JP2003286242A - Method for producing nitrone compound and catalyst therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for industrially more advantageously producing a nitrone compound by reaction between a secondary amine (wherein, at least one of the two carbon atoms bound to the amino group has at least one hydrogen atom) and hydrogen peroxide. <P>SOLUTION: The method for producing the nitrone compound comprises the reaction of hydrogen peroxide with the secondary amine in the presence of a metal oxide catalyst prepared by reaction of hydrogen peroxide with at least one selected from the group consisting of metallic tungsten, metallic molybdenum, a tungsten compound made from tungsten and a group IIIb element, group IVb element, group Vb element or group VIb element except oxygen and a molybdenum compound made from molybdenum and a group IIIb element, group IVb element, group Vb element or group VIb element except oxygen. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing nitrones and a catalyst thereof.

[0002]

BACKGROUND OF THE INVENTION Nitrones are important compounds as synthetic intermediates for pharmaceuticals such as α-substituted amine compounds, amino acids and alkaloids, agricultural chemicals, and fine chemicals (see, for example, Patent Document 1). A method of reacting a secondary amine (provided that at least one of two carbon atoms bonded to an amino group has at least one hydrogen atom) with hydrogen peroxide is known. Hydrogen peroxide has been attracting attention in recent years as a clean and excellent oxidizer that is inexpensive, easy to handle, and becomes harmless water after the reaction. A method for producing nitrones by reacting hydrogen is important.

As a method for producing the nitrones by reacting the secondary amine with hydrogen peroxide, for example, a method using a tris (cetylpyridinium) peroxotungstophosphoric acid catalyst (see, for example, Non-Patent Document 1) and tungsten. A method using a sodium acid catalyst (for example, refer to Patent Document 2), a method using a selenium dioxide catalyst (for example, refer to Patent Document 1), a method using a methylrhenium trioxide catalyst (for example, refer to Non-Patent Document 2) and the like are known. Has been. However, the method (1) is complicated in the preparation of the catalyst, the method (2) has a low yield depending on the kind of the amine, and the method (2) uses a highly toxic catalyst. The above methods are not necessarily industrially sufficiently satisfactory in that the catalyst is expensive.

[0004]

[Patent Document 1] JP-A-63-63651

[Patent Document 2] JP-A-59-164762

[Non-Patent Document 1] Chemistry Letter
s, 289 (1992)

[Non-Patent Document 2] Bull. Chem. Soc. Jp
n. , 70 , 877 (1997)

[0005]

Under these circumstances, the present inventors have found that at least one of the two carbon atoms bonded to the secondary amine (wherein the amino group is bonded to at least one hydrogen atom). We have conducted intensive studies to develop a method for producing nitrones industrially more advantageously by reacting hydrogen peroxide) with hydrogen peroxide, and found that tungsten compounds such as tungsten metal, molybdenum metal, and tungsten sulfide, which are inexpensive and easily available, are available. That the metal oxide obtained by reacting the same with hydrogen peroxide exhibits good catalytic activity in the reaction between the secondary amine and hydrogen peroxide, and the secondary oxide is present in the presence of the metal oxide catalyst. The inventors have found that nitrones can be obtained by reacting an amine with hydrogen peroxide, and completed the present invention.

[0006]

That is, the present invention relates to tungsten metal, molybdenum metal, tungsten and IIIb.
Group V element, Group IVb element, Group Vb element or V excluding oxygen
At least one selected from the group consisting of a tungsten compound composed of an Ib group element and molybdenum and a molybdenum compound composed of a molybdenum group IIIb element, a group IVb element, a group Vb element or a group VIb element other than oxygen, and hydrogen peroxide. In the presence of a metal oxide catalyst obtained by reacting with, a secondary amine (provided that at least one of the two carbon atoms bonded to the amino group has at least one hydrogen atom) and hydrogen peroxide. The present invention provides a method for producing nitrones, which comprises reacting with.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst used in the present invention will be described first. The present invention includes a tungsten compound containing tungsten metal, molybdenum metal, tungsten and a Group IIIb element, a Group IVb element, a Group Vb element or a Group VIb element except oxygen, and molybdenum and a Group IIIb element, IVb. A metal oxide formed by reacting at least one selected from the group consisting of molybdenum compounds consisting of Group V elements, Group Vb elements or Group VIb elements excluding oxygen (hereinafter abbreviated as metal compound) with hydrogen peroxide. Physical catalyst is used.

