass, more preferably from 7.5 to 8.5 times by mass to the nitro compound. The reaction temperature is preferably from 40 to 60°C, particularly preferably from 45 to 55°C. Further, the reaction pressure is preferably from 0 to 1 MPa-G (gauge pressure), more preferably from 0.1 to 0.4 MPa-G. A specific reduction reaction is preferably as follows. That is, in a reactor such as an autoclave, the nitro compound as the starting material, the reducing catalyst and a lower alcohol as the reaction solvent are charged, and hydrogen as the reducing agent is introduced preferably at from 40 to 60°C with stirring, followed by stirring preferably for from 1 to 20 hours. Completion of the reaction may be determined by the hydrogen absorption amount or by thin layer chromatography or high-performance liquid chromatography.
In such a manner, the nitro compound represented by the formula (3) is reduced, and the bisaminophenylalkylurea is produced. The formed bisaminophenylalkylurea may be recovered as it is, or may be preferably treated with hydrazine to further increase the purity. Hydrazine is added in an amount of preferably from 0 to 0.3 mol, more preferably from 0.15 to 0.25 mol per 1 mol of the bisaminophenylalkylurea to the lower alcohol solution containing the bisaminophenylalkylurea preferably maintained at from 4.5 to 5.5°C, followed by stirring preferably for from 1 minute to 1 hour.
From the lower alcohol solution containing the bisaminophenylalkylurea represented by the formula (4) thus obtained, the desired bisaminophenylalkylurea is recovered by an existing method. That is, the lower alcohol solution containing the bisaminophenylalkylurea is subjected to filtration and washed to remove the catalyst used and the like. A poor solvent is added to crystallize the desired product from the filtrate, and by crystallization, the bisaminophenylalkylurea is recovered. The poor solvent in such a case may, for example, be isopropanol or butanol.
According to the present invention, various bisaminophenylalkylureas are produced as mentioned above, and examples thereof include compounds represented by the following formulae (1-4) to (1-10). Among such bisaminophenylalkylureas, compounds represented by the formulae (1-6), (1-7) and (1-8) are novel compounds and are provided for the first time by the present invention.


Now, the present invention will be described in further detail with reference to Examples. However, it should be understood that the present invention is by no means restricted thereto.
DMF: dimethylformamide
DMAP: 4-N,N-dimethylaminopyridine
THF: tetrahydrofuran
BNPU; 1,3-bis(4-nitrophenylethyl)urea
BAPU: 1,3-bis(4-aminophenylethyl)urea
EXAMPLE 1: Preparation of BNPU
Into a 500 ml_ four-necked flask, 13.98 g (69.0 mmol) of 4-nitrophenethylamine hydrochloride, 10.00 g (32.9 mmol) of bisnitrophenyl carbonate and 60 g of DMF were charged, the mixture was heated to 60°C with stirring by an agitating blade, and 13.34 g (131.5 mmol) of triethylamine was dropwise added at from 59 to 63°C over a period of from 3 to 5 minutes, followed by stirring at from 58 to 62°C for 2 hours. The reaction yield was 94%.
Then, 100 g of methanol was dropwise added over a period of from 10 to 15

minutes, and the reaction liquid was totally dissolved. Then, after cooling to 5°C, the precipitated crystals were collected by filtration, washed with 80 g of methanol and vacuum dried to obtain 10.01 g (purity: 99.7%) (yield: 86.0%) of white crystals.
The crystals were confirmed to be BNPU by 1H NMR analysis results.
1H NMR (DMSO-d6, dppm): 8.2 (d, J=8.6Hz, 4H), 7.5 (d, J=8.8Hz, 4H), 5.9 (t, J=5.6Hz, 2H), 3.3 (dt, J=6.8, 6.1 Hz 4H), 2.8 (t, J=6.8Hz, 4H)
The reaction in Example 1 is as folows.
COMPARATIVE EXAMPLE 1
Into a 2,000 ml_ jacketed separable flask, 31.50 g (155.4 mmol) of 4-nitrophenethylamine hydrochloride, 1.81 g (14.8 mmol) of DMAP, 89.88 g (888.3 mmol) of triethylamine and 338 g of THF were charged, the mixture was heated to 60°C with stirring by an agitating blade, and a solution having 22.51 g (74.02 mmol) of bisnitrophenylcarbonate dissolved in 225 g of THF was dropwise added at from 57 to 63°C over a period of 42 minutes, folowed by stirring at from 58 to 62°C for 4 hours.
Then, 113 g of methyl isobutyl ketone and 450 g of pure water having 47.37 g (1,184 mmol) of sodium hydroxide dissolved were added, followed by stirring at 60°C, and the aqueous layer was removed. Then, a step of washing the organic layer with 450 g of pure water and removing the aqueous layer was repeatedly carried out twice. Then, 225 g of heptane was dropwise added over a period of from 10 to 15 minutes. After cooling to 20°C, the precipitated crystals were collected by filtration, washed with 113 g of methanol and vacuum dried to obtain 22.70 g (purity: 99.8%) (yield: 85.6%) of pale yellow crystals of BNPU. REFERENCE EXAMPLE
60 g (396 mmol) of 4-nitrophenethylamine hydrochloride and 720 g of ODB (ortho-dichlorobenzene) were charged, and phosgene gas (from 1.5 to 2.2 mol) was blown at 120°C for from 5 to 6 hours. Further, 30 g (148 mmol) of 4-nitrophenethylamine hydrochloride was dissolved in water, and a 48% sodium hydroxide solution was added

