The invention relates to a 2-(2apos; -hydroxy-3apos,-hydroxy-3apos; -methallyl-5apos,-methallyl-5apos; high-conversion-rate preparation method of-methylphenyl) benzotriazole

Abstract

The invention relates to the technical field of fine chemical synthesis, and discloses a high-conversion-rate preparation method of 2-(2 '-hydroxy-3'-methallyl-5 '-methylphenyl) benzotriazole, which comprises the following steps: mixing 2-(5-methyl-2-((2-methallyloxy) phenyl)-2H-benzo [1, 2, 3] triazole with a solvent, carrying out rearrangement reaction, cooling, crystallizing, washing and drying to obtain 2-(2'-hydroxy-3 '-methallyl-5'-methylphenyl) benzotriazole. The 2-(2 '-hydroxyl-3'-methallyl-5 '-methylphenyl) benzotriazole is prepared through a one-pot method; the solvent is selected from N, N-dialkylaniline compounds or N, N-dialkylaniline compounds with alkyl substituted on a benzene ring. By screening and replacing the Claisen rearrangement solvent, the reaction time is effectively shortened, the reaction conversion rate is greatly improved, the side reaction is remarkably inhibited, the post-treatment difficulty is reduced, and the material and production cost is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical synthesis, and in particular to a high-conversion preparation method of 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole. Background Art

[0002] 2-(2′-Hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole is an important intermediate of drometrizole trisiloxane, which is obtained by Claisen rearrangement of 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole.

[0003]

[0004] The traditional method for preparing 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole uses diphenyl ether, phenol, etc. as solvents for the Claisen rearrangement reaction. The main problems are low rearrangement yield, a large number of isomeric impurities, difficulty in post-processing purification, and high production cost. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present application provides a method for preparing 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole with high conversion rate.

[0006] To solve the above problems, the present invention provides the following technical solutions:

[0007] The present application provides a high conversion rate preparation method of 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole, comprising the following steps:

[0008] Mixing 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole with a solvent, performing a rearrangement reaction, cooling, crystallizing, washing, and drying to obtain 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole;

[0009] The solvent is selected from N,N-dialkylaniline compounds or N,N-dialkylaniline compounds with alkyl groups substituted on the benzene ring.

[0010] In one embodiment of the present application, the N,N-dialkylaniline compound is represented by the general formula (I):

[0011]

[0012] Wherein, R1 and R2 are each independently selected from methyl, ethyl or n-propyl, and R1 and R2 are the same or different.

[0013] In one embodiment of the present application, the N,N-dialkylaniline compound with alkyl substituted on the benzene ring is represented by the general formula (II):

[0014]

[0015] Wherein, R1, R2, and R3 are each independently selected from methyl, ethyl, or n-propyl, and R1, R2, and R3 are the same or different.

[0016] In one embodiment of the present application, the number of R3 groups is 1-5; the R3 group is one or more of the ortho, meta, and para positions of the amino group.

[0017] In one embodiment of the present application, the weight ratio of 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole to the solvent is 1:1-5.

[0018] In one embodiment of the present application, the weight ratio of 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole to the solvent is 1:2-4.

[0019] In one embodiment of the present application, the temperature of the rearrangement reaction is 200-250° C., and the time of the rearrangement reaction is 2-10 h.

[0020] In one embodiment of the present application, the temperature of the rearrangement reaction is 230-240° C., and the time of the rearrangement reaction is 4-8 h.

[0021] Compared with the prior art, the present application provides a high conversion rate preparation method of 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole, by selecting N,N-dialkylaniline or N,N-dialkylaniline solvent substituted with alkyl on the benzene ring as the solvent for Claisen rearrangement, which not only effectively shortens the reaction time, but also greatly improves the reaction conversion rate, significantly inhibits the occurrence of side reactions, reduces the difficulty of post-processing, and greatly reduces the material and production costs. Compared with the traditional process, this process is more competitive in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole 1 HNMR spectrum. DETAILED DESCRIPTION

[0023] The following will provide a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0024] The "range" disclosed in this application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range.