Examples of the tungsten compound composed of tungsten and a Group IIIb element include tungsten boride and the like, and examples of the tungsten compound composed of tungsten and a Group IVb element include tungsten carbide and tungsten silicide. Examples of the tungsten compound including the group Vb element include tungsten nitride and tungsten phosphide, and examples of the tungsten compound including the tungsten and the group VIb element excluding oxygen include tungsten sulfide.

Examples of molybdenum compounds composed of molybdenum and Group IIIb elements include molybdenum boride and the like.
Examples of molybdenum compounds containing molybdenum and Group IVb elements include molybdenum carbide and molybdenum silicide, and examples of molybdenum compounds containing molybdenum and Group Vb elements include molybdenum nitride and molybdenum phosphide. Examples of the molybdenum compound composed of a group VIb element excluding oxygen and oxygen include molybdenum sulfide and the like.

Of these metal compounds, tungsten metal, molybdenum metal and tungsten sulfide are preferable. Further, such metal compounds may be used alone or in combination of two or more.

An aqueous solution is usually used as the hydrogen peroxide reacted with the metal compound. Of course, an organic solvent solution of hydrogen peroxide may be used, but hydrogen peroxide solution is preferably used from the viewpoint of easy handling. The concentration of hydrogen peroxide in the hydrogen peroxide solution or the solution of hydrogen peroxide in the organic solvent is not particularly limited, but is practically 1 to 60% by weight in consideration of volume efficiency, safety and the like. When hydrogen peroxide water is used, a commercially available product may be used as it is, or one whose concentration has been adjusted by diluting, concentrating, etc., if necessary. When an organic solvent solution of hydrogen peroxide is used, for example, a solution prepared by a method such as extracting hydrogen peroxide solution with an organic solvent or distilling hydrogen peroxide solution in the presence of an organic solvent is used. You can use it.

The amount of hydrogen peroxide used to react with the metal compound is usually 3 mol times or more, preferably 5 mol times or more, with respect to the metal compound, and there is no particular upper limit.

The reaction between the metal compound and hydrogen peroxide is usually carried out in an aqueous solution. Of course, for example, ether solvents such as diethyl ether, methyl tert-butyl ether, tetrahydrofuran, etc., ester solvents such as ethyl acetate, eg, methanol, ethanol, tert-
It may be carried out in an organic solvent such as an alcohol solvent such as butanol, a nitrile solvent such as acetonitrile or propionitrile, or a mixed solvent of the organic solvent and water.

The reaction between the metal compound and hydrogen peroxide is usually carried out by mixing and contacting both of them, in order to further improve the contact efficiency between the metal compound and hydrogen peroxide,
It is preferable to carry out the reaction in the metal oxide preparation liquid while stirring so that the metal compound is sufficiently dispersed. In addition, it is preferable to use a metal compound having a small particle size, such as a powdery metal compound, from the viewpoint of increasing the contact efficiency between the metal compound and hydrogen peroxide and facilitating the control during preparation of the metal oxide.

The temperature for preparing the metal oxide is usually -1.
It is 0 to 100 ° C.

By reacting the metal compound with hydrogen peroxide in water, an organic solvent or a mixed solvent of an organic solvent and water, a part or all of the metal compound is dissolved to contain a metal oxide. Although a homogeneous solution or suspension can be prepared, the metal oxide may be taken out from the preparation liquid by, for example, concentration treatment and used as a catalyst, or the preparation liquid may be directly used as a catalyst. .

Then, in the presence of the above metal oxide catalyst,
A secondary amine (provided that at least one of the two carbon atoms bonded to the amino group has at least one hydrogen atom; hereinafter abbreviated as secondary amine) and hydrogen peroxide are reacted, A method for producing nitrones will be described.

