JPS6038385B2 - Method for producing 2-benzothiazolones - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 2-penzothiazolones, and more particularly to a method for producing the corresponding 2-penzothiazolones from o-halogenonitrobenzenes in a single reaction.

2-Penzothiazolones themselves are bactericides, sedatives,
It is not only used as an agricultural chemical, but also as an intermediate for producing various pharmaceuticals and agricultural chemicals, and has a wide range of industrial uses.

Various methods for producing such 2-penzothiazolones are already known.

For example, Hakama Kosho No. 47-51347 describes a method in which o-halogenonitrobenzenes are reacted with sodium sulfide and the resulting product is reacted with phosgene. However, this method requires two reaction steps as described above, and since it uses a large amount of phosgene, there are problems with work safety, environmental protection, etc., and it is not satisfactory as an industrial method. Therefore, as a method that does not use phosgene, Mochiseki No. 53-I 772 discloses that o-halogenonitrobenzenes are reacted with a polysulfide metal to form the corresponding disulfide, and then a metal sulfide is reacted to form the corresponding o-halogenonitrobenzene. - Aminothiophenols are obtained, which are further reacted with chloroformic acid ester to form the corresponding 2-layer fusuma thioanilines, and then ring-opened in the presence of an acid catalyst to obtain the desired 2-benzothiazolones. Although a method for obtaining the product is described, it requires multiple steps and is difficult to obtain. Since the rugate ester is expensive, it is disadvantageous for industrial implementation. On the other hand, JP-A-48-34875 describes a method for obtaining 2-penzothiazolone by reacting o-nitrothiophenol with carbon monoxide using rhodium chloride and vanadium pentoxide as catalysts. This method is the same as the former two methods in that it requires a separate process for producing o-nitrothiophenol from o-halogenonitrobenzene, and 2-penzothiazolone is obtained from o-halogenonitrobenzene through multiple steps.

Furthermore, this method requires severe reaction conditions of high temperature and high pressure, and the noble metal catalyst used is also expensive. For the above method, the corresponding 2-benzene is prepared in one step by reacting a nitrobenzene in which at least one o-position is unsubstituted with carbonyl sulfide in the presence of an organic phosphorus compound, an inorganic antimony compound, or sodium hydrogen sulfide. A method for obtaining thiazolones has already been proposed (U.S. Pat. No. 3)
(Part No. 6690 and Specification No. 3 $6691), it is necessary to use carbonyl sulfide, which is ubiquitous and difficult to handle, in large excess with respect to the raw material nitrobenzene, and the reaction conditions are high temperature and high pressure, which further reduces the yield. is extremely low.

The present invention has been made in order to solve the various problems described above, and provides a method for obtaining 2-benzothiazolones with a high degree of filtration in a high yield from o-halogenonitrobenzenes in a one-step reaction. The purpose is to

The method for producing 2-penzothiazolones according to the present invention uses the general formula (where x represents a halogen and Y represents hydrogen or a substituent that does not participate in the reaction.

) is reacted with sulfur and carbon monoxide in the presence of a base and water to form a compound of the general formula (where Y is the same as above).

) is characterized by obtaining 2-penzothiazolones represented by:

In the raw material compound o-halogenonitrobenzenes (1), halogen X includes fluorine, chlorine, bromine and iodine, preferably chlorine or bromine.

Y represents hydrogen or a substituent that does not participate in the reaction. Examples of such substituents include halogen, such as fluorine, chlorine,
Bromine and iodine, alkyl groups, preferably C, ~ C, o
Methyl, ethyl, propyl, butyl, hexyl, octyl etc., aryl groups such as phenyl, benzyl etc., trihalomethyl groups such as trichloromethyl, tribromomethyl, trifluoromethyl, dichlorofuromomethyl etc., alkoxy groups and aryloxy groups , preferably C, ~C
,. Methoxy, ethoxy, propoxy, butoxy, hexyloxy, octyloxy, phenoxy, etc., carboalkoxy groups, preferably carbomethoxy, carboethoxy, carpopropoxy, carbobutoxy, etc., containing a C, to C, o alkyl group, substituted Amino groups, such as acetylamino, tosylamino, etc. The above-mentioned substituents are illustrative, and the substituents of the o-halogenonitrobenzenes that can be used in the present invention are not limited to these, and do not substantially participate in the reaction and do not cause undesirable side reactions. As far as possible, for example, alicyclic hydrocarbon groups, heterocyclic groups, and other magnetic groups can also be used as the dandelion substituent. Preferred specific examples of o-halogenonitrobenzenes include o-chloronitrobenzene, o-fromnitrobenzene, 2,3-dichloronitrobenzene, 2,5-dichloronitrobenzene, 2-chloro-3-nitrotoluene, and 4-chloronitrobenzene.

