JP2864475B2 - Method for producing 2-phenylbenzotriazoles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides 2-phenylbenzotriazoles represented by the following general formula I, which are useful as ultraviolet absorbers for plastics, paints, oils, etc., at low cost and industrially. To a very advantageous production method.

General formula I (Wherein R ₁ represents a hydrogen atom or a chlorine atom, a lower alkyl group having 1 to 4 carbon atoms, a lower alkoxyl group having 1 to 4 carbon atoms, a carboxyl group, or a sulfonic acid group, and R ₂ represents a hydrogen atom or Represents a chlorine atom, a lower alkyl group having 1 to 4 carbon atoms, a lower alkoxyl group having 1 to 4 carbon atoms, R ₃ is a hydrogen atom or a chlorine atom, an alkyl group having 1 to 12 carbon atoms, lower alkoxyl group, a cycloalkyl group, a phenyl group, a phenyl group substituted with an alkyl group having 1 to 8 carbon atoms, represents a phenoxy group or an alkyl moiety phenylalkyl group having 1 to 4 carbon atoms, R ₄ is a hydrogen atom Or a chlorine atom, a hydroxyl group or an alkoxyl group having 1 to 4 carbon atoms, and R ₅ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a phenylalkyl group having 1 to 4 carbon atoms in the alkyl portion.) PRIOR ART Conventionally, these 2-phenyl benzotriazoles of the general formula III (Wherein R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ are the same as those in the general formula I), which is produced by chemically or electrolytically reducing o-nitrohydroxyazobenzenes. However, each of these methods has advantages and disadvantages, and is not a satisfactory method.
For example, Japanese Patent Publication No. 375934 and U.S. Patent No. 3,773,751
In the above publication, the corresponding 2-phenylbenzotriazoles are obtained in good yield by chemically reducing o-nitroazobenzenes with zinc dust in an alcoholic sodium hydroxide solution. -The zinc system has drawbacks such as wastewater pollution due to the generation of zinc sludge and difficulty in treating waste.

U.S. Pat.No. 2,362,988 uses ammonium sulfide, zinc alkali sulfide-ammonia, hydrogen sulfide-sodium and zinc-hydrochloride as reducing agents, but this method produces large amounts of sulfites and zinc salts. However, there are disadvantages such as a problem of wastewater pollution and difficulty in treating waste.

In JP-B-52-113974 and JP-B-52-113973, o
-Nitroazobenzenes were reduced with hydrogen in the presence of a hydrogenation catalyst and a basic substance to give the corresponding 2-phenylbenzotriazoles with good production rates. However, many kinds of impurities were generated, and the reaction product was washed with methanol and reconstituted with ethanol.
Impurities cannot be removed. Therefore, this method has a problem in terms of quality and economic superiority to currently distributed 2-phenylbenzotriazoles.

[Object] An object of the present invention is to provide a new method for producing 2-phenylbenzotriazole.

Another object of the present invention is to provide a method for obtaining the desired product, 2-phenylbenzotriazole, with high yield and high quality by reduction using phosphorus trihalide.

[Constitution] The present invention relates to a method for producing a 2-phenylbenzotriazole represented by the general formula I by reducing a 2-phenylbenzotriazole-N-oxide represented by the general formula II with phosphorus trihalide. The reduction reaction includes two steps of a step of obtaining monophosphates using phosphorus trihalide (Step 1) and a step of further hydrolyzing monophosphates to obtain a compound of the general formula I (Step 2). More specifically, the reaction of step 2 may be carried out after isolating the monophosphate ester as a product of step 1, or the reaction of step 2 may be carried out without isolation.

The outline of one embodiment of the present invention is as follows.
-Phenylbenzotriazole-N-oxides are dissolved in the solvent described below, and phosphorus trihalide is added to perform a gentle reflux reaction. After completion of the reaction, water is added, and most of the solvent is distilled off with stirring to obtain a monophosphate.

The hydrolysis of monophosphate ester is carried out by using a solvent such as toluene or 1,1,2,2-tetrachloroethane, and is easily hydrolyzed in an acidic region to produce high-yield, high-quality crude 2-hydroxybenzotriazoles. Can be obtained. Further purification by recrystallization or the like yields purified 2-phenylbenzotriazoles.

General formula II used as a raw material in the method of the present invention
Specific examples of the compound of the following are listed below.

