JP2001288119A - New halogenating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new halogenating agent for organic compounds having alcoholic hydroxyl groups, and to provide a method for producing halogenated compounds by use of the new halogenating agent. SOLUTION: This halogenating agent represented by the general formula (1) [A is a substituted or nonsubstituted alkyl or alkoxy; (n) is 0 to 4; X1 and X2 are each the same or different halogen atom, but a case wherein both X1 and X2 are fluorine atoms, is excluded; R1 and R2 are each the same or different substituted or nonsubstituted alkyl].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel halogenating agent and a method for producing and using the same.

[0002]

2. Description of the Related Art Many methods have been known for halogenation reactions of organic compounds since ancient times. Commonly used halogenating agents include hydrogen halides, phosphorus compounds of halogens, sulfur compounds of halogens, simple halogens, etc., which are highly corrosive and toxic, and require special equipment for handling. There are many things that require technology. Therefore, from the viewpoints of handling, safety, reaction selectivity, etc., research and development of various halogenated reagents are still ongoing.

[0003] 1,3-Dialkyl-2-halogenoimidazolinium halogenides are mentioned as halogenating agents for overcoming these problems of the prior art (Japanese Patent Publication No. 59-2).
No. 5375). 1,3-Dialkyl-2-halogenoimidazolinium halogenides are less corrosive and less toxic than conventional halogenating agents, and can be easily produced from general-purpose compounds. Further, alcohols and carboxylic acids can be halogenated under mild reaction conditions, and can be used as a halogenating agent having functional group selectivity (JP-A-4-308538 and JP-A-9-308538). -67299). Further, after being used as a halogenating agent in the reaction, the starting material 1,3
-It is an industrially useful compound because it can be easily recovered and reused as dialkylimidazolidinone.

[0004] However, 1,3-dialkyl-2-
Since halogenoid imidazolinium halogenides have high hygroscopicity, it is necessary to handle and store them under an inert gas atmosphere and to pay attention to avoid contact with water as much as possible. Furthermore, since it does not have thermal stability in a high temperature range (around 140 ° C.), there is a problem that the operating temperature is limited. As described above, 1,3-dialkyl-2-halogenoimidazolinium halides have a functional group selectivity in terms of reactivity and are very useful, but have a high handling and storage stability. There is still room for improvement in terms of thermal stability and thermal stability.

It is an object of the present invention to provide a technically and economically improved industrial halogenating agent which overcomes the above problems.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve these problems, and as a result, the general formula (1)

[0007]

Embedded image (In the formula, A represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group, and n is 0 to 4. X ₁ and X ₂ may be the same or different, and represent a halogen atom. Provided that X ₁ and X ₂ are both fluorine atoms, and R ^{1 to} R ^{2 each} represent a substituted or unsubstituted alkyl group, which may be the same or different. It has been found that the compound is excellent as a novel halogenating agent selectively of an alcoholic hydroxyl group, and that it is very safe to use in a halogenation reaction, has good thermal stability, and can be easily performed.

That is, the present invention is as shown in the following 1) to 4). 1) General formula (1)

[0009]

Embedded image (In the formula, A represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group, and n is 0 to 4. X ₁ and X ₂ may be the same or different, and represent a halogen atom. Provided that X ₁ and X ₂ are each a fluorine atom, and R ^{1 to} R ^{2 each} represent a substituted or unsubstituted alkyl group, which may be the same or different. Agent. 2) The halogenating agent represented by the general formula (1) is a compound represented by the formula (2)

[0010]

Embedded image The halogenating agent according to 1), which is 2-chloro-1,3-dimethylbenzimidazolium chloride represented by the formula: 3) Equation (2)

Embedded image 2-chloro-1,3-dimethylbenzimidazolium chloride represented by the formula: 4) General formula (3)

[0011]

Embedded image (Wherein, R ³ represents a substituted or unsubstituted saturated or unsaturated alkyl group or a saturated or unsaturated aralkyl group) and a compound having an alcoholic hydroxyl group represented by the general formula (1):

[0012]

Embedded image (Wherein, A, R ¹ , R ² , X ₁ , and X ₂ have the same meanings as described above), and are reacted with a halogenating agent represented by the following general formula (4):

[0013]

Embedded image (Wherein, R ³ and X ₂ have the same meanings as described above).

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The halogenating agent of the present invention has the general formula (1)

[0015]

Embedded image (In the formula, A represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group, and n is 0 to 4. X ₁ and X ₂ may be the same or different, and represent a halogen atom. Provided that X ₁ and X ₂ are both fluorine atoms, and R ^{1 to} R ^{2 each} represent a substituted or unsubstituted alkyl group, which may be the same or different. is there.

In the formula (1), X ₁ and X ₂ represent halogen atoms, which may be the same or different. Where X ₁ ,
Except when both X ₂ are F atoms. As a combination example of X ₁ and _{X 2, Cl-Cl, Cl} -Br, Cl-I,
Br-Br, Br-I, II, F-Cl, F-Br,
FI is a specific example. A preferred halogenating agent is 2-chloro-1,3-dimethylbenzimidazolium chloride represented by the general formula (2).

A represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group, and is preferably a lower alkyl such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group or an n-butyl group. And an alkoxy group such as a methoxy group and an ethoxy group. In the general formula (1), R ¹ and R ² represent a substituted or unsubstituted alkyl group, which may be the same or different. Preferred examples include lower alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group and n-butyl group.

The halogenating agent represented by the general formula (1) of the present invention is, for example, chlorinated 1,3-dialkyl-benzimidazol-2-ones using a chlorinating agent or a brominating agent, Alternatively, the compound can be produced by bromination, or by subjecting each compound obtained by chlorination or bromination and an alkali metal salt of halogen to halogen exchange in a non-reactive solvent.

The raw material 1,3-dialkyl-benzimidazol-2-one is represented by the general formula (5)

[0020]

Embedded image (Wherein A represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group, and n is 0 to 4.), and a benzimidazol-2-one represented by the formula:
It can be produced by reacting a commonly used alkylating agent such as iodomethane, dimethyl sulfate, diethyl sulfate and the like.

Using the halogenating agent represented by the general formula (1), the compound represented by the general formula (3)

[0022]

Embedded image (Wherein, R ³ represents a substituted or unsubstituted saturated or unsaturated alkyl group or a saturated or unsaturated aralkyl group.) A compound having an alcoholic hydroxyl group represented by the following formula: it can.

In the general formula (3), R ³ is a substituted or unsubstituted saturated or unsaturated alkyl group or a saturated or unsaturated aralkyl group, and is an example of a compound having an alcoholic hydroxyl group which can be used for the reaction. Examples thereof include the following.

Methyl alcohol, ethyl alcohol, n
-Propyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-methyl-1-butanol, n-amyl alcohol, neoamyl alcohol, isoamyl alcohol, n-hexyl alcohol, 2-methyl-1-
Pentanol, 2-ethyl-1-butanol, n-heptyl alcohol, n-octyl alcohol, 2-ethylhexyl alcohol, n-nonyl alcohol, 3,5
5-trimethyl-1-hexanol, n-decyl alcohol, n-undecyl alcohol, n-dodecyl alcohol, allyl alcohol, methallyl alcohol, crotyl alcohol, benzyl alcohol, phenethyl alcohol, cinnamyl alcohol, propargyl alcohol, etc. Primary alcohols; and isopropyl alcohol,
sec-butyl alcohol, sec-amyl alcohol, sec-isoamyl alcohol, 1-ethyl-1-
Propanol, 4-methyl-2-pentanol, 1-methylhexyl alcohol, 1-ethylpentyl alcohol, 1-methylheptyl alcohol, cyclohexyl alcohol, 2-methylcyclohexanol, 3-methylcyclohexanol, 4-methylcyclohexanol,
secondary alcohols such as sec-phenethyl alcohol;
And alcohols such as tertiary alcohols such as tert-butyl alcohol, tert-amyl alcohol, 1-methylcyclohexanol and α-terpineol. However, it is not limited to these.

When the halogenation reaction is carried out, the amount of the halogenating agent represented by the general formula (1) is usually required to be at least 1 equivalent to the alcoholic hydroxyl group. The halogen compound formed by the reaction is represented by the general formula (4)

[0026]

Embedded image (Wherein, R ³ and X ₂ have the same meanings as described above).

The reaction solvent is not particularly limited as long as it does not react with the reaction substrate, the reaction reagent or the product, but is preferably acetonitrile, dichloromethane, ethylene dichloride, glyme, diglyme, dimethylformamide, 1,3-dimethyl. -2-imidazolidinone, benzene, toluene, monochlorobenzene, dichlorobenzene, hexane and the like. The reaction solvent only needs to have an amount capable of efficiently stirring the reaction reagent and the reaction substrate. Preferably,
It is usually 1 to 5 times the reaction reagent.

The reaction temperature is usually -40 to 150 ° C, preferably -20 to 100 ° C. The reaction temperature may usually be about 0.5 to 5 hours. The product can be easily removed from the reaction mixture by distillation or the like.

As an example of an actual reaction mode, a halogenating agent represented by the general formula (1) and an alcohol compound are charged into a dry solvent free of moisture, and the mixture is stirred at an appropriate temperature for several hours. A method of performing a time reaction can be exemplified. With respect to charging of the alcohol compound, a method of charging by dropping is more preferable.

Further, as long as it does not adversely affect the reaction, as a hydrogen halide scavenger to be produced,
A base such as a tertiary amine may be added.

The halogenating agent represented by the general formula (1) can be recovered as the corresponding urea after the completion of the reaction.

[0032]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.
The concentration of each halogenating agent shown in the examples was measured by high-performance liquid chromatography (hereinafter abbreviated as HPLC) after each halogenating agent was derivatized by reacting it with aniline. The halogen atom was determined by a silver nitrate titration method.