[0025] Unless otherwise specified, the percentages between liquids and liquids in the present invention are volume / volume percentages; the percentages between liquids and solids in the present invention are volume / weight percentages; the percentages between solids and liquids in the present invention are weight / volume percentages; and the rest are weight / weight percentages.

[0026] Example 1

[0027] 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole (70.00 g, 1 w / w) was mixed with N,N-dimethylaniline (140.00 g, 2 w / w), heated to 230-240°C under nitrogen protection for reaction for 6 hours, cooled to 50-70°C, added with 420 g of anhydrous ethanol, stirred evenly and then slowly cooled to 5-10°C, gradually precipitated a large amount of off-white solid, filtered to dryness, took out the filter cake, added with 140 g of anhydrous ethanol, slurried at 5-10°C for 2 hours, filtered, washed the filter cake with 70 g of anhydrous ethanol, and dried with air to obtain 56.71 g of 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole, with a yield of 81.0% and a HPLC purity of 99.2%. 1 HNMR(400MHz,DMSO-d6):10.74(s,1H),8.08-8.10(dd,2H),7.90(s,1H),7.59- 7.62(dd,2H),4.84(s,1H),4.73(s,1H),3.43(s,2H),2.36(s,3H),1.76(s,3H).

[0028] Example 2

[0029] 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole (50.00 g, 1 w / w) was mixed with N,N-dimethyl-m-methylaniline (100.00 g, 2 w / w), heated to 230-240°C under nitrogen protection for reaction for 7 hours, cooled to 50-70°C, added with 300 g of anhydrous ethanol, stirred evenly and then slowly cooled to 5-10°C, gradually precipitated a large amount of off-white solid, filtered to dryness, took out the filter cake, added with 100 g of anhydrous ethanol, slurried at 5-10°C for 2 hours, filtered, washed the filter cake with 50 g of anhydrous ethanol, and dried by air to obtain 36.60 g of the product 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole, with a yield of 73.2% and a HPLC purity of 97.4%.

[0030] Example 3

[0031] The difference between Example 3 and Example 1 is that N,N-diethylaniline is used instead of N,N-dimethylaniline, and the mixture is heated to 230-240° C. under nitrogen protection for 6 hours, and the sample is taken and controlled by HPLC.

[0032] Example 4

[0033] The difference between Example 4 and Example 2 is that N,N-dimethyl-m-ethylaniline is used instead of N,N-dimethyl-m-methylaniline, and the reaction is heated to 230-240° C. under nitrogen protection for 7 hours, and sampling is performed using HPLC.

[0034] Comparative Example 1

[0035] 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole (20.00 g, 1 w / w) was mixed with p-chlorophenol (40.00 g, 2 w / w), heated to 230-240°C under nitrogen protection for reaction for 6 hours, cooled to 50-70°C, 120 g of anhydrous ethanol was added, stirred evenly and then slowly cooled to 5-10°C, a large amount of brown solid was gradually precipitated, filtered to dryness, the filter cake was taken out and 40 g of anhydrous ethanol was added, pulped at 5-10°C for 2 hours, filtered, the filter cake was washed with 20 g of anhydrous ethanol, and dried with air to obtain 12.50 g of the product 2-(2′-hydroxy-3′-methallyl-5′-methylphenyl)benzotriazole with an HPLC purity of 68.3%.

[0036] Comparative Example 2

[0037] The difference between Comparative Example 2 and Comparative Example 1 is that no solvent is used, the reaction is heated to 230-240° C. under nitrogen protection for 2-10 hours, and sampling is performed using HPLC.

[0038] Comparative Example 3

[0039] The difference between Comparative Example 3 and Comparative Example 1 is that 2,6-dimethylaniline is used instead of p-chlorophenol, the mixture is heated to 230-240° C. under nitrogen protection for 6 hours, and the sample is taken for central control by HPLC.