3-nitrotoluene, 3-nitro-4-chlorobenzotrichloride, 3-nitro-4-chlorobenzotrifluoride, 4-chloro-3-nitroanisole, 4-k. Lou 3-nit. Phenethol, 2-chloro-5-phenoxynitrobenzene, 4-chloro-3-nitrobenzene. Methyl benzoate, butyl 4-chloro-3-nitrobenzoate, 5
-acetylamino-2-chloronitrobenzene and the like. According to the method of the present invention, o-halogen/
2-benzothiazolone is obtained from nitrobenzenes,
o-ha having a substituent. 2-penzothiazolones having corresponding substituents are obtained from genonitrobenzenes. The sulfur used in the present invention is preferably applied in powder form, and general commercially available products can be used as they are.

The more Io is used, the faster the reaction progresses,
Considering the ease of post-treatment, the amount used is 1 to 10 mol per 1 mol of o-halogenonitrobenzene (1),
Preferably it is 1 to 5 mol. There is no particular need to use a large amount exceeding 10 mol.

Under the reaction conditions of the present invention, sulfur reacts with carbon monoxide and water in the reaction system to form sulfides, unless used in excess, and usually does not need to be removed from the resulting reaction mixture.

However, it can also be recovered if necessary. In the present invention, tertiary amines are preferably used as the base, and specific examples include aliphatic tertiary amines such as trimethylamine, triethylamine, and tripropylamine;
Aromatic tertiary amines such as N-dimethylaniline and N,N-dimethylaniline, pyridine, picoline, lutidine,
Aromatic tertiary amines such as quinoline, pyrazine, and pyrimidine; N-alkylpyrrolidines such as N-methylpyrrolidine and N-ethylpyrrolidine; -Alkylpiveridine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undecene-
Mention may be made of heterocyclic tertiary aminones such as 7 and the like.

The amount of the base used is not particularly limited, but is usually 1 to 20 mol, preferably 2 to 10 mol, per 1 mol of o-halogenonitrobenzene (1). In the present invention, the reaction is preferably carried out in a solvent.

The reaction solvent may be any solvent as long as it is not reduced under the reaction conditions, such as ethers, amides, amines, aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons. One type or a mixture of two or more of these can be used. Preferably, one or a mixture of two or more of tetrahydrofuran, dioxane, diethylable, dimethylformamide, dimethylacetamide, triethylamine, pyridine, N-methylpyrrolidone, benzene, toluene, xylene, hexane, cyclohexane, etc. is used. In the present invention, as will be described later, the presence of water in the reaction solvent is required, so when an organic solvent is used, it is desirable that it be compatible with water, and therefore,
Tetrahydrofuran, dioxane, triethylamine,
Pyridine, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrylodone and the like are preferably used. As is easily understood, tertiary amines such as triethylaminone and pyridine can serve both as a base and as a solvent. Moreover, water can also serve as a solvent.
Without being limited in any way by theory, the present invention includes the formation of a carbon-sulfur bond by substitution of an active halogen in the o-position of a nitro group, catalyzed by a base in the presence of sulfur, carbon monoxide, and water; It is thought that the reduction of the nitro group and the ring-opening reaction to the thiazolone ring occur in a controlled order to produce 2-penzothiazolones, and although its exact function is not clear, the presence of water in the reaction system suggests that 2-penzothiazolones are produced. is necessary.

In the present invention, water is usually used in a molar amount of 1 to 100 times the amount of the raw material o-halogenonitrobenzene. IO
Although more than N sonic moles can be used, preferably 2
It is ~3 otomo. The carbon monoxide pressure in the reaction is usually 1 to 50 kg/m, preferably 5 to 20 kg/m. The reaction proceeds sufficiently quickly and smoothly even at a low pressure of 10 kg' or less, and does not require particularly high pressure.

However, higher pressures can be used if necessary. The reaction temperature may generally range from 0 to 30°C, but preferably from 50 to 100°C, and the time required for the reaction is usually within ten hours or less, although it depends on other reaction conditions. In most cases, the reaction is completed in about 1 additional hour.

The reaction is preferably carried out in an autoclave, in which case carbon monoxide may be supplemented continuously or intermittently during the course of the reaction. In the method of the invention, the reaction is typically substantially in solution.

After the reaction is completed, the solvent is removed from the reaction mixture if necessary, water is added to precipitate any iodine that may remain in the system, and then Hina-lacquer alcohol is added to the water to form a reaction product. After extracting the product and removing sulfur in a furnace, the alcohol layer is separated and the alcohol is distilled off to obtain 2-benzothiazolones corresponding to the raw material compounds.
As the extraction alcohol, for example, a C4 to C9 aliphatic or alicyclic alcohol is used, and specific examples include butanol, bentanol, hexanol, cyclohexanol, and the like. Another simple work-up method is to simply remove the solvent from the reaction mixture under reduced pressure.