to make it free, followed by extraction with 300 mL of ODB, and the resulting extract was added to the above solution.
The precipitated crystals were collected by filtration, and the resulting solid was redissolved in 800 mL of dimethylformamide and 500 g of water was added. The precipitated crystals were again collected by filtration and vacuum dried to obtain 48.7 g (purity: 99.3%) (yield: 92%) of cream-colored crystals of BNPU. EXAMPLE 2
Into a 120 mL autoclave, 6.01 g (16.8 mmol) of BNPU, 0.076 g of 10% Pd/C (50%wet), 0.60 g of activated carbon and 48 g of methanol were charged, and the mixture was heated to 50°C with stirring by a magnetic stirrer, and stirred in a 0.3 MPa-G hydrogen gas atmosphere at from 50 to 55°C for 11 hours.
Then, 0.17 g of hydrazine monohydrate was added to the reaction liquid, followed by filtration at 50°C and washing with 12 g of methanol to remove the catalyst and the activated carbon. 3/4 of the reaction liquid was put in a 100 mL four-necked flask, and 1.4 g of a strongly acidic H+ ion exchange resin was added, followed by stirring at 50°C for one hour, filtration and washing with 9 g of methanol. 2/3 of the resulting reaction liquid was mixed with 12 g of isopropanol, concentrated under from 120 to 150 Torr at 40°C up to 15 g, and 15 g of isopropanol was dropwise added. Then, after cooling to 5°C, the precipitated crystals were collected by filtration, washed with 6 g of isopropanol and vacuum dried to obtain 2.18 g (purity: 99.2%) (yield: 86.5%) of white crystals of BAPU. The above activated carbon was used to prevent coloring of the formed product, and the ion exchange resin was used to remove contained metals.
The crystals were confirmed to be BAPU by 1H NMR analysis results.
1H NMR (DMSO-d6, dppm): 6.8 (d, J=7.8Hz, 4H), 6.5 (d, J=7.6Hz, 4H), 5.8 (t, J=5.4Hz, 2H), 3.8 (dt, J=6.6, 6.4Hz 4H), 2.5 (t, J=6.9Hz, 4H)
By the metal analysis of the crystals, each of the contents of Na, K, Al, Ca, Cr, Cu, Mg, Mn, Ni, Fe, Pd and Zn was confirmed to be less than 1 ppm.
Tho rasirtinn in thic Fyamnlo ic a« fnlnwc

COMPARATIVE EXAMPLE 2
Into a 2,000 mL autoclave, 18.06 g (50.3 mmol) of BNPU, 0.90 g of 5% Pd/c (50%wet), 1.80 g of activated carbon and 540 g of THF were charged, the mixture was heated to 40°C with stirring by an agitating blade and stirred in a 0.3 MPa-G hydrogen gas atmosphere at from 40 to 46°C for 2 hours.
Then, the reaction liquid was subjected to filtration at 40°C, followed by washing with 54 g of THF to remove the catalyst and the activated carbon. The reaction liquid was put in a 1,000 mL four-necked flask, and 180 g of heptane was dropwise added with stirring by an agitating blade over a period of from 10 to 15 minutes. Then, after cooling to 5°C, the precipitated crystals were collected by filtration, washed with a solvent mixture comprising 25.2 g of THF and 10.8 g of heptane and vacuum dried to obtain 19.38 g (purity: 99.3%) (yield: 85.2%) of white crystals of BAPU.
By the metal analysis of the crystals, each of the contents of Na, K, Al, Ca, Cr, Cu, Mg, Mn, Ni, Fe, Pd and Zn was confirmed to be less than 1 ppm. EXAMPLE 3
Into a 500 mL four-necked flask, 21.07 g (104 mmol) of 4-nitrophenethylamine hydrochloride, 8.02 g (49.3 mmol) of carbonyldiimidazole and 90 g of DMF were charged, the mixture was heated to 60°C with stirring by an agitating blade, and 19.97 g (197.2 mmol) of triethylamine was dropwise added at from 57 to 63°C over a period of from 3 to 5 minutes. Then, 1.21 g (6.6 mmol) of DMAP was added, followed by stirring at from 58 to 62°C for 5 hours.
Then, 150 g of methanol was dropwise added over a period of from 10 to 15 minutes, and the reaction liquid was totally dissolved. Then, after cooling to 5°C, the precipitated crystals were collected by filtration, washed with 120 g of methanol and vacuum dried to obtain 14.8 g (purity: 100%) (yield: 84.2%) of white crystals of BNPU. EXAMPLE 4
Into a 500 mL four-necked flask, 14.08 g (69.5 mmol) of 4-nitrophenethylamine hydrochloride, 7.07 g (33.0 mmol) of diphenylcarbonate and 60 g of DMF were charged, the mixture was heated to 60°C with stirring by an agitating blade, and 40.03 g (395.6 mmol) of triethylamine was dropwise added at from 59 to 68°C over a period of from 3 to 5 minutes. Then, 0.80 g (6.6 mmol) of DMAP was added, followed by stirring at from 58 to 62°C for 5 hours.