[0040] Comparative Example 4

[0041] The difference between Comparative Example 4 and Comparative Example 1 is that dimethyl sulfoxide is used instead of p-chlorophenol, the reaction is heated to 230-240° C. under nitrogen protection for 6 hours, and the samples are taken for HPLC control.

[0042] Comparative Example 5

[0043] The difference between Comparative Example 5 and Comparative Example 1 is that diphenyl ether is used instead of p-chlorophenol, the reaction is heated to 230-240° C. under nitrogen protection for 6 hours, and the sampling is controlled by HPLC.

[0044] Comparative Example 6

[0045] The difference between Comparative Example 6 and Comparative Example 1 is that p-methylbenzonitrile is used instead of p-chlorophenol, the reaction is heated to 230-240° C. under nitrogen protection for 6 hours, and sampling is performed using HPLC.

[0046] Comparative Example 7

[0047] The difference between Comparative Example 7 and Comparative Example 1 is that o-nitrophenol is used instead of p-chlorophenol, the reaction is heated to 230-240° C. under nitrogen protection for 6 hours, and sampling is performed using HPLC.

[0048] Comparative Example 8

[0049] The difference between Comparative Example 8 and Comparative Example 1 is that 2,4-dichlorophenol is used instead of p-chlorophenol, the mixture is heated to 230-240° C. under nitrogen protection for 6 hours, and sampling is performed using HPLC.

[0050] The results of the HPLC control of the above embodiments and comparative examples are shown in Table 1. The embodiments use N,N-dialkylaniline compounds or N,N-dialkylaniline compounds substituted with alkyl groups on the benzene ring as solvents for Claisen rearrangement, which not only effectively shortens the reaction time, but also greatly improves the reaction conversion rate, significantly inhibits the occurrence of side reactions, reduces the difficulty of post-processing, and greatly reduces material and production costs. Compared with traditional processes, this process is more competitive in the market.

[0051] Table 1 Effect of different solvents on rearrangement reaction

[0052]

[0053] The structural formulas of isomeric impurity 1 and isomeric impurity 2 are shown below:

[0054]

[0055] The present application is described in detail above in conjunction with specific implementation methods and exemplary embodiments, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, the technical solution of the present application and its implementation methods may be subjected to a variety of equivalent substitutions, modifications or improvements, all of which fall within the scope of the present application.

Claims

1. A high conversion rate preparation method of 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole, characterized in that: The following steps are involved: Mixing 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole with a solvent, performing a rearrangement reaction, cooling, crystallizing, washing, and drying to obtain 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole; The solvent is selected from N,N-dialkylaniline compounds or N,N-dialkylaniline compounds with alkyl groups substituted on the benzene ring.

2. The high conversion rate preparation method of 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole according to claim 1, characterized in that: The N,N-dialkylaniline compound is represented by the general formula (I): Wherein, R1 and R2 are each independently selected from methyl, ethyl or n-propyl, and R1 and R2 are the same or different.

3. The high conversion rate preparation method of 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole according to claim 1, characterized in that: The N,N-dialkylaniline compound with alkyl substituted on the benzene ring is shown in the general formula (II): Wherein, R1, R2, and R3 are each independently selected from methyl, ethyl, or n-propyl, and R1, R2, and R3 are the same or different.

4. The high conversion rate preparation method of 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole according to claim 3, characterized in that: The number of R3 groups is 1-5; R3 groups are one or more of the ortho, meta, and para positions of the amino group.

5. The high conversion rate preparation method of 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole according to claim 1, characterized in that: The weight ratio of 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole to the solvent is 1:1-5.

6. The high conversion rate preparation method of 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole according to claim 5, characterized in that: The weight ratio of 2-(5-methyl-2-((2-methylallyl)oxy)phenyl)-2H-benzo[1,2,3]triazole to the solvent is 1:2-4.

7. The method for preparing 2-(2'-hydroxy-3'-methallyl-5'-methylphenyl)benzotriazole with high conversion rate according to claim 1, characterized in that: The temperature of the rearrangement reaction is 200-250° C., and the time of the rearrangement reaction is 2-10 h.

Images