JPS59110632A - Preparation of bromine compound containing aromatic group - Google Patents

Abstract

PURPOSE:To prepare the titled substance useful as a preparation intermediate of herbicide, in one step, in high yield, by reacting a compound containing aromatic group with an N-bromohydantoin derivative in the presence of an organic peroxide. CONSTITUTION:The objective compound of formula III can be prepared by reacting the compound of formula I (Ar is aromatic group; R<1> and R<2> are 1-5C alkyl or H) with the compound of formula II (R<3> and R<6> are H, Br or 1-4C alkyl, provided that one of R<3> and R<6> is Br; R<4> and R<5> are 1-3C alkyl or phenyl) in the presence of an organic peroxide at 50-55 deg.C. The organic peroxide is selected from those capable of generating radicals easily at low temperature and transportable and handleable safely, i.e. those having a decomposition temperature of <=55 deg.C corresponding to the half-life time of 10hr, e.g. diisopropyl peroxydicarbonate, etc., and the amount of the peroxide is 0.1-1wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a bromine compound, and more specifically,
The present invention relates to a method for producing an aromatic group-containing bromine compound.

N-(α,α-dialkylbenzyl)-phenylacetamide derivatives developed as active ingredients of herbicides are α
, produced from α-dialkylbenzylamine and a phenylacetic acid derivative (see Japanese Patent Publication No. 110655/1983). Here, α,α-dialkylbenzylamine is
Usually, the carbon atom at the α position of α,α-dialkyltoluene, which is one of the aromatic group-containing compounds of the above general formula, is brominated to produce α,α-dialkylbenzyl bromide, and the tertiary benzyl position of this compound is It is obtained by replacing the bromine atom bonded to carbon with an amine group using liquid ammonia.

In this case, the following three methods are conventionally known as methods for producing α,α-dialkylbenzyl bromide.

(In the formula, R'o is a hydrogen atom,) represents a rogene atom;
R' and R'2 may be the same or different and each represents an alkyl group having 1 to 5 carbon atoms; when l is an integer of 1 to 5 and 4 is an integer of 2 or more, R' .

may be the same or different),
α-Dialkyltoluene is oxidized with oxygen in a 50% caustic soda aqueous solution at 85 to 95°C for about 30 to 40 hours to obtain an α,α-dialkylbenzyl alcohol derivative, which is then reacted with hydrogen bromide to form a tertiary carbon This is a reaction that bromines .

The method consists of a two-step process, with a yield of 30-40% in the first step and a yield of 90-95% in the second step, so the overall yield is 30%. It gets lower before and after.

R'o, A! has the same meaning as above) (wherein, R4 and 7 both have the same meaning as above)
A Grignard reagent represented by the following formula =R7-c
By reacting a ketone represented by o-R'2 (in the formula, R'1 and R'2 both have the same meanings as above), α,
This is a method in which an α-dialkylbenzyl alcohol derivative is synthesized and the desired product is obtained from it through a subsequent reaction in the first method.

In this method, the yield of α,α-dialkylpencyl alcohol is relatively high (80 to 90%), but the reaction takes a long time and the steps are complicated, so it is not an industrially suitable method. Can not.

The third method involves brominating the Al α,α-dialkyltoluene, the raw material of the first method, with N-70 mosuccinimide in the presence of an organic peroxide such as benzoyl peroxide.

However, in this method, the reaction temperature is high (70
~80°C), and the main product is a compound represented by the following formula: (both have the same meanings as above), and the selectivity of the target product, α,α-dialkylbenzyl bromide, is low.

As is clear from the explanation using α,α-dialkyltoluene as a typical starting material, all conventional bromination methods have low yields and complicated steps, resulting in poor product quality. There was an industrial problem in that it led to an increase in costs.

The purpose of the present invention is to provide a method for producing an aromatic group-containing bromine compound in one step and with a high yield, by solving the above-mentioned problems in the conventional production method of an aromatic group-containing bromine compound. shall be.

The method of the present invention is characterized by selectively brominating the α-position carbon of the aromatic group-containing bromine compound described below by a radical reaction using an N-bromohydantoin derivative. That is, the method of the present invention includes 1, (wherein Ar represents an aromatic group, R1 and R2 may be the same or different,
(respectively represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom) and an aromatic group-containing compound represented by (wherein R3 and R6 may be the same or different; Bromine atom or carbon number 1-4
represents an alkyl group having 1 to 3 carbon atoms or a phenyl group, one of which is a bromine atom. (in the formula, Ar
, R' and R2 each have the above meanings) This is a method for producing an aromatic group-containing bromine compound.

Aromatic Funds Used as Starting Materials of the Invention 2 In the formula, Ar is a benzene-based aromatic group, a polynuclear aromatic group, or a heterocyclic aromatic group. Among these aromatic groups, phenyl is an example of a benzene-based aromatic group.

Tolyl, ethylphenyl, isopropylphenyl.

Examples include xylyl, chlorphenyl, bromphenyl, fluorophenyl, and nitrophenyl. Examples of polynuclear aromatic groups include naphthyl, anthranyl, phenanthryl, chrysyl, and pyryl.