2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole-N-
Oxide 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole-N-oxide 2- (2'-hydroxy-3', 5'-di-t- Amylphenyl) benzotriazole-N-oxide 2- (2'-hydroxy-5'-methylphenyl) benzotriazole-N-oxide 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole-N- Oxide 2- (2'-hydroxy-5'-t-butylphenyl)
Benzotriazole-N-oxide 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole-N-oxide 2- (2'-hydroxy-3'-t-butyl-5' -Methylphenyl) benzotriazole-N-oxide 2- (2 ', 4'-dihydroxyphenyl) -5-chlorobenzotriazole-N-oxide 2- (2', 4'-dihydroxyphenyl) benzotriazole-N-oxide 2- (2'-hydroxy-4'-methoxyphenyl) benzotriazole-N-oxide 2- [2'-hydroxy-3,5-di (α, α-dimethylbenzyl) phenyl] benzotriazole-N-oxide 2 -(2'-hydroxy-3'-α-methylbenzyl-
5'-methylphenyl) benzotriazole-N-oxide These N-oxides of the general formula II are represented by the general formula III
Can be produced by various known reduction methods using o-nitroazobenzenes as a raw material.

Although there is no particular limitation on the solvent used in the present invention, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, tetrachloroethylene, trichloroethylene, chloroform are used in both the first step and the second step. benzene,
Examples include dichlorobenzene, toluene, xylene, 1,4-dioxane, carbon tetrachloride, n-hexane, n-heptane, and ligroin. The amount used is suitably 1 to 8 times the amount of the 2-phenylbenzotriazole-N-oxide represented by the general formula (II). Of course, using larger amounts does not hinder the reaction.

As the phosphorus trihalide used in the present invention, phosphorus trichloride is most preferable from the viewpoint of cost, and then phosphorus tribromide. Is obtained in high yield.

The benzotriazoles obtained according to the invention are compounds of the general formula I, for example 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole 2- (2'-hydroxy-3', 5'-di-t-amylphenyl) benzotriazole 2- (2'-hydroxy-5'-methylphenyl) benzotriazole 2- (2'-hydroxy-5'-t-butylphenyl)
Benzotriazole 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole 2- (2'-hydroxy -3'-t-butyl-5'-methylphenyl) benzotriazole 2- (2 ', 4'-dihydroxyphenyl) benzotriazole 2- (2', 4'-dihydroxyphenyl) benzotriazole 2- (2'- Hydroxy-4'-methoxyphenyl) benzotriazole 2- [2'-hydroxy-3 ', 5'-di (α, α-dimethylbenzyl) phenyl] benzotriazole 2- (2'-hydroxy-3'-α- Methylbenzyl-
5'-methylphenyl) benzotriazole and the like.

[Examples] The present invention will be described below with reference to examples, but the present invention is not limited only to these examples.

Example 1 Synthesis of monophosphate monohydrate of 2- (2'-hydroxy-3't-butyl-5'-methylphenyl) -5-chlorobenzotriazole 200 ml having a calcium chloride tube attached to the upper part of a cooling tube. −
4- (2'-hydroxy-3'-t-)
13.3 g (1/25 mol) of butyl-5'-methylphenyl) -5-chlorobenzotriazole-N-oxide and 30 ml of chloroform were added and melted. 8.2 g of phosphorus trichloride (1.5 / 25 mol
l) was added and the mixture was stirred and reacted under gentle reflux for 2 hours. After confirming the disappearance of unreacted components by TLC, water was added and the mixture was stirred well, chloroform was distilled off, and after cooling, the precipitated pale orange-yellow solid was filtered off with suction and washed with water.

Dry in a vacuum desiccator for 24 hours to obtain pale yellow-orange crystals 1
6.3 g (98.5%) were obtained.

The crude product was recrystallized from chloroform to analyze to obtain white crystals.

mp from 191.5 to 192.3 ° C. NMR (acetone _{-d 6, δppm): 1.1 (} S, 9H, -Bu t), 2.2 (S, 3H, -CH 3), 6.8 (S, 4H, -OH and H ₂ O) 7.1 ～ 7.9 （m, 5H, ph） 、 Quantification of water of crystallization is 100 ～ 110 ℃ / 2mmHg.
A decrease in 1H ₂ O was observed.

The elemental analysis values of C ₁₇ H ₁₉ O ₄ N ₃ ClP · H ₂ O were as follows.

C% H% N% Analytical value 49.19 5.24 10.18 Calculated value 49.35 5.12 10.16 Example 2 Monophosphate ester of 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole Synthesis of monohydrate 200ml-
4- (2'-hydroxy-3 ', 5'-)
14.9 g (1/25 mol) of di-t-butylphenyl) -5-chlorobenzotriazole-N-oxide and chloroform
45 ml was added and melted. Phosphorus trichloride (6.6 g, 1.2 / 25 mol) was added, and the mixture was stirred and reacted under gentle reflux for 2 hours. After confirming the disappearance of the unreacted product by TLC, water was added and the mixture was stirred well. Chloroform was distilled off. After cooling, the precipitated pale yellow crystals were separated and washed with water. Dry for 24 hours in a vacuum desiccator. Yield 17.6g (96.6%).