The secondary amine used in the present invention includes:
There is no particular limitation as long as two substituents are bonded to the amino group and at least one of the two carbon atoms bonded to the amino group has at least one hydrogen atom. Further, it may have one such amino group or two or more such amino groups in its molecule.

Examples of such secondary amines include those represented by the general formula (1) (In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted aralkyl group. ³ represents an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted aralkyl group, wherein
Any two or three of R ¹ , R ² and R ³ may combine to form a ring. ) The secondary amine shown by these is mentioned.

The alkyl group which may be substituted includes, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group. Group, an n-decyl group, a cyclopropyl group, a 2,2-dimethylcyclopropyl group, a cyclopentyl group, a cyclohexyl group, a menthyl group and the like, which has a linear, branched or cyclic carbon number of 1 to 2.
Alkyl groups of 0 and these alkyl groups are, for example, alkoxy groups such as methoxy group and ethoxy group, aryloxy groups such as phenoxy group, aralkyloxy groups such as benzyloxy group, and halogen atoms such as fluorine atom and chlorine atom. An acyl group such as an acetyl group or a benzoyl group, a carboalkoxy group such as a carbomethoxy group or a carboethoxy group, a carboaryloxy group such as a carbophenoxy group, a carboaralkyloxy group such as a carbobenzyloxy group, or a carboxyl group. Examples thereof include a fluoromethyl group, a chloromethyl group, a trifluoromethyl group, a methoxymethyl group, an ethoxymethyl group, a methoxyethyl group, and a carbomethoxymethyl group, which are substituted with a substituent such as a group.

Examples of the aryl group which may be substituted include, for example, a phenyl group, a naphthyl group and the like, and an aromatic ring which constitutes these phenyl group, naphthyl group and the like, which may be the alkyl group or aryl group which may be substituted as described below. Substituted with an aralkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, a halogen atom, an acyl group, or the like,
For example, 2-methylphenyl group, 4-chlorophenyl group,
4-methylphenyl group, 4-methoxyphenyl group, 3-
Examples thereof include a phenoxyphenyl group.

Examples of the optionally substituted aralkyl group include those which are composed of the above optionally substituted aryl group and the above optionally substituted alkyl group, and examples thereof include a benzyl group and 4-chloro group. Benzyl group, 4-
Methylbenzyl group, 4-methoxybenzyl group, 3-phenoxybenzyl group, 2,3,5,6-tetrafluorobenzyl group, 2,3,5,6-tetrafluoro-4-methylbenzyl group, 2,3,3 5,6-tetrafluoro-4-
Examples thereof include a methoxybenzyl group and a 2,3,5,6-tetrafluoro-4-methoxymethylbenzyl group.

When any two or three of R ¹ , R ² and R ³ are bonded to form a ring, examples of the ring include cyclopentane ring, cyclohexane ring, cycloheptane ring, cyclo Dodecane ring, pyrrolidine ring, piperidine ring, tetrahydroisoquinoline ring and the like can be mentioned.

Examples of such secondary amines include N, N
-Dimethylamine, N, N-diethylamine, N, N-
Di (n-propyl) amine, N, N-di (n-butyl)
Amine, N, N-di (n-amyl) amine, N, N-di (n-hexyl) amine, N, N-di (n-heptyl)
Amine, N, N-di (n-octyl) amine, N, N-
Di (n-nonyl) amine, N, N-di (n-decyl) amine, N, N-di (n-dodecyl) amine, N, N-diisopropylamine, N, N-diisobutylamine,
N, N-di (sec-butyl) amine, N, N-diisoamylamine, N-ethyl-tert-butylamine,
N, N-dibenzylamine, N-benzyl-tert-
Butylamine, N-benzylaniline, 1,2,3,4
-Tetrahydroisoquinoline, 6,7-methylenedioxy-1,2,3,4-tetrahydroisoquinoline, pyrrolidine, 2-methylpyrrolidine, 2-carbomethoxypyrrolidine, 3,4-dimethoxypyrrolidine, piperidine, 2-methylpiperidine, 2-carbomethoxypiperidine, 2,6-dimethylpiperidine and the like can be mentioned.