Examples include tyryl and derivatives thereof. Further, as the heterocyclic aromatic group, oxygen-containing heterocyclic aromatic groups such as furyl and benzofuryl; nitrogen-containing five-membered aromatic groups such as pyrrolyl and indolyl; pyridyl, quinolyl, oxazyl, pyrazyl, quinardyl, Examples include nitrogen-containing six-membered aromatic groups such as revidyl, isoquinolyl, cinnolyl, quinazolyl, and quinoxalyl; and sulfur-containing heterocyclic aromatic groups such as chenyl, benzochenyl, and thianaphthyl.

Among these aromatic groups, benzene-based aromatic groups are preferred in the present invention, and phenyl groups substituted with nuclear halogens such as chlorophenyl, bromphenyl, and fluorophenyl are particularly preferred.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R1 and R2 include a methyl group, an ethyl group, a propyl group, a butyl group, and an isopropyl group.

In the method of the present invention, the α-position carbon of the above-mentioned aromatic group-containing compound is brominated by a radical reaction.

First, the compound is mixed with a bromination solvent. In addition to the compound itself, examples of the solvent include solvents that do not dissolve the N-bromohydantoin derivatives described below, such as carbon tetrachloride, benzene, and carbon disulfide. Among these, carbon tetrachloride is preferable. The amount of solvent is preferably as large as the amount of the compound, but is usually 5 to 30 times the amount.

An organic peroxidant is added to this mixed system as an initiator for a radical reaction with the N-bromohydantoin derivative described below, and the whole is heated to a predetermined temperature.

The organic peroxidant used is not particularly limited and various types can be used, but it is particularly preferable to select one that easily generates radicals even at low temperatures and is safe to handle during transportation. Specifically, those having a decomposition temperature of 55° C. or lower to obtain a half-life of 10 hours, BIJ eu, diimpropyl peroxydicarbonate, di-n-propyl peroxycarbonate.

t-Butyl peroxyneodecanate, di-(2-ethoxyethyl) peroxydicarbonate, di-myristyl peroxydicarbonate, di-(methoxyinglovir) peroxydicarbonate, di-(2-ethylexyl) peroxydicarbonate, di- (3-methyl-3
-methoxybutyl) peroxydicarbonate, 2,4
-dichlorobenzoyl peroxide and t-butyl peroxybivalate. Addition of these organic peroxides:? is usually about 0.1 to 1 weight factor. The temperature of the entire mixing system is usually between 50 and 55, RB,
R', R' and R6 each represent the same meaning as above. However, either R3 or R6 is a bromine atom) N-bromohydantoin derivative h is added. R
4 and R5 as an alkyl group having 1 to 4 carbon atoms, such as methyl group, ethyl group, isopropyl group, n
-propyl group and n-butyl group. Specifically, the N-bromohydantoin derivatives used in the present invention include 1,3-dibromo-5,5-dimethylhydantoin, 3-bromo-5,5-dimethylhydantoin, 1-bromo-5,5- Methyl ethylhydantoin and 1,3-dibromo-5,5-diphenylhydantoin can be mentioned. It is preferable that these N-bromohydantoin derivatives are not added to the reaction system all at once, but are added in predetermined amounts in small portions. However, if the addition takes too much time, by-products will be produced, which will lower the selectivity of the desired bromide compound and lower the overall yield. The time required for addition is usually about 2 to 3 hours. The added liquid is usually in an equimolar amount to the aromatic group-containing compound.

After the reaction is completed, the reaction solution is filtered, and the generated hydantoin derivative crystals are separated from each other. Moreover, if the solvent is distilled off from the F solution and further separated from the target product, the solvent can be reused, and hydantoin can be regenerated into an N-bromohydantoin derivative and reused.

As described above, the uninvented method can be carried out at low temperatures, in a short time, and with extremely simple reaction operations without producing any by-products, and moreover, it can bromine 80 to 90% of the α-position carbons. I can do it. Furthermore, since the solvent and hydantoin can be separated from the reaction mother liquor and reused, this method is also useful from the viewpoint of industrial economy.

The method of the present invention will be explained in more detail below based on examples.

Example 1 p-chloroisopropylbenzene 15.5 r (0,
1 mol) and carbon tetrachloride 78F (0.5 mol) were placed in a reaction vessel and mixed. To this, 30 my of diisopropylboxycarbonate was added and the whole was heated to 50°C. Without stirring, add 1,3-dibromo-5 here.
,5-dimethylhydantoin 14.3 F (0,05
When a radical reaction was carried out by adding mol) little by little over 2.5 hours, white crystals were precipitated in the reaction solution. After cooling, the mixture was separated and the carbon tetrachloride of the ν liquid was distilled off to obtain 24.7f of p-chloro-α,α-dimethylbenzyl bromide.

14 selectivity: 96%, yield: 91%, melting point: 47~-4
4℃.

Proton nuclear magnetic resonance spectrum (% absorption ppm *
Solvent CC)6. Internal standard TMS): 2.2 (CH3
, 6H), 7.1-7.5 (benzene ring proton, 4
H).