Recrystallization was performed with ethanol to obtain white granular crystals. The analytical values of this purified product are as follows.

mp 214.3~214.5 ℃ NMR (DMSO-d 6, δppm): 0.9 (t, 3H, -CH 3), 1.2 (S, 9H, -Bu t), 1.4 (S, 9H, -Bu t), 3.5 ( _{q, 2H, -CH 2 -)} , 7.2~8.1 (m, 5H, ph), 8.3 (S, 3H, -OH), elemental analysis as _{C 20 H 25 O 4 N 3} ClP · C 2 H 5 OH Value C% H% N% Analytical value 54.18 6.45 8.48 Calculated value 54.60 6.46 8.68 Due to the sublimability, water of crystallization could not be measured.

Example 3 Synthesis of monophosphate hydrate of 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) -benzotriazole 2- (2'-hydroxy-3', 5'- Di-t-aluminphenyl) -benzotriazole-N-oxide 14.7 g
(1/25 mol), chloroform 30 ml, phosphorus trichloride 6.6 g (1.2
/ 25mol) and 18.4 g of pale orange-yellow crystals in the same manner as in Example 1.
(100%). Recrystallization from benzene gave white crystals (85%).

mp 179~180 ℃ NMR (DMSO-d 6, δppm): 0.7 (t, 6H, -CH 3), 1.3 (S, 6H, -CH 3), 1.4 (S, 6H, -CH 3), 1.5~ _{2.1 (m, 4H, -CH 2} -), 7.0 (S, 5H, -OH and _{H 2 O), 7.3~8.2 (m} , 6H, ph), C 22 H 30 O 4 N 3 P1 1 / 2H 2 Elemental analysis as O C% H% N% Analysis 57.89 6.99 9.09 Calculated 57.63 7.26 9.16 It has sublimability.

Example 4 Synthesis of monophosphate hydrate of 2- (2'-hydroxy-5'-methylphenyl) -benzotriazole 2- (2'-hydroxy-5'-methylphenyl)-
Dissolve 9.6 g (1/25 mol) of benzotriazole-N-oxide in 30 ml of chloroform, and add 6.6 g of phosphorus trichloride (1.2 / 25 mol
Using l), the reaction was carried out in the same manner as in Example 1 to obtain white crystals.
2 g (100%) were obtained. Recrystallization from chloroform yielded white crystals.

mp 153~154 ℃ NMR (DMSO-d 6, δppm): 2.3 (S, 3H, -CH 3), 7.2~8.1 (m, 9H, ph and -OH), a _{C 13 H 12 O 4 N 3} P Elemental analysis value of C% H% N% Analysis value 50.94 4.10 13.74 Calculated value 51.16 3.96 13.77 Table 1 summarizes the structural formulas, NMR and elemental analysis values of each monophosphate produced in Examples 1 to 4.

Example 5 2- (2'-hydroxyphenyl-3'-t-butyl-
Synthesis of 5'-methylphenyl) -5-chlorobenzotriazole 2- (2'-hydroxy-
3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole monophosphate hydrate 16.5 g
(1 / 25mol), 35ml of toluene, 15ml of pH 5.1 buffer
(0.5N acetic acid: 0.5M sodium acetate aqueous solution = 1: 4) was poured, and the mixture was stirred and reacted under reflux for 1.5 hours. The toluene layer was separated, the reaction solution was further extracted with toluene, and the extracted toluene layers were combined, and toluene was distilled off and collected to obtain 12.4 g (98.2%) of the target compound as pale yellow needle crystals.

mp 136.5-138.5 ° C. Example 6 Synthesis of 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole 2- (2′-hydroxy-3 ′, 5′-di-t) The reaction was carried out in the same manner as in Example 5 using 18.3 g (1/25 mol) of hydrate of (-amylphenyl) benzotriazole monophosphate and 35 ml of toluene. However, the buffer was 0.5N acetic acid: 0.5M aqueous sodium acetate solution = 1: 20, the pH was 5.8, and the reaction was completed in 1.5 hours. 13.8 g (98.3%) of the desired pale yellow needle crystals were obtained.

mp 81.0-82.0 ° C. Example 7 Synthesis of 2- (2′-hydroxy-5′-methylphenyl) -benzotriazole 12.2 g of 2- (2′-hydroxy-5′-methylphenyl) benzotriazole monophosphate ester It carried out similarly to Example 5. However, 15 ml of the buffer solution was 0.5N acetic acid: 0.5 M aqueous sodium acetate solution = 19: 1 and the pH was 3.2. 9.0 g (100%) of the target compound as white to pale white yellow needles was obtained.