As the secondary amine, a salt of an acid with a secondary amine such as a secondary amine / hydrochloride or a secondary amine / sulfuric acid may be used.

In this reaction, a secondary amine is reacted with hydrogen peroxide in the presence of the metal oxide catalyst, and nitrones in which the amino group of the secondary amine is oxidized are produced.

When the secondary amine represented by the general formula (1) is used as the secondary amine, the following general formula (2) is used. (In the formula, R ¹ , R ² and R ³ have the same meanings as described above.) The nitrones shown by the formula are obtained.

The amount of the metal oxide used in the reaction between the secondary amine and hydrogen peroxide is usually 0.
The amount is 001 mol times or more, and there is no particular upper limit, but from an economical viewpoint, it is practically 1 mol times or less with respect to the secondary amine.

Hydrogen peroxide is usually used as an aqueous solution. Of course, an organic solvent solution of hydrogen peroxide may be used. The concentration of hydrogen peroxide in the hydrogen peroxide solution or the organic solvent solution is not particularly limited, but is practically 1 to 60% by weight in consideration of volume efficiency, safety and the like. As the hydrogen peroxide solution, a commercially available product is usually used as it is or after adjusting the concentration by diluting, concentrating or the like as necessary.
The organic solvent solution of hydrogen peroxide can be prepared by, for example, a method of extracting hydrogen peroxide solution with an organic solvent, or distilling hydrogen peroxide solution in the presence of the organic solvent.

The amount of hydrogen peroxide used is usually at least 1 mol times the amino group of the secondary amine, and there is no particular upper limit to the amount used, but considering the economic aspects, it is practically used. Is 10 mol times or less with respect to the amino group of the secondary amine. When a preparation liquid containing a metal oxide is used as the catalyst, the amount of hydrogen peroxide used may be set including the amount of hydrogen peroxide in the preparation liquid.

This reaction is usually carried out in water, an organic solvent or a mixed solvent of an organic solvent and water. Examples of the organic solvent include ether solvents such as diethyl ether, methyl tert-butyl ether, and tetrahydrofuran,
For example, ester solvents such as ethyl acetate, for example, methanol, ethanol, alcohol solvents such as tert-butanol, for example, acetonitrile, nitrile solvents such as propionitrile, for example, aromatic hydrocarbon solvents such as toluene, xylene, chlorobenzene, etc., Examples include aliphatic hydrocarbon solvents such as cyclohexane and n-heptane. The amount of water or organic solvent used is not particularly limited, but in consideration of volumetric efficiency and the like, it is practically 100 times or less the weight of the secondary amine.

If the reaction temperature is too low, the reaction is difficult to proceed, and if the reaction temperature is too high, side reactions such as decomposition of the secondary amine as a raw material or nitrones to be produced may proceed. Is in the range of −20 to 100 ° C.

The reaction may be carried out in the coexistence of ammonia, and any of ammonia water, ammonia gas, and ammonia / organic solvent solution may be used as ammonia. The amount used is not particularly limited, but it is economically disadvantageous if it is too large, and therefore it is practically 10 mol times or less with respect to the secondary amine.

This reaction is usually carried out by mixing and contacting a secondary amine, hydrogen peroxide and a metal oxide catalyst, and the mixing order is not particularly limited. Further, for example, a metal compound, hydrogen peroxide and a secondary amine may be mixed and brought into contact with each other to carry out the operation for preparing the metal oxide catalyst and the reaction between the secondary amine and hydrogen peroxide at the same time.

This reaction may be carried out under normal pressure conditions or under elevated pressure conditions. The progress of the reaction can be confirmed by ordinary analytical means such as gas chromatography, high performance liquid chromatography, thin layer chromatography, NMR and IR.

After completion of the reaction, the reaction solution is left as it is or, if necessary, residual hydrogen peroxide is decomposed with a reducing agent such as sodium thiosulfate, and then subjected to concentration treatment, crystallization treatment, etc. to obtain the objective. Nitrons can be taken out. If necessary, water and / or an organic solvent insoluble in water may be added to the reaction solution for extraction, and the resulting organic layer may be concentrated to extract nitrones. The taken out nitrones may be further purified by means such as distillation, column chromatography and the like.