Then, 100 g of methanol was dropwise added over a period of from 10 to 15 minutes, and the reaction liquid was totally dissolved. Then, after cooling to 5°C, the precipitated crystals were collected by filtration, washed with 80 g of methanol and vacuum dried to obtain 9.80 g (purity: 100%) (yield: 82.9%) of very pale yellow crystals of BNPU.
INDUSTRIAL APPLICABILITY
The bisaminophenylalkylureas produced by the present invention are applicable to various applications, and particularly, a polyamic acid obtainable by a polycondensation reaction with a tetracarboxylic acid derivative such as a tetracarboxylic acid dihydrate, a polyimide formed by imidization of such a polyamic acid, and the like are useful as a material of a polymer for preparation of a liquid crystal alignment film to be used for a liquid crystal display element.
The entire disclosure of Japanese Patent Application No. 2010-105935 filed on April 30, 2010 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.

1. A process for producing a bisaminophenylalkylurea represented by the following
formula (4), which comprises subjecting a (nitrophenyi)alkylamine hydrohalide
represented by the following formula (1) and a carbonyl compound represented by the
following formula (2) to a condensation reaction in an amide solvent in the presence of a
base to produce a nitro compound represented by the following formula (3), and
reducing the obtained nitro compound in a lower alcohol solvent:

wherein R is a Gi«3 alkylene group, and Y is a phenoxy group which may have a nitro group as a substituent on an optional carbon atom, or a 1-imidazolyl group.
2. The process for producing a bisaminophenylalkylurea according to Claim 1,
wherein a lower alcohol is added to a reaction mixture containing the nitro compound
obtained by the condensation reaction, and the nitro compound is crystallized and
isolated.
3. The process for producing a bisaminophenylalkylurea according to Claim 1,
wherein a lower alcohol is added to a reaction mixture containing the nitro compound
obtained by the condensation reaction, and the nitro compound is reduced without
being isolated.
4. The process for producing a bisaminophenylalkylurea according to any one of
Claims 1 to 3, wherein the bisaminophenylalkylurea obtained by the reduction reaction
is subjected to hydrazine treatment.
5. The process for producing a bisaminophenylalkylurea according to any one of
Claims 1 to 4, wherein the (nitrophenyl)alkylamine hydrohalide is 2-(4-
nitrophenyl)ethylamine hydrochloride or (4-nitrophenyl)methylamine hydrochloride.

6. The process for producing a bisarninophenylalkylurea according to any one of Claims 1 to 5, wherein the carbonyl compound is bis(4-nitro-substituted or non-substituted phenyl) carbonate or carbonyldiimidazole.
7. The process for producing a bisarninophenylalkylurea according to any one of Claims 1 to 6, wherein the bisarninophenylalkylurea is bis(4-aminophenylmethyl)urea.
8. The process for producing a bisarninophenylalkylurea according to any one of Claims 1 to 6, wherein the bisarninophenylalkylurea is bis(4-aminophenylethyl)urea.
9. A process for producing a nitro compound represented by the above formula (3), which comprises subjecting a (nitrophenyl)alkylamine hydrohalide represented by the above formula (1) and a carbonyl compound represented by the above formula (2) to a condensation reaction in an amide solvent in the presence of a base, and adding a lower alcohol to a reaction mixture containing the nitro compound represented by the above formula (3) and crystallizing the nitro compound.