Synthesis Example 1 1,3-dimethylbenzimidazol-2-one (DM
Synthesis benzimidazoles 100g and dimethylformamide BI)
400 g was charged into a 1 L reaction vessel equipped with a stirrer, thermometer, and cooling condenser, and was dissolved while stirring. Next, while continuing stirring, potassium tertiary butoxy 5
0 g was charged and kept at 19-40 ° C. for 30 minutes. Next, 63.15 g of iodomethane was gradually charged and maintained for 30 minutes. During this time, the reaction temperature was maintained at 30 to 60 ° C.
Further, three times, alternately, potassium tertiary butoxy 5
After repeating charging of 0 g and 63.15 g of iodomethane, the reaction was terminated. 400 ml of water and 400 ml of dichloromethane were added to the reaction mass, followed by stirring and extraction. After separating and washing the dichloromethane layer with water, dehydration and dichloromethane distillation were carried out to obtain 92.5 g of crude DMBI. Finally, recrystallized and purified with carbon tetrachloride
88 g were obtained (GC purity 99%, yield 73%).

Example 1 2-chloro-1,3-dimethylbenzimidazolium-
Synthesis of chloride (CDMBI) 45 g of DMBI obtained in the above synthesis and monochlorobenzene
175 g was placed in a reaction vessel and a chlorination reaction with phosgene was performed. Reaction temperature 100 ° C, reaction time 15 hours.
After completion of the reaction, filtration, washing and drying were carried out to obtain 35 g of white crystals of CDMBI (purity: 100%, yield: 58%). The physical properties of the obtained CDMBI are as follows. Cl content analysis value 32.7% (calculated value 32.3%), FABMS: 118 ((M-Cl) ⁺ ), 397 ((2
× M-Cl) ⁺ ) ¹ H-NMR (δ, ppm, DMSO solvent, TMS standard, 21.8 ° C.): 4.05 (s, 6H, —CH ₃ ×)
2), 7.72 (q, 2H, -CH x 2), 8.10
(Q, 2H, —CH × 2) ¹³ C-NMR (δ, ppm, DMSO solvent, DMSO standard, 22.4 ° C.): 32.73 (—CH ₃ × 2), 1
13.18 (-CHx2), 126.73 (-CHx
2), 131.17 (-CH x 2), 141.38 (-
(C-Cl × 2) IR spectrum is shown in FIG.

Example 2 Synthesis of benzyl chloride In a small reaction vessel equipped with a thermometer, a stirrer and a cooling condenser, 1.232 g of CDMBI synthesized in Example 1 (1.
(074 mmol), 10 ml of acetonitrile and 0.116 g (1.072 mmol) of benzyl alcohol were charged and reacted at 80 ° C. for 1 hour. GC after reaction
And GC-MS measurement showed that benzyl chloride 0.0
The production of 824 g (0.763 mmol) was confirmed.

[0036]

Industrial Applicability The compound of the present invention is a novel halogenating agent which is safe, easy to handle, has good thermal stability and is highly selective with respect to organic compounds having an alcoholic hydroxyl group. In addition, from production to use, it can be used economically and industrially without requiring any special technology.

[Brief description of the drawings]

FIG. 1 shows the 2-chloro-1,3-synthesized in Example 1.
Dimethylbenzimidazolium chloride (CDMB
It is an IR spectrum of I).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junko Naruse 30 Asamuta-cho, Omuta-shi, Fukuoka Mitsui Chemicals, Inc. 72) Inventor Hideaki Oikawa 30 Asamuta-cho, Omuta-shi, Fukuoka F-term (reference) 4H006 AA02 AC30 AD11 BA51 BB11 BB12 BB14 BB20 BB21 BB24 BC10 BC19

Claims (4)

[Claims] 1. A compound of the general formula (1) (In the formula, A represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted alkoxy group, and n is 0 to 4. X ₁ and X ₂ may be the same or different, and represent a halogen atom. Provided that X ₁ and X ₂ are each a fluorine atom, and R ^{1 to} R ^{2 each} represent a substituted or unsubstituted alkyl group, which may be the same or different. Agent. 2. A halogenating agent represented by the general formula (1):
Formula (2) The halogenating agent according to claim 1, which is 2-chloro-1,3-dimethylbenzimidazolium chloride represented by the formula: (3) Formula (2) 2-chloro-1,3-dimethylbenzimidazolium chloride represented by the formula: 4. A compound of the general formula (3) (Wherein R ³ represents a substituted or unsubstituted saturated or unsaturated alkyl group or a saturated or unsaturated aralkyl group) and a compound having an alcoholic hydroxyl group represented by the general formula (1): Formula 5 (Wherein A, R ¹ , R ² , X ₁ and X ₂ have the same meanings as described above), characterized by reacting a halogenating agent represented by the following general formula (4): (Wherein, R ³ and X ₂ have the same meanings as described above).