As mentioned above, most of the sulfur used in the reaction usually reacts under the reaction conditions, and the reaction product is evaporated during the process of returning the inside of the autoclave to normal pressure or distilling off the reaction solvent under reduced pressure after the reaction. This is because substantially no sulfur remains in the resulting residue. As another method, after distilling off the solvent from the reaction mixture under reduced pressure, an aqueous alkaline solution is added to the residue to dissolve it, filtered, and the resulting furnace solution is made acidic with acidic acid to obtain the corresponding 2-penzothiazolone. can also be precipitated. According to the present invention, the commonly obtained 2-penzothiazolones have high purity, but can be purified by recrystallization if necessary.

As the recrystallization solvent, alcohol, water, aromatic hydrocarbons, etc. can be used depending on the substituents of the 2-benzothiazolones. The method of the present invention, as described above, reacts o-halogenonitrobenzenes with sulfur and carbon monoxide in the presence of a base and water to obtain the corresponding 2-penzothiazolones, and has the following advantages: has.

'i} oM halogenonitrobenzenes as raw material compounds,
All raw materials and reaction reagents required for the reaction, such as sulfur, carbon monoxide, and a base, are easily and inexpensively available.

(o} Corresponding 2-penzothiazolone compounds can be obtained from o-halogenonitrobenzenes in one step, and the yield and purity of penzothiazolones are generally high.

The reaction conditions are mild, especially when the carbon monoxide pressure is 10
Since the reaction proceeds quickly and smoothly even below k9/average,
No special reaction equipment is required.

The reaction does not require high temperatures and the reaction time is relatively short. Q Reaction operation and post-reaction treatment are also simple.

■ If necessary, IO can be easily recovered after the reaction is completed;
It can be reused as is. Examples of the present invention are listed below, but the present invention is not limited to these Examples.

EXAMPLE 1 10 sail' capacity stainless steel autoclave with magnetic light bulb 2,5-dichloronitrobenzene 0
．． 96 hours (8 hmol), sulfur powder 0.8 hours (28 hours)
mol), water 0.54 (3 hmol) and triethylamine 2.8 [(20 hmol) were charged with 20 hmol of tetrahydrofuran, and after purging the inside of the autoclave with carbon monoxide, the carbon monoxide pressure was reduced to 10 k9. 'By chance,
Next, the inside of the autoclave was flooded with 80oo, and 8000
I reacted to the fly Azusa for one hour.

After the reaction was completed, the autoclave was cooled to room temperature and the pressure inside the autoclave was returned to normal pressure, and the solvent was distilled off from the resulting reaction mixture under reduced pressure to remove a slight brown solid content as residual bamboo. Obtained.

This was recrystallized from toluene to obtain 0.65 g of 5-chloro-2-penzothiazolone (yield 70%) as white crystals. Example 2 The reaction was carried out in exactly the same manner as in Example *1, except that the o-halogenonitrobenzenes shown in Table 1 were used in mol each instead of 2,5-dichronitrobenzene as the raw material compound. The resulting solid residue was quantitatively analyzed by gas chromatography to determine the yield.

The results are shown in Table 1. Table 1 Example 3 1.13 hours of 3-nitro-4-chlorobenzotrifluoride (8 hm
The reaction was carried out in exactly the same manner as in Example 1, except that ol) was used.

After the reaction was completed, the solvent was distilled off from the reaction mixture under reduced pressure, and the resulting solid residue was dissolved in a 5% aqueous solution of caustic soda, filtered through a furnace, and concentrated hydrochloric acid was added to the resulting furnace liquid to make it acidic. Crystals were precipitated. Take this out in the oven, wash it with water, dry it, and
-trifluoromethyl-2-penzothiazolone 0.97
(% total yield) was obtained. Example 4 A reaction was carried out with 5-dichloronitrobenzene in exactly the same manner as in Example 1, except that the base and solvent shown in Table 2 were used.

After the reaction was completed, the solvent was distilled off from the resulting reaction mixture, and the solid residue was quantitatively analyzed by gas chromatography to determine the yield of the resulting 5-chloro-2-penzothiazolone. The results are shown in Table 2. Table 2

Claims (1)

[Claims] 1 o-halogenonitrobenzenes represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (where, X represents a halogen, and Y represents hydrogen or a substituent not involved in the reaction) 2- expressed by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, Y is the same as above.) Method for producing benzothiazolones. 2. The method for producing 2-benzothiazolones according to claim 1, wherein the base is a tertiary amine. 3 In general formula (I), Y is hydrogen, halogen, alkyl group, aryl group, trihalomethyl group, alkoxy group,
2-2 according to claim 1, which is an allyloxy group, a carbalkoxy group, or a substituted amino group.
Method for producing benzothiazolones. 4. 2- of Claim 1, characterized in that the reaction is carried out under a carbon monoxide pressure of 1 to 5 kg/cm^2.
Method for producing benzothiazolones. 5. 2 of Claim 1, characterized in that the reaction is carried out under a carbon monoxide pressure of 5 to 20 kg/cm^2.
- A method for producing benzothiazolones.