Example 2 p-chloroisopropylbenzene 15.517' was replaced with p-ri-5ee-butylbenzene 16.91
Example 1 except that / (0.1 mol) was used.
In the same manner as above, p-chloro-α,α-methylethylbenzyl bromide 26.14 was obtained.

Steam selectivity: 96%, yield: 92%, melting point: 45~-40
℃.

Proton nucleus (marine resonance spectrum (characteristic absorption ppm).

Solvent C (J!, , internal standard TMS): 0.7-1
．． 0(CH,,3H).

2.1 (CH3,3H), 2.0-2.4 (C
H2, 2H), 7.1-745 (benzene ring proton, 4H).

Example 3 3.1 F (0.02 mol) of 2-ethylnaphthalene and 15 mol of carbon tetrachloride were mixed, and 6Tq of diisobrohydralveroxydicarbonate (6Tq) was added thereto and heated to 60°C. 1,3-dibromo-5.5- at a reaction temperature of 57-62°C.
When 2.9 g (0.01 mol) of dimethylhydantoin was added little by little over 2 hours to carry out a radical reaction, white crystals were precipitated in the reaction solution. After cooling, the mixture was separated and the carbon tetrachloride of the p liquid was distilled off to obtain 5.12 grams of 2-(α-bromoethyl)naphthalene.

Selectivity = 90%, yield: 87%, melting point: 56-61°C.

Proton nuclear magnetic resonance spectrum (characteristic absorption ppm.

Solvent CCl4. Internal standard TMS): 2.0-2.
1 (CH8,3H).

5.0~5.4 (CI*,, IH), 7.1~
7,8 (naphthane protons.

7H).

Example 4 6.7 F (0.06 mol) of 2-ethylthiophene and 401 mol of carbon tetrachloride were mixed, 127 Mf of t-butylperoxyneotecane was added thereto, and the mixture was heated to 50°C. 1,3-dibromo-5,5 at a reaction temperature of 50-55°C
-dimethylhydantoy” 8.69 (0.03 mon,
) was added little by little over 2.5 hours to carry out a radical reaction, and white crystals were precipitated in the reaction solution.

After cooling this, it was separated into a furnace, and the carbon tetrachloride in the P liquid was distilled off.
-(αbromoethyl)thiophene 11.6? I got it.

Selectivity = 96%, yield: 91%, melting point = 77-83°C.

Proton nuclear magnetic resonance spectrum (% absorption ppm.

Solvent CCZ4. Internal standard TMS): 2.0-2.1
(CH3, 3H).

5.2-5.6 (CH, IH), 6.6-7.1 (thiophene ring proton.

3H).

Example 5 4.8 y (o, o 5 mol) of 2-ethylimidazole and 481 carbon tetrachloride were mixed, 8 mg of di-n-propyl peroxycarbonate) was added thereto, and the mixture was heated to 50°C. 10.41 (0.05 mol) of 3-bromo-5,5-dimethylhydantoin was added little by little at a reaction temperature of 50 to 55° C. for reaction. After the reaction, white crystals were precipitated. After cooling this, the carbon tetrachloride of P liquid was distilled off and 2-
(Bromoethyl)imidazole 9.42 was obtained.

Selectivity: 286%, Yield: 82%, Melting point: 112-119
℃.

Proton nuclear magnetic resonance spectrum (characteristic absorption ppm.

Solvent CC)6. Internal standard TIVIS): 2.0~
2.1 (CH3, 3H).

5.1-5.5 (CH, IH), 6.8-7.1 (imidazole ring proton.

3H).

Comparative example p-ri-o-5ec-butylbenzene 16.9 f (
0.1 mol) and carbon tetrachloride 78 f (0.5 mol), and then benzoyl peroxide 307+17
was added and the whole was heated to 70°C. While stirring, 17.8 t (0.1 mol) of N-bromosuccinimide was added little by little over 2.5 hours to react, and pale yellow crystals were precipitated. After cooling it, it is distributed door to door.
Carbon tetrachloride in the P solution was distilled off to obtain a reaction product 30.2f.

Selectivity: 28%, Yield: 27%, Melting point: 50~-46
℃.

Claims (1)

[Claims] Primary formula: %Formula% (In the formula, Ar represents an aromatic group, R1 and R2 may be the same or different, and each represents an alkyl group having 1 to 5 carbon atoms. (representing a group or a hydrogen atom) and an aromatic group-containing compound represented by
represents an alkyl group, one of which is a bromine atom, and LR' and R5 may be the same or different and each represents an alkyl group having 1 to 3 carbon atoms or a phenyl group) The following formula: R1 Ar-C-Br 2 (wherein Ar + R' and R2 each represent the above-mentioned A method for producing an aromatic group-containing bromine compound represented by: 2. The manufacturing method according to claim 1, wherein the aromatic group is a benzene-based aromatic group, a polynuclear aromatic group, or a heterocyclic aromatic group. 3. The method for manufacturing a ship arrangement according to claim 1 or 2, wherein the aromatic group is a benzene-based aromatic group. 4. The manufacturing method according to claim 3, wherein the aromatic group is a nuclear halogen-substituted phenyl group.