Examples of the water-insoluble organic solvent include aromatic hydrocarbon solvents such as toluene, xylene and chlorobenzene, halogenated hydrocarbon solvents such as dichloromethane, dichloroethane and chloroform, such as diethyl ether and methyl tert-butyl ether. Examples thereof include ether solvents such as tetrahydrofuran, and ester solvents such as ethyl acetate, and the amount thereof is not particularly limited.

The aqueous layer obtained by extracting the filtrate or the reaction solution after the desired nitrones have been taken out by the crystallization treatment contains the metal oxide catalyst of the present reaction and may be used as it is or if necessary. It can be used again in this reaction after being subjected to concentration treatment and the like.

Examples of the nitrones thus obtained are N-methylidenemethylamine N-oxide, N-ethylidenemethylamine N-oxide, N-propylidenemethylamine N-oxide, N-butylidenebutylamine N-oxide, N-Pentylidene amylamine N-oxide, N-hexylidenehexylamine N-
Oxide, N-heptylideneheptylamine N-oxide, N-octylideneoctylamine N-oxide, N-nonylidenenonylamine N-oxide, N-
Decylidenedecylamine N-oxide, N-dodecylidenedodecylamine N-oxide, N-isopropylideneisopropylamine N-oxide, N-isobutylideneisobutylamine N-oxide, N-sec-
Butylidene-sec Butylamine N-oxide, N-
Isoamylidene isoamylamine N-oxide, N-
Ethylidene-tert-butylamine N-oxide,

N-benzylidenebenzylamine N-oxide, N-benzylidene-tert-butylamine
N-oxide, N-benzylideneaniline N-oxide, 3,4-dihydroisoquinoline N-oxide,
6,7-Methylenedioxy-3,4-dihydroisoquinoline N-oxide, 1-pyrroline N-oxide, 2
-Methyl-1-pyrroline N-oxide, 2-carbomethoxy-1-pyrroline N-oxide, 3,4-dimethoxy-1-pyrroline N-oxide, 2,3,4,5-
Tetrahydropyridine N-oxide, 2-methyl-
2,3,4,5-Tetrahydropyridine N-oxide, 2-carbomethoxy-2,3,4,5-tetrahydropyridine N-oxide, 2,6-dimethyl-2,
3,4,5-tetrahydropyridine N-oxide and the like can be mentioned.

[0041]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 A 50 mL flask was charged with 16 mg of tungsten metal and 250 mg of 30% by weight hydrogen peroxide, and the internal temperature was 40.
The temperature was raised to 0 ° C., and the mixture was stirred and held at the same temperature for 0.5 hours to prepare a tungsten oxide catalyst aqueous solution. Internal temperature of the prepared solution 2
Cool to 0 ° C., methanol 3 g and N-benzyl-t
355 mg of ert-butylamine was charged. After dropping 1150 mg of 30 wt% hydrogen peroxide solution over 5 minutes,
The mixture was stirred at the same temperature for 5 hours, kept and reacted. After completion of the reaction, 10 g of methyl tert-butyl ether and 1 part of water
After adding 0 g, stirring, and allowing to stand, liquid separation treatment was performed, and the obtained organic layer was subjected to gas chromatography analysis (hereinafter abbreviated as GC analysis). The yield of N-benzylidene-tert-butylamine N-oxide was 95%. The obtained organic layer was concentrated to give N-benzylidene-tert-
370 mg of white crystals of butylamine N-oxide were obtained.

Example 2 A 50 mL flask was charged with 16 mg of tungsten metal and 250 mg of 30% by weight hydrogen peroxide, and the internal temperature was 40%.
The temperature was raised to 0 ° C., and the mixture was stirred and held at the same temperature for 0.5 hours to prepare a tungsten oxide catalyst aqueous solution. Internal temperature of the prepared solution 2
After cooling to 0 ° C., 3 g of water and 396 mg of N, N-dibenzylamine were charged. 30 wt% hydrogen peroxide water 115
After 0 mg was added dropwise over 5 minutes, the mixture was stirred at the same temperature for 3 hours,
Hold and react. After the reaction was completed, 10 g of methyl tert-butyl ether and 10 g of water were added, and the mixture was stirred, left standing, and then subjected to liquid separation treatment, and the obtained organic layer was concentrated to obtain white crystals of N-benzylidenebenzylamine N-oxide 4
30 mg was obtained. Melting point: 81-83 ° C.

