Method for preparing 4-nitroso-substituted aromatic amine

Details Method for preparing 4-nitroso-substituted aromatic amine Method for preparing 4-nitroso-substituted aromatic amine

2002-07-31

2003-04-22

Barts, Samuel (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Amino nitrogen containing

C564S441000

Reexamination Certificate

active

06552229

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for preparing a 4-nitroso-substituted aromatic amine and, more particularly, to a method for selectively preparing a 4-nitroso-substituted aromatic amine by contacting an amide compound with a nitroaromatic compound in the presence of a base in a polar organic solvent.
2. Related Prior Art
In general, 4-nitroso-substituted aromatic amines partly used as an intermediate of dye or hair dyes and a light stabilizer have not been studied much with regard to their applications because of their complicated method of preparation. Among the 4-nitroso-substituted aromatic amines, 4-nitrosoaniline is used as an intermediate of dye or hair dyes and usually reduced to a raw material for preparation of p-phenylenediamine (U.S. Pat. No. 6,245,943).
Conventionally, 4-nitrosoaniline is prepared by contacting aniline with sodium nitrite (NaNO2) to produce N-nitrosoaniline and then subjecting the N-nitrosoaniline to Fischer-Hepp rearrangement in acidic condition (Tetrahedron, 1975, 31, 1343-9), or by contacting p-nitrosophenol with ammonia or ammonium chloride (NH4Cl) (U.S. Pat. No. 3,338,966; and J. Chem. Soc., 1955, 2049).
The former method involves denitrosation during the Fischer-Hepp rearrangement step to produce waste containing lots of nitroso (NO) compounds destructive to the environment. The latter one using 4-nitrosophenol has a problem in regard to an excessively low yield of 4-nitrosoaniline, which problem causes the difficulty in mass production of 4-nitrosoaniline and hence the limited uses of 4-nitrosoaniline.
Recently, there has been developed a method for selectively preparing nitroaniline by nucleophilic aromatic substitution of hydrogen (NASH). For example, benzamide or benzonitrile is contacted with nitrobenzene in the presence of an organic base, tetramethylammonium hydroxide (hereinafter, referred to as “TMA(OH)”) to prepare N-(4-nitrophenyl)benzamide as an intermediate, which is isolated and decomposed into 4-nitroaniline and benzoic acid (or benzamide) by addition of water (or ammonia) (J. Org. Chem., 1993, 58(24), 6883-8; U.S. Pat. Nos. 5,436,371 and 5,331,099; and International Publication No. WO 93/24447). This method is a direct amination with nitrobenzene using NASH that produces 4-nitroaniline, also called “para-nitroaniline” in two steps.
Other similar methods for preparing substituted nitroaromatic compounds through direct amination using NASH reaction are also known (European Publication No. EP 695739; and Japanese Publication No. JP 8040994).
In addition, another known method involves contacting an aliphatic amide, isobutyramide with benzene to produce N-(4-nitrophenyl)butyramide as an intermediate (U.S. Pat. No. 5,331,099). In this method, N-(4-nitrophenyl)butyramide is decomposed with ammonia or subjected to hydrolysis to yield 4-nitroaniline.
As is well known, the direct amination of an amide compound with a nitroaromatic compound using NASH reaction produces an intermediate of 4-nitro-substituted aromatic amine, which is decomposed with water or ammonia into 4-nitro-substituted aromatic amine. But there is no related document on the production of 4-nitroso-substituted aromatic amine.
However, 4-nitroso- or 4-nitro-substituted aromatic amine can also be produced through direct amination that involves contacting aniline as an aromatic amine other than an amide compound with nitrobenzene for NASH reaction (J. Am. Chem. Soc., 1992, 114(23), 9237-8; and U.S. Pat. No. 5,117,063).