Example 12 Synthesis of 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole 300 ml 4-port colben 2- (2'- Hydroxy-
13.2 g of 3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole-N-oxide (1 / 25mo
l) and 30 ml of chloroform, and 6.5 g of phosphorus trichloride (1.18 /
(25 mol) The mixture was stirred and reacted under gentle reflux for 2 hours, and then chloroform was distilled off.

70 ml of water and 23 g of sodium acetate were added to adjust the pH to 5.5. Further, 130 ml of toluene was added and reacted under reflux for 2 hours. Toluene was separated, extracted with toluene, and the toluene layer was collected. Then, toluene was recovered to obtain 12.6 g (100%) of the target compound as pale yellow crystals. The crystals were washed with IPA-methanol to obtain 11.6 g (92%) of pale yellowish white crystals.

Example 9 Synthesis of 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole 14.9 g (1/25 mol) of the corresponding N-oxide as described above. , 50 ml of chloroform and 6.6 g (1.2 / 25 mol) of phosphorus trichloride. 14.3 g (100%) of the target product as pale brown crystals
I got After washing with methanol, 12.1 g of pale yellow-white crystals (84.6 g
%).

Example 10 Synthesis of 2- (2'-hydroxy-3 ', 5'-di-t-aluminphenyl) benzotriazole 14.7 g (1/25 mol) of the corresponding N-oxide, CHCl ₃ 35m
l, The same procedure as in Example 8 was carried out using 6.6 g (1.2 / 25 mol) of phosphorus trichloride. 14.4 g (102.6%) of the target product as pale yellowish white crystals was obtained. After washing with ethanol, 12.9 g (92%) of pale yellowish white crystals
I got

Example 11 Synthesis of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole 9.6 g (1/25 mol) of the corresponding N-oxide, 40 ml of chloroform, 6.6 g of phosphorus trichloride (1.2 / 25 mol) in the same manner as in Example 8. However, 8.5 g of sodium acetate was added, and pH 3.
And 2. 8.8 g (97.7%) of the desired product as pale yellow crystals was obtained.
After washing with ethanol, 7.5 g (83.3%) of pale white yellow crystals were obtained.

mp 128.5 to 129.5 ° C. [Effect] The present invention provides a method for producing a novel 2-phenylbenzotriazole which reduces 2-phenylbenzotriazole-N-oxide represented by the general formula II with phosphorus trichloride as a starting material. At the same time, compared to the conventional method, side reactions such as cleavage of amino groups do not occur, and the separation and purification of the target product is extremely easy, resulting in high quality,
The desired benzotriazoles can be obtained in high yield.

Continued on the front page (58) Fields investigated (Int. Cl. ⁶ , DB name) C07D 487/04 132 C08K 5/3467 C09D 5/00 C09D 5/32 C09K 3/00 104 CA (STN) REGISTRY (STN) WPIDS (STN)

Claims (1)

(57) [Claims] 1. A compound of the general formula II (Wherein R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ are the same as in the general formula I.) The reduction of 2-phenylbenzotriazole-N-oxides represented by Characteristic general formula I (Wherein R ₁ represents a hydrogen atom or a chlorine atom, a lower alkyl group having 1 to 4 carbon atoms, a lower alkoxyl group having 1 to 4 carbon atoms, a carboxyl group, or a sulfonic acid group, and R ₂ represents a hydrogen atom or Represents a chlorine atom, a lower alkyl group having 1 to 4 carbon atoms, a lower alkoxyl group having 1 to 4 carbon atoms, R ₃ is a hydrogen atom or a chlorine atom, an alkyl group having 1 to 12 carbon atoms, lower alkoxyl group, a cycloalkyl group, a phenyl group, a phenyl group substituted with an alkyl group having 1 to 8 carbon atoms, represents a phenoxy group or an alkyl moiety phenylalkyl group having 1 to 4 carbon atoms, R ₄ is a hydrogen atom Or a chlorine atom, a hydroxyl group or an alkoxyl group having 1 to 4 carbon atoms, and R ₅ represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a phenylalkyl group having 1 to 4 carbon atoms in the alkyl portion.) Method for producing 2-phenyl benzotriazole represented.