Example 3 A 50 mL flask was charged with 160 mg of tungsten metal and 2.5 g of 30% by weight hydrogen peroxide solution, and the internal temperature was 40%.
The temperature was raised to 0 ° C., and the mixture was stirred and held at the same temperature for 0.5 hours to prepare a tungsten oxide catalyst aqueous solution. The internal temperature of the prepared liquid is 0
Cooled to 30 ° C., water 30 g and N, N-di (n-butyl)
2.6 g of amine was charged. After 6.9 g of 30 wt% hydrogen peroxide solution was added dropwise over 30 minutes, the mixture was stirred and held at the same temperature for 3 hours to be reacted. After completion of the reaction, methyl tert
-Add 50 g of butyl ether and 10 g of water, stir,
After standing, liquid separation was performed, and the obtained organic layer was concentrated,
3.1 g of a pale yellow oil containing -butylidene butylamine N-oxide was obtained. When the pale yellow oil was analyzed by gas chromatography (hereinafter abbreviated as GC), the content of N-butylidenebutylamine N-oxide was 87% (GC area percentage value). Yield: 9
4%.

Example 4 A 50 mL flask was charged with 160 mg of tungsten metal and 2.5 g of 30% by weight hydrogen peroxide solution, and the internal temperature was 40%.
The temperature was raised to 0 ° C., and the mixture was stirred and held at the same temperature for 0.5 hours to prepare a tungsten oxide catalyst aqueous solution. Internal temperature of the prepared solution 2
After cooling to 0 ° C., 30 g of water and 1.7 g of 1,2,3,4-tetrahydroisoquinoline were charged. After 6.9 g of 30 wt% hydrogen peroxide solution was added dropwise over 30 minutes, the mixture was stirred and held at the same temperature for 3 hours to be reacted. After completion of the reaction, 50 g of methyl tert-butyl ether and 10 g of water were added, and the mixture was stirred at room temperature, allowed to stand, and then subjected to liquid separation treatment, and the obtained organic layer was concentrated to obtain a light residue containing 3,4-dihydroisoquinoline N-oxide. 2.1 g of yellow oil was obtained. When the pale yellow oil was analyzed by GC, the content of 3,4-dihydroisoquinoline N-oxide was 80% (GC area percentage value). Yield: 90%.

Example 5 A 50 mL flask was charged with 74 mg of tungsten metal and 500 mg of 30% by weight hydrogen peroxide, and the internal temperature was 40%.
The temperature was raised to 0 ° C., and the mixture was stirred and held at the same temperature for 0.5 hours to prepare a tungsten oxide catalyst aqueous solution. The internal temperature of the prepared liquid is 0
Cooled to ℃, water 4g, 28 wt% ammonia water 600m
g and 850 mg piperidine were charged. 30% by weight
After 3.4 g of hydrogen peroxide solution was added dropwise over 30 minutes, the mixture was stirred and held at the same temperature for 3 hours to be reacted. After the reaction was completed, 50 g of methyl tert-butyl ether and 10 g of water were added, and the mixture was stirred at room temperature, allowed to stand, and then subjected to liquid separation treatment, and the obtained organic layer was concentrated to give 2,3,4,5-tetrahydropyridine N-. 780 mg of a pale yellow oil containing oxide was obtained. GC analysis of the pale yellow oil revealed that
The content of 4,5-tetrahydropyridine N-oxide was 90% (GC area percentage value). Yield: 70
%.

Example 6 Example 6 was repeated except that 16 mg of molybdenum metal was used instead of 16 mg of tungsten metal and 3 g of methanol was used instead of 3 g of water as a solvent, and N-benzylidene was used. 410 mg of white crystals of benzylamine N-oxide were obtained.