As stated above, the conventional method involving the reaction between an amide compound and nitrobenzene is a two-step process that first produces an intermediate of 4-nitro-substituted aromatic amide and then hydrolyzes the intermediate with ammonia or water into the final product, 4-nitro-substituted aromatic amine. In this method, the process for production of the 4-nitroso-substituted aromatic amine is unknown.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the inventors of the present invention have explored a one-step method for preparing a 4-nitroso-substituted aromatic amine using NASH reaction by contacting an amide compound with a nitroaromatic compound in an appropriate condition without producing 4-nitroso- or 4-nitro-substituted amide as an intermediate.
It is therefore an object of the present invention to provide a method for preparing a 4-nitroso-substituted aromatic amine and 4-nitro-substituted aromatic amine with high selectivity and high yield in one step of contacting a nitroaromatic compound with an amide compound in the presence of a base.
To achieve the object of the present invention, there is provided a method for preparing a 4-nitroso-substituted aromatic amine that includes contacting a nitroaromatic compound represented by the following formula 3 with an amide compound represented by the following formula 4 in the presence of a base to directly prepare a 4-nitroso-substituted aromatic amine represented by the following formula 1 as a main product and a 4-nitro-substituted aromatic amine as a by-product in one step:
wherein Ar is a C
4
to C
16
aromatic group having one or at least one ring and containing one or two hetero atoms of N, O or S; X is a halogen atom, a cyano group, a C
1
to C
4
alkyl group, a halongenated C
1
to C
4
alkyl group, a C
1
to C
4
alkoxy group, a C
1
to C
4
halogenated alkoxy group, a C
1
to C
4
alkylsulfonyl group, or a C
1
to C
4
alkylnitro group; and n is an integer of 0 to 3, wherein X is different from one another when n is greater than 1;
wherein Ar, X and n are as defined above;
wherein Ar, X and n are as defined above; and
wherein R is a hydrogen atom, a C
1
to C
8
alkyl group, a C
2
to C
8
alkenyl group, or a C
3
to C
7
cycloalkyl group, which substituent may be replaced with 1 to 3 halogen atoms, C
1
to C
4
alkyl groups, amino groups or C
1
to C
4
alkoxy groups.
The 4-nitroso- and 4-nitro-substituted aromatic amines thus obtained are susceptible to normal hydrogenation to yield a diamine-substituted aromatic compound.
The present invention is directed to a method for preparing a 4-nitroso-substituted aromatic amine with a very high selectivity from an amide compound and a nitroaromatic compound in the presence of an inorganic or organic base in a polar organic solvent.
In the preparation method of the present invention, the nitroso-substituted aromatic amine prepared from the nitroaromatic compound of the formula 3 and the amide compound of the formula 4 is represented by the formula 1 and produced together with a small amount of a nitro-substituted aromatic amine (formula 2). The oxygen and air atmosphere may suppress production of azoxybenzene as a by-product and therefore enable selective production of the nitroso-substituted aromatic amine.
More specifically, examples of the nitroaromatic compound of the formula 3 suitable as a starting material may include nitrobenzene, 3-nitroanisole, 3-nitrotoluene, 2-nitroanisole, 2-nitrotoluene, m-chloronitrobenzene, 2,3,4-nitropyridine, and 5,6,7-nitroquinoline.
Specific examples of the amide compound of the formula 4 being contacted with the nitroaromatic compound may include urea, acetamide, formamide, biuret, phenylurea, and isobutyramide.
The base available in the present invention includes both inorganic and organic bases. Specific examples of the inorganic base may include alkali metal hydroxides, alkali metal amides, alkali metal alkoxides, and alkali metal hydrides. Among these inorganic bases, the preferred alkali metal hydroxides are sodium hydroxide (NaOH), potassium hydroxide (KOH), and potassium tert-butoxide (t-BuOK), which are preferably in the form of powder or fine particles.
Specific examples of the organic base may include tetraalkylammonium hydroxides, and TMA(OH) is particularly preferred.
The use of a phase transfer catalyst with the inorganic base may increase the reactivity Specific examples of the phase transfer catalyst may include crown ethers and tetraalkylammonium salts. Among these catalysts, 18-crown-6 and tetramethylammonium c

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