Example 7 N-benzylidene was prepared in the same manner as in Example 2 except that 20 mg of tungsten sulfide was used instead of 16 mg of tungsten metal and 3 g of methanol was used instead of 3 g of water as a solvent. 425 mg of white crystals of benzylamine N-oxide were obtained.

Example 8 N-benzylidenebenzylamine N-oxide is obtained by the same procedure as in Example 2 except that tungsten boride is used instead of tungsten metal.

[0050]

INDUSTRIAL APPLICABILITY According to the present invention, in the presence of a metal oxide catalyst obtained by reacting a hydrogen peroxide with a tungsten compound or a molybdenum compound such as tungsten metal, molybdenum metal, or tungsten sulfide, which is inexpensive and easily available. , A secondary amine (provided that at least one carbon atom of the two carbon atoms bonded to the amino group has at least one hydrogen atom) is reacted with hydrogen peroxide to obtain nitrones. Therefore, it is industrially advantageous.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07D 217/08 C07D 217/08 // C07B 61/00 300 C07B 61/00 300 F term (reference) 4C054 AA04 CC07 DD01 EE01 FF01 4G069 AA03 AA08 BB04A BB04B BB09C BB11C BB13C BB15C BB18C BC59A BC59B BC59C BC60A BC60B BC60C CB07 CB61 DA02 FA01 BB41 BA36 BA15 BA36 BA15 BA34 BA35 BA31 BA35 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA31 BA32

Claims (11)

[Claims] 1. A tungsten compound comprising tungsten metal, molybdenum metal, tungsten and a group IIIb element, a group IVb element, a group Vb element or a group VIb element except oxygen, and molybdenum and a group IIIb element, IVb. Group elements,
In the presence of a metal oxide catalyst obtained by reacting hydrogen peroxide with at least one selected from the group consisting of molybdenum compounds consisting of a Group Vb element or a Group VIb element excluding oxygen, a secondary amine (however, At least one of the two carbon atoms bonded to the amino group has at least one hydrogen atom.) And hydrogen peroxide are reacted with each other. 2. A secondary amine is represented by the general formula (1): (In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted aralkyl group. ³ represents an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted aralkyl group, wherein
Any two or three of R ¹ , R ² and R ³ may combine to form a ring. The method for producing nitrones according to claim 1, which is a secondary amine represented by the formula (1). 3. The method for producing a nitrone according to claim 1, wherein the Group IIIb element is boron. 4. The method for producing a nitrone according to claim 1, wherein the Group IVb element is carbon. 5. The method for producing a nitrone according to claim 1, wherein the Group Vb element is nitrogen or phosphorus. 6. The method for producing nitrones according to claim 1, wherein the Group VIb element other than oxygen is sulfur. 7. The method for producing nitrones according to claim 1, wherein hydrogen peroxide water is used. 8. The method for producing nitrones according to claim 1, wherein the reaction is carried out in the presence of ammonia. 9. A tungsten compound containing tungsten metal, molybdenum metal, tungsten and a group IIIb element, a group IVb element, a group Vb element or a group VIb element other than oxygen, and molybdenum and a group IIIb element, IVb. Group elements,
A secondary amine formed by reacting at least one selected from the group consisting of molybdenum compounds consisting of Group Vb elements or Group VIb elements excluding oxygen with hydrogen peroxide (provided that two carbons bonded to an amino group are used). At least one of the atoms has at least one hydrogen atom.) A metal oxide catalyst for the production of nitrones. 10. A tungsten compound containing tungsten metal, molybdenum metal, tungsten and a group IIIb element, a group IVb element, a group Vb element or a group VIb element except oxygen, and molybdenum and a group IIIb element, IVb. A secondary amine (provided that it binds to an amino group) by reacting at least one selected from the group consisting of molybdenum compounds consisting of Group V elements, Group Vb elements or Group VIb elements excluding oxygen with aqueous hydrogen peroxide. At least one of the two carbon atoms having at least one hydrogen atom is oxidized to produce a nitrone. 11. A secondary amine comprising the aqueous metal oxide catalyst solution according to claim 10 and an organic solvent, provided that at least one of the two carbon atoms bonded to the amino group is at least one hydrogen atom. A metal oxide catalyst solution for the production of nitrones.